Electrode pair having a sawtooth configuration and artificial muscle including the same

Abstract

To provide an electrode pair having a saw-tooth configuration and an artificial muscle including the same.SOLUTION: An electrode pair includes a first electrode and a second electrode. The first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outwardly from the first end. The lead has a first width at the first end. The second end of at least one of the first electrode and the second electrode has a recess that is formed in the second end and that has a first terminal and a second terminal. A second width extends between the first terminal and the second terminal of the recess. The recess is defined by a saw-tooth pattern. When the first electrode is positioned on the second electrode, At least one recess in the first electrode is adjacent to the lead of the other electrode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates generally to devices and methods for actuating electrode pairs, and more particularly to devices and methods using electrode pairs configured to receive increased voltage inputs without shorting. [Background technology]

[0002] The force output of a device including an electrode pair is directly related to the amount of voltage delivered to the electrode pair. However, if the amount of voltage delivered to the electrode pair exceeds the maximum operating voltage, the electrode pair will exhibit voltage breakdown and short circuiting will occur. Thus, the amount of voltage delivered to a device operated by an electrode pair is limited by the amount of voltage the electrode pair can withstand without short circuiting or exhibiting voltage breakdown. As a result, in order to increase the force output of the device, it is desirable to increase the maximum operating voltage of the electrode pair.

[0003] Furthermore, current robotics technology relies on rigid components, such as servomotors, to perform tasks, often in structured environments. This rigidity creates limitations in many robotics applications, at least in part due to the power-to-weight ratio of servomotors and other rigid robotic devices. The field of soft robotics improves on these limitations by using artificial muscles and other soft actuators. Artificial muscles attempt to mimic the versatility, performance, and reliability of biological muscles. Some artificial muscles rely on fluidic actuators, which require a supply of pressurized gas or liquid to transport the fluid through a system of channels and tubes, limiting the speed and efficiency of the artificial muscles. Other artificial muscles use thermally activated polymer fibers, which are inefficient and difficult to control and operate.

[0004] One particular artificial muscle design is described in a paper by E. Acome, SK Mitchell, TG Morrissey, MB Emmett, C. Benjamin, M. King, M. Radakovitz, and C. Keplinger entitled "Hydraulically amplified self-healing electrostatic actuators with muscle-like performance" (Science 05 Jan 2018: Vol. 359, Issue 6371, pp. 61-65). These hydraulically amplified self-healing electrostatic (HASEL) actuators use electrostatic and hydraulic forces to achieve various actuation modes. However, HASEL actuator artificial muscles have a limited actuator power per unit volume.

[0005] As a result, there is a need for improved electrode pairs and artificial muscles containing same that can accept increased voltage inputs without shorting and provide increased actuator power per unit volume. Summary of the Invention

[0006] In one embodiment, an electrode pair includes a first electrode and a second electrode, each having an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end. The lead has a first width at the first end. The second end of at least one of the first electrode and the second electrode has a recess formed in the second end, the recess having a first end and a second end. A second width extends between the first end and the second end of the recess. The recess is defined by a sawtooth pattern. The second width is greater than the first width. When the first electrode is positioned above the second electrode, the recess of at least one of the first electrode and the second electrode is adjacent to the lead of the other electrode.

[0007] In another embodiment, an artificial muscle includes a housing including an electrode region and an expandable fluid region, an electrode pair located in the electrode region of the housing, and a dielectric fluid contained within the housing. The electrode pair includes a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing. The first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end. The lead has a first width at the first end. The second end of at least one of the first electrode and the second electrode has a recess formed in the second end, the recess having a first end and a second end. The second width extends between the first end and the second end of the recess. The recess is defined by a sawtooth pattern. The second width is greater than the first width. At least one of the first electrode and the second electrode includes a central opening surrounding the expandable fluid region. When the first electrode is positioned above the second electrode, the recess of the at least one of the first electrode and the second electrode is adjacent to the lead of the other electrode, and the electrode pair is actuable between the unactuated state and the actuated state such that actuation from the unactuated state to the actuated state directs the dielectric fluid to the expandable fluid region.

[0008] In yet another embodiment, a method for operating an artificial muscle includes generating a voltage using a power source electrically coupled to an electrode pair of the artificial muscle. The artificial muscle includes a housing including an electrode region and an expandable fluid region, the electrode pair located in the electrode region of the housing, and a dielectric fluid contained within the housing. The electrode pair includes a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing. The first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end. The lead has a first width at the first end. The second end of at least one of the first electrode and the second electrode has a recess formed in the second end, the recess having a first end and a second end. The second width extends between the first end and the second end of the recess. The recess defines a sawtooth pattern. The second width is greater than the first width. The first electrode can be positioned over the second electrode such that the recess of at least one of the first electrode and the second electrode is adjacent to the lead of the other electrode. At least one of the first electrode and the second electrode includes a central opening that surrounds the expandable fluid region. The voltage is applied to the electrode pair of the artificial muscle, thereby actuating the electrode pair from an unactuated state to an actuated state to move the dielectric fluid into the expandable fluid region of the housing and expand the expandable fluid region.

[0009] These and additional features provided by the embodiments described herein will be better understood by considering the following detailed description in conjunction with the drawings.

[0010] The embodiments set forth in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of exemplary embodiments can be understood when read in conjunction with the following drawings, in which like structure is indicated with like reference numerals and in which: [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1A schematically illustrates a perspective view of an exemplary electrode pair in an exploded state according to one or more embodiments shown and described herein. [Figure 2] FIG. 10 schematically illustrates a perspective view of an assembled electrode pair according to one or more embodiments shown and described herein. [Figure 3] FIG. 1A schematically illustrates an exploded view of an exemplary artificial muscle according to one or more embodiments shown and described herein. [Figure 4] FIG. 4 schematically illustrates a top view of the artificial muscle of FIG. 3 according to one or more embodiments shown and described herein. [Figure 5] FIG. 5 schematically illustrates a cross-sectional view of the artificial muscle of FIG. 3 along line 5-5 of FIG. 4 in an unactuated state, according to one or more embodiments shown and described herein. [Figure 6] FIG. 4 schematically illustrates a cross-sectional view of the artificial muscle of FIG. 3 in an actuated state, according to one or more embodiments shown and described herein. [Figure 7] FIG. 1A schematically illustrates a cross-sectional view of an exemplary artificial muscle in an unactuated state, according to one or more embodiments shown and described herein. [Figure 8] FIG. 8 schematically illustrates a cross-sectional view of the artificial muscle of FIG. 7 in an actuated state, according to one or more embodiments shown and described herein. [Figure 9] FIG. 4 schematically illustrates a perspective view of an artificial muscle assembly including a plurality of the artificial muscles of FIG. 3 according to one or more embodiments shown and described herein. [Figure 10] 1 illustrates a schematic diagram of an actuation system for operating an artificial muscle according to one or more embodiments shown and described herein. DETAILED DESCRIPTION OF THE INVENTION

[0012] The embodiments described herein are directed to electrode pairs, artificial muscles including electrode pairs, artificial muscle assemblies including multiple artificial muscles, and methods of using the same. The electrode pairs described herein include at least a first electrode and a second electrode operable to selectively engage and disengage with each other when a voltage is applied and removed. The first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end. The lead has a first width at the first end. The second end of at least one of the first electrode and the second electrode has a recess formed in the second end and having a first end and a second end. The recess has a second width extending between the first end and the second end. The recess is defined by a sawtooth pattern. The second width of the recess is greater than the first width of the lead. When assembled, the first electrode is positioned over the second electrode such that the recess of at least one of the first electrode and the second electrode is adjacent to the lead of the other electrode. Providing this recess adjacent to the associated electrodes minimizes shorting and facilitates increasing the operable voltage. Various embodiments of artificial muscles and their operation are described in more detail herein. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts.

[0013] 1 and 2, an electrode pair 10 is shown. The electrode pair 10 includes a first electrode 12 and a second electrode 14. While only the first electrode 12 and the second electrode 14 are shown for ease of illustration, it should be understood that the electrode pair 10 may be combined or used with any suitable components, such as intermediate insulating layers, housings, electrical components, etc., as discussed herein and illustrated in FIGS. 3-10. As such, the electrode pair 10 may be used in any number of applications, such as, for example, robotics, medical devices, tools, and may be incorporated into artificial muscles, as discussed in more detail herein. In this regard, the electrode pair 12 may include any suitable support structure to enable the first electrode 12 and the second electrode 14 to actuate relative to one another.

[0014] The first electrode 12 includes an inner surface 16, an outer surface 18, a first end 20, and an opposite second end 22. In some embodiments, the first electrode 12 includes a pair of opposite sides 24, 26 extending between the first end 20 and the second end 22 and defining a body 27. As shown, the body 27 of the first electrode 12 has a rectangular shape defined by the first end 20, the second end 22, and the pair of sides 24, 26. However, it should be understood that the shape of the first electrode 12 is not limited to those illustrated herein. For example, the body 27 of the first electrode 12 may have a square shape, a circular shape, a star shape, or any other suitable shape.

[0015] The first electrode 12 includes a lead 28 extending outward from the first end 20 of the first electrode 12, with a terminal attached thereto for carrying charge to the first electrode 12. In some embodiments, the lead 28 extends perpendicularly from the first end 20 of the first electrode 12. The lead 28 is integrally formed with the first electrode 12 so that the first electrode 12 forms a unitary monolithic structure. The lead 28 extends from the first end 20 of the first electrode 12 at lead connection points P1 and P2, which define a width W1 of the lead 28. The second end 22 of the first electrode 12 is deformed to provide a recess 30 extending toward the first end 20 of the first electrode 12. The recess 30 has a first end T1 and a second end T2, which define a width W2 of the recess 30. The width W2 of the recess 30 is greater than the width W1 of the lead 28. In some embodiments, the recess 30 is defined by a sawtooth pattern 32 formed on the second end 22 of the first electrode 12 along a concave arc extending toward the first end 20 of the first electrode 12. The sawtooth pattern 32 formed on the second end 22 of the first electrode 12 includes a plurality of teeth 34 extending between the sides 24, 26 of the first electrode 12. The number of teeth 34 is determined by the angle A1 of each tooth 34. As the angle A1 of each tooth 34 increases, the sawtooth pattern 32 includes fewer teeth 34. As the angle A1 of each tooth 34 decreases, the sawtooth pattern 32 includes more teeth 34. In some embodiments, the angle A1 of each tooth 34 is between 20° and 90°. In some embodiments, the angle A1 of each tooth 34 is between 30° and 60°. Each tooth 34 does not need to have the same angle A1. As such, some teeth 34 of the sawtooth pattern 32 may be narrower than other teeth 34 of the sawtooth pattern 32. However, the particular pattern formed on the second end 22 of the first electrode 12 is not limited to the sawtooth patterns 32 illustrated herein. In some embodiments, the second end 22 of the first electrode 12 may extend toward the first end 20 of the first electrode 12 and may include a curved indentation, a V-shaped indentation, or any other suitable shape formed on the second end 22 of the first electrode 12.

[0016] In some embodiments, the second electrode 14 is identical to the first electrode 12. As such, the second electrode 14 includes an inner surface 36, an outer surface 38, a first end 40, and an opposite second end 42. In some embodiments, the second electrode 14 includes a pair of opposite sides 44, 46 that extend between the first end 40 and the second end 42 and define a body 47. As shown, the body 47 of the second electrode 14 has a rectangular shape defined by the first end 40, the second end 42, and the pair of sides 44, 46. However, it should be understood that the shape of the second electrode 14 is not limited to those illustrated herein. For example, the body 47 may have a square shape, a circular shape, a star shape, or any other suitable shape.

[0017] The second electrode 14 includes a lead 48 extending outward from the first end 40 of the second electrode 14, with a terminal attached thereto for carrying charge to the second electrode 14. In some embodiments, the lead 48 extends perpendicularly from the first end 40 of the second electrode 14. The lead 48 is integrally formed with the second electrode 14 so that the second electrode 14 forms a unitary monolithic structure. The lead 48 extends from the first end 40 of the second electrode 14 at lead connection points P3 and P4, which define a width W3 of the lead 48. The second end 42 of the second electrode 14 is deformed to provide a recess 50 extending toward the first end 40 of the second electrode 14. The recess 50 has a first end T3 and a second end T4 that define a width W4 of the recess 50. The width W4 of the recess 50 is greater than the width W3 of the lead 48. In some embodiments, the recess 50 is defined by a sawtooth pattern 52 formed on the second end 42 of the second electrode 14 along a concave arc extending toward the first end 40 of the second electrode 14. The sawtooth pattern 52 formed on the second end 42 of the second electrode 14 includes a plurality of teeth 54 extending between the sides 44, 46 of the second electrode 14. The number of teeth 54 is determined by the angle A2 of each tooth 54. As the angle A2 of each tooth 54 increases, the sawtooth pattern 52 includes fewer teeth 54. As the angle A2 of each tooth 54 decreases, the sawtooth pattern 52 includes more teeth 54. In some embodiments, the angle A2 of each tooth 54 is between 20° and 90°. In some embodiments, the angle A2 of each tooth 54 is between 30° and 60°. Each tooth 54 does not need to have the same angle A2. As such, some teeth 54 of the sawtooth pattern 52 may be narrower than other teeth 54 of the sawtooth pattern 52. However, the particular pattern formed on the second end 42 of the second electrode 14 is not limited to the sawtooth pattern 52 illustrated herein. In some embodiments, the second end 42 of the second electrode 14 extends toward the first end 40 of the second electrode 14 and may include a curved indentation, a V-shaped indentation, or any other suitable shape formed on the second end 42 of the second electrode 14.

[0018] In some embodiments, the first electrode 12 and the second electrode 14 may not be identical. By way of non-limiting example, the first electrode 12 may have a rectangular shape, and the second electrode 14 may have a circular shape. Furthermore, the sawtooth patterns 32, 52 and the leads 28, 48 are not necessarily located at opposite ends of the first electrode 12 and the second electrode 14, respectively. In some embodiments, the sawtooth patterns 32, 52 may be formed on any other suitable side, edge, end, or other portion of the first electrode 12 and the second electrode 14 adjacent to the leads 28, 48 of the first electrode 12 and the second electrode 14. However, as discussed in more detail herein and shown in FIGS. 1 and 2 , in an assembled state, the sawtooth pattern 32 of the first electrode 12 is disposed over the lead 48 of the second electrode 14, and the sawtooth pattern 52 of the second electrode 14 is disposed over the lead 28 of the first electrode 12. Although both the first electrode 12 and the second electrode 14 are shown as having recesses 30, 50, embodiments are contemplated in which only one of the first electrode 12 and the second electrode 14 has a recess.

[0019] 1 and 2, the first electrode 12 and the second electrode 14 each have a rectangular shape. In a disassembled state, as shown in FIG. 1, with the inner surface 16 of the first electrode 12 facing the inner surface 36 of the second electrode 14 and the lead 28 of the first electrode 12 extending in the opposite direction from the lead 48 of the second electrode 14, the first electrode 12 and the second electrode 14 are spaced apart from each other.

[0020] 2, the first electrode 12 and the second electrode 14 are assembled and in contact with each other such that the inner surface 16 of the first electrode 12 is adjacent to the inner surface 36 of the second electrode 14. In this arrangement, the second end 42 of the second electrode 14, having the sawtooth pattern 52 formed thereon, is adjacent to the first end 20 of the first electrode 12 and the lead 28, and the second end 22 of the first electrode 12, having the sawtooth pattern 23 formed thereon, is adjacent to the first end 40 of the second electrode 14 and the lead 48. In particular, the lead 28 is located laterally between the first end T3 and the second end T4 of the recess 50, and the lead 48 is located laterally between the first end T1 and the second end T2 of the recess 30.

[0021] Without the recess 50 formed in the second end 42 of the second electrode 14, a vertical crossover would be formed between the second end 42 (shown in dashed lines) of the second electrode 14 and the lead 28 of the first electrode 12 at lead connection points P1 and P2. Similarly, without the recess 30 formed in the second end 22 of the first electrode 11, a vertical crossover would be formed between the second end 22 (shown in dashed lines) of the first electrode 12 and the lead 48 of the second electrode 14 at lead connection points P3 and P4. These potential vertical crossovers between the first electrode 12 and the second electrode 14 are susceptible to shorting or voltage breakdown when subjected to excessive voltage. By providing the sawtooth patterns 32, 52 on the first electrode 12 and the second electrode 14, respectively, these vertical crossovers are eliminated. As a result, the electrode pair 10 can withstand higher voltages without shorting or exhibiting voltage breakdown at the lead 28 of the first electrode 12 and the lead 48 of the second electrode 14. Conventional electrodes short out and exhibit voltage breakdown at approximately 8 kilovolts (kV). In some embodiments, the electrode pair 10 can withstand voltages in excess of 8 kV without shorting out. In some embodiments, the electrode pair 10 can withstand voltages of at least 9 kV without shorting out. In some embodiments, the electrode pair 10 can withstand voltages of at least 10 kV without shorting out. In use, an electrical charge is transferred to the leads 28, 48 through the associated terminals, creating an attractive force that draws the first electrode 12 and the second electrode 14 together. When the electrical charge is broken, the attractive force between the first electrode 12 and the second electrode 14 is removed. As discussed in more detail herein, the above disclosure of the first electrode 12 and the second electrode 14 including the sawtooth pattern 32, 52 covering the lead 28, 48 of the other electrode 12, 14 can be used in artificial muscles to improve the amount of voltage the artificial muscle can withstand without shorting out the electrode pair 10.

[0022] 3 and 4, an artificial muscle 100 is shown. The artificial muscle 100 includes a housing 102, an electrode pair 104 including a first electrode 106 and a second electrode 108 secured to opposing surfaces of the housing 102, a first electrical insulator layer 110 secured to the first electrode 106, and a second electrical insulator layer 112 secured to the second electrode 108. In some embodiments, the housing 102 is a unitary, monolithic layer including a pair of opposing inner surfaces, such as a first inner surface 114 and a second inner surface 116, and a pair of opposing outer surfaces, such as a first outer surface 118 and a second outer surface 120. In some embodiments, the first inner surface 114 and the second inner surface 116 of the housing 102 are at least partially heat-sealable. In other embodiments, the housing 102 may be a pair of separately manufactured film layers, such as a first film layer 122 and a second film layer 124. Thus, the first film layer 122 includes the first inner surface 114 and the first outer surface 118 , and the second film layer 124 includes the second inner surface 116 and the second outer surface 120 .

[0023] Throughout the following description, a housing 102 including a first film layer 122 and a second film layer 124 may be referred to as being a unitary housing 102. However, it should be understood that either arrangement is contemplated. In some embodiments, the first film layer 122 and the second film layer 124 generally comprise the same structure and construction. For example, in some embodiments, the first film layer 122 and the second film layer 124 each comprise biaxially oriented polypropylene.

[0024] The first electrode 106 and the second electrode 108 are each located between the first film layer 122 and the second film layer 124. In some embodiments, the first electrode 106 and the second electrode 108 are each an aluminum-coated polyester, such as Mylar®. Furthermore, one of the first electrode 106 and the second electrode 108 is a negatively charged electrode, and the other of the first electrode 106 and the second electrode 108 is a positively charged electrode. For purposes discussed herein, either of the electrodes 106, 108 can be positively charged, as long as the other electrode 106, 108 of the artificial muscle 100 is negatively charged.

[0025] The first electrode 106 has a film-facing surface 126 and an opposing inner surface 128. The first electrode 106 is positioned against the first film layer 122, specifically against the first inner surface 114 of the first film layer 122. Additionally, the first electrode 106 includes a first lead 130 that extends from the first electrode 106 beyond the edge of the first film layer 122 so that the first lead 130 can be connected to a power source to activate the first electrode 106. Specifically, as shown in FIG. 10 , the lead 130 is directly or in series connected to a power source and controller of the actuation system 400 via terminals. The lead 130 extends from the first electrode 106 at lead connection points P5 and P6, which define a width W5 of the lead 130. Similarly, the second electrode 108 has a film-facing surface 148 and an opposing inner surface 150. The second electrode 108 is positioned against the second film layer 124, and specifically against the second inner surface 116 of the second film layer 124. The second electrode 108 includes a lead 152 that extends from the second electrode 108 beyond the edge of the second film layer 124 so that the lead 152 can be connected to a power source and controller of the actuation system 400 via terminals to actuate the second electrode 108. The lead 152 extends from the second electrode 108 at lead connection points P7, P8, which define a width W7 of the lead 152.

[0026] The first electrode 106 includes two or more tab portions 132 and two or more bridge portions 140. Each bridge portion 140 is located between and interconnects adjacent tab portions 132. Each tab portion 132 has a first end 134 and extends radially from a central axis C of the first electrode 106 to a second end 136 opposite the tab portion 132, the second end 136 defining a portion of the outer periphery 138 of the first electrode 106. Similar to the first electrode 12 of the electrode pair 10 discussed herein, at least one of the tab portions 132 of the first electrode 106 includes a recess 133 formed in the second end 136 of the tab portion 132. The recess 133 has a first end T5 and a second end T6 that define a width W6 of the recess 133. The width W6 of the recess 133 is greater than the width W5 of the lead 130. In some embodiments, the recesses 133 are defined by a sawtooth pattern 137. Each bridge portion 140 has a first end 142 and extends radially from the central axis C of the first electrode 106 to an opposite second end 144 of the bridge portion 140, which defines another portion of the outer periphery 138 of the first electrode 106. Each tab portion 132 has a tab length L1, and each bridge portion 140 has a bridge length L2, where the tab length L1 and the bridge length L2 extend radially from the central axis C of the first electrode 106. The tab length L1 is the distance from the first end 134 to the second end 136 of the tab portion 132, and the bridge length L2 is the distance from the first end 142 to the second end 144 of the bridge portion 140. The tab length L1 of each tab portion 132 is longer than the bridge length L2 of each bridge portion 140. In some embodiments, the bridge length L2 is between 20% and 50% of the tab length L1, such as between 30% and 40% of the tab length L1.

[0027] In some embodiments, the two or more tab portions 132 are arranged in one or more pairs of tab portions 132. Each pair of tab portions 132 includes two tab portions 132 arranged at opposite polarities. In some embodiments, the first electrode 106 may include only two tab portions 132 located on opposite or opposite ends of the first electrode 106. In some embodiments, as shown in FIGS. 1 and 2 , the first electrode 106 includes four tab portions 132 and four bridge portions 140 connecting adjacent tab portions 132 to each other. In this embodiment, the four tab portions 132 are arranged as two pairs of tab portions 132 at opposite polarities. Furthermore, as shown, the first lead 130 extends from the second end 136 of one of the tab portions 132 and is integrally formed with the tab portion 132. As shown, the first lead 130 extends from the second end 136 of the tab portion 132 opposite the tab portion 132 having the sawtooth pattern 137 formed thereon. However, as discussed herein, the sawtooth pattern 137 may be formed on any suitable tab portion 132, such as, for example, the tab portion 132 adjacent to the tab portion 132 from which the first lead 130 extends.

[0028] Similar to the first electrode 106, the second electrode 108 includes at least one pair of tab portions 154 and two or more bridge portions 162. Each bridge portion 162 is located between and interconnects adjacent tab portions 154. Each tab portion 154 has a first end 156 and extends radially from a central axis C of the second electrode 108 to a second end 158 opposite the tab portion 154, the second end 158 defining a portion of the outer periphery 160 of the second electrode 108. Similar to the second electrode 14 of the electrode pair 10 discussed herein, at least one of the tab portions 154 of the second electrode 108 includes a recess 135 formed in the second end 158 of the tab portion 154. The recess 135 has a first end T7 and a second end T8 that define a width W8 of the recess 135. The width W8 of the recess 135 is greater than the width W7 of the lead 152. In some embodiments, the recesses 135 are defined by a sawtooth pattern 139. While both the first electrode 106 and the second electrode 108 are shown as having recesses 133, 135, embodiments are contemplated in which only one of the first electrode 106 and the second electrode 108 has a recess. Because the first electrode 106 and the second electrode 108 are coaxial with one another, the centroidal axis C of the first electrode 106 and the second electrode 108 is the same. Each bridge portion 162 has a first end 164 and extends radially from the centroidal axis C of the second electrode to an opposite second end 166 of the bridge portion 162, which defines another portion of the outer periphery 160 of the second electrode 108. Each tab portion 154 has a tab length L3, and each bridge portion 162 has a bridge length L4, where the tab length L3 and the bridge length L4 extend radially from the centroidal axis C of the second electrode 108. Tab length L3 is the distance from first end 156 to second end 158 of tab portion 154, and bridge length L4 is the distance from first end 164 to second end 166 of bridge portion 162. Tab length L3 is longer than bridge length L4 of each bridge portion 162. In some embodiments, bridge length L4 is between 20% and 50% of tab length L3, for example, between 30% and 40% of tab length L3.

[0029] In some embodiments, the two or more tab portions 154 are arranged in one or more pairs of tab portions 154. Each pair of tab portions 154 includes two tab portions 154 arranged at opposite polarities. In some embodiments, the second electrode 108 may include only two tab portions 154 located on opposite sides or both ends of the first electrode 106. In some embodiments, as shown in FIGS. 1 and 2, the second electrode 108 includes four tab portions 154 and four bridge portions 162 connecting adjacent tab portions 154. In this embodiment, the four tab portions 154 are arranged as two pairs of tab portions 154 at opposite polarities. Additionally, as shown, a second lead 152 extends from a second end 158 of one of the tab portions 154 and is integrally formed with the tab portion 154. As shown, the second lead 152 extends from the second end 158 of the tab portion 154 opposite the tab portion 154 on which the sawtooth pattern 139 is formed. However, as discussed herein, the sawtooth pattern 139 may be formed on any suitable tab portion 154, such as, for example, the tab portion 154 adjacent to the tab portion 154 from which the second lead 152 extends.

[0030] 3-8, at least one of the first electrode 106 and the second electrode 108 has a central opening. In FIGS. 3 and 4, the first electrode 106 has a central opening 146 formed therein between the first end 134 of the tab portion 132 and the first end 142 of the bridge portion 140, and the second electrode 108 has a central opening 168 formed therein between the first end 156 of the tab portion 154 and the first end 164 of the bridge portion 162. However, it should be understood that if the central opening 168 is also provided in the second electrode 108, as shown in FIGS. 5 and 6, then the first electrode 106 need not include the central opening 146. Alternatively, if the central opening 146 is also provided in the first electrode 106, then the second electrode 108 need not include the central opening 168.

[0031] 2-8 , the first and second electrical insulator layers 110, 112 have shapes that generally correspond to the first and second electrodes 106, 108, respectively. As such, the first and second electrical insulator layers 110, 112 have tab portions 170, 172 and bridge portions 174, 176 that correspond to similar portions on the first and second electrodes 106, 108, respectively. Furthermore, when positioned on the first and second electrodes 106, 108, the first and second electrical insulator layers 110, 112 have perimeters 178, 180 that correspond to the perimeter 138 of the first electrode 106 and the perimeter 160 of the second electrode 108, respectively. Because first electrical insulator layer 110 has a shape corresponding to first electrode 106, a recess defined by sawtooth pattern 141 is formed on one outer periphery 178 of tab portion 170 of first electrical insulator layer 110, which corresponds to sawtooth pattern 137 formed on first electrode 106. Similarly, because second electrical insulator layer 112 has a shape corresponding to second electrode 108, a recess defined by sawtooth pattern 143 is formed on one outer periphery 180 of tab portion 172 of second electrical insulator layer 112, which corresponds to sawtooth pattern 139 formed on second electrode 108. As described herein, the structure and characteristics of sawtooth patterns 32, 52 of electrode pair 10 can be similarly applied to each of sawtooth patterns 137, 139, 141, 143 of artificial muscle 100.

[0032] It should be understood that in some embodiments, the first electrical insulator layer 110 and the second electrical insulator layer 112 generally comprise the same structure and configuration. As such, in some embodiments, the first electrical insulator layer 110 and the second electrical insulator layer 112 each comprise adhesive surfaces 182, 184 and opposing non-sealable surfaces 186, 188. Thus, in some embodiments, the first electrical insulator layer 110 and the second electrical insulator layer 112 are adhered to the inner surface 128 of the first electrode 106 and the inner surface 150 of the second electrode 108, respectively, with polymer tape.

[0033] 4-8 , the artificial muscle 100 is shown in an assembled state with the first lead 130 of the first electrode 106 and the second lead 152 of the second electrode 108 extending beyond the periphery of the housing 102, i.e., beyond the first film layer 122 and the second film layer 124. As shown in FIG. 4 , the second electrode 108 is stacked on top of the first electrode 106; therefore, the first electrode 106 and the second electrical insulator layer 112 are not shown. Only a portion of the first electrical insulator layer 110 is shown proximate the first lead 130 extending from the first electrode 106. Furthermore, the first lead 130 is located laterally between the first end T7 and the second end T8 of the recess 135 of the second electrode 108. Similarly, although not shown, the second lead 152 is located laterally between the first end T5 and the second end T6 of the recess 133 of the first electrode 108. In an assembled state, the first electrode 106, the second electrode 108, the first electrical insulator layer 110, and the second electrical insulator layer 112 are sandwiched between the first film layer 122 and the second film layer 124. The first film layer 122 is partially sealed to the second film layer 124 in an area surrounding the perimeter 138 of the first electrode 106 and the perimeter 160 of the second electrode 108. In some embodiments, the first film layer 122 is partially sealed to the second film layer 124. In particular, in some embodiments, the first film layer 122 is sealed to the second film layer 124 to define a seal 190 surrounding the first electrode 106 and the second electrode 108. The first film layer 122 and the second film layer 124 may be sealed in any suitable manner, for example, using an adhesive, heat sealing, or the like.

[0034] The first electrode 106, the second electrode 108, the first electrical insulator layer 110, and the second electrical insulator layer 112 provide a barrier that prevents the first film layer 122 from being completely sealed to the second film layer 124, thereby forming an unsealed portion 192. The unsealed portion 192 of the housing 102 includes an electrode region 194 where the electrode pair 104 is provided and an expandable fluid region 196 surrounded by the electrode region 194. The central openings 146, 168 of the first electrode 106 and the second electrode 108 form the expandable fluid region 196 and are arranged to stack axially on top of each other to define the expandable fluid region 196. Although not shown, the housing 102 may be cut to match the shape of the electrode pair 104, thereby reducing the size of the artificial muscle 100, i.e., the size of the sealed portion 190.

[0035] Dielectric fluid 198 is disposed within unsealed portion 192 and flows freely between first electrode 106 and second electrode 108. As used herein, a "dielectric" fluid is a medium or material that transmits electrical power without conducting and therefore has low electrical conductivity. Non-limiting examples of dielectric fluids include perfluoroalkanes, transformer oil, and deionized water. It should be understood that dielectric fluid 198 may be injected into unsealed portion 192 of artificial muscle 100 using a needle or other suitable injection device.

[0036] 5 and 6, the artificial muscle 100 is actuable between an unactuated state and an actuated state. In the unactuated state, as shown in FIG. 5, the first electrode 106 and the second electrode 108 are partially spaced apart from each other near their central openings 146, 168 and the first ends 134, 156 of the tab portions 132, 154. The second ends 136, 158 of the tab portions 132, 154 remain in position relative to each other due to the housing 102 being sealed at the periphery 138 of the first electrode 106 and the periphery 160 of the second electrode 108. As such, the sawtooth pattern 137 of the first electrode 106 and the sawtooth pattern 141 of the first electrical insulator layer 112 are disposed adjacent to the periphery 160 of the second electrode 108 and the second lead 152. Similarly, the sawtooth pattern 139 of the second electrode 108 and the sawtooth pattern 143 of the second electrical insulator layer 112 are disposed adjacent to the periphery 138 of the first electrode 106 and the first lead 130. In an actuated state, as shown in FIG. 6 , the first electrode 106 and the second electrode 108 are in contact with each other and oriented parallel to each other, forcing the dielectric fluid 198 into the expandable fluid region 196. This allows the dielectric fluid 198 to flow through the central openings 146, 168 of the first electrode 106 and the second electrode 108, expanding the expandable fluid region 196.

[0037] Referring now to FIG. 5 , the artificial muscle 100 is shown in an unactuated state. The electrode pair 104 is disposed within an electrode region 194 of an unsealed portion 192 of the housing 102. The central opening 146 of the first electrode 106 and the central opening 168 of the second electrode 108 are coaxially aligned within an expandable fluid region 196. In the unactuated state, the first electrode 106 and the second electrode 108 are partially spaced apart and nonparallel to each other. Due to the first film layer 122 being sealed to the second film layer 124 around the electrode pair 104, the second ends 136, 158 of the tab portions 132, 154 contact each other. Thus, a dielectric fluid 198 is disposed between the first electrode 106 and the second electrode 108, thereby separating the first ends 134, 156 of the tab portions 132, 154 in proximity to the expandable fluid region 196. In other words, the distance between the first end 134 of the tab portion 132 of the first electrode 106 and the first end 156 of the tab portion 154 of the second electrode 108 is greater than the distance between the second end 136 of the tab portion 132 of the first electrode 106 and the second end 158 of the tab portion 154 of the second electrode 108. This causes the electrode pair 104 to zipper against the expandable fluid region 196 upon activation. In some embodiments, the first electrode 106 and the second electrode 108 may be flexible. Thus, as shown in FIG. 5 , the first electrode 106 and the second electrode 108 are convex relative to one another such that the second ends 136, 158 of their tab portions 132, 154 may remain close to one another but be spaced apart near the central openings 146, 168. In the unactuated state, the expandable fluid region 196 has a first height H1.

[0038] Upon activation, as shown in FIG. 6 , the first electrode 106 and the second electrode 108 pinch toward each other at the second ends 144, 158 of their tab portions 132, 154, thereby forcing the dielectric fluid 198 into the inflatable fluid region 196. As shown, in the actuated state, the first electrode 106 and the second electrode 108 are parallel to each other. In the actuated state, the dielectric fluid 198 flows into the inflatable fluid region 196, inflating it. As a result, the first film layer 122 and the second film layer 124 expand in opposite directions. In the actuated state, the inflatable fluid region 196 has a second height H2 that is greater than the first height H1 of the inflatable fluid region 196 in the unactuated state. It should be noted that, although not shown, the electrode pair 104 may be partially actuated to a position between the unactuated and actuated states. This would allow for partial inflation and adjustment of the inflatable fluid region 196 as needed.

[0039] A voltage is applied by a power supply to move the first electrode 106 and the second electrode 108 toward each other. In some embodiments, the power supply may provide a voltage of up to 10 kV, generating an electric field within the dielectric fluid 198. The resulting attractive force between the first electrode 106 and the second electrode 108 forces the dielectric fluid 198 toward the expandable fluid region 196. Pressure from the dielectric fluid 198 within the expandable fluid region 196 causes the first film layer 122 and the first electrical insulator layer 110 to deform in a first axial direction along the central axis C of the first electrode 106 and the second film layer 124 and the second electrical insulator layer 112 to deform in an opposite second axial direction along the central axis C of the second electrode 108. Once the voltage supplied to the first electrode 106 and the second electrode 108 is removed, the first electrode 106 and the second electrode 108 return to their initial non-parallel position in the unactuated state.

[0040] It should be appreciated that the present embodiments disclosed herein, particularly the tab portions 132, 154 having sawtooth patterns 137, 139 formed therein, offer numerous improvements over actuators, such as HASEL actuators, that do not include tab portions 132, 154 having sawtooth patterns 137, 139. Embodiments of the artificial muscle 100 that include two pairs of tab portions 132, 154 on each of the first electrode 106 and the second electrode 108, reduce the overall mass and thickness of the artificial muscle 100 without reducing the amount of resulting force after actuation, reduce the amount of voltage required during actuation, and reduce the overall volume of the artificial muscle 100, compared to known HASEL actuators that include doughnut-shaped electrodes with uniform, radially extending widths. More specifically, the tab portions 132, 154 of the artificial muscle 100 provide a tightened front surface that provides localized and uniform hydraulic actuation of the artificial muscle 100, thereby increasing actuation power, compared to HASEL actuators that include doughnut-shaped electrodes. Notably, compared to a donut-shaped HASEL actuator, a single pair of tab portions 132, 154 provides twice the actuator power per unit volume, while two pairs of tab portions 132, 154 provide four times the actuator power per unit volume. The bridge portions 174, 176 interconnecting the tab portions 132, 154 also limit buckling of the tab portions 132, 154 by maintaining a distance between adjacent tab portions 132, 154 during actuation. Because the bridge portions 174, 176 are integrally formed with the tab portions 132, 154, they also prevent leakage between the tab portions 132, 154 by eliminating attachment points that increase the risk of fracture. Moreover, as discussed herein, the sawtooth patterns 137, 139 eliminate perpendicular intersection points between the tab portions 132, 154 and the leads 130, 152. This allows the artificial muscle 100 to sustain higher voltages while reducing the risk of short circuits and voltage breakdown.

[0041] In operation, when the artificial muscle 100 is actuated, the expandable fluid region 196 expands to, for example, one cubic centimeter (cm) of the actuator volume. 3 ) or more than 3 Newton millimeters (N.mm) per 1 cm of actuator volume3 4N.mm or more per 1cm of actuator volume 3 5N.mm or more per 1cm of actuator volume 3 6N.mm or more per 1cm of actuator volume 3 7N.mm or more per 1cm of actuator volume 3 8N.mm or more per 1cm of actuator volume 3 9N.mm or more per 1cm of actuator volume 3 10N.mm or more per 1cm of actuator volume 3 11 N.mm or more per cm of actuator volume 3 In one example, when the artificial muscle 100 is actuated with a voltage of 9.5 kilovolts (kV), the artificial muscle 100 provides a resulting force of 5 N. In another example, when the artificial muscle 100 is actuated with a voltage of 10 kV, the artificial muscle 100 provides a 440% tension under a load of 500 grams.

[0042] Furthermore, the size of the first electrode 106 and the second electrode 108 is proportional to the amount of displacement of the dielectric fluid 198. Thus, if a large displacement within the expandable fluid region 196 is desired, the size of the electrode pair 104 is increased relative to the size of the expandable fluid region 196. It should be understood that the size of the expandable fluid region 196 is defined by the central openings 146, 168 of the first electrode 106 and the second electrode 108. Thus, alternatively or additionally, the degree of displacement within the expandable fluid region 196 may be controlled by increasing or decreasing the size of the central openings 146, 168.

[0043] As shown in Figures 7 and 8, another embodiment of an artificial muscle 200 is illustrated. The artificial muscle 200 is substantially similar to the artificial muscle 100. As such, like structures are indicated with like reference numerals. However, as shown, the first electrode 106 does not include a central opening 146. Thus, only the second electrode 108 includes a central opening 168 formed therein. As shown in Figure 7, the artificial muscle 200 is in an unactuated state in which the first electrode 106 is planar and the second electrode 108 is convex relative to the first electrode 106. In the unactuated state, the expandable fluid region 196 has a first height H3. In the actuated state, as shown in Figure 8, the expandable fluid region 196 has a second height H4 that is greater than the first height H3. It should be understood that by providing the central opening 168 only in the second electrode 108, as opposed to both the first electrode 106 and the second electrode 108, an entire deformation may be formed on one side of the artificial muscle 200. Furthermore, because the entire deformation is formed on only one side of the artificial muscle 200, the second height H4 of the expandable fluid region 196 of the artificial muscle 200 extends further from the longitudinal axis perpendicular to the central axis C of the artificial muscle 200 than the second height H2 of the expandable fluid region 196 of the artificial muscle 100, all other dimensions, orientation, and volume of the dielectric fluid being the same.

[0044] Referring now to FIG. 9 , an artificial muscle assembly 300 is shown including multiple artificial muscles, such as multiple artificial muscles 100. However, it should be understood that multiple artificial muscles 200 may similarly be arranged in a stacked configuration. Each artificial muscle 100 may be identical in structure and arranged in a stack, such that the expandable fluid region 196 of each artificial muscle 100 covers the expandable fluid region 196 of an adjacent artificial muscle 100. The leads 130, 152 of each artificial muscle 100 are electrically connected to each other so that the artificial muscles 100 can simultaneously actuate between an unactuated state and an actuated state. By arranging the artificial muscles 100 in a stacked configuration, the overall deformation of the artificial muscle assembly 300 is the sum of the deformation within the expandable fluid region 196 of each artificial muscle 100. Therefore, the degree of deformation resulting from the artificial muscle assembly 300 is greater than the degree of deformation that would be caused by the artificial muscles 100 alone.

[0045] 10 , an actuation system 400 may be provided to operate an electrode pair, artificial muscle, or artificial muscle assembly, such as electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300, between an unactuated state and an actuated state. As such, actuation system 400 may include a controller 402, an actuation device 404, a power source 406, and a communication path 408. The various components of actuation system 400 will now be described.

[0046] The controller 402 includes a processor 410 and non-transitory electronic memory 412, with various components communicatively coupled. In some embodiments, the processor 410 and non-transitory electronic memory 412, and / or other components are contained within a single device. In other embodiments, the processor 410 and non-transitory electronic memory 412, and / or other components may be distributed among multiple communicatively coupled devices. The controller 402 includes a non-transitory electronic memory 412 that stores a set of machine-readable instructions. The processor 410 executes the machine-readable instructions stored in the non-transitory electronic memory 412. The non-transitory electronic memory 412 may comprise RAM, ROM, flash memory, a hard drive, or any device capable of storing machine-readable instructions such that the machine-readable instructions are accessible by the processor 410. Consequently, the operating system 400 described herein may be implemented in any conventional computer programming language as a pre-programmed hardware element or as a combination of hardware and software components. The non-transitory electronic memory 412 may be implemented as a single memory module or as multiple memory modules.

[0047] In some embodiments, non-transitory electronic memory 412 includes instructions for carrying out the functions of actuation system 400. The instructions may include instructions for operating electrode pairs 10, artificial muscles 100, 200, or artificial muscle assemblies 300 based on user commands.

[0048] The processor 410 may be any device capable of executing machine-readable instructions. For example, the processor 410 may be an integrated circuit, a microchip, a computer, or other computing device. The non-transitory electronic memory 412 and the processor 410 are coupled to a communication path 408, which provides signal interconnectivity between the various components and / or modules of the operating system 400. As a result, the communication path 408 may communicatively couple several processors to each other, allowing the modules coupled to the communication path 408 to operate in a distributed computing environment. In particular, each module may operate as a node that may transmit and / or receive data. As used herein, the term "communicatively coupled" means that the coupled components can exchange data signals with each other, such as, for example, electrical signals through a conductive medium, electromagnetic signals through the air, optical signals through an optical waveguide, etc.

[0049] 10, a communication path 408 communicatively couples a processor 410 and non-transitory electronic memory 412 of the controller 402 to several other components of the actuation system 400. For example, the actuation system 400 shown in FIG. 10 includes a processor 410 and non-transitory electronic memory 412 communicatively coupled to an operating device 404 and a power source 406.

[0050] The actuation device 404 allows a user to control the operation of the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300. In some embodiments, the actuation device 404 may be a switch, a toggle, a button, or any combination of controls that result in user action. As a non-limiting example, by activating the control of the actuation device 404 to a first position, a user may actuate the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300 to an activated state. While in the first position, the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300 will remain in an activated state. By operating the control of the actuation device 404 from the first position to a second position, a user may switch the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300 to an inactivated state.

[0051] The operating device 404 is coupled to a communication path 408 such that the communication path 408 communicatively couples the operating device 404 to other modules in the actuation system 400. The operating device 404 may provide a user interface for receiving user commands according to a particular operating configuration of the electrode pair 10, the artificial muscle 100, 200, or the artificial muscle assembly 300. Additionally, the user commands may include commands to operate the electrode pair 10, the artificial muscle 100, 200, or the artificial muscle assembly 300 only under certain conditions.

[0052] A power source 406 (e.g., a battery) provides power to the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300. In some embodiments, the power source 406 is a rechargeable DC power source. It should be understood that the power source 406 may be a single power source or a battery for providing power to the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300. A power adapter (not shown) may be provided and electrically coupled via a wire harness or the like to provide power to the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300 via the power source 406.

[0053] In some embodiments, the actuation system 400 also includes a display device 414. The display device 414 is coupled to the communication path 408 such that the communication path 408 communicatively couples the display device 414 to other modules in the actuation system 400. The display device 414 may output a notification in response to an indication of an actuation state of the electrode pair 10, the artificial muscle 100, 200, or the artificial muscle assembly 300, or a change in the actuation state of the electrode pair 10, the artificial muscle 100, 200, or the artificial muscle assembly 300. Furthermore, in addition to providing optical information, the display device 414 may be a touchscreen that detects the presence and location of tactile input on a surface of or adjacent to the display device 414. As a result, the display device 414 may include the actuation device 404 and receive mechanical input directly on the optical output provided to the display device 414.

[0054] In some embodiments, the actuation system 400 includes network interface hardware 416 for communicatively coupling the actuation system 400 to a mobile device 418 over a network 420. The mobile device 418 may include, but is not limited to, a smartphone, a tablet, a personal media player, or other electrical device including wireless communication functionality. It should be understood that the mobile device 418, if provided, may serve to provide user commands to the controller 402 instead of the actuation device 404. As such, a user could control or set a program for controlling the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300 without using control of the actuation device 404. As such, the electrode pair 10, artificial muscle 100, 200, or artificial muscle assembly 300 may be remotely controlled via the mobile device 418, which communicates wirelessly with the controller 402 over the network 420.

[0055] By now it should be appreciated that artificial muscles are defined herein for expanding or deforming the surface of an object by selectively activating the artificial muscle to raise or lower areas thereof, thereby providing a low-profile expansion member that can be actuated on demand.

[0056] It should be noted that the terms "substantially" and "about" may be used herein to express the inherent degree of uncertainty that may result from any quantitative comparison, value, measurement, or other representation. These terms are also used herein to express the extent to which a quantitative representation may vary from the stated basis without resulting in a change in the basic functionality of the subject matter in question.

[0057] While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be used in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter. The invention disclosed in this specification includes the following aspects. [Aspect 1] an electrode pair comprising a first electrode and a second electrode, each having an outer surface, an inner surface, a first end, a second end, and a lead extending outwardly from the first end; the lead has a first width at the first end, the second end of at least one of the first electrode and the second electrode has a recess formed in the second end and having a first end and a second end, a second width extending between the first end and the second end of the recess, the recess being defined by a sawtooth pattern, the second width being greater than the first width; When the first electrode is located above the second electrode, the recess of at least one of the first electrode and the second electrode is adjacent to the lead of the other electrode. Electrode pair. [Aspect 2] The electrode pair of aspect 1, wherein the first electrode and the second electrode each have a recess formed in the second end of the first electrode and the second electrode, and when the first electrode is positioned above the second electrode, the lead of the first electrode is positioned laterally between the first end and the second end of the recess of the second electrode, and the lead of the second electrode is positioned laterally between the first end and the second end of the recess of the first electrode. Aspect 3 The electrode pair of aspect 1, wherein the first electrode and the second electrode each have a body defined by the first end, the second end, a first side, and an opposite second side, the first side and the second side extending between the first end and the second end, and the lead extending perpendicularly from the body. Aspect 4 The electrode pair of aspect 3, wherein the bodies of the first electrode and the second electrode are rectangular so that the first end of each of the first electrode and the second electrode faces the second end of each of the first electrode and the second electrode. Aspect 5 2. The electrode pair of embodiment 1, wherein the sawtooth pattern of the recess comprises a plurality of teeth. Aspect 6 6. The electrode pair of embodiment 5, wherein the angle between adjacent teeth of the sawtooth pattern is 10° to 100°. Aspect 7 7. The electrode pair of embodiment 6, wherein the angle between adjacent teeth of the sawtooth pattern is between 30° and 60°. Aspect 8 2. The electrode pair of embodiment 1, wherein the sawtooth pattern extends along a concave arc. Aspect 9 a housing having an electrode region and an expandable fluid region; an electrode pair located in the electrode region of the housing, the electrode pair including a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing; a dielectric fluid contained in the housing, the first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end, the lead having a first width at the first end; the second end of at least one of the first electrode and the second electrode has a recess formed in the second end, the recess having a first end and a second end, a second width extending between the first end and the second end of the recess, the recess being defined by a sawtooth pattern, the second width being greater than the first width; At least one of the first electrode and the second electrode includes a central opening surrounding the expandable fluid region; When the first electrode is located above the second electrode, the recess of at least one of the first electrode and the second electrode is adjacent to the lead of the other electrode; the electrode pair is actuable between an unactuated state and an actuated state such that actuation from the unactuated state to the actuated state moves the dielectric fluid into the expandable fluid region. Artificial muscles. Aspect 10 10. The artificial muscle of claim 9, wherein the first electrode and the second electrode each include at least two tab portions and at least two bridge portions, the at least two tab portions defined by the first end and the second end, and each of the at least two bridge portions interconnecting adjacent tab portions. Aspect 11 11. The artificial muscle of claim 10, wherein the sawtooth pattern is formed on a first tab portion of the at least two tab portions of each of the first electrode and the second electrode, the lead extends perpendicularly from a second tab portion of the at least two tab portions of each of the first electrode and the second electrode, and the first tab portion faces the second tab portion. Aspect 12 10. The artificial muscle of embodiment 9, wherein the sawtooth pattern comprises a plurality of teeth. Aspect 13 Aspect 13. The artificial muscle according to aspect 12, wherein the angle between adjacent teeth of the sawtooth pattern is 30° to 60°. Aspect 14 10. The artificial muscle of embodiment 9, wherein the sawtooth pattern extends along a concave arc. Aspect 15 when the electrode pair is in the unactuated state, the first electrode and the second electrode are non-parallel to each other; when the electrode pair is in the actuated state, the first electrode and the second electrode are parallel to one another such that the first electrode and the second electrode are configured to tighten toward one another and toward the central opening when actuated from the unactuated state to the actuated state. 10. The artificial muscle of embodiment 9. Aspect 16 1. A method of actuating an artificial muscle, the method comprising: generating a voltage using a power source electrically coupled to an electrode pair of the artificial muscle; the artificial muscle comprises: a housing having an electrode region and an expandable fluid region; an electrode pair located in the electrode region of the housing, the electrode pair including a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing; and a dielectric fluid contained within the housing; the first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end, the lead having a first width at the first end, the second end of at least one of the first electrode and the second electrode having a recess formed in the second end and having a first end and a second end, a second width extending between the first end and the second end of the recess, the recess being defined by a sawtooth pattern, the second width being greater than the first width, the first electrode can be positioned over the second electrode such that the recess of at least one of the first electrode and the second electrode is adjacent the lead of the other electrode, and at least one of the first electrode and the second electrode includes a central opening surrounding the expandable fluid region; actuating the electrode pair from an unactuated state to an actuated state so as to apply the voltage to the electrode pair of the artificial muscle, thereby moving the dielectric fluid into the expandable fluid region of the housing and expanding the expandable fluid region; A method comprising: Aspect 17 The method of claim 16, wherein the housing comprises a first film layer and a second film layer, the first film layer and the second film layer being partially heat-sealed to each other to define a sealed portion of the housing, the housing further comprising a non-sealed portion surrounded by the sealed portion, and the electrode region and the expandable fluid region of the housing being disposed in the non-sealed portion. Aspect 18 17. The method of claim 16, wherein a controller is communicatively coupled to the electrode pair, the controller transferring the voltage from the power source across the first electrode and the second electrode to actuate the artificial muscle from the unactuated state to the actuated state. Aspect 19 17. The method of claim 16, wherein the sawtooth pattern comprises a plurality of teeth extending along a concave arc, and an angle between adjacent teeth of the sawtooth pattern is between 30° and 60°. [Aspect 20 〕 17. The method of claim 16, wherein the voltage applied to the artificial muscle is greater than 9 kV.

Claims

1. an electrode pair comprising a first electrode and a second electrode, each having an outer surface, an inner surface, a first end, a second end, and a lead extending outwardly from the first end; the lead has a first width at the first end; the second end of each of the first electrode and the second electrode has a recess formed therein and having a first end and a second end; a second width extending between the first end and the second end of the recess; the recesses are defined by a sawtooth pattern; the second width is greater than the first width; When the first electrode is located above the second electrode, the recesses of the first electrode and the second electrode are adjacent to the lead of the other electrode; the lead of the first electrode is located laterally between the first end and the second end of the recess of the second electrode; the lead of the second electrode is located laterally between the first end and the second end of the recess of the first electrode; Electrode pair.

2. 2. The electrode pair of claim 1, wherein the first electrode and the second electrode each have a body defined by the first end, the second end, a first side, and an opposite second side, the first side and the second side extending between the first end and the second end, and the lead extending perpendicularly from the body.

3. 3. The electrode pair of claim 2, wherein the bodies of the first electrode and the second electrode are rectangular such that the first end of each of the first electrode and the second electrode faces the second end of each of the first electrode and the second electrode.

4. The electrode pair of claim 1 , wherein the sawtooth pattern of the recess comprises a plurality of teeth.

5. The electrode pair of claim 4 , wherein the angle between adjacent teeth of the sawtooth pattern is between 20° and 90°.

6. The electrode pair of claim 5, wherein the angle between adjacent teeth of the sawtooth pattern is between 30° and 60°.

7. The electrode pair of claim 1 , wherein the sawtooth pattern extends along a concave arc.

8. a housing having an electrode region and an expandable fluid region; an electrode pair located in the electrode region of the housing, the electrode pair including a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing; a dielectric fluid contained in the housing, the first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end, the lead having a first width at the first end; the second end of at least one of the first electrode and the second electrode has a recess formed in the second end, the recess having a first end and a second end, a second width extending between the first end and the second end of the recess, the recess being defined by a sawtooth pattern, the second width being greater than the first width; At least one of the first electrode and the second electrode includes a central opening surrounding the expandable fluid region; When the first electrode is located above the second electrode, the recess of at least one of the first electrode and the second electrode is adjacent to the lead of the other electrode; the electrode pair is actuable between an unactuated state and an actuated state such that actuation from the unactuated state to the actuated state moves the dielectric fluid into the expandable fluid region. Artificial muscles.

9. 9. The artificial muscle of claim 8, wherein the first electrode and the second electrode each include at least two tab portions and at least two bridge portions, the at least two tab portions defined by the first end and the second end, and each of the at least two bridge portions interconnecting adjacent tab portions.

10. 10. The artificial muscle of claim 9, wherein the sawtooth pattern is formed on a first of the at least two tab portions of each of the first electrode and the second electrode, the lead extends perpendicularly from a second of the at least two tab portions of each of the first electrode and the second electrode, and the first tab portion faces the second tab portion.

11. 9. The artificial muscle of claim 8, wherein the sawtooth pattern comprises a plurality of teeth.

12. 12. The artificial muscle of claim 11, wherein the angle between adjacent teeth of the sawtooth pattern is between 30° and 60°.

13. The artificial muscle of claim 8 , wherein the sawtooth pattern extends along a concave arc.

14. when the electrode pair is in the unactuated state, the first electrode and the second electrode are non-parallel to each other; when the electrode pair is in the actuated state, the first electrode and the second electrode are parallel to one another such that the first electrode and the second electrode are configured to tighten toward one another and toward the central opening when actuated from the unactuated state to the actuated state. The artificial muscle according to claim 8.

15. 1. A method of actuating an artificial muscle, the method comprising: generating a voltage using a power source electrically coupled to an electrode pair of the artificial muscle; The artificial muscle comprises: a housing having an electrode region and an expandable fluid region; an electrode pair located in the electrode region of the housing, the electrode pair including a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing; and a dielectric fluid contained within the housing; the first electrode and the second electrode each have an outer surface, an inner surface, a first end, a second end, and a lead extending outward from the first end, the lead having a first width at the first end, the second end of at least one of the first electrode and the second electrode having a recess formed in the second end and having a first end and a second end, a second width extending between the first end and the second end of the recess, the recess being defined by a sawtooth pattern, the second width being greater than the first width, the first electrode can be positioned over the second electrode such that the recess of at least one of the first electrode and the second electrode is adjacent the lead of the other electrode, and at least one of the first electrode and the second electrode includes a central opening surrounding the expandable fluid region; actuating the electrode pair from an unactuated state to an actuated state so as to apply the voltage to the electrode pair of the artificial muscle, thereby moving the dielectric fluid into the expandable fluid region of the housing and expanding the expandable fluid region; A method comprising:

16. 16. The method of claim 15, wherein the housing comprises a first film layer and a second film layer, the first film layer and the second film layer being partially heat-sealed to one another to define a sealed portion of the housing, the housing further comprising a non-sealed portion surrounded by the sealed portion, the electrode region and the expandable fluid region of the housing being disposed in the non-sealed portion.

17. 16. The method of claim 15, wherein a controller is communicatively coupled to the electrode pair, the controller transferring the voltage from the power source across the first electrode and the second electrode to actuate the artificial muscle from the unactuated state to the actuated state.

18. 16. The method of claim 15, wherein the sawtooth pattern comprises a plurality of teeth extending along a concave arc, and the angle between adjacent teeth of the sawtooth pattern is between 30° and 60°.

19. 16. The method of claim 15, wherein the voltage applied to the artificial muscle is greater than 9 kV.

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