WO2014117125A1 - Electroactive polymer actuators and feedback system therefor - Google Patents

Abstract

Various apparatus and methods: are disclosed to: provide haptic feedback, A method and apparatus are disclosed: for biometric priming of closed-loop haptic feedback. Also disclosed are various mechanisms for vibrotactile feedback in a wearable system using electroactive polymers. Also disclosed, are a method and apparatus for adapting to resonant frequency shifts m a haptic device. Various aspects of wearable dielectric elastomer actuator(s) with compliant conductive shields and ground fault circuit interrupt circuit breaker therefor are also disclosed, An array of deformable surface actuators to provide force feedback upon touching a surface of a display/touch sensor to confirm action is also disclosed.

Description

[0001] This application claims the benefit under 35 USC § 1 19(e), of U.S.

Provisional Application Nos.: 61/757,312 filed January 28, 2013 entitled

"HAPTIC BUTTON"; 61/776,942 FILED March 12, 2013 entitled "WEARABLE DIELECTRIC ELASTOMER ACTUATOR(S)"; 61/834,971 FILED June 14, 2013 entitled "METHOD AND APPARATUS FOR ADAPTING RESONANT FREQUENCY SIFTS IN A HAPTIC DEVICE"; 61/834,976 FILED June 14, 2013 entitled "METHOD AND APPARATUS FOR BIOMETRIC PRIMING OF CLOSED-LOOP HAPTIC FEEDBACK"; and 61/878,151 filed September 16, 2013 entitled "MECHANISM FOR VIBROTACTILE FEEDBACK IN

WEARABLE SYSTEMS USING ELECTROACTIVE POLYMERS"; the entirety of each of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention is directed in general to wearable electroactive polymer devices and feedback systems therefor. In particular, the present invention is directed to electroactive polymer devices that provide a force feedback upon touching a surface of the electroactive polymer device for confirmation of action. More particularly, the present invention is directed to a wearable electroactive polymer device. Still, more particularly, the present invention is directed to adapting to resonant frequency shifts In an electroactive polymer device. Yet, more particularly, the present invention Is directed to biometric priming of a closed-loop electroactive polymer device ieedback. More particularly, the present inventio is directed to vibrotactile feedback in a wearable electroactive polymer device.

BACKGROUND OF THE INVENTIO

[0003] A tremendous variety of devices used today rely on actuators of one sort or another to convert electrical energy to mechanical energy. Conversely, many power generation applications operate by converting mechanical action into eleetricai energy. Employed to harvest mechanical energy in this fashion, the same type of device may be referred to as a generator. Likewise, when the structure is employed to convert physical stimulus such as vibration or pressure into an electrical signal for measurement purposes, it may be characterized as a sensor, Yet, the term "transducer" may be used to generically refer to any electroactive devices described herein,

[000 j A number of design considerations fa vor the selection and use of advanced dielectric elastomer materials, also referred to as "electroactive polymers", for the fabrication of transducers. These considerations include potential force, power density, power conversion/consumption, size, weight, cost, response time, duty cycle, sendee requirements, environmental impact, etc. As such, in many applications, electroactive polymer technology offers an ideal replacement for piezoelectric, shape-memory alloy and electromagnetic devices such as motors and solenoids.

[0005] An electroactive polymer transducer comprises two electrodes having deformable characteristics and separated by a thin elastomeric dielectric material. When a voltage difference is applied to the electrodes, the oppositely charged electrodes attract each other thereby compressing the polymer dielectric layer therebetween. As the electrodes are pulled closer together, the dielectric polymer film becomes thinner (the Z-axis component contracts) as it expands in the planar directions ( along the X- and Y-axes), i.e. , the displacement of the film is in-plane. The electroactive polymer film may also be configured to produce movement in a direction orthogonal to the film structure (along the Z-axis), i.e., the displacement of the film is out-of-plane. U.S. Pat. No. 7,567,681 discloses electroactive polymer film constructs which provide such out-of-plane displacement - also referred to as surface deformation or as thickness mode deflection.

[0006] The material and physical properties of the electroactive polymer film may be varied and controlled to customize the deformation undergone by the transducer. More specifically, factors such as the relative elasticity between the polymer film and the electrode material, the relative thickness between the polymer film and electrode material and/or the varying thickness of the polymer film and/or electrode material, the physical pattern of the polymer film and/or electrode material (to provide localized active and inactive areas), the tension or pre-sirain placed on the electroactive polymer film as a whole, and the amount of voltage applied to or capacitance induced upon the film may be controlled and varied to customize the features of the film when in an active mode.

[0007] Numerous applications exist that benefit from the advantages provided by such electroactive polymer films whether using the film alone or using it in an electroactive polymer actuator. One of the many applications involves the use of electroactive polymer transducers as actuators to produce haptic feedback (the communication of information to a user through forces applied to the user's body) in user interface devices. There are many kno wn user interface devices which employ haptic feedback, typically in response to a force initiated by the user. Examples of user interface devices that may employ haptic feedback include keyboards, keypads, game controller, remote control, touch screens, computer mice, trackballs, stylus sticks, joysticks, etc. The user interface surface can comprise any surface that a user manipulates, engages, and/or observes regarding feedback or information from the device. Examples of such interface surfaces include, but are not limited to, a key (e.g., keys on a keyboard), a game pad or buttons, a display screen, etc.

[0008] The haptic feedback provided by these types of interface devices is in the form of physical sensations, such as vibrations, pulses, spring forces, etc., which a user senses either directly (e.g., via touching of the screen), indirectly (e.g., via a vibrational effect such a when a cell phone vibrates in a purse or bag) or otherwise sensed (e.g., via an action of a moving body that creates a pressure disturbance sensed by the user). The proliferation of consumer electronic media devices such as smart phones, personal media players, portable computing devices, portable gaming systems, electronic readers, etc., can create a situation where a sub- segment of customers would benefit or desire an improved haptic effect in the electronic media device. However, increasing haptic capabilities in every model of an electronic media device may not be justified due to increased cost or increased profile of the device, Moreover, customers of certain electronic media devices may desire to temporarily improve the haptic capabilities of the electronic media device for certain activities.

[0009] Use of electroactive polymer materials in consumer electronic media devices as well as the numerous other commercial and consumer applications highlights the need to increase production volume while maintaining precision and consistency of the films,

[0010J Most haptic actuators can generate greater maximum accelerations at some frequencies compared to others. It may be desirable to render haptic effects with spectrum intensities that are highest near the resonant frequency. Unfortunately, the resonant frequency of a typical vibrotactile system may shift by 10 Hz or more depending on application parameters such as an individual user's hand dynamics and grip strength while using the haptic device. This problem is typically ignored or approximated by designing haptic effects with wider than-optimal frequency distributions for a particular user, resulting in less compelling haptic effects. Additional drawbacks of prior art solutions include lower perceived haptic effect intensities and haptic effects that do not feel as compelling.

[00111 Effective high definition haptic feedback systems typically require update rates of 1000 Hz, or higher, and latencies of 5 ms, or lower. These performance requirements are challenging to meet with many contemporary computing systems. Conventional solutions for providing closed-loop haptic feedback typically involve measuring position, velocity, and acceleration motion, updating a model, and then rendering an updated haptic effect. A drawback of such conventional approach is a latency time that is often too long for compelling haptic feedback.

[0012J Furthermore, conventional wearable haptic feedback devices that can fit into a wearable device form factor, such as a wristband computing device, fail to create compelling vibrotactile feedback within a frequency range of 5 - 500 Hz. Conventional solutions typically place a vibrotactile actuator, such as an Eccentric Rotating Mass (ERM), Linear Resonant Actuator (LRA), or Piezoelectric actuator ( Piezo), within the wearable mechanical housing of the device. Such solutions require different mechanical assemblies to transfer vibrotactile feedback to the person and such assemblies typically have narrower operating frequency bandwidths and/or physical dimensions that are not desirable for a wearable device and/or reduced qualitative haptic "feel,"

[0013] Dielectric elastomer actuators integrated with wearable items need to be electrically shielded from the skin with a compliant electrical insulation to avoid injury to the user. The compliant insulation optionally should incorporate a conductive compliant layer to shunt any stray current away from the user and to provide a means of detecting fault current, Accordingly, it would be desirable to equip wearable haptic wrist bands or bracelets with size and stiffness sufficient to maintain contact of the actuated regions to the skin with a compliant elec trical insulation layer.

[0014] Additionally, force feedback upon touching a surface with a digit is desired for confirmation of action, A glass display/touchscreen can make it.

difficult to type because of a lack of "press" feedback. It is also difficult to determine the location of the digit on the touchscreen because every point on the touchscreen feels the same. A standard keyboard has individual keys and ridges to make location detennmation easy. On a display/touch screen, this is not possible, so visual or audio feedback must be used instead. This is not as satisfying or accurate as touch feedback.

^■SUMMARY OF_, THE INVENTION

[0015] In one embodiment, the present invention provides an apparatus comprising an electroactive polymer actuator; at least one biometric sensor configured to measure a physiological characteristic of a user; and at least one motion, sensor configured to measure motion of a body part, wherein the motion of the body part is associated with the physiological characteristic measured by the biometric sensor, wherein the response time of the biometric sensor is faster than the response time of the motion sensor; and a processor coupled to the

electroactive polymer actuator, the biometric sensor, and the motion sensor, the processor configured to receive and process a signal from the biometric sensor before a signal is received and processed from the motion sensor.

[0016] In another embodiment, the present invention provide a vibrolactile feedback apparatus comprising a housing having a first and second end, the housing configured to allows mechanical displacement in at least one direction; a mounting at each end of the housing; and one or more sheets of electroactive polymer arranged to form a an electroactive polymer stack actuator in a cross- sectional arrangement located within the housing, wherein the electroactive polymer stack actuator is configured for mechanical displacement upon the application of a corresponding electrical voltage potential to positive and negative electrical contacts located on opposite ends of the electroactive polymer stack actuator.

[0017] in yet another embodiment, the present invention provides a method for adapting a haptic effect rendered on a haptic device. The method comprises providing a haptic device, the haptic device including a sensor for detecting body motion, a processor for receiving body motion s gnals from the sensor, and an electroactive polymer actuator for producing a haptic effect, the sensor and the actuator are coupled to a mechanical accessory and are positioned relative to one another. In a computer system, the method further comprises sensing, by the computer system, a frequency response of the haptic effect while the haptic device is in use; determining, on the computer system, a frequency distribution of a rendered haptic effect; and mapping, on the computer system or in hardware, a function of the haptic effect to generate a new frequency response on the haptic device.

[0018] In yet another embodiment, the present invention provides a haptic device comprising a first sensor for capturing body motions of a person: a first actuator for rendering haptic effects to a person; and a processor for receiving the said body motion of the person and outputting haptic effects. 0019] In yet another embodiment, the present invention provides an electroactive polymer actuator comprising a first electrical shield to provide a first shunt path for stray current from a high voltage potential node to a low voltage potential node to shunt the stray current to the low potential node and isolate the stray current from the user; and a first ground fault circuit interrupt circuit breaker configured to detect the stray current in the first shunt path and shut down a high voltage power supply when the stray current is detected.

[0020] in yet another embodiment, the present invention provides an apparatus comprising a touch sensor: and an electroactive polymer layer disposed above the touch sensor, wherein the electroactive polymer layer comprises electrode areas configured to deform when touched to provide feedback,

[0021] These and other features and advantages of the embodiments of the present invention will become apparent to those persons skilled in the art upon reading the details of the invention as more fully described below. In addition, variations of the processes and devices described herein include combinations of the embodiments or of aspects of the embodiments where possible are within the scope of this disclosure even if those combinations are not explicitly shown or discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The various embodiments of the invention are best understood from the following detailed description when read in conjunction with the accompanying drawings. To facilitate understanding, the same reference numerals have been used (where practical) to designate similar elements are common to the drawings. Included in the drawings are the following:

[0023] FIGS. 1A and IB illustrate a top perspective view of an electroactive device before and after application of a voltage to electrodes in accordance with one embodiment of the present invention;

[0024] FIG, 2 illustrates a haptic feedback system comprising a configuration of sensors and actuators configured to provide biometric primed haptic feedback in accordance with one embodiment of the present invention; [0025] FIG. 3 illustrates an information flow diagram depicting the relative response times of the biometric sensor(s) 104 and motion sensor(s) of the biometrie primed haptic feedback system shown in FIG. 2 in accordance with one embodiment of the present invention;

[0026] FIG, 4 illustrates a gesture interaction system comprising a vibrotactiie feedback wristband for use in an interactive dance game in accordance with one embodiment of the present invention;

[0027] FIG. 5 illustrates a timing diagram of a vibrotactiie haptic effect having a faster response time rendered by a biometric feedback signal in accordance with one embodiment of the present invention;

[0028] FIG. 6 illustrates an architectural or component view of a computing system that may be employed with the haptic feedback systems described in connection with FIGS. 2-5 in accordance with one embodiment of the present invention;

[0029] FIG. 7 illustrates a vibrotactiie feedback mechanism comprising multiple sheets of electroactive polymer material arranged in a stacked configuration in accordance with one embodiment of the present invention;

[0Θ30] FIG. 8 illustrates a configuration of multiple electroactive polymer sheets arranged in a stack to provide a vibrotactiie haptic wearable band with a stiff actuator holder in accordance with one embodiment of the present invention ;

[0031] FIG. 9 illustrates an example of an electroactive polymer vibrotactiie haptic wearable band with a rigid housing in accordance in accordance with one embodiment of the present invention;

[0032] FIG. 10 illustrates the vibrotactiie haptic band being worn on the wrist of a user, where the vibrotactiie haptic band includes an accelerometer and a processor for quantitatively measuring vibrotactiie "feel" to be conveyed in a consumer device in accordance with one embodiment of the present invention;

[0033] FIG. 11 illustrates a retainer module situated in mechanical series with a wrist band in accordance with one embodiment of the present invention; [0034] FIG. 12 is a graphical representation of a shift in frequency response of a vibrotactiie haptic actuator in accordance with one embodiment of the present invention;

[0035] FIG. 13 illustrates an adaptive resonant frequency system that monitors the acceleration changes of the vibrotactiie haptic device, adapts the frequency spectrum of a rendered haptic effect, and renders the adapted haptic effect to the user in accordance with one embodiment of the present invention;

[0036] FIG. 14 is a graphical representation of frequency responses of the same electroactive polymer based vibrotactiie haptic actuator in the same game controller in accordance with one embodiment of the present invention;

[0037] FIG. 15 illustrates an exploded view of a compliant actuator module configuration for a touch interface in accordance with one embodiment of the present invention;

[0038] FIG. 16 illustrates an exploded view of the solid dielectric elastomer transducer roll module and various connection options in accordance with one embodiment of the present invention;

[0039] FIG. 17 is an exploded view of the compliant actuator module shown in FIG. 15 configured to electrically mount to a flex circuit in accordance with one embodiment of the present invention;

[0040] FIG. 18 illustrates a bottom perspective view of the electrical shield in accordance with one embodiment of the present, invention;

[0041] FIG. 19 illustrates a schematic diagram of the compliant actuator module electrical isolation feature making it electrically safe for a user to touch the actuator module with the fingertip in accordance with one embodiment of the present invention in accordance with one embodiment of the present invention;

[0042] FIG. 20 is a graphical representation illustrating the dependency of thermal hazard of a fault upon resistance in accordance with one embodiment of the present invention; [0043] FIG, 21 illustrates a schematic diagram of a ground fault circuit interrupter (GFCi) configured to detect current on a shield in accordance with one embodiment of the present invention;

[0044] FIG. 22A is a side sectional view of an array of deformable surface actuators in accordance with one embodiment of the present invention; and

[0045] FIG. 22B i s a top view of the array of deformable surface actuators shown in FIG. 22 A in accordance with one embodiment of the present invention,

[0046] Variation of the invention from that shown in the figures is contemplated.

DETAILED DESCRIPTION OF THE INVENTION

[0047] Examples of electroactive polymer devices and their applications are described, for example, in U.S. Pat. Nos. 7,394,282; 7,378,783; 7,368,862;

7,362,032; 7,320,457; 7,259,503; 7,233,097; 7,224,106; 7,211,937; 7,199,501; 7,166,953; 7,064,472; 7,062,055; 7,052,594; 7,049,732; 7,034,432; 6,940,221; 6,91 1,764; 6,891,317; 6,882,086; 6,876,135; 6,812,624; 6,809,462; 6,806,621 ; 6,781,284; 6,768,246; 6,707,236; 6,664,718; 6,628,040; 6,586,859; 6,583,533; 6,545,384; 6,543,110; 6,376,971; 6,343,129; 7,952,261 ; 7,911,761; 7,492,076; 7,761,981; 7,521,847; 7,608,989; 7,626,319; 7,915,789; 7,750,532; 7,436,099; 7,199,501 ; 7,521,840; 7,595,580; 7,567,681 ; 7,595,580; 7,608,989; 7,626,319; 7,750,532; 7,761,981 ; 7,911,761; 7,915,789; 7,952,261; 8,183,739; 8,222,799; 8,248,750, and in U.S. Patent Application Publication Nos. 2007/0200457;

2007/0230222; 2011/0128239; and 2012/0126959, the entireties of which are incorporated herein by reference.

[0048] It is noted that the figures discussed herein schematically illustrate exemplary configurations of devices and processes thai employ electroactive polymer films or transducers having such electroactive polymer films. Many variations are within the scope of this disclosure, for example, in variations of the device, the electroactive polymer transducers can be implemented to control the size of apertures having varying geometries. [0049] Em bodiments of the present iivvention may be manufactured using various processes.

[0050] Various embodiments of electroactive polymer transducers are described in detail hereinbelow. Prior to describing such embodiments, however, the description turns briefly to FIGS. 1 A-l B, which illustrate a top perspective view of an electroactive device before and after application of an electric voltage potential to electrodes in accordance with one embodiment of the present invention. A brief description of general electroactive polymer structures and processes for producing such structures are provided in connection with FIGS. 1A-1B.

[0051] Turning now to FIGS. 1 A and IB where an example of an electroactive polymer film or membrane 10 structure is illustrated. A thin elastomenc dielectric film or layer 12 is sandwiched between compliant or stretchable electrode plates or layers 14 and 16, thereby forming a capacitive structure or film. The length "1" and width "w" of the dielectric layer, as well as that, of the composite structure, are much greater than its thickness "t". Preferably, the dielectric layer has a thickness in the range from about 10 μιη to about 100 μιη, with the total thickness of the struct ure in the range from about 1 5 μηι to about 10 cm. Additionally, it is desirable to select the elastic modulus, thickness, and/or the geometry of electrodes 14, 16 such that the additional stiffness they contribute to the actuator is generally less than the stiffness of the dielectric layer 12, which has a relatively low modulus of elasticity, i.e.. less than about 100 MPa and more preferably less than about 10 MPa, but. is likely thi cker than each of the electrodes. Electrodes suitable for use with these compliant capacitive structures are those capable of withstanding cyclic strains greater than about 1 % without failure due to mechanical fatigue.

[0052] As seen in FIG. IB, when a voltage is applied across the electrodes, the unlike charges in the two electrodes 14, 16 are attracted to each other and these electrostatic attractive forces compress the dielectric film 12 (along the Z-axis). The dielectric film 12 is thereby caused to deflect with a change in electric field. As electrodes 14, 16 are compliant, they change shape with dielectric layer 12. In the context of the present disclosure, "deflection" refers to any displacement, expansion, contraction, torsion, linear or area strain, or any other deformation of a portion of dielectric film 12. Depending on the architecture, e.g., a frame, in which capacitive structure 10 is employed (collectively referred to as a

"transducer'), this deflection may he used to produce mechanical work. Various different transducer architectures are disclosed and described in the above- identified patent references.

[0053] With a voltage applied, the transducer film 10 continues to deflect until mechanical forces balance the electrostatic forces driving the deflection. The mechanical forces include elastic restoring forces of the dielectric layer 12, the compliance or stretching of the electrodes 14, 16 and any external resistance provided by a device and/or load coupled to transducer 10. The resultant deflection of the transducer 10 as a result of the applied voltage may also depend on a number of other factors such as the dielectric constant of the elastomeric material and its size and stiffness. Removal of the voltage difference and the induced charge causes the reverse effects.

[0054] In some cases, the electrodes 14 and 16 may cover a limited portion of dielectric film 12 relative to the total area of the film. This may be done to prevent electrical breakdown around the edge of the dielectric or achieve customized deflections in certain portions thereof. Dielectric material outside an active area (the latter being a portion of the dielec tric material having sufficient electrostatic force to enable deflection of that portion) may be caused to act as an external spring force on the active area during deflection. More specifically, material outside the active area may resist or enhance active area deflection by its contraction or expansion.

[0055] The dielectric film 12 may be pre-strained. The pre-strain improves conversion between electrical and mechanical energy, i.e., the pre-strain allows the dielectric film 12 to deflect more and provide greater mechanical work. Pre- strain of a film may be described as the change in dimension in a direction after pre-straining relative to the dimension in thai direction before pre-straining. The pre-strain may include elastic defonnation of the dielectric film and be formed, for example, by stretching the film in tension and fixing one or more of the edges while stretched. The pre-strain may be imposed at the boundaries of the film or for only a portion of the film and may be implemented by using a rigid frame or by stiffening a porti on of the film.

[0056] The transducer structure of FIGS. 1 A and IB and other similar compliant structures and the details of their constr ucts are more fully described in many of the referenced patents and publications disclosed herein. The following description now turns to various embodiments of electroactive devices for varying the size of or deforming an aperture defined within a pretensioned electroactive polymer film constrained on its perimeter edges by a rigid frame.

[0057] Method and Apparatus For Biometric Priming Of Closed-loop Haptic Feedback

[0058] In various embodiments, the present invention provides haptic feedback systems. In one embodiment, the haptic feedback systems are vibrotactile feedback systems that are effective high definition haptic feedback systems with update rates of about 1000 Hz, or higher, and latencies of about 5 ms, or lower, in one embodiment, the present invention leverages the relatively faster response of biometric responses, such as electromyography (E G), electroencephalography (EEG), and heart rate, which often occur before biological motor responses, such as movement of a body part.

[0059] Embodiments of the in vention described hereinbelow in connection with FIGS. 2-6 provide faster and more accurate closed loop haptic feedback systems as compared to conventional haptic feedback systems. It will be appreciated that various embodiments of the present invention can be applied to all body sites, biometric sensing technologies, and haptic actuators. Audio, visual, and other sensory modalities, can be coupled into the closed loop feedback system.

[0060] FIG. 2 illustrates a haptic feedback system 100 comprising a configuration of sensors and actuators configured to provide biometric primed haptic feedback ίη accordance with one embodiment of the present invention. The haptie feedback system 100 shown in FIG. 2 comprises an arrangement of sensor and actuator components that employ biometric priming. Biometric responses, such as EMG, EEG, and heart rate, often occur before a biological motor response, such as finger or arm movement. T herefore, incorporating biometric measurements, such as EMG, EEG, and heart rate, in the closed loop haptic feedback system 100 improves the speed and quality of the haptic feedback.

[0061] in the particular embodiment shown in FIG. 2, the haptie feedback system 100 comprises at least one motion sensor 101, a computing system 102, at least one biometric sensor 104, and at least one haptic actuator 103. The sensors and actuators are arranged on a wearable device such as a vibrotactile feedback wristband 106 or other wearable device suitable for transmitting vibrotactile sensations to the user. The haptic feedback system 100 is configured to monitor the physiologic characteristics of the user associated with corresponding musculoskeletal motion of the user's 108 body or body part including, without limitation, the user's 108 arm, hand, finger, leg, foot, toe, head, neck, torso, or any part of the user's 108 body, for example. In the illustrated embodiment, the haptic feedback system 100 is located on a vibrotactile feedback wristband 106 that is worn on the arm 110 of the user 108 making it particularly useful for detecting motion and biometric responses of the user's 108 arm, hand, and/or fmger(s).

[0062] The at least one motion sensor 101 is coupled to the user and may comprise any suitable motion sensor such as an inertial sensor. An inertial sensor may comprise an accelerometer, a gyroscope, and/or a magnetometer, alone or in any combination thereof. In various embodiments, the accelerometer, gyroscope, and/or the magnetometer may be single, double, or triple axis. The at least one biometric sensor 104 is coupled to the user and may comprise any suitable biometric sensor for measuring the physiologic characteristics of the user 108, such as EMG, EEG, heart rate, among other physiologic parameters associated with the user 108. The at least one haptic actuator 103 may comprise any suitable haptic actuator comprising, for example, an electroactive polymer based actuator described in connection with FIGS. 1A-1B and/or FIGS, 15-19 below, for example, among other suitable haptic actuators.

[0063] The motion sensor(s) 101, biometric sensor(s) 104, and/or hapiic actuator(s) 103 are coupled to the computing system 102, which may contain a microcontroller or processor to control the sampling of the sensors 101, 104 and the actuation of the haptic actuator(s) 103. Data from the motion sensor(s) 101 may be used to sense muscle movements. For example, data from a triple axis accelerometer may be employed to monitor muscle motion. However, in accordance with the current embodiment, data from an accelerometer, gyroscope, and/or magnetometer may be fused and employed to track body motion, it will be appreciated that the motion sensor(s) 101 may comprise a plurality of inertial sensors where each inertial sensor comprises a subset of inertial sensors, e.g. , accelerometer, gyroscope, magnetometer, among others, or may comprise additional inertial sensors. The response time of the biometric sensor 104 is faster than the response time of the motion sensor 101.

[0064] In one embodiment the processor of the computing system 102 may be implemented with an ATmegal28RFAl chip available from Atmel Corporation, The accelerometer may be implemented with an ADXL345 Digital Accelerometer board available from Analog Devices. The gyroscope may be implemented with an IT G3200 board available from InvenSense Inc. The magnetometer may be implemented with an HMC58833L 3 -Axis Digital Compass IC available from Honeywell international Inc. It will be appreciated that such inertial sensor components may be replaced with any equivalent components without limiting the scope of the present invention. In one embodiment, the processor of the computing system 102 may be linked to the accelerometer, gyroscope, and/or magnetometer of the motion sensor 101 via an internal wired I2C bus interface. In one embodiment, the motion sensors 101 may be connected to each other and to a wireless device using a wired Serial Peripheral Interface (SP1), for example.

[0065] FIG. 3 illustrates an information flow diagram 120 depicting the relative response times of the biometric sensor(s) 104 and motion sensor(s) 101 of the biometric primed hap tic feedback system 100 shown in FIG. 2 in accordance with one embodiment of the present invention. The information flow diagram 120 illustrates a closed loop feedback path showing the speed advantage provided by biometric priming. According to the information flow diagram 120, a biometric sensor 104 monitors EMG activity in a person's arm corresponding to the user's muscle activity that con-elates to a leftward finger movement is identified first (tl ) and is combined with spatial coordinates obtained from an accelerometer type of motion sensor 101 (t2). The response time (tl) of the biometric sensor 104 is faster than the response time (t2) of the motion sensor 101 such that response time (tl ) of the biometric sensor 104 occurs before the response time (t2) of the motion sensor 101. Thus, before the data from the motion sensor 101 has been fully processed by the computing system 102, a predictive haptic effect model may be updated with the current data from the biometric sensor(s) 104 and previous data from the motion sensor(s) 101 as appropriate for a leftward finger movement, for example. The haptic effect is then rendered on the haptic actuator(s) 103 to provide feedback to the user. Accordingly, the biometric. priming of the haptic feedback loop 100 shown in FIG. 2 reduces the perceived system lag in the haptic feedback system 100 and provides effective high definition haptic feedback at update rates of about 1000 Hz, or higher, and latencies of about 5 ms, or lower.

[0066] The haptic feedback system 100 shown in FIG. 2 and the relative response times illustrated in FIG. 3, leverage the fact that biometric responses, such as EMG, EEG, and heart rate, often occur before a corresponding biological motor response, such as movement of a finger, hand, or arm. For example, the signal produced by a biometric sensor 104 monitoring EMG activity in a person's ann is generated before the signal produced by the motion sensor 101 triggered by the actual muscle activity that correlates to a leftward finger movement, for example. The compara tive speed of biometric response times relative to motion response times are described in A. C. Guimaraes et al, "The EMG-Force Relationship Of The Cat Soleus Muscle And Its Association With Contractile Conditions During Locomotion," The Journal of Experimental Biology 198, Great Britain, 1 95, pp. 975-987, which is incorporated herein by reference. The reference describes that an EMG signal is fired 3-5 ms faster than a resulting force. Examples of different firing rates for EMG signals may he found at the following link:

Rgnl-2-Basic-EMG-AANEM-Koontz.pdf.aspx , p. 23, which is incorporated herein by reference. In addition, an example of an EMG in a jogging application is described in Mamix G. J. Gazendam, "Averaged EMG Profiles In Jogging And Running At Different Speeds," Gate and Posture 25, The Netherlands, 2007, pp. 604-614, which is also incorporated herein by reference.

[0067] FIG. 4 illustrates a gesture interaction system I 30 comprising a vibrotactile feedback wristband 106 for use in an interactive dance game in accordance with one embodiment of the present invention. This example describes a typical use of biometric priming for closed-loop haptic feedback using the haptic feedback system 100 described in connection with FIG. 2. FIG. 4 illustrates a typical gaming context that benefits from vibrotactile haptic feedback provided by the haptic feedback system 100. The user 108 wears a haptic wristband 106 to control the characters 132 displayed on the video game display 134 and audio speakers 136. The haptic wristband 106 provides game control with vibrotactile haptic feedback to the user 108. The wristband 106 controller is connected to a video game system 138. As the user 108 performs a gesture with his/her arm 110, the biometric sensor(s) 104 and the motion sensor(s) 101 track the motion of the a m 110. Haptic feedback is provided to the user 108 via electroactive polymer stack actuator(s) 103 within the wristband 106. Haptic feedback aids positioning of the dancers 132 or beat matching of music in the game, A microcontroller 102 within the wristband 106 rapidly and continuously senses muscle activity data from the EMC} sensor 103 and motion data from the accelerometer 101. The wristband 106 is a specialized game controller that is linked to the video game system 138. Typical update rates for the haptic feedback system 100 range between 1000 Hz to 10,000+ Hz (1 ms to 0.1 ms),

[0068] FIG. 5 illustrates a timing diagram 140 of a vibrotactile haptic effect having a faster response time rendered by a biometric feedback signal in accordance with one embodiment of the present invention. The response time is faster because, as previously discussed, bionietric data such as EMG waveforms of arm muscle activity 142 is sensed before any corresponding physical movement of the arm of the user is sensed by an accelerometer 144. As shown in FIG. 5, biometric priming results in faster, higher quality haptic feedback.

[0069] The EMG muscle activity is indicated by the EMG waveform 142 and is sensed before the accelerometer activity 144. As shown by the biometric timeline 146, sensed bionietric data relating to the user's arm gesture for the game is acquired over period ΪΕΜΟ is processed by the microcontroller's 150 haptic effect functions 148 before the acceleration data 144 acquired over period t_acc is presented to the microcontroller 150 as shown by the motion timeline 154, Consequently, an appropriate haptic effect update can be actuated on the electroactive polymer actuators 152 faster and with better quality than only using spatial data, such as acceleration 144 updates.

[0070] FIG. 6 illustrates an architectural or component view of a computing system 160 that may be employed with the haptic feedback systems described in connection with FIGS. 2-5 in accordance with various embodiments of the present invention. In various embodiments, as illustrated, the computing system 16Θ comprises one or more processors 162 (e.g., microprocessor, microcontroller) coupled to various sensors 174 (e.g., motion sensors, biometric sensors) and. at least one haptic actuator 172 (e.g., electroactive polymer stack actuator) via a suitable driver 170 circuit, in addition, to the processor(s) 162, a storage 164 (having operating logic 166) and communication interface 168, are coupled to each other as shown.

[0071] As described earlier, the sensors 174 may be configured to detect and collect biometric data associated with position, posture, and/or movement of any part of the user's body, such as, for example, the user's arms(s), hand(s), finger(s), leg(s), foot/feet, toe(s), head, neck, torso, among other body parts. The processor 162 processes the biometric and motion sensor data received from the sensors s) 174 to provide haptic feedback to the user by actuating the haptic actuator 1 2 via the driver 170 circuit. [0072] The processor 162 may be configured to execute the operating logic 166. The processor 162 may be any one of a number of single or multi-core processors known in the art. The storage 164 may comprise volatile and non-volatile storage media configured to store persistent and temporal (working) copy of the operating logic 166.

[0073] In various embodiments, the operating logic 166 may be configured to process the collected biometric associated with motion data of the user, as described above, in various embodiments, the operating logic 166 may be configured to perform the initial processing, and transmit the data to the computer hosting the application to determine and generate instructions on the visual and/or tactile feedback to be provided. For these embodiments, the operating logic 166 may be further configured to receive the biometric and motion data associated with the user and provide tactile feedback to a hosting computer. In alternate embodiments, the operating logic 166 may be configured to assume a larger role in receiving the biometric and motion data and determining the tactile feedback, e.g., but not limited to, the generation of vibratory sensations by driving 170 the haptic actuator 172. In either ease, whether determined on its own or responsive to instructions from a hosting computer, the operating logic 166 may be further configured to control the haptic actuator 172 to provide or tactile feedback to the user,

[0074| In various embodiments, the operating logic 166 may be Implemented in instructions supported by the instruction set architecture (ISA) of the processor 162, or in higher level languages and compiled into the supported ISA. The operating logic 166 may comprise one or more logic units or modules. The operating logic 166 may be implemented in an object oriented manner. The operating logic 1 6 may be configured to be executed in a multi-tasking and/or multi-thread manner, in other embodiments, the operating logic 166 may be implemented in hardware such as a gate array.

[0075] In various embodiments, the communication interface 168 may be configured to facilitate communication between a peripheral device and the computing system 160. The communication may include transmission of the collected biornetric data associated with position, posture, and/or movement data of the user's body part(s) to a hosting computer, and transmission of data associated with the tactile feedback from the host computer to the peripheral device, in various embodiments, the communication interface 168 may be a wired or a wireless communication interface. An example of a wired communication interface may include, but is not limited to, a Universal Serial Bus (USB) interface. An example of a wireless communication interface may include, but is not limited to, a Bluetooth interface.

[0076] For various embodiments, the processor 162 may be packaged together with the operating logic 166. in various embodiments, the processor 162 may be packaged together with the operating logic 166 to form a System in Package (SiP). In various embodiments, the processor 162 may be integrated on the same die with the operating logic 166. In various embodiments, the processor 162 may be packaged together with the operating logic 166 to form a System on Chip (SoC).

[ΘΘ77] Mechanism For Vihrotactile Feedback In A Wearable System Using Electro ctive Polymers

[0078] In various other embodiments, the present invention provides haptic feedback devices configured to fit into a wearable device form factor, such as a wristband. In one embodiment, the wearable haptic feedback device according to the present invention may comprise a computing device. In one embodiment, the wearable haptic feedback device provides compelling vihrotactile feedback within a frequency range of 5 to 500 Hz. In one embodiment, the wearable haptic feedback device according to the present invention comprises stacked layers or sheets of electroactive polymer materials and in some embodiments, the electroactive polymer stack may be located within a retainer module and can be either pre-stressed or unstressed. 0079J Embodiments of the invention described below in connection with FIGS. 7-11 provide a mechanical assembly that can leverage electroactive polymer to provide vihrotactile haptic feedback over a wider frequency range and in a more convenient form factor than conventional realizations. Fonn factor improvements include mechanical compliance suitable for wearable computing devices and a tension sheath that provides tension over the electroactive polymer stacks to improve overall acceleration intensity and frequency response consistency as well as mechanical support for the wearable device. Other possible uses of these embodiments include industrial and consumer applications where vibration on a object is desired without applying adhesives or fasteners directly to the object(s) to receive the vibration.

[0080] FIG. 7 illustrates a vibrotactile feedback mechanism 200 comprising multiple sheets of electroactive polymer material arranged in a stacked

configuration 208 in accordance with one embodiment of the present invention. In the illustrated embodiment, the vibrotactile feedback mechanism 200 is coupled to a tension sheath 2Θ4 to provide a vibrotactile haptic wearable band 202. in various embodiments, the invention is typically incorporated in a wearable device 202 to provide touch feedback (vibrotactile haptic feedback) on a person's body, such as the wrist 2Θ6 or arm. Multiple electroactive polymer sheets are arranged to fonn a stack 208 of electroactive polymer sheets or materials in a cross- sectional arrangement and are attached to a rigid base 210 that is firmly mounted to the wearable device 202. An electrical contact mechanism 212 attaches to positive and negative electrical contacts to the opposing ends or edges of the electroactive polymer stack 208. A tension sheath 204 provides continuous forces 214 to keep the electroactive polymer stack 208 tightly connected to the main device assembly 202 while providing suitable compliance and flexibility to generate effective vibrotactile haptic feedback forces 214. The electroactive polymer stack 208 predominantly creates vibrotactile displacements perpendicular to the electroactive polymer surface axis 216; however, some parallel

displacements also may occur.

[0081] FIG. 8 illustrates a configuration 250 of multiple electroactive polymer sheets arranged in a stack 258 to provide a vibrotactile haptic wearable band 252 with a stiff actuator holder in accordance with one embodiment of the present invention. As shown in FIG. 8, the electroactive polymer stack 258 are housed within a rigid assembly 262, 263 where a section 261 is able to move back and forth along an axis 256 because the right edge of the electroactive polymer stack 258 housing 263 has compliance along the axis 256. Similar to the embodiment described in connection with FIG, 7, vibrotactile haptic feedback forces 264 occur as voltage is applied across the surface of each electroactive polymer sheet within the stack 258. The electroactive polymer stack 258 predominantly creates vibrotactile displacements perpendicular to the electroactive polymer surface axis 256; however, some parallel displacements also may occur.

[Θ082] An electrical contact mechanism 266 attaches to positive and negative electrical contacts to the opposing edges of the electroactive polymer stack 258. An electrical grounding sheath 253 protects the user from electrical shock and protects the electroactive polymers from environmental hazards such as moisture. The vibrotactile assembly is contained within a wearable device 252 that is placed in contact with a user's body, such as the wrist 256, In one embodiment, the electroactive polymer stack 258 may be held in the stiff assembly 262, 263 in a pre-compressed state whereas in other embodiments, the electroactive polymer stack 258 is held in the rigid assembly 262, 263 in a non-compressed state.

[0083] FIG, 9 illustrates an example of an electroactive polymer vibrotactile haptic wearable band 270 with a rigid housing in accordance with one

embodiment of the present invention. The embodiment shown in FIG . 9 is a prototype of the electroactive polymer vibrotactile haptic wearable band 270 incorporated in a watch strap 272 form factor.

[0084] FIG. 10 illustrates the vibrotactile haptic band 270 being worn on the wrist 274 of a user, where the vibrotactile haptic band includes an accelerometer 276 and a processor 278 for quantitatively measuring vibrotactile "feel" to be conveyed in a consumer device in accordance with one embodiment of the present invention. The embodiment shown FIG. 10 is an example of the electroactive polymer vibrotactile haptic wearable band 270 incorporated in a watch band 272 and worn on a person's wrist 274. In the illustrated embodiment, 40 electroactive polymer stacks 5 mm wide by 18 mm long were driven with a voltage difference of 1800 V. As a result, vibrotactile "feels" between 0 - 3 Gs of acceleration and 30-250 Hz were conveyed to the person's wrist 274.

[0Θ85] FIG. 11 illustrates a retainer module 300 situated in mechanical series with a wrist band in accordance with one embodiment of the present invention. As shown in FIG. 11, the retainer module 300 may be situated in mechanical series with a wrist band. A central gap is defined by a re-curved face 302 of a flexure 304. The central gap is slightly shorter than the thickness of a electroactive polymer stack actuator module 306 to hold it in a pre-compressed state. Electrical terminals 308 located on the stack actuator module 306 electrically mate with corresponding terminals in the retainer module 300. The retainer module 300 has a face 310 that is optionally integral with the body of a watch or other personal electronic device to be worn by the user. In various embodiments, the stack actuator module 3Θ6 is similar to the elastomer transducer roll module 504 shown in connection with FIGS. 15-17 and 19.

[0086] With reference again to FIGS. 7-11 , in various embodiments, a vibrotactile feedback apparatus includes a housing having a first and second end that allows mechanical displacement in at least one direction, a mounting at each end of the housing, and one or more sheets of electroactive polymer stacked in a cross- sectional arrangement located within the housing, in one embodiment., the mechanical displacement provides movement perpendicular to the sheets of electroactive polymer and the mechanical displacement is rigid to prevent movement in both axes parallel to the sheets of electroactive polymer. In another embodiment, the mechanical displacement provides movement perpendicular to the sheets of electroactive polymer and the mechanical displacement also provides movement in one or two axes parallel to the sheets of electroactive polymer. In yet another embodiment, the housing is a semi-rigid plastic body and in one such embodiment the housing comprises two or more semi-rigid bodies that are connected by an elastic sheath material. In yet another embodiment, the housing is a wearable computing accessory such as, but not limited to, a wristband, hand band, arm band, torso band, ankle band, headband, or ear attachment sheets of electroactive polymer. Yet in another embodiment, the elastic sheath material provides tensions between 0 - 5 N of force. In another embodiment, the vibrotactile feedback s operated at frequencies between 0 to 500 Hz when electric voltage potentials between 0 to 2000 V are applied across the sheets of electroactive polymer.

[0087] Method And Apparatus For Adapting To Resonant Frequency Shifts In A Haptic Device

[0088] In various other embodiments, the present invention provides haptic actuators configured to generate greater maximum accelerations near the resonant frequency. In one embodiment, the haptic feedback effects are rendered within a spectrum of intensities that are highest near the resonant frequency. In one embodiment, the haptic actuators according to the present invention compensate for any shifts in the resonant frequency depending on hand dynamics and grip strength of an individual user while using the haptic device. Accordingly, in one embodiment, the haptic actuators according to the present invention are configured to provide haptic effects within an optimal frequency distribution for a particular user, resulting in more compelling haptic effects.

[0089] Irs various embodiments, the present in vention provides a method and apparatus that adapts to resonant frequency shifts in a handheld vibrotactile haptic device, it would be desirable to render haptic effects with a spectrum of intensities that are highest near or at the resonant frequency. Unfortunately, the resonant frequency of a typical vibrotactile system may shift by up to 10 Hz or more depending on an individual user's hand dynamics and grip strength while using the haptic device.

[0090] Embodiments of the invention described below in connection with FIGS. 12-14 provide haptic effects that are more intense and compelling and/or maintain similar intensity and perceived haptic quality levels while increasing lifespan, lowering operating voltages, and lowering production costs for implementations using actuators such as electroactive polymers. Other possible uses of these various embodiments of the present invention include adapting a vibrotactile effect to maximize resonant frequencies in applications other than haptics, such as electroactive polymer valve operations, for example,

[0Θ91] FIG. 12 is a graphical representation 400 of a shift in frequency response of a vibrotaetile haptic actuator in accordance with one embodiment of the present invention. Acceleration (g) is shown along the vertical axis and frequency (Hz) is shown along the horizontal axis. A first curve 402 represents the frequency response Fd (default frequency response) centered at first resonant frequency Rd for a vibrotaetile haptic actuator. A second curve 404 represents the shifted frequency response F_s (shifted frequency response) centered at a second resonant- frequency R_s because of a user's hand dynamics and grip strength. This results in a resonant frequency shift from Rd to R_s.

[0092] FIG. 13 illustrates an adaptive resonant frequency system 410 that, monitors the acceleration changes of the vibrotaetile haptic device, adapts the frequency spectrum of a rendered haptic effect, and renders the adapted haptic effect to the user in accordance with one embodiment of the present invention. The adapted haptic effect provides improved "feel" attributes such as greater intensity and wider perceived frequency range. The system 410 adapts the haptic effect frequency distribution in response to a user's body dynamics such that the user feels effects at or near a resonant frequency. Haptic effects at or near resonant frequency are typically perceived as more intense and are desirable in many haptic applications including gaming, medical, automotive, and home appliance domains.

[0093] Still with reference to FIG. 13 the system 410 is configured to implement the steps for vibrotaetile haptic effect frequency adaptation in accordance with one embodiment of the present invention. As shown in FIG. 13, at Step 1, an accelerometer 412 system monitors the frequency response 418 of the haptic system. At Step 2, a haptic effect model 414 is updated in response to the frequency experienced by a particular user. At Step 3. the frequency spectrum, adapted haptic effect is rendered to the haptic actuator 416. As shown in FIG. 13, the system 410 monitors the acceleration changes of the vibrotaetile haptic actuator 416 using an accelerometer 412, then adapts the frequency spectrum of a rendered haptic effect in a haptic effect model 414, and finally renders the adapted haptic effect to the user via the haptic actuator 416. The adapted haptic effect provides improved "feel" attributes such as greater intensity and wider perceived frequency range.

[0094] Haptic effects can be adapted using purely software, purely hardware, or a combination of software and hardware approaches. Software approaches would typically involve filtering the haptic model 414 using band pass filters, gain adjustments, and other techniques to create a new waveform with dominant frequencies near the system resonant frequency and less dominant frequencies elsewhere. Hardware approaches include physical assemblies that alter the dynamic properties, such as stiffness and damping, of the haptic system while monitoring the system's resonant frequency. Adaptation to haptic effects should consider perceptual sensitivities of users to frequency changes. For example, users may not notice a frequency shift of 5 to 10 Hz, but may notice a shift in 20 Hz. Consequently, the adaptive resonant frequency system 410 needs to consider both the physical characteristics of the haptic device and human sensitivi ties and preferences. User preferences can be satisfied with a user controllable switch, an automated recommendation system, or other embodiments.

[0095] FIG. 14 is a graphical representation 450 of frequency responses of the same electroactive polymer based vibrotactile haptic actuator in the same game controller in accordance with one embodiment of the present invention.

Acceleration (g) is shown along the vertical axis and Frequency (Hz) is shown along the horizontal axis and various frequency responses are depicted by the graphical representation 450. The dashed lines 452, 454 show two frequency responses for a particular user while holding the game controller with a light grip. The dark solid lines 456, 458 show two frequency responses for the same user holding the controller, but with a different grip. The light solid line 460 shows a user holding the same game controller with a light grip. The various curves 452, 454, 456, 458, 46Θ suggest that a pulsing haptic effect might best span a frequency band similar to Target Frequency Band A while users hold the controller with a light grip and a frequency band similar to Target Frequency Band B while users hold the controller with a tight grip.

[0096] Additional considerations are the perceived intensity of the target body site, such as an index finger or palm of hand, for a particular acceleration at a particular frequency, if the dominant frequency of the haptic effect is at 65 Hz during a tight grip, for example, FIG. 14 shows that high accelerations between 2.0 to 2.3 g can be expected; however, with a tight grip, the same 65 Hz frequency would result in accelerations less than 1.0 g. Conversely, if a haptic effect is updated to have a dominant frequency of 90 Hz, accelerations of 1.5 g can be expected. Haptic effects can be adapted using well known techniques such as band pass filtering and gain adjustments with decision trees, or more sophisticated machine learning approaches. The hapiic effects should typically span a relatively wide frequency band, with varying high intensity components near certain desirable frequencies, such as the resonant frequency for the system. This wide irequency range enables acceleration measurements to continuously monitor the dynamic frequency response of the system while user interacts with the haptic device. Although stability may present an issue in these and all haptic systems, closed-loop control is designed to maximize acceleration or perceived intensity of a vibrotactile hapiic effect using actuators such as electroactive polymers or piezoelectric devices.

[0097] Accordingly, in one embodiment, the present invention described in connection with FIGS. 12-14 provides a method for adapting a haptic effect rendered on a haptic device. The method comprises providing a haptic device, the haptic device including a sensor for capturing body motion, a processor for receiving the body motion, and an actuator for providing haptic feedback to the person. The sensor and the actuator are coupled to a mechanical accessory and positioned relative to one another. In a computer system, the method further comprises sensing the frequency response of the haptic effect while a person uses the haptic device, performing, on the computer system, a calculation to determine the frequency distribution of a rendered hapiic effect, performing, on the computer or in hardware, a mapping function of a haptic effect to generate a new frequency response on the haptic device. Filtering or other modifications of a haptic effect may be influenced by the haptic device user.

[0098] In another embodiment, the mapping function involves filtering frequencies between 5 to 500 Hz. in yet another embodiment, the calculation updates at rates between 500 to 50,000 Hz. In another embodiment, the calculation includes a calculation to define a peak frequency.

[0099] Yet in another embodiment, the body motion is a hand motion of the person, in various other embodiments, the sensor is an accelerometer. a position sensor, or a combination thereof. In various other embodiments, the actuator is an eleetroactive polymer, a piezoelectric material, or a combination thereof.

[0100] In another embodiment, the present invention provides a haptic device comprising: a first sensor for capturing body motions of a person, a first actuator for rendering haptic effects to a person, and a processor for receiving the body motion of the person and outputting haptic effects. Each of the haptic effects based on a calculation where the calculation adapts to changes in the frequency distribution as a dynamic physical system changes. The dynamic physical system comprises the haptic device.

[0101] Wearable Dielectric Elastomer Act atorfs) With Compliant Conductive Shield And Ground Fault Circuit interrupt Circuit Breaker Therefor

[0102] In various other embodiments, the present invention provides dielectric elastomer actuators integrated with wearable items that are electrically shielded from the user's skin with a compliant electrical insulation to avoid injury to the user. In one embodiment, the compliant insulation optionally incorporates a conductive compliant layer or shield to shunt any stray current away from the user and to provide a means of detecting fault current. In one embodiment, the haptic wrist bands or bracelets are equipped with a size and stiffness suffic ent to maintain contact of the actuated regions to the skin w^rith a compliant electrical insulation layer. In other embodiments, the present invention provides electrical circuits configured with ground fault circuit interrupters (GFCI) to detect any current on the conductive compliant layer or shield and cut off the current flow when it is detected. Θ103] Dielectric elastomer actuators are integrated with a wearable item. They are electrically shielded from the skin with a compliant insulation. The compliant insulation optionally incorporates a conductive compliant layer that shunts any stray current away from the user and provides a means of detecting fault current. One embodiment of the invention is a wrist band or bracelet with size and stiffness sufficient to maintain contact of the actuated regions to the skin.

[0104] FIG. 15 illustrates an exploded view of a compliant actuator module 500 configuration for a touch interface in accordance with one embodiment of the present invention. The compliant actuator module 500 is packaged in a manner that is safe to touch, in the embodiment shown in FIG. 15, the compliant actuator module 500 is integrated with a case or housing 512 defining an aperture 514 to provide touch access to a portion of the compliant actuator module 500. In one embodiment, the compliant actuator module 500 comprises a compliant electrically conductive housing 502 and a solid dielectric elastomer transducer roll module 504 attached to a module support 508, which is specific to the case or housing in which the compliant actuator module 500 is integrated with. The module support 508 is configured to fixedly attach the substrate 506 to the housing 512. Optionally, the compliant actuator module 500 may comprise mounting fasteners 510. A portion of the compliant conductive housing 502 protrudes through an opening 514 defined in the housing 512 or housing of a device. The compliant conductive housing 502 is made of an electrically conductive material and is electrically connected to case ground (shield ground) at terminal 518 by an electrically conductive adhesive 520. In one embodiment, a flex connector 522 electrically couples the solid dielectric elastomer transducer roll module 504 to an electronic system through electrical contacts and/or traces 524.

[0105] FIG. 16 illustrates an exploded view of the solid dielectric elastomer transducer roll module 504 and vaiious connection options in accordance with one embodiment of the present invention. The solid dielectric elastomer transducer roll module 504 comprises a substrate 506 which includes holes 526a, 526b for injection molding and for wire termination. The substrate also includes electrically conductive terminals 528 that are suitable for soldering wires or for soldering surface mount technology (SMT) components thereto. The conductive terminals 528a, 528b are accessible above and below the substrate as discussed hereinbelow. SMT terminal points 530 are soldered to the conductive terminals 528a, 528b, A solid dielectric elastomer transducer roll 531 is then attached to the substrate 506 and conductive silicone 534 is applied at the ends of the solid dielectric elastomer transducer roll 531, by insert molding or other techniques, to electrically couple the transducer roll 534 to the terminal points 530 and the conductive terminals 528s, 528b. An electrically insulative silicone coating 516 is applied to the exterior surface of the transducer roll 534, by insert molding, or other techniques. The electrically insulative silicone coating 516 is interposed between the transducer roll 534 and the compliant electrically conductive housing 502.

[0106] There are various options for providing electrical connections to the solid dielectric elastomer transducer roll module 504. One option includes attaching the flex circuit 522 to the transducer module 504 via SM T conductive terminals 536a, 536b provided underneath the substrate 506. The conductive terminals of the ilex circuit 522 are coupled to a high voltage driver circuit. The SMT conductive terminals 536a, 536b on the bottom layer of the substrate 506 are electrically coupled to the SMT conductive terminals 528a, 528b on the top layer of the substrate 506. The bottom SMT conductive terminals 536a, 536b may be used to attach the transducer roll module 504 to other substrates and / or external devices. Alternatively, the transducer roll module 504 may be electrically coupled by electrical wires 538a, 538b attached through conductive via through-holes 526a, 526b through the substrate 506, The high voltage positive (HV+) lead wire 538a is connected to the positive terminal of a high voltage drive circuit and the high voltage ground (HV GND) lead wire 538b is connected to the ground terminal of the high voltage drive circuit. Housing ground (SHIELD GND) is connected to teraiinal 518. Alternatively, the transducer roll module 504 may be electrically connected to other systems and / or substrates by way of quick-connect interconnects such as those described in commonly owned PCT International Patent Application PCT/US 13/55304, which is hereby incorporated by reference in its entirety.

[0107] FIG. 17 is an exploded view of the compliant actuator module 500 shown in FIG. 15 configured to electrically mount to a flex circuit 522 in accordance with one embodiment of the present invention. The compliant actuator module 500 comprises a solid dielectric elastomer transducer roll module 504, an electrical shield 532. and a flex circuit 522. The electrical shield 532 provides electrical isolation and makes it electrical iy safe for a user to touch the actuator module 500 with the fingertip.

[0108] FIG. 18 illustrates a bottom perspective view of the electrical shield 532 in accordance with one embodiment of the present invention. With reference to FI G. 18. the illustrated embodiment of the electrical shield 532 is fabricated by laminating thermoplastic urethane to an electrically conductive fabric and vacuum forming it to make a stretchable conductive shield. The electrical shield 532 is soft to the touch with a durometer (Shore A 50-80) and can be configured as an active button for handsets, game controllers, and the like. In one embodiment, an electrically insulating film allows the actuator the most freedom to move. In other embodiments, the electrically conductive fabric can be sandwiched between two thinner layers of thermoplastic polyurethane, for example, 5/1000" (5 mil),

[0109] FIG. 19 illustrates a schematic diagram of the compliant actuator module 500 electrical isolation feature making it electrically safe for a user to touch the actuator module 500 with the fingertip in accordance with one embodiment of the present invention. As shown the HV÷ terminal on the flex circuit 522 is electrically coupled to the positive terminal (528a as shown in FIG. 16) of the solid dielectric elastomer transducer roll module 504. The SHIELD GND terminal of the flex circuit 522 is electrically coupled to the electrical shield 532 through the terminal 518. To connect the shield 532 to the terminal 518, a small portion of the conductive textile is exposed and soldered to the terminal 518, In the event a fault occurs, such as short circuit between the solid dielectric elastomer transducer roll module 504 and the shield 532 through the electrically insulative silicone coating 516, the shield provides a shunt path (-3 Ω) from a high voltage potential node to a low voltage potential node such as the SHIELD G D relative to a high impedance user resistance path (~2000 Ω) to ground. Accordingly, any stray current is shunted to ground and the shunt current is isolated from the user with a layer of compliant insulation, such as for example, electrically insulative silicone coating 516. When the shunt current is detected, a signal is provided to a ground fault circuit interrupter (GFCI) circuit breaker that shuts down the high voltage power supply to prevent the user from being shocked. A robust chain of electrical and mechanical connections are employed to couple the compliant actuator module 500 to rigid electronics,

[0110] FIG. 20 is a graphical representation 600 illustrating the dependency of thermal hazard of a fault upon resistance in accordance with one embodiment of the present invention. Thermal power into a fault (Watt) is shown along the vertical axis and resistance of carbonized hole in potting (Ohm) is shown along the horizontal axis. A partial cross-sectional view of a compliant actuator module 602 is shown inset within the graph 600. From the most inner layer to the most outer layer, the compliant actuator module 602 includes a conductive silicone layer covered by a potting compound, The potting compound is covered by the conductive case ground and the thermoplastic polyurethane layer covers the conductive case ground. A carbon coated tunnel is formed through the potting compound betwee the conductive case ground and the conductive silicone to simulate a fault.

[0111] FIG. 21 illustrates a schematic diagram 650 of a GFCI circuit breaker configured to detect current on a shield in accordance with one embodiment. The schematic diagram 650 shown in FIG. 21 includes two separate GFCI circuit breakers suitable to detect shunt current on two separate shields. Cun-ent from a first shield ("shield 1") is received by a first conductor 658 through a connector 656 and is routed to a first GFCI circuit breaker network 652. Current from a second shield ("shield 2") is received by a second conductor 660 through the connector 656 and is routed to a second GFCI circuit breaker network 654. Each GFCI circuit breaker network 652, 654 includes a bleed charge resistor R2, Rl Ito receive the stray current from the current shunt path and a capacitor CI 1 , C 14 to accumulates charge based on the stray current. Diode Dl, D3 shunts current spikes to prevent false triggers. A comparator U2, U4 receives a voltage reference on its negative terminal and the capacitor voltage representing the accumulated charge on the capacitor CI 1, C14 on its positive terminal. When the voltage on the positive terminal exceeds the reference voltage on the negative terminal, the first comparator U2 triggers a first flip-flop 662 to generate a first signal to shut down a first high voltage power supply. When the voltage on the positive terminal exceeds the reference voltage on the negative terminal, the second comparator U4 triggers a second flip-flop 664 to generate a first signal to shut down a first high voltage power supply. Thus, the GFCI circuit breaker networks 652, 654 detect the shunt current on the shield and interrupt the current by shutting down the high voltage power supply when it exceeds a predetermined threshold set by each one of the voltage references.

[0112] Array Of Deformable Surface Actuators To Provide Force Feedback Upon Touching A Surface Of A Display/! ouch Sensor To Confirm Action

[0113] in various other embodiments, the present invention provides deforniable surface actuators configured to provide force feedback upon sensing a touch on the surface of an electroactive polymer layer positioned above a display/touch sensor to provide feedback of the action. In accordance with one embodiment, the present invention provides a glass display/touch sensor configured to provide haptic feedback to a force simulating the "pressing" of a virtual key displayed on the touch sensor. In one embodiment, the deformable surface actuators provide haptic feedback to assist a user to determine the location of a virtual key on the touch sensor without resorting to visual or audio feedback alone.

[0114] The embodiment of the invention described in connection with FIGS. 22A-22B provide localization or feedback that is lacking on conventional touch sensors, which are l imited by moving the entire screen or handset. With this embodiment, tactile feedback is localized to the spot, or "key" that is touched by the user to provide a sensation similar to a standard keyboard and therefore it is easier and more accurate to type.

[0115] FIG. 22A is a side sectional view of an array of deformable surface actuators 700 in accordance with one embodiment of the present invention. FIG. 22 B is a top view of the array of deformable surface actuators 700 shown in FIG. 22 A in accordance with one embodiment of the present invention. With reference to FIGS. 22A-22B, although only two deformable surface actuators 702, 704 are shown, it will be appreciated that the array 700 may comprises a plurality of actuators arranged in any predetermined pattern. In one embodiment, the surface of a display/touchscreen 706 is covered by a deformable electroacti ve polymer surface layer 712. The electroactive polymer layer 712 comprises sensitive areas 708, 710 that deform into the actuators 702, 704 when touched to provide feedback to the user. The electroactive polymer surface layer 712 is incorporated into the surface above the display/touchscreen 706. The actuators 702, 704 are activated by high voltage when the appropriate sensitive area 70S, 710 senses a touch. When the touch is detected or sensed in the defined area 708, 710 the electroactive polymer surface layer 712 expands/contracts in defined areas 708, 710 and is deformed in such a manner as to generate the actuator 702, 704 bumps that are detectable by the person touching the display/touchscreen. The actuators 702, 704 can also be a part of the surface of the display/touchscreen 706 that deforms to the shape of keys. This can be either a permanent feature or a temporary feature that appears on demand. The flexible electroactive polymer dielectric film layer 712 would be the deformable surface. The electroactive polymer surface layer 712 should needs to be very flexible to be an effective electroactive polymer actuator. Printed on the electroactive polymer surface layer 712 film would be an electrode pattern 708, 710 that when activated would produce a movement/vibration to provide the haptic feedback to the finger by the actuator bumps 702, 704 to indicate that a press was sensed and confirmed. A simple actuator design of just a circle that expands and contracts could be used. The expansion/contract on vibration would provide the forced feedback to the finger. Other suitable patterns beside a circle may be employed for the actuator pattern 708, 710. Such patterns include ellipses, triangles, rectangles, squares, rhombus, any suitable polygon, as wel l as irregular or randomly formed patterns.

[0116J As for other details of the present invention, materials and alternate related configurations may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to process-based aspects of the invention in terms of additional acts as commonly or logically employed, in addition, though the invention has been described in reference to several examples, optionally incorporating various features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various changes may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be substituted without departing from the true spirit and scope of the invention. Any number of the Individual parts or s ubassemblies shown may^¬ be integrated in their design. Such changes or others may be undertaken or guided by the principles of design for assembly.

[0117] Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in

combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms "a," "an," "said," and "the" include plural referents unless the specifically stated otherwise. In other words, use of the articles al low for "at least one" of the subject item in the description above as well as the claims below, it is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as "solely," "only" and the like in connection with the recitation of claim elements, or use of a "negative" limitation. Without the use of such exclusive terminology, the term "comprising" in the claims shall allow for the inclusion of any additional element - irrespective of whether a given number of dements are enumerated in the claim, or the addition of a feature could be regarded as transforming the nature of an element set. forth in the claims. Stated otherwise, unless specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood meaning as possible while maintaining claim validity.

[0118] Various aspects of the subject matter described herein are set out in the following numbered clauses:

[0119] 1. An apparatus comprising: a first sensor for measuring one or more body motions of a person; a first actuator for rendering one or more haptic effects to a person; and a processor for receiving the one or more body motions of the person and outputting one or more haptic effects.

[0120] 2, The apparatus according to clause 1 further comprising at least one biometric sensor configured to measure a physiological characteristic of a user, wherein response time of the biometric sensor is faster than response time of the first sensor for measuring one or more body motions of a person.

[0121] 3. The apparatus according to one of clause 1 and 2, wherein the first actuator comprises an electroactive polymer transducer,

[0122] 4, The apparatus according to clause 3, wherein the electroactive polymer transducer is a surface deformation transducer configured to provide

programmable surface features,

[0123] 5. The apparatus according to clause 3, wherein the electroactive polymer transducer comprises two or more stacked layers of electroactive polymer film.

[0124] 6. The apparatus according to clause 3, wherein the electroactive polymer transducer is configured to provide both haptic effects and sensing responses.

[0125] 7. The apparatus according to clause 3, wherein the electroactive polymer transducer is electrically shielded and connected to a ground fault circuit interrupt circuit,

[0126] 8. The apparatus according to clause 3, wherein the electroactive polymer transducer is mounted in a housing comprising a structural element, the element providing a compressive prestrain on the transducer and transmitting a force generated by activation of the electroactive polymer transducer to a separate portion of the apparatus,

[0127] 9. The apparatus according to any one of clauses 1 to 8, wherein one or more selected from the group consisting essentially of the electroactive polymer actuator, the biometric sensor, the processor and the motion sensor are located on a wearable device.

[0128] 10. The apparatus according to clause 9, wherein the wearable device is selected from the group consisting essentially of a wristband, a hand band, an arm band, a torso band, an ankle band, a headband, and an ear attachment, and any combination thereof.

[0129] 11. The apparatus according to clause 1 , wherein the first sensor comprises any one of an accelerometer, a gyroscope, a magnetometer, a touch sensor, and any combination thereof and wherein the first sensor is configured to measure musculoskeletal motion.

[0130] 12. The apparatus according to clause 2, wherein the least one biometric sensor is configured to measure one or more physiological characteristics selected from the group consisting essentially of electromyography (EMG),

electroencephalography (EEG), and heart rate, and any combination thereof,

[0131] 13. The apparatus according to clause 2, wherein the processor is configured to drive the electroactive actuator in accordance with electrical signals received from the biometric and first sensors.

[0132] 14. The apparatus according to clause 2, wherein the processor is configured to receive and process an electrical signal from the biometric sensor before a signal is received and processed from the first sensor.

[0133] 15. A method for adapting a haptic effect rendered on a haptic device, the method comprising: providing the apparatus according to any of clauses 1. to 14; sensing, by the computer system, a frequency response of the haptic effect while the haptic device is in use; determining, on the computer system, a frequency distribution of a rendered haptic effect: and mapping, on the computer system or in hardware, a function of the haptic effect to generate a new frequency response on the haptic device.

Claims

WHAT IS CLAIMED.IS:

1. An apparatus comprising:

a first sensor capable of measuring one or more body motions of a person; a first actuator capable of rendering one or more haptic effects to a person: and

a processor capable of receiving the one or more body motions of the person and outputting one or more haptic effects.

2. The apparatus according to Claim 1 further comprising at least one biometric sensor configured to measure a physiological characteristic of a user, wherein response time of the biometric sensor is faster than response time of the first sensor for measuring one or more body motions of a person.

3. The apparatus according to one of Claims 1 and 2, wherein the first actuator comprises an. electroactive polymer transducer,

4. The apparatus according to Claim 3, wherein the electroactive polymer transducer comprises a surface deformation transducer configured to provide programmable surface features.

5. The apparatus according to Claim 3, wherein the electroactive polymer transducer compri ses two or more stacked layers of electroactive polymer film,

6. The apparatus according to Claim 3, wherein the electroactive polymer transducer is configured to provide both haptic effects and sensing responses.

7. The apparatus according to Claim 3, wherein the electroactive polymer transducer is electrically shielded and connected to a ground fault circuit interrupt circuit.

8. The apparatus according to Claim 3, wherein the electroactive polymer transducer is mounted in a housing comprising a structural element, the element providing a compressive prestrain on the transducer and transmitting a force generated by activation of the electroactive polymer transducer to a separate portion of the apparatus.

9. The apparatus according to any one of Claims 1 to 8, wherein one or more selected from the group consisting essentially of the electroactive polymer actuator, the biomeixic sensor, the processor and the motion sensor are located on a wearable device.

10. The apparatus according to Claim 9, wherein the wearable device is selected from the group consisting essentially of a wristband, a hand band, an arm band, a torso band, an ankle band, a headband, and an ear attachment, and any combination thereof.

11. The apparatus according to Claim 1 , wherein the first sensor comprises any one of an aceelerometer, a gyroscope, a magnetometer, a touch sensor, and any combination thereof and wherein the first sensor is configured to measure musculoskeletal motion.

12. The apparatus according to Claim 2, wherein the least one biometric sensor is configured to measure one or more physiological characteristics selected from the group consisting essentially of electromyography (EMG),

electroencephalography (E.EG), and heart rate, and any combination thereof.

13. The apparatus according to Claim 2, wherein the processor is configured to drive the electroactive actuator in accordance with electrical signals received from the biometric and first sensors. 1 , he: p ar tus according: to Claim 2₅ wherein the processor is i figiired to receive and process anelectrical signal from the bsomcirie sensor before signal is received and processed from the first sensor.

15. - A. method fm da tng a .iiaptfe eflec i'epdfercd on. a. haptic device, the met od cor« rssi»g:

providing the apparatus according to any of Claims I to 14;

sensing, by the computer system,

while the t i tio device is In use

deierffihilng, on. the computer system., a frequenc distribution. f a rendered haptic effect; and

m ping, m. the computer system or in hardware, aiimCismi of the haptic effect to generate a new iret|W«ncy response on the haptle device,.