Compact linear electrostatic clutch

Abstract

The compact linear clutch of the embodiment of the present application can maintain a consistent overlap area between the clutch members using the coupling mechanism. The winding device can also be connected with a flexible clutch component or an electrode for use so as to furthest shorten the length of the clutch in a contraction state.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 433,125, filed on December 16, 2022, which is incorporated herein by reference.

[0003] Statement on federally funded research

[0004] This work was partly funded by the Defense Health Service SBIR Phase 1 project W81XWH-22-P-0039. The government holds certain rights to this invention. Background Technology

[0005] Linear clutches are used to controllably establish and disengage a connection in applications where the relative motion of components is largely limited to linear translation. These devices, typically electromagnetic, pneumatic, or hydraulic, can lock the position of the linear joint or act as a mechanical fuse to disengage a drive element such as a transmission or motor from its load. These types of devices are commonly used in heavy machinery, component securing in manufacturing, and in home and hospital equipment such as height-adjustable desks or adjustable beds.

[0006] Due to their size, weight, and power consumption, linear clutches are uncommon in mobile robots, medical robots, aerospace, or robotic exoskeleton applications. In these cases, the motor or other actuator is used not only to achieve motion but also to hold a static load. These static behaviors can consume significant amounts of power but do not generate mechanical work. Besides motors, clutches used in linear applications are typically bulky, heavy, inefficient, or require additional accessories to operate, such as compressors and hydraulic or air wiring.

[0007] While electrostatic clutches offer the size, weight, and power savings required for specific applications, clutch travel length is also a significant factor. For electrostatic clutches, the total clutch travel is limited by the electrode length. This means that when selecting the clutch electrode length, the overlap area of ​​the electrodes must be sufficient to transmit the load required for maximum extension, as the overlap area between the two electrodes will decrease. This also requires that the length of the clutch at full retraction be at least the sum of the length required to withstand the predetermined load and the required travel length. If space is limited, the retraction length may be too long to be usable.

[0008] Linear electrostatic clutches can also be used for rotary functions, utilizing space that is currently underutilized or even wasted in mechanical components. For example, rotary joints typically include a large number of components such as bearings, encoders, motors, gearboxes, torque sensors, etc. Adding extra components to the joint is not feasible due to space constraints or environmental interference.

[0009] Therefore, it would be advantageous to develop a clutch overlap area that can maintain a substantially constant value throughout the input or output stroke. Given a set of force and stroke requirements, these characteristics enable a more compact and flexible solution than a simple linear electrostatic clutch. Such linear clutches have shorter retraction lengths, making them particularly useful in applications where space is limited and strokes of several inches or longer are typically required. This includes, but is not limited to, exoskeletons, mobile robots, linear motion platforms, and aerospace applications. Summary of the Invention

[0010] An embodiment of this application provides a compact linear clutch that uses at least two electrodes separated by a dielectric material, wherein a voltage applied to the electrodes generates an electrostatic attraction. A connecting mechanism and a winding device (such as rollers) maintain a nearly constant electrode overlap area. This compact linear clutch maintains a short overall length even when moving throughout its entire stroke range. Attached Figure Description

[0011] Figure 1 An electrostatic clutch according to one embodiment is shown, which utilizes rollers to change the circuit of electrodes associated with an output connection mechanism;

[0012] Figure 2 The contraction and extension states of a roller-based clutch are shown;

[0013] Figure 3 It is a linear clutch that uses a drum for electrode storage and discharge;

[0014] Figure 4 A constant-length linear clutch with a winding mechanism is shown;

[0015] Figure 5 It is a linear clutch with floating rollers;

[0016] Figure 6 An embodiment of a linear clutch for controlling the resistance of a rotary joint is shown;

[0017] Figure 7 Two linear clutches are arranged opposite each other to control the resistance of the rotary joint;

[0018] Figure 8 One embodiment is shown, in which electrodes transmit force to the input terminal and dielectric material transmits force to the output terminal;

[0019] Figure 9 This is an embodiment using an electrode shuttle with a flexible housing;

[0020] Figure 10 This is an exploded view of an embodiment using an electrode shuttle with a flexible housing and tether attachments;

[0021] Figure 11 This is a detailed exploded view of an embodiment using an electrode shuttle with a flexible housing and tether attachments;

[0022] Figure 12 This is one embodiment of a clutch element, wherein electrodes are arranged on the belt that drives the rotary joint;

[0023] Figure 13 A clutch element is shown, which includes a toothed timing belt inserted between two flexible clutch members, each flexible clutch member including an electrode with a dielectric material disposed on its surface.

[0024] Figure 14 A clutch assembly is shown, in which the electrodes are located between two rows of synchronizing teeth;

[0025] Figure 15 The input electrode interacts with the outer periphery of the clutch element;

[0026] Figure 16 One embodiment of the clutch element includes electrodes located on the outer periphery of the belt ring;

[0027] Figure 17 An electrostatic clutch is shown mounted on both sides of a linear platform;

[0028] Figure 18 It is a compact linear clutch, including a wound clutch element with electrodes on both the top and bottom surfaces;

[0029] Figure 19 It is a compact linear clutch, including a retractable clutch element;

[0030] Figure 20 It is a compact linear clutch, a wearable device that uses a tether and a flexible housing to achieve a fit. Detailed Implementation

[0031] According to an embodiment of this application, a compact linear clutch 100 is provided. For example... Figure 1 As shown, the linear clutch 100 has an electrode 102, a dielectric material 103 separating the electrode 102, and a connecting member 105. Figure 1 In the embodiment shown, the first electrode 102 is connected to the input connection member 105, and the second electrode 102 is connected to the output connection member 105. Figure 1 A winding device 110 is also shown, in Figure 1 In one embodiment, the winding device includes a roller. The winding device 110 may include rollers, spools, pulleys, or similar mechanisms that affect the overall length or position of the flexible electrode 102.

[0032] A linear electrostatic clutch 100 can be used to resist motion in most devices with linear degrees of freedom, limited range of rotational degrees of freedom, or rotational degrees of freedom in which a portion of the linear clutch 100 remains stationary relative to a continuously traveling belt. Each clutch 100 includes at least two electrodes 102 separated by a dielectric material 103. In the closed state (i.e., without electrostatic attraction), the electrodes 102 are free to move relative to each other. In the engaged state (i.e., with electrostatic attraction), a voltage is applied between the electrodes 102, causing them to adhere to each other. This behavior can be used to provide a resistive load between an input connection mechanism 105 and an output connection mechanism 105, which are the input and output phases of the clutch 100, respectively. The mechanical connection of the clutch to an external mechanical system is referred to as the clutch input and output. These connections 105 can be achieved by bolting, adhesive, riveting, welding, press fitting, clamping, flange connection, threaded connection, epoxy resin, pressure-sensitive adhesive, or other connection methods. The standard used in this disclosure is to consider the moving electrode 102 or clutch component or clutch component assembly as the output end, but this definition may not apply to all cases. For example, when both clutch electrodes 102 or clutch components are moving, either one can be defined as an input or an output.

[0033] The amount of resistance load provided by clutch 100 is controlled by the applied voltage and the electrode overlap area. Other factors, which are generally not change as part of real-time control, also affect the resistance load. These factors include: the coefficient of friction of the materials interacting on the clutch engagement area, the stiffness of clutch electrode 102, the dielectric constant of dielectric material 103, the thickness of dielectric material, and other properties of the design and materials used. The magnitude of the resistance is proportional to the square of the applied voltage. This relationship does not hold true when the voltage is very low (less than 10V) or close to the breakdown voltage of dielectric material 103.

[0034] Figure 1 The clutch 100 shown achieves a smaller retraction length than previous electrostatic clutch devices by accommodating the flexible electrode 102 within the winding device 110, by winding and covering the roller surface, and by using a shuttle or clamping a portion of the travel belt 111 or chain.

[0035] The linear clutch 100 may include some or all of the following elements: two or more electrodes 102, a dielectric layer 103 attached to or otherwise disposed between the electrodes 102, structural elements or connecting parts 105 connecting the electrodes 102 to an input or output stage, a tensioner 120, a winding device 110 (i.e., a roller, idler pulley), a spring, a semi-flexible reinforcing plate, a linear bearing, a housing, a dry or wet lubricant, and a circuit 170, which includes some or all of the following: a microcontroller, a voltage transformer, a battery, a sensor, a contact area, a relay, MOSFETs (metal-oxide-semiconductor field-effect transistors), and transistors, electrical connections between the electrodes and the circuit, and electrically insulating materials.

[0036] Electrode 102 can be flexible, rigid, or semi-flexible, or a combination thereof. In some embodiments, electrode 102 can be very thin and disposed on a carrier, substrate, or structural member. In this case, the entire electrode 102 or selected portions of electrode 102 can be confined to the carrier, substrate, or structural member. In other embodiments, electrode 102 can be the electrode 102 itself or a structural member or frame capable of transmitting mechanical loads with or without additional support. Any of these configurations is effective as long as at least one electrode 102 is flexible, semi-flexible, or compliant.

[0037] For brevity, this application uses the term "clutch component" to describe any assembly or group of assemblies capable of acting as electrodes 102 and transmitting mechanical loads generated by electrostatic attraction between the electrodes 102 of the clutch component. A single clutch component may be an electrode 102, an electrode 102 with a carrier, a rigid substrate coated with a conductive layer, etc. Multiple clutch components may include a dielectric material 103. Multiple clutch components may consist solely of electrodes 102 capable of transmitting mechanical loads, as is the case in embodiments where a metal plate serves as both an electrode 102 and a structural component. In other embodiments, multiple clutch components may be used, including both electrodes 102 and reinforcing structural components. Each clutch component is associated with both the input and output ends of the clutch 100. The electrostatic clutch 100 requires at least two clutch components to operate. One component is connected to the mechanical input end, and the other component is connected to the mechanical output end. Clutch components may also be used in groups. In this case, a first group of clutch components is connected to the mechanical input end of the clutch, and a second group of clutch components is connected to the mechanical output end of the clutch.

[0038] "Clutch engagement area (interface)" refers to the overlapping area of ​​the input and output electrodes 102, which generates adhesion when engaged.

[0039] In several embodiments, both the output clutch assembly and the input clutch assembly include electrode 102. In these cases, when engaged, the output electrode 102 and the input electrode 102 maintain different voltages. When disengaged, these electrodes 102 are shorted together, bringing them to the same voltage potential. The electrical connection can be established via swages, clips, or other conductive clamping methods, or by soldering or conductive adhesive. In some embodiments, a portion of the electrode 102 may be shaped to facilitate insertion into an electrical connector, such as a card edge connector, a zero insertion force (ZIF) connector, or a pin header. A sliding electrical connection can be used to maintain connection with a moving component. This can include spring-loaded contacts, carbon brushes, wire brushes, or other sliding connections. If a sliding electrical connection is not used, a cable can be used instead.

[0040] Please refer to the attached diagram again. Figure 1 An embodiment of a linear clutch 100 is shown, wherein the output clutch component includes a flexible electrode 102, one end of which is connected to an output base or connecting member 105, and the other end of which is connected to a tensioner frame or connecting member 105. In this embodiment, the output clutch component includes the flexible electrode 102. The output clutch component covers a roller 110, and its tensioner frame 105 is connected to the output frame 105 via one or more tensioners 120. The position of the roller 110 such that the gap between the input electrode 102 and the output electrode 102 is between 0 and 0.050 inches, but this gap may vary depending on the applied voltage and the intended use. The input clutch component includes an input base, a tensioner frame, and a clutch component, wherein the clutch component contains the electrode 102 and a dielectric material 103 coated on its surface. The input electrode 102 may be flexible, rigid, or semi-flexible. In other embodiments, the single component of the input clutch component may simultaneously serve as both the electrode 102 and the frame. The tensioner 120 can be made of rubber, an elastomer, an elastic rope, a coil spring, a torsion spring, or other deformable elements. Tension can also be maintained by suspending a weight or an inertial element. In other embodiments, both electrodes 102 can be coated with a dielectric material 103, or a separate dielectric layer 103 can exist between the two electrodes 102.

[0041] Figure 2 Showing with Figure 1 The same embodiment illustrates the behavior of clutch 100 during contraction and extension. As the output frame moves downward, the output clutch member rolls on roller 110, shortening the clutch area stored on the left side, but maintaining the same overlap area with input electrode 102. The maximum extension state of clutch 100 is limited by the tension rod extending to roller 110. To maintain a constant clutch overlap area, the maximum travel distance of clutch 100 must be less than half the total length of the output clutch member.

[0042] Figure 3 An embodiment of a linear clutch 100 is shown, employing a spool 110 to store excess length of the output electrode 102, thereby reducing the overall length of the clutch 100 in its retracted and contracted states. The spool 110 includes a cylindrical surface and a tensioning assembly 120. The tensioning assembly 120 may include a torsion spring, a clock spring, a linear spring driving the spool 110 to rotate, or an elastic spring wound on a spool and detached at its end from the spool. Other tensioning strategies, such as suspended counterweights or eccentric counterweight spools, may provide tension to the spool 110. The illustrated embodiment also includes a roller 121 associated with the tensioner 120. The roller 121 is aligned such that the gap between the output electrode 102 and the input electrode 102 is less than 0.050 inches. The roller 121 may maintain a constant gap, while the diameter of the spool 110 changes with the stored electrode length. The illustrated embodiment also includes a tensioner 120 connected between the output frame and the input tension bar to maintain alignment of the input clutch assembly and the output clutch assembly.

[0043] Figure 4 An embodiment of a linear clutch 100 is shown, employing two spools 110 to store and release the output electrode 102, thereby achieving a constant length of the clutch 100. The input electrode 102 is shorter than the output electrode 102 and is not wound. The wound output electrode 102 maintains a constant contact area with the input electrode 102. Both spools 110 are mounted on a base or within a housing. One spool 110 is a tension spool, and the other is an output spool. The tension spool 110 includes a tensioner 120, which retracts the output electrode 102 when the external force on the output end is released and the clutch is disengaged. The output spool 110 may or may not include the tensioner 120. When the output cable extends, the output electrode 102 winds around the output spool 110 and unwinds from the tension spool 110. When the cable retracts, the output electrode 102 unwinds from the output spool and winds back onto the tension spool 110. The output cable is wound around the output spool 110 such that the cable tension is counteracted by the output clutch member. In this embodiment, there are two input electrodes 102 and two output electrodes 102, such that the output cable is connected in the middle of the output spool 110. Each spool 110 has an associated roller 121, which can maintain a constant gap between the output clutch member and the input clutch member as the diameter of the spool 110 changes during the stroke. Other embodiments may include more electrodes 102 with cable reels or a winch located on one side of the clutch engagement area. In some embodiments, the output end may be a gear mounted on the shaft of the output spool 110 instead of the output cable shown. Figure 4 The calibration roller 121 shown may be excluded in some embodiments.

[0044] Figure 5In the illustrated embodiment, the flexible output electrode 102 is retracted and extended in a loop managed by floating rollers 110. The floating rollers 110 are connected to one or more tensioners(s) that maintain tension on the output clutch members but allow the rollers 110 to move parallel to the direction of movement of the output electrode. When the clutch 100 is disengaged and the tension at the output end is released, the tensioner 120 contracts to increase the distance between the rollers 110 and the length of each ring of the output electrode 102. When the clutch 100 is disengaged and the force applied to the output electrode 102 is large enough to extend the tensioner 120, the tensioner 120 extends and the length of each ring of the output electrode 102 decreases. When the clutch 100 is engaged, the shear force at the engagement area of ​​the input and output clutch members provides a resistive load against the extension of the output clutch members. In other embodiments, multiple floating rollers 110 may be used to form additional loops, further extending the maximum travel of the clutch.

[0045] Figure 6 An embodiment of using a linear clutch 100 in a rotating application is shown. The linear clutch 100 is mounted on a first link 131, which is connected to a second link via a rotary joint 130. An input electrode 102 is fixed relative to the first link, and an output electrode 102 slides parallel to the input electrode 102 as the second link rotates about the joint 130. In this embodiment, a thin electrically insulating or insulating tether is provided on the output electrode 102 to transfer mechanical loads from the output clutch assembly to the tether and ultimately to the second link 132. When the clutch 100 is engaged, the clockwise rotation of the second link 132 relative to the first link 131 is limited by forces at the clutch engagement region. Due to the flexibility of the tether and the output electrode 102, this configuration can be used to provide resistance loads in only a single direction. In other embodiments, such as... Figure 7 As shown, the second clutch 100 and the tether can be used in reverse to provide bidirectional action. For illustrative purposes, a linear clutch 100 including a tension spool 110 is shown. Any embodiment of the linear clutch 100 described herein can be used for this purpose.

[0046] In some embodiments, the tensioner 120 may be a rubber-based elastic band or rope, a helical spring, a torsion spring, a clock spring, a constant force spring, a synthetic elastomer, or a counterweight element. The tensioner 120 may be connected between electrode frames, or may otherwise be connected to the clutch housing or the input or output of a device using the clutch 100. In some embodiments, the force required to deform the tensioner 120 is less than the maximum force that can be transmitted through the clutch engagement area.

[0047] The winding device 110 may include some or all of the following components: a cylindrical surface, a center pin, a sliding bearing, a ball bearing, a needle roller bearing, a thrust bearing, a spring, a mounted bearing, an adjusting screw, and mounting hardware. The cylindrical surface may have an end braking structure, a shoulder, a through hole, or a blind hole. The roller surface may be cylindrical, crown-shaped, a straight tapered shape with a central plane, a straight tapered shape, a concave crown shape, or other shapes. The roller end may or may not have a flange.

[0048] The dielectric material 103 of the separator electrode 102 can be applied as a coating to one or both electrodes 102. The dielectric material 103 can also be placed between the two electrodes 102. Figure 8 An embodiment is depicted in which dielectric material 103 includes one of the clutch components and transmits force to the output terminal. In this embodiment, when a voltage is applied to electrode 102, electrostatic attraction pulls the electrodes 102 together, causing the dielectric material 103 in the middle to be compressed. Both electrodes 102 are connected to the input terminal. When the clutch 100 is energized, the frictional forces at the two engagement areas between the dielectric material 103 and the electrodes 102 counteract the force as the applied force extends the output terminal relative to the input terminal. For dielectric material 103 of the same thickness, the holding force achievable in this embodiment is twice that experienced in an embodiment where one electrode 102 is attached to the input clutch component and the other electrode 102 is attached to the output clutch component, and the dielectric material 103 is located between the two electrodes 102. When no voltage is applied to the clutch engagement area, the electrodes 102 are not subject to attraction.

[0049] In other embodiments, the dielectric component may include an electrode 102 that has no explicit electrical connection to the circuit except through the dielectric surface itself. In this particular embodiment, the clutch 100 uses three electrodes 102, wherein the engagement regions are connected in parallel on the circuit, and one of the electrodes is not connected to a power source, thus eliminating the need for a moving electrical connection such as a brush.

[0050] Figure 9An embodiment is shown in which the use of a tether coupled with the electrode shuttle 113 reduces the overall length of the clutch 100 in the extended state compared to a configuration without the electrode shuttle 113. In this embodiment, the output electrode 102 is shorter than the input electrode 102. The clutch assembly including the short electrode is referred to as the shuttle 113. In the disengaged state, the output electrode shuttle 113 moves along the length of the input electrode 102. When tension is applied to the tether and the output electrode 102 is pulled back by the two tensioners 120, the clutch 100 extends. A guide rail 141 is provided on the output electrode 102, and the opening of the guide rail 141 restricts the input electrode 102, thereby allowing the shuttle 113 to move along the length of the input electrode 102 without significant displacement in a direction perpendicular to the input electrode 102. The guide rail 141 can be provided on any clutch assembly or can be part of the clutch housing 140. In this embodiment, the clutch housing 140 is flexible. The top and bottom surfaces of the housing are constructed of flexible sheets separated by separators. In this embodiment, the separator is a compressible foam material. Multiple short foam segments are arranged on the side of the housing 140, with gaps between the foam segments. In other embodiments, the separator may be a single component with slits or V-shaped cuts, a single continuous component, or multiple rigid components. In other embodiments, the function of the separator may be achieved by housing walls fabricated in other ways. The housing 140 may be flexible, semi-flexible, have different flexibility in different directions, or may be rigid.

[0051] Figure 10 Further detailed description is shown. Figure 9 An exploded view of the shuttle 113 of the illustrated embodiment is provided to further describe its structure in detail. Figure 13 and Figure 14In the illustrated embodiment, the shuttle 113 comprises two clutch components, each containing an output electrode 102. An input electrode 102 is located between the two output electrodes 102 and connected to an input connection component 105. Both output electrodes 102 are mounted on a polymer carrier. A small portion of each output electrode 102 is adhered to the carrier using a pressure-sensitive adhesive. In this embodiment, the adhesive is applied in a single strip at the center of the shuttle 113, but other patterns are also possible. The guide rail 141 consists of four planar components bonded with pressure-sensitive adhesive. The guide rail 141 is mounted on one of the output electrodes 102, and the input electrode 102 and the second output electrode 102 are disposed within the guide rail 141. Compared to the electrodes 102, the tether has the advantage of a smaller size and greater flexibility, making it easier to connect to external connection points. This also ensures that the area of ​​the clutch 100 remains constant throughout the stroke of the shuttle 113. Since the engagement and response time of clutch 100 may depend on the overlap area, this design enables clutch 100 to have predictable engagement and response times regardless of how extended clutch 100 is.

[0052] The clutch element may include a belt serving as a connecting member 105 and may include an electrode 102. These belts may include, but are not limited to, friction belts, V-belts, and toothed belts. These belt clutch components may have various structures. The flexible electrode 102 may be made of a thin conductive sheet of metal or carbon fiber. In this case, the flexible electrode 102 may simultaneously include the electrode 102 and the connecting member 105, or it may be attached to a frame or carrier serving as the connecting member 105. In other embodiments, the flexible electrode 102 may be disposed on a polymer carrier, or it may be an inherently conductive polymer sheet, such as carbon-filled polyimide or other flexible conductive elements. The flexible electrode 102 may be attached to its structural frame by pressure-sensitive adhesive or glue, or by clamping force generated by bolts, screws, rivets, or other connecting hardware.

[0053] Figure 11A detailed exploded view of clutch 100 is shown. This embodiment uses a tether and electrode shuttle 113 including an output clutch component, wherein the output clutch component includes an output electrode 102, an adhesive, a carrier, a structural plate, and a rigid connector. In this embodiment, the shuttle 113 moves along the input electrode 102 and is maintained under tension by a spring. In some embodiments, a thin tether may extend the length of one or two clutch components. The tether may be attached to the entire surface of electrode 102, to only a portion of the surface, or indirectly connected to electrode 102 via any number of additional components, such as structural frame elements. The connection between the tether and electrode 102 can be established by an adhesive, glue, tape, clamping force achieved by connecting hardware such as bolts, screws, or rivets, or other methods. A support structure may be provided near the connection between the tether and electrode 102. The length of the tether can be further extended by connecting an additional tether element that may have different characteristics from the first portion of the tether. In some embodiments, this extended portion of the tether may be a cord, rope, or cable with a thickness greater than the tether element near the output electrode 102.

[0054] Figure 12 An embodiment of a belt-based clutch assembly is shown, wherein electrodes 102 are mounted on the inner surface of a timing belt 111. The electrodes 102 mounted on the belt can move and deform with the belt 111. The input clutch assembly containing the electrodes 102 is located near the inner circumference of the belt 111 annulus and close to the surface of the electrodes mounted on the belt, such that when a voltage is applied between the electrodes 102, the two surfaces can adhere together, and force can be transmitted between the stationary electrode 102 and the electrode mounted on the belt. Any number of idlers or rollers 121 can be added to maintain proper spacing and alignment between the clutch assemblies.

[0055] Figure 13 An embodiment of an electrode 102 mounted on a belt is shown, wherein two clutch components are disposed on both sides of a synchronizing gear 115 and are coplanar with the synchronizing gear 115. The synchronizing gear 115 prevents slippage and keeps the connected rotating components aligned. The flexible electrode 102 is disposed on a flexible carrier. The flexible electrode 102 is encapsulated or packaged with a dielectric material 103.

[0056] Figure 14 An embodiment of a belt-type delivery electrode 102 disposed between two rows of synchronizing teeth 115 and coplanar with the synchronizing teeth 115 is shown.

[0057] Figure 15An embodiment of the clutch 100 is shown, wherein a fixed electrode 102 is mounted on a structure adjacent to the belt 111. In some embodiments, this structure may be a housing or a belt with protective features. A movable electrode 102 is mounted on the outer surface of the timing belt 111 and aligns with the timing belt as the timing belt 111 moves around the pulley and cylindrical surface. In other embodiments, there may be one or more fixed clutch components. These components may be straight or curved.

[0058] Figure 16 One embodiment of an output clutch assembly is shown, comprising a belt 111 having electrodes 102 disposed on the outer periphery of a belt loop opposite a friction surface or toothed surface 112 of the belt. In this embodiment, the electrodes 102 are disposed on a polymer carrier and encapsulated by a dielectric material 103. The polymer carrier is mechanically attached to the surface of the belt 111 by selective use of a flexible adhesive, such that a portion of the carrier and the electrodes 102 has greater out-of-plane flexibility than the adhered area. In other embodiments, the polymer carrier may be adhered to its entire surface, or other forms of adhesive may be used. In other embodiments, the polymer may be held on the surface of the belt 111 solely by friction or belt tension.

[0059] The belt mounting configuration can include various configurations. The belt 111 may include electrodes 102, or flexible electrodes 102 may be disposed on the belt 111. Fixed clutch members may include conductive material and serve as electrodes 102, or fixed clutch members may have additional electrodes 102 flexibly or rigidly disposed on their surface. Any number of idlers or rollers 121 can be used to keep the belt 111 and clutch elements aligned. Clutch electrodes 102 may be mounted on the inner or outer surface of the belt 111, or in other embodiments, along the outer edge perpendicular to the pulley surface. Clutch electrodes 102 may be disposed on one side of the teeth or friction surfaces 112 of the belt 111, between these elements, or mounted on both sides. One or more clutch members may be disposed on the belt 111. Clutch members may be arranged continuously along the surface of the belt 111, or may exist as one or more short segments. In some embodiments, the belt 111 may be a friction belt or a V-belt. The belt 111 may include clutch members, or clutch members may be disposed on both sides or between the friction surfaces 112 of the belt 111. In some embodiments, the clutch component can serve multiple purposes as friction surface 112 or a belt structure. The flexible electrode 102 and the carrier can be made of polymer film, glass fiber, rubber, plastic or other materials.

[0060] In some embodiments, the clutch component includes an electrode 102 selectively adhered to the belt 111, allowing a portion of its surface to be freely flexible. In these embodiments, a dielectric material 103 is disposed on the outer surface of the belt conveyor electrode 102. In other embodiments, the electrode 102 may be completely enclosed by the dielectric material 103 and the belt 111. In other embodiments, the belt 111 itself may be made of a conductive material or coated with a conductive coating to act as the dielectric material 103. The dielectric material 103 may be disposed on the belt-side electrode 102, the stationary electrode 102, or both.

[0061] Figure 17 An embodiment of a linear clutch 102 is shown, which is integrated into the structure of a belt-driven linear platform. A movable electrode 102 is attached to the bottom surface of both sides of the platform or shuttle 113. A fixed electrode 102 is attached to the surface of the linear platform housing such that when a voltage is applied to the electrode 102, the platform 113 is constrained to the linear platform housing. In some embodiments, the surface of the linear platform housing itself may serve as the clutch electrode 102. In other embodiments, the movable electrode 102 may be mounted on a portion of the belt 111 located within the linear platform housing, and the fixed electrode 102 may be disposed on the inner surface of the linear platform housing. The movable electrode 102 may be connected to either side of the movable belt 111 and may or may not have brushes that establish a connection with the non-moving portion of the actuator.

[0062] Figure 18 An embodiment of a compact linear clutch 100 is shown, comprising a long, flexible carrier with electrodes 102 on its upper and lower surfaces. The clutch component has the carrier and two insulated electrodes 102 wound around the overlapping upper and lower surfaces. In the region where the wound components overlap, a dielectric material 103 is coated or disposed on the surface of one electrode 102, such that the two electrodes 102 are separated by the dielectric material. The electrode surfaces may be separated by a flexible insulating substrate 160. When a voltage is applied between the two electrodes 102, the wound upper and lower surfaces adhere together and transmit a force preventing relative displacement of the input and output connections. The electrodes 102 may be entirely adhered to the carrier, or only partially adhered. The carrier may comprise a single layer or multiple layers of sheets capable of transmitting mechanical loads. These sheets may be selectively adhered to each other, allowing each layer to bend independently of each other, or allowing the overall thickness of the carrier to expand or contract in a direction perpendicular to the operating axis of the linear clutch 100. The ends of the clutch component include structural components capable of transmitting mechanical loads. These structural components may have features for connecting to larger devices, such as pin holes as shown in the figure, or employ other mechanical connection methods, such as bolts, screws, rivets, or clamps like split hub clamps or collars. These structural elements may also have through holes for the passage of other components such as shafts, rods, or cables.

[0063] In some embodiments, the compact linear clutch 100 may be mechanically connected to a Bowden cable. The Bowden cable housing may terminate at the clutch housing 140 or at a structure spatially fixed relative to the fixed electrode 102.

[0064] Figure 19 A telescopic compact clutch 100 is shown, which can translate in a straight line. The telescopic clutch 100 requires at least two independent clutch components of similar shape but different dimensions, so that one component can slide within the other component, and a slight contact or small gap is maintained between their surfaces. Each clutch component includes at least one electrode 102. The electrode 102 can form the main body of the clutch component, or it can be applied as an accessory, a film, or a coating. A dielectric material 103 is placed between the electrodes 102. The dielectric material 103 can be applied to one or both electrodes 102, or placed between them. One or more intermediate carriers can be provided between the telescopic component structure and the electrodes 102, making it possible for limited movement of the electrode 102 surface perpendicular to the telescopic element. This can be achieved by selectively adhering partial carriers, allowing the unsupported portion to bend in a direction perpendicular to the telescopic action. In the engaged state, there must be a potential between the electrodes 102 on the inner and outer diameters of the clutch engagement area. Each clutch electrode 102 can be disconnected from the circuit or maintained at a different voltage potential, allowing all or some of the clutch electrodes 102 to engage. The telescopic clutch component shown in the figure is cylindrical, but it can also be of various shapes, including but not limited to square or rectangular. The cylindrical linear clutch 100 allows for translational freedom along the telescopic axis and rotational freedom about the telescopic axis. Other shapes can be used to restrict the degrees of freedom of the clutch 100.

[0065] Figure 20 One embodiment of a flexible sling clutch 100 is shown, which selectively connects a seatbelt waist belt and a helmet via a tether. In this embodiment, the flexibility of the housing 140 allows for unrestricted user movement while preventing jamming caused by compression when the user is seated, such as while sitting in a chair.

[0066] In some embodiments of the linear clutch 100, a sensor located inside or outside the clutch 100 may be included to measure the extension of the clutch and / or other associated joints in a larger assembly. This sensor may be an optical sensor, a magnetic sensor, a brush or spring contact interacting with a patterned conductive surface, or an inductive sensor. Signals from this sensor can be used to inform or control the behavior of the clutch 100; for example, a larger voltage may be applied near the boundaries of the clutch 100's range of motion, while a lower voltage may be applied near the center of its travel.

[0067] In some embodiments, clutch 100 may be activated based on data from an accelerometer, pressure-sensitive switch, inertial measurement unit accelerometer, biosensor (e.g., electromyography sensor), optical sensor, encoder, or other sensor. The sensors provide data to the controller, controlling the behavior of clutch 100, and may also control a motor, linear actuator, or other output. For example, movement of the linear platform triggers a pressure-sensitive switch positioned at a specific location, which in turn triggers the controller to activate clutch 100, thereby locking the linear platform into place.

[0068] The input and output base frames can be connected to external components of the clutch 100 in a variety of ways, including but not limited to: pressure-sensitive adhesive, glue, welding, riveting, screws, bolts, pins, clamps, stitching, heat riveting, crimping, snap-fit, hook-and-loop fasteners, or other methods. The base frames can have various structural forms, including planar structures as shown in the multiple figures, or more complex three-dimensional components. The base frames can have a variety of applications, including but not limited to housings for larger devices such as robots.

[0069] Some embodiments may include a housing 140. The housing 140 may have multiple functions: preventing compression between the input and output electrodes, providing electrical isolation, providing environmental protection, enhancing aesthetics, or a combination of the above functions. The housing 140 may include a sealing ring or gasket for environmental sealing. The housing 140 may be made of a semi-flexible material, such as glass fiber, carbon fiber, spring steel, or polymer sheet. Flexible supports may be used within the housing 140. A portion of the housing assembly is compressible at least in a direction perpendicular to the surface of electrode 102.

[0070] Each embodiment shown can be used alone or in combination. Each clutch 102 must contain at least two electrodes 102, but may contain any number of electrodes 102. Any embodiment of the compact linear electrostatic clutch 100 described herein can be used in pairs or in any number of combinations.

[0071] Electrical connections between the clutch electrodes 102 can be established via wires, sliding electrical contacts, or via tensioner 120 or other conductive and deformable connections. In some embodiments, the movable electrodes 102 may not have explicit electrical connections. These electrodes 102 act as series capacitors, connected to the clutch circuit 170 via a dielectric material 103 placed between the electrodes 102. In the engaged state, these electrodes are maintained at an intermediate voltage between the voltages of adjacent electrodes 102.

[0072] Clutch 100 can be engaged by applying a voltage between electrodes 100. The maximum force that clutch 100 can transmit depends on the magnitude and waveform of the applied voltage, the area of ​​the clutch engagement region, the thickness of the dielectric layer 103, and its material composition. The slip force of the linear clutch 100 can be adjusted by regulating the magnitude and waveform frequency of the applied voltage. When the voltage is higher than 10V and lower than the breakdown voltage of the dielectric material 103, the holding force varies with the square of the voltage. The transmittable force can be adjusted by changing the number of clutch components engaged in parallel. Whether the clutch components engage with a voltage difference across their ends, disengage with equal potentials on each electrode 102, or are in a floating state can be controlled by switches, MOSFETs (metal-oxide-semiconductor field-effect transistors), transistors, or other electrical components.

[0073] The terms “comprising,” “including,” and variations thereof, as used in this specification and claims, mean that the specified features, steps, or elements are included. These terms should not be construed as excluding the presence of other features, steps, or components.

[0074] The present invention may also broadly include any and all combinations of parts, elements, steps, examples, and / or features individually mentioned or specified in the specification, or two or more of the said parts, elements, steps, examples, and / or features. In particular, one or more features in any embodiment described herein may be combined with one or more features in any other embodiment described herein.

[0075] In conjunction with this disclosure, protection may be sought for any feature disclosed in any of the publications cited herein. Although certain exemplary embodiments of the invention have been described, the scope of the appended claims is not intended to be limited to these embodiments. The claims should be interpreted literally, objectively, and / or including equivalents.

Claims

1. An electrostatic clutch, comprising: First electrode; Second electrode; Dielectric material disposed between the first electrode and the second electrode; An input connection member associated with at least one of the first electrode and the second electrode; and The output connection component associated with the second electrode or the dielectric material, The displacement of the input connection member relative to the output connection member will not cause a change in the overlapping area of ​​the first electrode and the second electrode.

2. The clutch according to claim 1, further comprising a winding device attached to the first electrode or the second electrode, wherein the winding device comprises a roller, a spool or a pulley.

3. The clutch according to claim 2 further includes a belt having a friction surface.

4. The clutch according to claim 3, wherein the belt includes the input connection member or the output connection member, wherein one or both of the first electrode and the second electrode are coplanar with the friction surface of the belt.

5. The clutch of claim 3, wherein the belt includes the input connection member and the output connection member, wherein one or both of the first electrode and the second electrode are attached to the belt at a surface opposite to the friction surface.

6. The clutch according to claim 1, wherein the output connection member includes a shuttle.

7. The clutch according to claim 2, wherein at least one of the first electrode and the second electrode surrounds the winding device.

8. The clutch of claim 7, wherein the second electrode is configured to rotate 180 degrees about at least one roller attached to the input connection member.

9. The clutch of claim 8, wherein a tensioner connects the output connection member to one end of the second electrode.

10. The clutch of claim 8, wherein a tensioner connects the output connection member to one end of the first electrode.

11. The clutch of claim 8, wherein the maximum stroke length does not exceed half the length of the second electrode, wherein the overlap area between the first electrode and the second electrode remains constant.

12. The clutch of claim 8, wherein the second electrode surrounds one or more additional movable rollers attached to one or more tensioners.

13. The clutch of claim 8, wherein the second electrode is wound around a winding device attached to the input connection member.

14. The clutch of claim 13, wherein the maximum stroke length is actually limited by the length of the second electrode stored on the winding device, wherein the overlap area between the first electrode and the second electrode remains constant.

15. The clutch of claim 13, wherein the output connection member comprises a cable wound around the output winding assembly.

16. The clutch of claim 15, wherein the second electrode is further wound around the winding device wound by the output connection member.

17. The clutch of claim 1, wherein the output connection member includes a cable terminating at a second link, the second link forming a rotary joint connection with a first link attached to the input connection member to guide torque at the rotary joint.

18. The clutch of claim 1, wherein the input connection member is connected to the first electrode and the second electrode, and wherein the output connection member is connected to the dielectric material.

19. The clutch according to claim 1, further comprising a flexible housing, the flexible housing including a shuttle guide and a spacer, such that compression of the housing does not cause friction between the first electrode, the second electrode, or the dielectric material.

20. The clutch of claim 19, wherein the spacer has a gap, a groove, a V-shape, or other structural member that allows the housing to bend slightly.

21. The clutch according to claim 1, wherein one or both of the input connecting member and the output connecting member are belts, timing belts, toothed belts, V-belts or other flexible connectors.

22. The clutch of claim 21, wherein the first engagement region between the input connection member and the first electrode and the second engagement region between the output connection member and the second electrode are selectively applied adhesives that keep the first electrode and the second electrode partially out of contact and unconnected.

23. The clutch of claim 21, wherein the belt is connected to a second link, the second link forming a rotary joint connection with a first link connected to the input connection member, such that the clutch effectively generates torque at the rotary joint.

24. The clutch of claim 23, wherein the input connection member includes the surface of the first connecting rod.

25. The clutch of claim 23, wherein the input connection member includes a third member adjacent to the first link or the second link.

26. The clutch of claim 6, wherein the shuttle is driven by a belt, a lead screw, a ball screw, or other linear displacement member driven by an actuator.

27. The clutch according to claim 26 further includes a linear platform.

28. The clutch according to claim 27, wherein the input connection member is a fixed structural surface of the linear platform, and the output connection member is the main body of the shuttle.

29. The clutch according to claim 27, wherein the input connection member is a fixed structural surface of the linear platform, and the output connection member is a belt that drives the shuttle.

30. The clutch of claim 1, wherein one or both of the input connection member and the output connection member include an adhesive layer, a clamping feature, a bolt feature, a cable, a tether, or other connecting mechanism.

31. The clutch of claim 17, wherein the plurality of clutches produce different torques in different directions or amplitudes of the rotary joint.

32. An electrostatic clutch, comprising: First electrode; Second electrode; Dielectric material disposed between the first electrode and the second electrode; Input the connecting components; Output connection components; as well as An electrically insulating flexible substrate disposed between the first electrode and the second electrode. The clutch is wound such that the voltage applied to the first and second electrodes causes a change in the frictional force in the overlapping area between the first and second electrodes, thereby generating resistance to the relative translation or rotation of the input connection member and the output connection member.

33. An electrostatic clutch, comprising: First electrode; Second electrode; Dielectric material disposed between the first electrode and the second electrode; The input connecting component includes a hollow mechanical feature; An output connecting member includes a matching positive mechanical feature, the size of which is equal to or smaller than the size of the hollow mechanical feature of the input connecting member, and is located inside the hollow mechanical feature of the input connecting member. Applying voltage to the first and second electrodes can cause resistance when the mechanical feature rotates relative to each other about a common axis, and / or cause resistance when the mechanical feature translates relative to each other along the common axis.

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