Patent Description:
Further, optional, features are provided in the dependent claims.

Examples are disclosed that relate to electrostatic clutching mechanisms that may be used for tactile feedback. One example provides a motion-restricting apparatus comprising a wearable base, and an electrostatic clutching mechanism coupled to the base, the electrostatic clutching mechanism comprising a base electrode, a plurality of individually-controllable opposing electrodes arranged at different locations across the base electrode and overlapping the base electrode, and one or more electrically insulating structures configured to electrically insulate the base electrode from the plurality of opposing electrodes. The motion-restricting apparatus further comprises a controller electrically coupled to the base electrode and to each of the opposing electrodes and configured to individually control a voltage applied to each opposing electrode relative to a voltage of the base electrode to control an electrostatic force between the base electrode and each opposing electrode.

Experiences provided by virtual and augmented reality display devices may be immersive in the visual and auditory sense, but not in the tactile sense. Thus, to provide haptic feedback for a virtual or augmented reality experience, a wearable device may be used to restrict motion to simulate the resistance felt when an object is touched. Some such motion-restricting devices may utilize electrostatic clutching mechanisms to selectively restrict joint motion. <FIG> shows an electrostatic clutch <NUM> that may be incorporated in a wearable glove structure. Electrostatic clutch <NUM> includes two multi-layer electrodes <NUM>, <NUM>, such that an applied voltage between the electrodes exerts a resistive force between the two electrodes to selectively control a sliding motion of the electrodes relative to one another. However, the depicted clutch <NUM> is not able to independently control restrictive forces for more than one finger.

As one possible solution, multiple instances of electrostatic clutch <NUM> may be arranged in a side-by-side manner to provide independently controllable clutching for more than one finger. However, because a voltage used to actuate the clutch may be dependent upon a surface area of a clutch, relatively wider electrodes may allow the use of lower voltages. Due to the electrode width, a housing <NUM> that contains the electrodes may be too large to allow side-by-side clutches to be positioned in desired locations with respect to each finger (e.g. along an axis of each finger).

Accordingly, examples are disclosed that relate to an electrostatic clutch arrangement that includes multiple independently controllable electrodes arranged in a compact configuration. Briefly, the disclosed examples utilize an electrode arrangement in which a common base electrode is used for a plurality of individually controllable opposing electrodes. The common base electrode and plurality of individually controllable opposing electrodes may be housed within a common housing, thereby allowing multiple individually controllable electrodes to be positioned side-by-side in locations that align with the axes of corresponding fingers, in example implementations involving a wearable glove. It will be understood that a wearable base supporting such an electrostatic clutch arrangement may be worn alternatively or additionally on the leg, shoulder, neck, or other body part in some examples. In still other examples, an electrostatic clutch arrangement may be used in other electromechanical applications. For example, the clutch may be used to provide positive braking for a servomechanical device (e.g., a robotic, soft robotic, prosthetic, and/or ball-joint).

<FIG> schematically shows an example wearable glove <NUM> coupled to a motion restricting apparatus <NUM> having an electrostatic clutching mechanism including a common base electrode <NUM> and a plurality of independently-controllable opposing electrodes <NUM>. One opposing electrode is provided for each finger of the glove <NUM>, including the thumb. The base electrode <NUM> is coupled to the back of the glove <NUM>, while each opposing electrode is coupled to a respective finger of the glove. As described in more detail below, each electrode may comprise multiple electrode layers in some examples, which may help to increase a surface area of each electrode for a given electrode width relative to single-layer electrodes. In such examples, the layers of the base electrode may be interleaved with the layers of each opposing electrode. Further, each electrode may be coated with an electrically insulating (dielectric) material to electrically insulate the opposing electrodes from the base electrode.

A controller <NUM> is electrically coupled to the base electrode <NUM> and each of the opposing electrodes <NUM> to control the voltages applied to each of the base electrode <NUM> and the opposing electrodes <NUM>. In some examples, an alternating voltage of suitable frequency may be used to facilitate dynamically changing the force applied, as charge may be added to or removed from electrodes by varying a duty cycle, type of waveform, and/or amplitude of the alternating voltage. To ensure that the electrostatic clutching mechanism imparts resistive force at the appropriate time, controller <NUM> may be communicatively coupled to a computing system, such as a display system, so that actuation of the clutching mechanism is triggered by a detected intersection of a user's hand with a displayed virtual object (e.g. as detected by image sensors, worn and/or stationary, in a use environment).

<FIG> illustrates an example operation of a motion-restricting apparatus <NUM> having a base electrode <NUM> and independently-controllable opposing electrodes <NUM>, <NUM>. In this example, only electrodes for the middle and index fingers are shown for clarity, but electrodes may be provided for any combination of fingers. A voltage is applied to opposing electrode <NUM> of the middle finger relative to base electrode <NUM> to bias the opposing electrode <NUM> relative to the base electrode, thereby restricting motion of opposing electrode <NUM> relative to base electrode <NUM>, while no bias voltage is applied to opposing electrode <NUM> of the index finger, allowing opposing electrode <NUM> to slide relative to base electrode <NUM>.

As mentioned above, in some examples, each electrode may comprise multiple electrode layers. <FIG> shows a sectional side view depicting example electrode layers of base electrode <NUM> and opposing electrode <NUM>, <NUM>. In this example, each electrode has seven electrode layers, forming an interleaving stack of <NUM> total layers. Each electrode layer includes an electrical conductor coated with a dielectric material. In a glove that has opposing electrodes for each finger, the electrode layers may be individually addressable by six output pins (one pin for each finger, and one for the common base) of the controller, rather than ten pins in arrangements where separate electrode pairs are used instead of a common base electrode. It will be understood that pins may provide an output to a suitable signal generator/amplifier circuit for generating a voltage (DC or AC) to apply to each electrode.

The individual electrode layers may have any suitable structure. In some examples, each electrode layer may comprise a flexible polymer substrate coated with a suitable electrical conductor (e.g. a thin metal film, such as copper or aluminum), and overcoated with a dielectric material. In other examples, each layer may comprise a conductive core material (e.g. a conductive metal strip, conductive fabric strip, conductive polymer strip, etc.), rather than a conductive thin film formed on a substrate.

The dielectric material may be selected to exhibit a high dielectric strength in order to support a large electric field without dielectric breakdown, and a high dielectric constant to achieve a higher electrostatic force at a given voltage. In some examples, the dielectric material may comprise a homogeneous thin film, such as a polymer of suitable dielectric constant and dielectric strength. In other examples, an electrically insulating structure may comprise a composite material, e.g. a ceramic compound (e.g. barium titanate) contained within a polymer matrix.

Where the electrode is formed from a conductive film formed on a substrate, each electrode layer may be coated on a single side with a conductor and dielectric layer, or on both sides.

Various structures may be used to mechanically and electrically connect layers of an electrode together. <FIG> shows a first example in which a hole <NUM> is formed through the layers of an electrode, such that a pin can be used to hold the electrode layers in position relative to one another. <FIG> shows a side sectional view of the electrode <NUM>, and illustrates each electrode layer as comprising a conductive core <NUM> coated on both sides with a dielectric material <NUM>. As described above, the core may be formed from a solid conductor, or from a multilayer structure, such as copper or aluminum deposited (e.g. by sputtering, evaporation, etc.) on a polymer core (e.g. polyethylene terephthalate, for example). The dielectric layers are adhered together with a conductive polymer adhesive <NUM> applied within hole <NUM>, such as a silver epoxy or other suitable material. Conductive polymer adhesive <NUM> adheres the electrode stack together and also electrically connects the layers so that the layers form a common conductor.

<FIG> show another example structure to mechanically and electrically connect a plurality of electrode layers. In this example, the electrode layers <NUM> are crimped at an end via a conductive sheet <NUM> having a zig-zag shape. In some examples, the conductive sheet <NUM> may be formed form copper. In other examples, other suitable conductive materials may be used. The electrode may be assembled by placing individual electrode layers between the layers of the metal sheet, and then clamping the metal sheet to crimp the layers together, thereby forming both the mechanical and electrical connections in a same step.

In some examples, the mechanical and electrical connection of the structure of <FIG> may be made more robust by use of an adhesive material positioned between the conductive sheet and each electrode layer. <FIG> show an electrode <NUM> comprising an electrically conductive tape <NUM> between each electrode layer and the metal sheet <NUM> to adhere the metal sheet <NUM> to the electrode layers. The use of such an adhesive also may help to keep the metal sheet in place during construction of the electrode stack.

<FIG> shows a partial, exploded view of a motion-restricting apparatus <NUM> coupled to a glove <NUM>. Motion-restricting apparatus <NUM> includes an electrostatic clutching mechanism <NUM> that includes a base electrode <NUM>, and opposing electrodes <NUM> and <NUM> for the middle and index fingers respectively. In other examples, additional opposing electrodes may also be included, e.g. one for every finger, including the thumb. Motion-restricting apparatus <NUM> includes a housing <NUM> that is coupled to glove <NUM> and configured to house base electrode <NUM> and at least a portion of each of opposing electrodes <NUM>, <NUM>. A top cover <NUM> (shown here detached) is configured to cover housing <NUM>. Inside housing <NUM>, fastening structures <NUM>, such as via snap interfaces <NUM>, may be used to fasten top cover <NUM>.

Motion-restricting apparatus <NUM> further includes dividers <NUM> configured to maintain spacing between electrodes <NUM> and <NUM>. As shown by way of example, one or more dividers <NUM> may be arranged between electrodes <NUM> and <NUM>, to ensure that the electrodes remain separate when sliding back and forth. Further, dividers <NUM> may act as support to add more height to the housing structure and top cover <NUM>. Such additional clearance in z-height may help contribute to the flexibility of motion-restricting apparatus <NUM>.

Motion-restricting apparatus <NUM> further may include pivots <NUM> disposed at the end of the electrodes <NUM>, <NUM> that attach the ends of the electrodes <NUM>, <NUM> to a Y-shaped force transmitter <NUM> that transfers force arising from a finger flexing against an actuated clutch to a haptic output located at a pad of a fingertip to provide a sensation of touch. pivot structures <NUM> may allow fingers to change angle with respect to the hand without putting undue lateral strain on the electrodes <NUM>, <NUM>.

Although not shown here, an electrode configuration for the thumb may differ compared to the electrode configurations for the other fingers due to the opposing position of the human thumb relative to the other fingers. For example, the electrode for the thumb may include one or more pivots configured to allow angular/rotational motion of the thumb. Further, additional dividers, walls, or other internal components and structures may help to guide an electrode for a thumb clutch within a housing.

<FIG> shows a method <NUM> of controlling a motion-restricting apparatus having an electrostatic clutching mechanism comprising a common base electrode and a plurality of opposing clutching electrodes. Method <NUM> includes, at <NUM>, applying a first voltage to a base electrode of the electrostatic clutching mechanism. Next, method <NUM> includes, at <NUM> applying the first voltage to a first opposing electrode to allow motion of the first opposing electrode relative to the base electrode. Method <NUM> further includes, at <NUM>, while applying the first voltage to the first opposing electrode, applying a second voltage to a second opposing electrode to restrict motion of the second opposing electrode relative to the base electrode. In devices having three or more individually-controllable clutching mechanisms, method <NUM> further may include, at <NUM>, individually controlling the voltages of three or more individually-controllable opposing electrodes relative to a voltage of the base electrode. In some examples, applying a voltage may include applying an AC voltage, which may allow a clutching force to be varied by varying a duty cycle, type of waveform, and/or amplitude of the AC voltage applied to the electrode.

Computing system <NUM> may take the form of one or more personal computers, server computers, tablet computers, home-entertainment computers, network computing devices, gaming devices, mobile computing devices, mobile communication devices (e.g., smart phone), and/or other computing devices, such as controller <NUM>.

Computing system <NUM> includes a logic subsystem <NUM> and a storage subsystem <NUM>.

Logic subsystem <NUM> includes one or more physical devices configured to execute instructions. For example, logic subsystem <NUM> may be configured to execute instructions that are part of one or more applications, services, programs, routines, libraries, objects, components, data structures, or other logical constructs.

Logic subsystem <NUM> may include one or more processors configured to execute software instructions. Additionally or alternatively, logic subsystem <NUM> may include one or more hardware or firmware logic machines configured to execute hardware or firmware instructions. Processors of logic subsystem <NUM> may be single-core or multicore, and the instructions executed thereon may be configured for sequential, parallel, and/or distributed processing. Individual components of logic subsystem <NUM> optionally may be distributed among two or more separate devices, which may be remotely located and/or configured for coordinated processing. Aspects of logic subsystem <NUM> may be virtualized and executed by remotely accessible, networked computing devices configured in a cloud-computing configuration.

Storage subsystem <NUM> includes one or more physical devices configured to hold instructions executable by the logic machine to implement the methods and processes described herein. When such methods and processes are implemented, the state of storage subsystem <NUM> may be transformed-e.g., to hold different data.

Storage subsystem <NUM> may include removable and/or built-in devices. Storage subsystem <NUM> may include optical memory (e.g., CD, DVD, HD-DVD, Blu-Ray Disc, etc.), semiconductor memory (e.g., RAM, EPROM, EEPROM, etc.), and/or magnetic memory (e.g., hard-disk drive, floppy-disk drive, tape drive, MRAM, etc.), among others. Storage subsystem <NUM> may include volatile, nonvolatile, dynamic, static, read/write, read-only, random-access, sequential-access, location-addressable, file-addressable, and/or content-addressable devices.

It will be appreciated that storage subsystem <NUM> includes one or more physical devices.

When included, display subsystem <NUM> may be used to present a visual representation of data held by storage subsystem <NUM>. Such display devices may be combined with logic subsystem <NUM> and/or storage subsystem <NUM> in a shared enclosure, or such display devices may be peripheral display devices.

Another example provides a motion-restricting apparatus, comprising a wearable base, and an electrostatic clutching mechanism coupled to the base, the electrostatic clutching mechanism comprising a base electrode, a plurality of individually-controllable opposing electrodes arranged at different locations across the base electrode and overlapping the base electrode, one or more electrically insulating structures configured to electrically insulate the base electrode from the plurality of opposing electrodes, and
a controller electrically coupled to the base electrode and to each of the opposing electrodes and configured to individually control a voltage applied to each opposing electrode relative to a voltage of the base electrode to control an electrostatic force between the base electrode and each opposing electrode. The wearable base may additionally or alternatively include a glove, and the plurality of individually-controllable opposing electrodes may additionally or alternatively be associated with fingers of the glove. The motion-restricting apparatus may additionally or alternatively include a housing coupled to the base, wherein the base electrode and at least a portion of each opposing electrode is located within the housing. One of the opposing electrodes may additionally or alternatively be associated with a thumb of the glove. The motion-restricting apparatus may additionally or alternatively include one or more dividers arranged within the housing to maintain spacing between the opposing electrodes. The housing may additionally or alternatively include a top cover covering the base electrode, and the top cover may additionally or alternatively be configured to flex with motion of a body part on which the motion-restricting apparatus is worn. The top cover may additionally or alternatively be configured to attach to the housing via one or more snap interfaces. Each opposing electrode may additionally or alternatively include a plurality of electrode layers at least partially interleaved with a plurality of electrode layers of the base electrode. The electrically insulating structures may additionally or alternatively be conductively connected by a conductive adhesive. The plurality of electrodes may additionally or alternatively be connected via a conductive crimp. The motion-restricting apparatus may additionally or alternatively include conductive tape adhering the conductive crimp to the plurality of electrode layers. The base electrode and the opposing electrodes may additionally or alternatively be flexible.

Another example provides a method of operating a motion-restricting apparatus comprising a base electrode and a plurality of individually-controllable opposing electrodes, the method comprising, applying a first voltage to a first opposing electrode to allow motion of the first opposing electrode relative to the base electrode, and while applying the first voltage to the first opposing electrode, applying a second voltage to a second opposing electrode to restrict motion of the second opposing electrode relative to the base electrode. The method may additionally or alternatively include individually controlling voltages of three or more of the plurality of individually-controllable opposing electrodes relative to a voltage of the base electrode.

Claim 1:
A body-worn motion-restricting apparatus (<NUM>), comprising
a wearable base;
a housing (<NUM>) coupled to the base; and
an electrostatic clutching mechanism coupled to the base, the electrostatic clutching mechanism comprising
a base electrode (<NUM>; <NUM>);
a plurality of individually-controllable opposing electrodes (<NUM>) arranged at different locations across the base electrode and overlapping the base electrode, wherein the base electrode and at least a portion of each opposing electrode is located within the housing;
one or more dividers (<NUM>) configured to maintain spacing between the opposing electrodes, wherein the one or more dividers are arranged within the housing;
one or more electrically insulating structures configured to electrically insulate the base electrode from the plurality of opposing electrodes; and
a controller (<NUM>) electrically coupled to the base electrode and to each of the opposing electrodes and configured to individually control a voltage applied to each opposing electrode relative to a voltage of the base electrode to control an electrostatic force between the base electrode and each opposing electrode.