Joint mechanism

Abstract

To provide a joint mechanism which can easily restrict rotation of arm members.SOLUTION: A joint mechanism includes a flexible electrode 10 having flexibility, a base electrode 20 having an opposite surface 23 to the flexible electrode 10 formed on an insulation layer 22, a power source 71 for applying a voltage between the flexible electrode 10 and the base electrode 20, and switching switches 81A to 81D for switching application and release of application of a voltage between the electrodes by the power source 71. The base electrode 20 is composed of an arm 20A to which first and second arm members 21A and 21B are rotatably connected. The flexible electrode 10 is arranged astride the first and second connected arm members 21A and 21B in a longitudinal direction of an arm 20A, and the flexible electrode 10 is adsorbed to the arm 20A by application of the voltage between the electrodes.SELECTED DRAWING: Figure 2A

Description

[Technical field]

[0001] The present invention relates to a joint mechanism including an arm in which a plurality of arm members are rotatably connected. [Background technology]

[0002] As an example of this type of technology, Patent Document 1 discloses a joint mechanism equipped with an arm in which multiple links (arm members) are connected. This joint mechanism is equipped with a motor that collectively rotates the connected arm members, and the rotation range of each arm member is restricted by controlling the motor that drives the arm member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-089736 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the joint mechanism disclosed in Patent Document 1, the rotation of the two connected arm members is limited by controlling the torque of the motor, which requires the provision of a motor and its control device, resulting in a complex device configuration.

[0005] The present invention has been made in view of the above, and an object of the present invention is to provide a joint mechanism that can more easily limit the rotation of arm members relative to each other. [Means for solving the problem]

[0006] In consideration of the above problems, the joint mechanism of the present invention comprises a flexible electrode having flexibility, a base electrode whose opposing surface to the flexible electrode is formed of an insulating layer, a power source that applies a voltage between the flexible electrode and the base electrode, and a change-over switch that switches between application and release of voltage between the electrodes by the power source, wherein the base electrode comprises an arm having a plurality of arm members connected so as to be freely rotatable, the flexible electrode is arranged along the longitudinal direction of the arm so as to straddle the connected arm members, and the flexible electrode is attracted to the arm when a voltage is applied between the electrodes.

[0007] According to the present invention, when a voltage is applied between the electrodes by the changeover switch, a voltage is applied between the flexible electrode and the base electrode (arm), and the flexible electrode is attracted to the arm by Coulomb force. Since the flexible electrode is arranged to straddle the arm members, the rotational resistance between the rotatably connected arm members is increased. On the other hand, when the application of the voltage between the electrodes is released by the changeover switch, the restriction on the rotation of the arm members is released. As a result, the restriction on the rotation of the arm members can be achieved with a simpler structure. In this specification, "restriction on the rotation of the arm members" refers to making it difficult to rotate the arm members relative to each other, and increasing the rotational resistance between the arm members relative to each other.

[0008] Here, the switching operation using the change-over switch may be performed manually, for example, but in a more preferred embodiment, the joint mechanism is provided with a control device that controls the switching of the change-over switch when the arm member is in a specific posture after rotation of the arm, or when the arm member is in a specific rotational motion.

[0009] According to this aspect, in a specific posture of the arm after the arm member has rotated or in a specific rotational motion of the arm member (specific motion of the arm), the control device controls the switching of the change-over switch to apply and release the voltage between the electrodes, thereby making it possible to change the rotation resistance for rotating the arm members relative to each other in a specific posture of the arm or in a specific motion of the arm.

[0010] For example, a voltage may be applied between the electrodes after the arm members have reached a specific rotation angle (i.e., after the arms have reached a specific bent position), and the application of the voltage may be continued at a rotation angle greater than this to increase the rotation resistance between the arm members when the arm members attempt to rotate further. In addition, when the arm attempts to bend further, the application of the voltage between the electrodes may be continued, and when the bent arm moves in the direction of extension (i.e., a rotational movement in which the rotation angle of the arm members decreases), the application of the voltage between the electrodes may be released to reduce the rotation resistance between the arm members. Note that in this specification, the "rotation angle" refers to an angle in which the arm members rotate in the direction in which the arms bend from their extended state, with the positive angle being the angle at which the arm members rotate.

[0011] In a further preferred embodiment, the joint mechanism further includes a voltage regulator for adjusting the magnitude of the voltage applied between the electrodes. This voltage regulator may be provided, for example, in the form of a variable resistor, inside the power source, or between the power source and the flexible electrode, or between the power source and the base electrode. By adjusting the magnitude of the voltage applied between the electrodes, the magnitude of the Coulomb force generated between the insulating layer and the flexible electrode can be adjusted, and as a result, the rotation resistance between the arm members can be adjusted.

[0012] In a further preferred embodiment, the flexible electrode is arranged such that, in a rotational direction in which the arm members rotate relative to each other so as to bend the arms, the outer surface in the rotational direction of the arms serves as the opposing surface, and one of the two ends of the flexible electrode along the longitudinal direction is fixed to the arm, and the other of the two ends protrudes beyond the end of the arm along the longitudinal direction within the range in which the multiple arm members rotate.

[0013] According to this embodiment, the flexible electrode protrudes from the end of the arm, and when a voltage is applied between the electrodes and the arm members are rotated so as to bend the arm, the contact area of ​​the flexible electrode with the arm (base electrode) increases, and the charge accumulated between the electrodes increases. As a result, as the arm members are rotated so as to bend the arm more, the rotation resistance between the arm members can be increased.

[0014] In a further preferred embodiment, there are two arm members, the joint mechanism further includes a calculation device, which estimates the amount of charge accumulated between the electrodes while a voltage is applied between the electrodes by the change-over switch, and estimates the rotation angle of the arm member based on the estimated amount of charge.

[0015] According to this aspect, as described above, when the arm members are rotated so as to bend the arm, the contact area of ​​the flexible electrode with the arm (base electrode) increases, and the charge accumulated between the electrodes increases, so that the posture of the arm can be easily estimated based on the amount of charge. Here, the posture of the arm refers to the degree of bending of the arm, and particularly when the multiple arm members are two arm members, that is, when the arm is composed of two arm members, the rotation angle of the two arm members can be accurately estimated. Effect of the Invention

[0016] According to the present invention, the rotation of the arm members relative to each other can be more easily restricted. [Brief description of the drawings]

[0017] [Figure 1A] 1 is a perspective view of a main part of a joint mechanism according to a first embodiment of the present invention; [Figure 1B] 1B is a perspective view of a main part of the joint mechanism shown in FIG. 1A in a bent state. FIG. [Figure 2A] 1B is a schematic diagram of the joint mechanism shown in FIG. 1A in a state where an arm is extended. FIG. [Figure 2B] 2B is a schematic diagram of the joint mechanism shown in FIG. 2A in which a voltage is applied between the electrodes with the arm bent. FIG. [Figure 2C] 2C is a schematic cross-sectional view of the joint mechanism in a state in which the arm is bent in the joint mechanism shown in FIG. 2B and the voltage applied between the electrodes is released to remove the charge accumulated between the electrodes. FIG. [Figure 3A] FIG. 11 is a schematic diagram of a joint mechanism according to a second embodiment, in which an arm is extended. [Figure 3B] 3B is a schematic diagram of the joint mechanism shown in FIG. 3A in which a voltage is applied between the electrodes in a state in which an arm is bent. FIG. [Figure 3C] FIG. 3C is a schematic diagram of the joint mechanism in which the application of a voltage between the electrodes is released from the state in which the arm is bent in the joint mechanism shown in FIG. 3B, and the charge accumulated between the electrodes is removed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components with the same reference numerals in each embodiment have the same functions in each embodiment unless otherwise specified, and description thereof will be omitted.

[0019] [First embodiment] The joint mechanism 1 of the first embodiment will be described with reference to Figs. 1A to 2C. Fig. 1A is a perspective view of a main part of the joint mechanism according to the first embodiment of the present invention. Fig. 1B is a perspective view of a main part of the joint mechanism 1 shown in Fig. 1A in a state in which an arm is bent. Fig. 2A is a schematic diagram of the joint mechanism 1 shown in Fig. 1A in a state in which an arm 20A is extended. Fig. 2B is a schematic diagram of the joint mechanism 1 shown in Fig. 2A in which a voltage is applied between the electrodes in a state in which the arm 20A is bent. Fig. 2C is a schematic cross-sectional view of the joint mechanism 1 shown in Fig. 2B in which the voltage application between the electrodes is released from the state in which the arm 20A is bent, and the charge accumulated between the electrodes is removed.

[0020] 1. Arm 20A of Joint Mechanism 1 1A and 1B, the joint mechanism 1 according to the first embodiment includes an arm 20A, which constitutes a base electrode 20 described below. In this embodiment, the arm 20A is made up of two arm members 21A and 21B that are rotatably connected along the longitudinal direction of the arm 20A.

[0021] The two arm members 21A, 21B are composed of a first arm member 21A which is the base end side of the arm 20A, and a second arm member 21B which is the tip end side of the arm 20A. The first arm member 21A and the second arm member 21B are connected by a hinge connection. Specifically, the first arm member 21A and the second arm member 21B are each formed with a through hole 21a for connection, and by inserting a connecting pin 24 into these through holes 21a, the first arm member 21A and the second arm member 21B are connected to each other so as to be freely rotatable (pivotable) via the connecting pin 24.

[0022] In this embodiment, as shown in FIG. 1A, the arm 20A is freely deformed from an extended position in which the first arm member 21A and the second arm member 21B are arranged in a straight line to a position in which the first arm member 21A and the second arm member 21B rotate and bent in one direction as shown in FIG. 1B. Here, an insulating layer 22, which will be described later, is formed on the outer surface (opposing surface 23, which will be described later) in the bending direction (rotation direction) of the arm 20A, which is bent in one direction from the extended state of the arm 20A. As shown in FIG. 2A and FIG. 2B, this insulating layer 22 is also formed on the outer surface exposed from the arm 20A by bending the arm 20A. Therefore, in this embodiment, the insulating layer 22 is formed up to the outer peripheral surface 21d of the semi-cylindrical base end portion 21b in which the above-mentioned through hole 21a is formed of the second arm member 21B.

[0023] 2. Flexible Electrode 10 and Base Electrode 20 2A to 2C, this embodiment includes a flexible electrode 10 having flexibility, and a base electrode 20 having a surface 23 facing the flexible electrode 10 formed of an insulating layer 22. The base electrode 20 is formed of the arm 20A described above. In this embodiment, a voltage is applied to the flexible electrode 10 and the base electrode 20 from a power source 71.

[0024] 2-1. Flexible electrode 10 The flexible electrode 10 is a sheet-like electrode formed of a flexible conductor. The flexible electrode 10 has flexibility that allows it to deform so as to be attracted to the base electrode 20 by the action of Coulomb force generated by applying a voltage between the flexible electrode 10 and the base electrode 20. However, when the application of voltage between the electrodes is stopped and the Coulomb force disappears, the attraction to the base electrode 20 is also released. For example, as shown in FIG. 1B, when an arm 20A corresponding to the base electrode 20 is bent downward from a position extending along the horizontal direction, the flexible electrode 10 may deform so as to follow the second arm member 21B due to its own weight.

[0025] The flexible electrode 10 is disposed so as to face the insulating layer 22 of the base electrode 20. Specifically, the flexible electrode 10 is disposed so as to face the outer surface (opposing surface 23) of the arm 20A in the rotation direction in which the first and second arm members 21A, 21B rotate relative to each other so as to bend the arm 20A. Specifically, the flexible electrode 10 is disposed so as to straddle the connected first and second arm members 21A, 21B along the longitudinal direction of the arm 20A.

[0026] Specifically, of the two ends of the flexible electrode 10 along the longitudinal direction of the arm 20A, the base end 11A is fixed to the arm 20A (specifically, the first arm member 21A) via a joint member 50. From the fixed base end 11A to the tip end 11B of the flexible electrode 10, the flexible electrode 10 is in an unconstrained state with respect to the arm 20A when no voltage is applied between the electrodes. Therefore, before a voltage is applied between the electrodes, the arm 20A is free to rotate without resistance due to adhesion of the flexible electrode 10. When a voltage is applied between the electrodes, the flexible electrode 10 is adhered to the arm 20A, and resistance to the rotation of the arm 20A is generated in the arm 20A due to adhesion of the flexible electrode 10.

[0027] 1B and 2B, as the bending of arm 20A progresses, the exposed portion of outer circumferential surface 21d of second arm member 21B increases. As a result, flexible electrode 10 is attracted to exposed outer circumferential surface 21d of the outer surface of second arm member 21B as well, so that flexible electrode 10 can be maintained in a state of being attracted to second arm member 21B. As the bending of arm 20A progresses, tip 11B of flexible electrode 10 moves toward base end 11A.

[0028] The flexible electrode 10 may be formed using conductive rubber or conductive gel. An example of the conductive rubber is elastomer formed by mixing a conductive material. Examples of the conductive material include fine powder of carbon black, acetylene black, or carbon nanotubes, fine metal powder of silver or copper, or fine conductive powder of a core-shell structure in which an insulator such as silica or alumina is coated with a metal by sputtering or the like. Examples of the conductive gel include functional gel materials in which a solvent such as water or a moisturizer, an electrolyte, and additives are held in a three-dimensional polymer matrix. Examples of the functional gel material include Technogel (registered trademark) by Sekisui Chemical Co., Ltd.

[0029] 2-2. Base electrode 20 The base electrode 20 corresponds to the arm 20A described above, and includes an electrode portion 25 made of a conductive material such as a metal material, and an insulating layer 22 covering the surface of the electrode portion 25. In this embodiment, the first and second arm members 21A and 21B both have an electrode portion 25 and an insulating layer 22. Specifically, the insulating layer 22 is formed on a surface 23 of the surface of the base electrode 20 that faces the flexible electrode 10. The base electrode 20 is fixed to a joining member 50, and a base end 11A of the flexible electrode 10 is fixed to the joining member 50.

[0030] In this embodiment, arm 20A is capable of freely transforming from an extended position in which first arm member 21A and second arm member 21B are arranged in a straight line to a position in which first arm member 21A and second arm member 21B rotate and are bent in one direction, as shown in FIG. 1B.

[0031] The electrode portion 25 is formed using a conductive metal material such as iron, copper, or aluminum, and ensures the shape retention of the base electrode 20. The electrode portions 25 of the first and second arm members 21A, 21B are electrically connected to each other, but if they are not electrically connected, the negative pole of the power source 71 may be connected to each of the electrode portions 25 of the first and second arm members 21A, 21B. The insulating layers 22 of the first and second arm members 21A, 21B are formed using a ferroelectric material made of ceramics so that the charge accumulated in the base electrode 20 by applying a voltage between the flexible electrode 10 and the base electrode 20 is reliably maintained.

[0032] In particular, the insulating layer 22 is formed using a ferroelectric material having a perovskite structure. Examples of ferroelectric materials having a perovskite structure include barium titanate (BaTiO3), lead titanate (PbTiO3), lead zirconate titanate (Pb(Zr,Ti)O3), lead lanthanum zirconate titanate ((Pb,La)(Zr,Ti)O3), strontium titanate (SrTiO3), barium strontium titanate ((Ba,Sr)TiO3), and potassium sodium niobate ((NaK)NbO3). Barium titanate may be solid-dissolved with a material such as CaZrO3 or BaSnO3.

[0033] Moreover, the material used to form the insulating layer 22 is preferably a material having a high relative dielectric constant that can generate a Coulomb force that deforms the flexible electrode 10. The relative dielectric constant of the insulating layer 22 may be 1000 or more, for example, by using ceramics (fine ceramics). Barium titanate has a relative dielectric constant of about 1000 to 10000. Lead zirconate titanate has a relative dielectric constant of 500 to 5000. Strontium titanate has a relative dielectric constant of 200 to 500. These ferroelectrics having a perovskite structure are materials having a high relative dielectric constant.

[0034] 2-3. Power supply 71 and changeover switches 81A to 81D In this embodiment, the joint mechanism 1 includes change-over switches 81A to 81D that switch between application and release of a voltage between the electrodes by the power source 71. In this specification, "application of a voltage between the electrodes" refers to a state in which an electric charge is stored between the electrodes and is maintained, and "release of application of a voltage between the electrodes" refers to a state in which the electric charge maintained between the electrodes is removed.

[0035] In this embodiment, the power supply 71 applies a voltage between the flexible electrode 10 and the base electrode 20, and is connected to the flexible electrode 10 and the base electrode 20 via change-over switches 81A and 81B. In this embodiment, the positive electrode of the power supply 71 and the flexible electrode 10 are connected via the change-over switch 81A, and the negative electrode of the power supply 71 and the base electrode 20 are connected via the change-over switch 81B.

[0036] Furthermore, in this embodiment, in the wiring on the flexible electrode 10 side of the change-over switch 81A, the flexible electrode 10 is connected to earth via a change-over switch 81C for static elimination. Similarly, in the wiring on the base electrode 20 side of the change-over switch 81B, the base electrode 20 is connected to earth via a change-over switch 81D for static elimination.

[0037] 2-4. About the control device 80 and the voltage regulator 75 In this embodiment, the changeover switches 81A-81D are connected to the control device 80, and the switching operations of the changeover switches 81A-81D are controlled by the control device 80. Specifically, the control device 80 controls the switching of the changeover switches 81A-81D in a specific posture of the arm 20A in which the first and second arm members 21A, 21B have rotated.

[0038] As for the control of the changeover switches 81A-81D, the control device 80 maintains the changeover switches 81A-81D in the OFF state when the arm 20A is not in use, as shown in Fig. 2A. Thereafter, when an external force is applied to the first and second arm members 21A, 21B to rotate relatively at a predetermined rotation angle, that is, when the arm 20A assumes a specific rotation posture, as shown in Figs. 1B and 2B, the control device 80 controls the changeover switches 81A, 81B to ON. If the first and second arm members 21A, 21B further rotate beyond this rotation angle, the control device 80 does not perform the changeover control, and the changeover switches 81A, 81B continue to be in the ON state.

[0039] Here, in this embodiment, the rotation angles of the first and second arm members 21A and 21B may be measured by providing an encoder (not shown) on the connecting pin 24, or may be measured by capturing an image of the posture of the arm 20A from a specific position with an imaging device. The rotational movements of the first and second arm members 21A and 21B, which will be described later, may be measured by the same method. Based on these measurement results, the control device 80 may estimate the rotation angle and control the changeover switches 81A and 81B to be switched ON. In addition, a detection switch (not shown) may be attached to the arm 20A so that a contact-type detection switch is activated when the first and second arm members 21A and 21B reach a predetermined rotation angle, and the control device 80 may control the changeover switches 81A and 81B to be ON based on a signal generated by the activation of the detection switch.

[0040] When the control device 80 controls the changeover switches 81A and 81B to ON, the flexible electrode 10 connected to the positive pole of the power source 71 is positively charged, and the electrode unit 25 connected to the negative pole of the power source 71 is negatively charged. As a result, the insulating layer 22 covering the opposing surface of the electrode unit 25 is dielectrically polarized. The insulating layer 22 of the electrode unit 25 is positively charged near the interface with the electrode unit 25, and negatively charged near the surface opposite the interface. Coulomb force is generated between the insulating layer 22 and the flexible electrode 10. The Coulomb force attracts the flexible electrode 10 to the insulating layer 22, and the flexible electrode 10 is attracted to the arm 20A when a voltage is applied between the electrodes.

[0041] In this embodiment, the flexible electrode 10 is disposed so as to straddle the first and second arm members 21A, 21B, and therefore the rotation resistance between the first and second arm members 21A, 21B that are rotatably connected can be increased by adhesion of the flexible electrode 10. Therefore, when attempting to further rotate the second arm member 21B relative to the first arm member 21A by applying an external force, a greater rotation force than before is required.

[0042] 2C, when the control device 80 turns the change-over switches 81A and 81B OFF and turns the change-over switches 81C and 81D ON, the charges stored in the flexible electrode 10 and the base electrode 20 (arm 20A) are removed. For example, in this embodiment, when the change-over switches 81C and 81D are ON and the first and second arm members 21A and 21B rotate relatively at a predetermined rotation angle (i.e., when the arm 20A assumes a specific rotation posture), the control device 80 controls the change-over switches 81A and 81B to OFF.

[0043] That is, in this state, since the bent arm 20A tries to straighten, if the first and second arm members 21A, 21B further rotate below this rotation angle, the control device 80 does not perform switching control, and the changeover switches 81A, 81B remain in the OFF state. Furthermore, if an attempt is made to bend the arm 20A again, the control device 80 performs switching control similar to the control described in FIG. 2B.

[0044] Additionally, in this embodiment, the controller 80 may control the switching of the changeover switches 81A to 81D during a specific rotational movement of the first and second arm members 21A, 21B.

[0045] For example, when arm 20A is about to bend further from a predetermined rotation angle, change-over switches 81A, 81B may be controlled to be switched ON, and when arm 20A is rotated beyond that angle, change-over switches 81A, 81B may be kept ON. Furthermore, when bent arm 20A moves in the extension direction (i.e., when the rotation angle of first and second arm members 21A, 21B decreases), the application of a voltage between the electrodes may be released to reduce the rotation resistance between first and second arm members 21A, 21B, as shown in Fig. 2C.

[0046] In the rotation angle in the series of controls described above, the state in which the first and second arm members 21A, 21B are extended from each other as shown in FIG. 1A is defined as zero, and the angle by which the first and second arm members 21A, 21B rotate from this extended state in the direction in which the arm 20A bends is defined as positive.

[0047] The joint mechanism 1 may further include a voltage adjusting device 75 that adjusts the magnitude of the voltage applied between the electrodes. By adjusting the magnitude of the voltage applied between the electrodes when a voltage is applied between the electrodes, it is possible to adjust the magnitude of the Coulomb force generated between the insulating layer 22 and the flexible electrode 10 and adjust the rotation resistance between the first and second arm members 21A, 21B.

[0048] In this embodiment, the adjustment of the voltage by the voltage regulator 75 is controlled by the control device 80. Specifically, the control device 80 may control the adjustment of the voltage by the voltage regulator 75 so that the applied voltage increases as the rotation angle of the first and second arm members 21A, 21B increases. Thereby, for example, when the joint mechanism 1 is attached to the back of the hand (specifically, the joints of the fingers) and the hand is clenched, the rotation resistance of the first and second arm members 21A, 21B increases, and the sensation of gripping an elastic body such as a ball can be reproduced.

[0049] In addition, when the rotation angle further increases from the above-mentioned predetermined rotation angle (first rotation angle) and exceeds another predetermined angle (second rotation angle larger than the first rotation angle), the control device 80 may stop applying the voltage between the electrodes. This suddenly eliminates the rotation resistance of the first and second arm members 21A, 21B, so that the sensation of squeezing an object and causing it to explode can be reproduced in the fingers.

[0050] Alternatively, the control device 80 may set in advance a voltage value to be applied according to the rotation speed of the first and second arm members 21A, 21B, and control the voltage of the voltage adjustment device 75 according to this set voltage value. For example, the control device 80 may increase the voltage value to be applied as the rotation speed increases.

[0051] In this way, by applying a voltage between the electrodes by the change-over switches 81A, 81B, it is possible to increase the rotation resistance between the first and second arm members 21A, 21B with a simpler structure and control.

[0052] [Second embodiment] The joint mechanism 1 of the second embodiment will be described with reference to Figures 3A to 3C. This embodiment differs from the first embodiment in the longitudinal length of the flexible electrode 10 and in that an ammeter 77 and a calculation device 90 are further provided instead of the voltage adjustment device 75. A detailed description will be given below.

[0053] 3A, in the rotation direction in which the first and second arm members 21A, 21B rotate relative to each other so that the arm 20A is bent, the flexible electrode 10 is disposed such that the outer surface in the rotation direction of the arm 20A serves as an opposing surface 23. Of both ends of the flexible electrode 10 along the longitudinal direction of the arm 20A, a base end 11A is fixed to the arm 20A via a joint member 50.

[0054] In the second embodiment, furthermore, the tip 11B of both ends of the flexible electrode 10 protrudes from the end (tip) of the arm 20A along the longitudinal direction within the range in which the first and second arm members 21A, 21B rotate. As the arm 20A is bent further, the tip 11B of the flexible electrode 10 moves toward the base end 11A, but regardless of the degree of bending of the arm 20A, the tip of the flexible electrode 10 remains protruding from the end of the arm 20A.

[0055] As in the first embodiment, when the arm 20A is further bent from the state shown in Fig. 3B, the exposed portion of the outer circumferential surface 21d of the second arm member 21B increases as the bending of the arm 20A progresses. Here, in this embodiment, the tip 11B of both ends of the flexible electrode 10 has a length that protrudes from the end (tip) of the arm 20A within the range in which the first and second arm members 21A and 21B rotate, so that as the bending of the arm 20A progresses, the exposed outer circumferential surface 21d increases, and the adsorption area of ​​the flexible electrode 10 increases. As a result, as the bending of the arm 20A progresses, the Coulomb force increases, and the rotation resistance of the first and second arm members 21A and 21B can be increased.

[0056] Here, as the bending of the arm 20A progresses, the adsorption area of ​​the flexible electrode 10 increases, and as a result, the amount of charge accumulated between the electrodes increases. Therefore, the joint mechanism 1 may further include an ammeter 77 that measures the amount of current flowing from the power source 71, and a calculation device 90 that estimates the bending angle of the arm 20A.

[0057] Specifically, ammeter 77 is disposed between flexible electrode 10 and power source 71, and measures the current flowing from power source 71 to flexible electrode 10. Calculation device 90 calculates the amount of charge based on the current value measured by ammeter 77, and estimates the amount of charge accumulated between the electrodes in a state in which a voltage is applied between the electrodes by change-over switches 81A, 81B. Specifically, after change-over switches 81A, 81B are turned ON, the current value flowing through ammeter 77 is integrated. Calculation device 90 estimates the amount of charge accumulated between the electrodes from this integrated current.

[0058] Next, the calculation device 90 estimates the rotation angles of the first and second arm members 21A, 21B based on the estimated amount of charge. Specifically, the contact area of ​​the flexible electrode 10 in contact with the arm 20A can be estimated from the estimated amount of charge, and the rotation angles of the first and second arm members 21A, 21B can be easily estimated from this contact area. Alternatively, an equation or table satisfying the relationship between the estimated amount of charge and the rotation angle may be prepared and used to estimate the rotation angles of the first and second arm members 21A, 21B.

[0059] When removing the charge between the electrodes, as in the first embodiment, the control device 80 may turn the changeover switches 81A and 81B OFF and the changeover switches 81C and 81D ON as shown in FIG. 3C.

[0060] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various design modifications can be made without departing from the spirit of the present invention described in the claims. In the present invention, the configuration of one embodiment can be added to the configuration of another embodiment, the configuration of one embodiment can be replaced with the configuration of another embodiment, or part of the configuration of one embodiment can be deleted.

[0061] In this embodiment, an arm formed by connecting two members, a first arm member and a second arm member, has been exemplified as the base electrode, but for example, an arm member formed by connecting three or more arm members in the longitudinal direction of the arm may be used as the base electrode 20. In this case, flexible electrodes 10 may be provided so as to straddle each of the connected arm members, or one flexible electrode may be provided so as to straddle all of the arm members.

[0062] The joint mechanism according to this embodiment may be used for handling in virtual reality (VR). By arranging these joint mechanisms on the back of the hand with five fingers, it is possible to provide feedback to the fingers, such as the sensation of grasping an object, in a virtual space. Furthermore, by holding the arithmetic device according to the second embodiment, it is possible to simultaneously detect the angle of the fingers. [Explanation of symbols]

[0063] 1: joint mechanism, 10: flexible electrode, 20: base electrode, 20A: arm, 21A: first arm member (arm member), 21B: second arm member (arm member), 23: opposing surface, 71: power source, 75: voltage regulator, 77: ammeter, 80: control device, 81A to 81D: changeover switches, 90: computing device

Claims

1. A flexible electrode having flexibility; a base electrode having an insulating layer formed on a surface facing the flexible electrode; a power source that applies a voltage between the flexible electrode and the base electrode; a changeover switch for switching between application and release of a voltage between the electrodes by the power source, The base electrode is made of an arm having a plurality of arm members rotatably connected to each other, the flexible electrode is disposed across the connected arm members along a longitudinal direction of the arm, the flexible electrode is attracted to the arm by application of a voltage between the electrodes; the flexible electrode is disposed such that an outer surface in a rotation direction of the arm is the opposing surface in the rotation direction of the arm members so that the arm is bent, A joint mechanism characterized in that one end of the flexible electrode along the longitudinal direction is fixed to the arm, and the other end of the flexible electrode extends beyond the end of the arm along the longitudinal direction within a range in which the multiple arm members rotate.

2. 2. The joint mechanism according to claim 1, further comprising a control device that controls switching of the change-over switch when the arm member is in a specific posture after rotation of the arm or when the arm member is in a specific rotational motion.

3. 3. The joint mechanism according to claim 1, further comprising a voltage regulator that adjusts the magnitude of the voltage applied between the electrodes.

4. The arm members are two in number, The joint mechanism further includes a computing device, 2. The joint mechanism according to claim 1, wherein the calculation device estimates an amount of charge accumulated between the electrodes while a voltage is applied between the electrodes by the change-over switch, and estimates a rotation angle of the arm member based on the estimated amount of charge.

Images