Gripping reaction force presentation device and control method of the same

Abstract

To provide a gripping reaction force presentation device that has a grippable size and preferable operability and can present a gripping force with high safety, and a presentation method.SOLUTION: A gripping reaction force presentation device 1 includes: a housing 5 that can be gripped by fingers; and an elastic body and an actuator that are arranged in parallel in the housing 5. The housing 5 includes an internal space V partitioned by a load applied to the housing 5 and cancellation of the load. The load occurs by a gripping force by gripping and / or a tensile force by the actuator. A reaction force of the load occurs by resilience of the elastic body. The gripping reaction force presentation device 1 can present, to fingers, a reaction force (gripping force) by cancellation of the tensile force from a force due to a load equal to the resilience.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a grip reaction force presentation device and a control method thereof. [Background technology]

[0002] Humans can smoothly carry out their daily lives by skillfully operating tools. This is achieved through the dexterity of the hands, and the need for quantitative evaluation and training of dexterity of the fingers has been recognized. For this reason, a training device for evaluating the ability to adjust grip strength by controlling muscle contraction has been developed, focusing on the dexterity of the hands.

[0003] Patent Document 1 describes a gripping sensation presentation device that uses a servo motor to drive a ball screw to open and close the fingertips during gripping, as a device that presents a reaction force or force sensation to human fingers. As a method of presenting a reaction force or force sensation other than this mechanism, Patent Document 2 describes a tactile stimulation device that presents a pressure sensation by controlling the restoring force of an elastic body such as a compression spring to control the length of an artificial muscle such as a dielectric elastomer. Patent Document 3 describes a method of variably controlling the pressing force by controlling an actuator that counters the restoring force of a return spring by a pressing rocker. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-102560 A [Patent Document 2] JP 2017-79034 A [Patent Document 3] Special Publication No. 2022-520543 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the mechanism described in Patent Document 1 has good controllability due to its high weight and high rigidity, but has a problem of low backdrivability, which is important for human operation. The invention described in Patent Document 2 has excellent backdrivability, but has nonlinear characteristics due to the dielectric elastomer, difficulty in control due to its flexibility, and safety issues due to the need for high voltage to drive the dielectric elastomer. The invention described in Patent Document 3 is a mechanism with excellent backdrivability and controllability, but is not used for the purpose of presenting a reaction force against a human finger. For this reason, there is no technology that enables the presentation of a gripping force that is easy to operate and has a high safety at a size that can be grasped. Therefore, the present invention aims to provide a gripping reaction force presentation device and a presentation method that enable the presentation of a gripping force that is easy to operate and has a high safety at a size that can be grasped. [Means for solving the problem]

[0006] The present invention which solves the above problems is as follows. [1] A gripping reaction force presentation device comprising a housing that can be grasped by fingers, and an elastic body and an actuator arranged in parallel to the housing, the housing having an internal space partitioned by a load applied to the housing and the release of the load, the load being generated by a gripping force due to the gripping and / or a tensile force due to the actuator, and a force that reacts to the load being generated by the restoring force of the elastic body, and a reaction force (the gripping force) can be presented to the fingers by releasing the tensile force from the force due to the load that is balanced with the restoring force. [2] A gripping reaction force presentation device as described in [1], wherein the internal space decreases when the load is applied and increases when the load is released. [3] The grip reaction force presentation device according to [1] or [2], further comprising a wire winding mechanism having a wire and a winding portion for the wire as the actuator. [4] A grip reaction force presentation device according to [1] or [2], further comprising sensors capable of detecting the restoring force of the elastic body and the tensile force of the actuator. [5] The grip reaction force presentation device according to [3], further comprising sensors capable of detecting the restoring force of the elastic body and the tensile force of the actuator. [6] The grip reaction force presentation device described in [5], wherein the actuator further has a motor and a control unit that controls the motor, and the reaction force is adjustable by control of the control unit. [7] A gripping reaction force presentation device according to [1] or [2], wherein the elastic body and / or the actuator are disposed in the internal space. [8] A gripping reaction force presentation device according to [3], wherein the elastic body and / or the actuator are disposed in the internal space. [9] A grip reaction force presentation device system comprising the grip reaction force presentation device described in [6], a power supply unit, and a display unit that displays the grip reaction force.

[10] [1] A method for controlling a grip reaction force (grip force) that uses the grip reaction force presentation device described in [1] and adjusts the tensile force to provide a displacement of the elastic body and / or any reaction force less than the restoring force. Effect of the Invention

[0007] The grip reaction force presentation device of the present invention does not use a gear reducer or the like as in the prior art, so it is small and lightweight, does not require a large device, and has excellent backdrivability, making it suitable for use by people in terms of operability, safety, and size. Furthermore, the method of presenting reaction force or force sense using a leaf spring, for example, has a simple structure, making it possible to produce a low-cost, sturdy device. [Brief description of the drawings]

[0008] [Figure 1] 1A is a diagram showing an external view (perspective view) of a grip reaction force presentation device according to one embodiment of the present invention, and FIG. 1B is a diagram showing a schematic cross section in the vertical direction. [Diagram 2] FIG. 2 is a diagram showing an internal configuration of a grip reaction force presentation device. [Diagram 3] 13 is a diagram showing the internal configuration of the grip reaction force presentation device as viewed from another angle. FIG. [Figure 4] (a) Appearance of the grip reaction force presentation device (oblique view), (b) A diagram showing the relationship between the restoring force, grip reaction force, and the pulling force of the motor. [Diagram 5] 1 is a block diagram of a control system including a grip reaction force presentation device. [Figure 6] FIG. 2 is a diagram showing an example of the input side (pulling force of a motor) and output (grip reaction force) of a grip reaction force presentation device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be made without departing from the scope of the invention. EXAMPLES

[0010] (Gripping reaction force presentation device) As shown in FIG. 1( a ), a grip reaction force presentation device 1 includes a semi-cylindrical part 2 and a grippable housing 5 having a semi-cylindrical part 3 . Semi-cylindrical part 2 (hereinafter sometimes referred to as "part 2") and semi-cylindrical part 3 (hereinafter sometimes referred to as "part 3") are connected by hinge structure 27 via hinge tube 2b (2b') formed at one end of side surface 2a of part 2 and hinge tube 3b (3b') formed at one end of side surface 3a of part 3. Semi-cylindrical parts 2 and 3 can move around pin 4 as an axis by means of pin 4 inserted into hinge tubes 2b to 3b'. Top surface 2c of part 2 and bottom surface 3d of part 3 are each circular, and bottom surface 2d of part 2 and top surface 3c of part 3 are each shaped like a semicircle connected to an approximate S-shape (see Figure 2). For example, when part 2 is viewed from the side opposite hinge structure 27, top surface 2c and bottom surface 2d protrude perpendicularly from side surface 2a at the positions of the top and bottom surfaces of side surface 2a.

[0011] The diameter of part 2 and the diameter of part 3, and the height of part 2 and the height of part 3 are almost the same, but the height to the top surface 2c of part 2 is slightly higher than the height to the top surface 3c of part 3, so that the top surfaces 2c and 3c can overlap smoothly.

[0012] Before the side surface 2a of the part 2 and the side surface 3a of the part 3 are gripped, there is a distance D between them. By gripping both sides, the top surface 2c and the top surface 3c overlap, which is the gripping direction, and the opposite direction to the gripping direction is the restoration direction. When the gripping reaction force presentation device 1 is viewed from above without the top surfaces 2c and 3c, as shown in FIG. 1(b), the gripping reaction force presentation device 1 has an internal space V of a predetermined volume. The volume of the internal space V is determined by the radius r, θ, and height h (see FIG. 2) of the semi-cylinder, as well as the parts and the like present in the internal space V, but since the parts and the like do not change before and after gripping, the radius r, θ, and height h may be considered for the change in the volume of the internal space V. Note that θ is the angle between the center line L passing through the center O of the circle of radius r and the line segment αβ (line segment αγ).

[0013] Before grasping, the internal space V includes a space v surrounded by points α (the axis center of the hinge structure 27), β, and γ, but as it is grasped (as a load is applied), both sides 2a and 3a move in the grasping direction (the angle θ becomes smaller) and the space v decreases. As a result, the volume of the internal space V decreases. On the other hand, if the space v is restored by releasing the grasp (load), the internal space V will be restored to its volume before grasping. In other words, the internal space V is an internal space partitioned before and after grasping. Note that the internal space V of the grasp reaction force presentation device may not have a portion such as the gap D and may be in a nearly sealed state.

[0014] A power button 6 is provided on the top surface 2c near the side surface 2a, and a power terminal 7 is provided on the bottom surface 2d of the side surface 2a near the tube 3b'.

[0015] 2, the internal configuration of the grip reaction force presentation device 1 can be roughly divided into a group of parts 3B provided inside part 3 and a group of parts 2B provided inside part 2 (including the internal structures of the grip reaction force presentation device 1 to be placed inside both parts). Group of parts 3A includes a motor 8, a bridge amplifier circuit 9, each part constituting a wire winding mechanism 25, a leaf spring 10, and a strain gauge 11 attached to the leaf spring 10.

[0016] A DD motor, for example, can be used as the motor 8, from the viewpoint of enabling high-precision positioning at low speed and high torque. The motor 8 is fixed to the inner surface of the component 3 with both axial end faces of the motor 8 sandwiched between a motor fixing part 20 fixed to the inner surface of the component 3 and a motor retaining wall 3e formed on the inner surface near the bottom surface 3d.

[0017] The components constituting the wire winding mechanism 25 include a large pulley 12 that is fitted and directly connected to the shaft of the motor 8, a small pulley 13, a wire 16 wound around the large pulley 12 and the small pulley 13, and a wire guide groove 14. The small pulley 13 is rotatably attached to a small pulley fixing part 21 formed on the inner surface of the opposite side of the hinge structure 27 of the part 3. The rotation of the large pulley 12 is transmitted to the small pulley 13 via the wire 16. The wire 16 of the large diameter cylinder of the wire magnetic attachment part 15, which is formed by connecting a large diameter cylinder to a small diameter cylinder, is wound around the small pulley 13. A magnet (not shown) is attached to the large diameter cylinder of the wire magnetic attachment part 15 on the opposite side to the small diameter cylinder. The rectangular leaf spring 10 is fixed to a leaf spring fixing part 3f formed on the inner surface near the hinge structure 27 of the part 3 with a screw.

[0018] The component group 2B includes a motor drive circuit 17, a microcomputer board 18 (see FIG. 3), a leaf spring 10', and a strain gauge 11' attached to the leaf spring 10'. A wire 16 is fixed to a locking component 19 (supported by a locking component fixing portion 24) inside the component 2 via a wire magnetic component 15. The leaf spring 10' is fixed to a leaf spring fixing portion 2f formed on the inner surface of the component 2 near the hinge structure 27 with a screw.

[0019] (Generation of pulling force by motor) The generation of a tensile force by the motor 8 and the movement of parts 2 and 3 in the gripping direction will be explained below. First, the wire magnetic part 15 is connected to the locking part 19. Meanwhile, when the shaft of the motor 8 rotates counterclockwise as viewed from the motor body and the large pulley 12 rotates in the same direction, the wire 16 is wound around the large pulley 12, generating a tensile force that pulls the wire in the direction of the hinge structure 27. The direction of the tensile force of the wire is changed by the small pulley 13. Therefore, the wire 16 is pulled in the direction of the small pulley 13, and both parts 2 and 3 move in the gripping direction. In other words, the movement in the gripping direction is generated by the torque caused by the rotation of the motor shaft. Conversely, the movement in the restoration direction can be performed by rotating the shaft of the motor 8 clockwise as viewed from the motor body, and releasing the pulling force by the motor 8. This pulling force alone or the pulling force and the gripping force f R The resultant force of the leaf spring (elastic body) 10 and the leaf spring (elastic body) 10' is the restoring force f R When the pulling force exceeds f, the internal volume of parts 2 and 3 decreases. On the other hand, when the pulling force alone or the pulling force and the gripping force f R The resultant force of the leaf spring (elastic body) 10 and the leaf spring (elastic body) 10' is the restoring force f R If the internal volume of part 2 and part 3 is increased, the internal volume of part 2 and part 3 will increase. R When the resultant force with the cylinder is zero, the internal volume returns to its initial state (see Figure 4(b)).

[0020] (Generation of restoring force by leaf spring) In a state where a thin rectangular region including the short side of the leaf spring 10 (10') is in contact with the leaf spring short side contact portion 22 (23) formed on the inner surface of the opposite side of the hinge structure 27 of the part 2 (3) without load, the distance (spacing) formed by the parts 2 and 3 in Fig. 1 is D. When the parts 2 and 3 move in the gripping direction from this state, the leaf spring 10 (10') bends, and a load is applied to the leaf spring 10 (10'). When this happens, a restoring force is generated as a reaction force corresponding to the load.

[0021] (Relationship between restoring force, gripping force, and motor pulling force) As shown in FIG. 4(a), the grip reaction force presentation device 1A includes a semi-cylindrical part 2A, a housing 5A having a semi-cylindrical part 3A, an elastic body 10A, and a motor 8A and a wire winding mechanism 25A as actuators arranged in parallel with the elastic body 10A. R , pulling force f by motor 8A M and gripping force (human gripping force) f H The relationship between the spring force and the displacement is as shown in FIG. 1(b), and the spring characteristic is such that the spring force f R =f H +f M holds true.

[0022] The housing 5A is provided with a load, ie, a tension (pulling force) f M and gripping force (human gripping force) f H is given, and the restoring force f by the elastic body 10A, which acts as a reaction force for the load, is R is given, and the tensile force f M and gripping force (human gripping force) f H The sum of these is the restoring force f due to the elastic body 10A. R In other words, it is in balance. From that state, the tensile force f M A gripping reaction force (grip force) generated by releasing the housing 5A is felt by the fingers of a person gripping the housing 5A.

[0023] More specifically, when the grip reaction force presentation device 1A is in a crushed state (when the parts 2A and 3A are in the gripping direction), the fingers are placed on the grip reaction force presentation device 1A to stop the movement of the fingers. Then, when the wire (wire 16, see FIG. 2) is loosened, the grip reaction force presentation device 1A generates a restoring force f R At that time, the fingers feel this restoring force, which represents the gripping reaction force (grip force). Then, the motor's pulling force f M Since is adjustable, the same restoring force f R The gripping reaction force (grip force) can be adjusted accordingly. H Since the displacement x can be adjusted by adjusting at least one of the pulling forces of the motors, the gripping force f can be adjusted in the same manner for the displacement x.H That is, the gripping reaction force (grip force) f H Adjustment is possible.

[0024] (Control System) As shown in Fig. 5, the grip reaction force presentation control system 30 has a grip reaction force presentation device 1, a power supply unit 33, and a display unit 32. The grip reaction force presentation device 1 is equipped with a control unit 31, a grip force detection unit 34, and a motor drive unit 35. As the power supply unit 33, from the viewpoints of ease of power supply and ease of storage due to compact size, for example, an AC adapter can be used as an external power source. As the display unit 32, from the viewpoints of beginner-friendliness and high security, for example, an iPad (registered trademark) can be used.

[0025] In Fig. 2, the control unit 31 corresponds to the microcomputer board 18, the gripping force detection unit 34 corresponds to the leaf spring 10 (10'), the strain gauge 11 (11'), and the bridge amplifier circuit 9, and the motor drive unit 35 corresponds to the motor 8, the motor drive circuit 17, and the wire winding mechanism 25. As the control unit 31, for example, an ESP32 microcomputer can be used from the viewpoints of analog input resolution of 12 bits, low cost, and low power consumption. The voltage generated corresponding to the strain detected by the strain gauge, i.e., the gripping force, can be input to the control unit 31 as a highly accurate voltage by the bridge amplifier circuit 9.

[0026] Necessary power is supplied from the power supply unit 33 to the control unit 31, the gripping force detection unit 34, and the motor drive unit 35. An AC adapter can be used as an external power source, and power is supplied directly or at a stepped-down voltage from a 12 V AC adapter.

[0027] The motor drive unit 35 includes a motor 8 and a motor drive circuit 17. The motor drive circuit 17 is equipped with a current sensor (motor drive circuit 17 with current sensor). A motor current corresponding to the motor drive is input to the control unit 31, which processes the motor current and outputs it to the motor drive circuit 17 as a motor current command value. The motor drive circuit 17 can control the motor current based on the motor current command value. If a sine wave, for example, is input to the motor drive circuit 17 as the motor current command value, the motor current can be periodically controlled like a sine wave. The current flowing through the motor and the tension of the wire generated by the current are proportional, and the tension can also be changed periodically. The grip reaction force presentation device 1 and the display unit 32 are electrically connected as shown in FIGS. 2, 3, and 5 so that they can perform the operation of FIG. 5.

[0028] 6, the display unit 32 can display at least the pulling force 41 and the grip force (reaction force) 42 calculated from the motor current command value, among the information processed by the control unit 31. Therefore, the user of the grip reaction force presentation device system 30 can visually grasp the grip force (reaction force) in addition to feeling it with his / her fingers, while being visually aware of the pulling force displayed on the display unit 32. For example, if you grip the grip reaction force presentation device 1 with a strong grip and feel a restoring force, you open your hand to eliminate the restoring force, which is expected to be useful for rehabilitation training.

[0029] By performing communication from the control unit 31 to the display unit 32 wirelessly via Bluetooth (registered trademark), it is possible to avoid restrictions on the range of use imposed by a cable for a wired connection. [Industrial Applicability]

[0030] It is expected to be used in the fields of disaster response and healthcare. It can be used as an input device that allows you to feel the gripping force, as a remote controller for VR games, surgery, disaster response, etc., and as an evaluation and training tool for (remote) rehabilitation by displaying the gripping force. [Explanation of symbols]

[0031] 1, 1A: Grip reaction force presentation device 2, 3, 2A, 3A: Semi-cylindrical parts 2B: Parts group provided inside part 2 2a: Side of part 2 2b, 2b´: Hinge tube formed at one end of side surface 2a 2c: Top surface of part 2 2d: Bottom surface of side surface 2a 2f: Leaf spring fixing part 3B: Parts group provided inside part 3 3a: Side of part 3 3b, 3b´: Hinge tube formed at one end of side surface 3a 3c: Top surface of part 3 3d: Bottom surface of side 3a 3e: Motor stop wall 3f: Leaf spring fixing part 4: Pin 5, 5A: Housing 6: Power button 7: Power supply terminal 8, 8A: Motor 9: Bridge amplifier circuit 10, 10´: Leaf spring 10A: Elastic body 11, 11´: Strain gauge 12: Large pulley 13: Small pulley 14: Wire guide groove 15: Wire magnetic parts 16: Wire 17: Motor drive circuit 18: Microcomputer board 19: Locking parts 20: Motor fixing parts 21: Pulley small fixed part 22, 23: Short side contact part of leaf spring 24: Locking part fixing part 25, 25A: Wire winding mechanism 27: Hinge structure 30: Grasp reaction force display control system 31: Control section 32: Display section 33: Power supply section 34: Grip force detection unit 35: Motor drive unit 41: Motor pulling force 42: Gripping force (reaction force) D: Spacing h: Height of the semi-cylindrical r: Radius of the semi-cylinder V:Internal space v: the space bounded by points α, β, and γ L: Center line passing through the center of the circle O θ: Angle between the center line and line segment αβ (line segment αγ) x: Displacement f R :Restoring force f H : Tensile force f M :Grip force (human grip force)

Claims

1. A gripping reaction force presentation device comprising a housing that can be grasped by fingers, and an elastic body and an actuator arranged in parallel to the housing, the housing having an internal space partitioned by a load applied to the housing and the release of the load, the load being generated by a gripping force due to the gripping and / or a tensile force due to the actuator, and a force that reacts to the load being generated by the restoring force of the elastic body, and a reaction force (the gripping force) generated by releasing the tensile force from the force due to the load that is balanced with the restoring force can be presented to the fingers.

2. The grip reaction force presentation device according to claim 1 , wherein the internal space decreases when the load is applied and increases when the load is released.

3. The grip reaction force presentation device according to claim 1 or 2, further comprising a wire winding mechanism having a wire as the actuator and a winding portion for the wire.

4. 3. The grip reaction force presentation device according to claim 1, further comprising sensors capable of detecting the restoring force of the elastic body and the tensile force of the actuator.

5. The grip reaction force presentation device according to claim 3 , further comprising sensors capable of detecting the restoring force of the elastic body and the tensile force of the actuator.

6. The grip reaction force presentation device according to claim 5 , wherein the actuator further comprises a motor and a control unit that controls the motor, and the reaction force is adjustable by control by the control unit.

7. The grip reaction force presentation device according to claim 1 , wherein the elastic body and / or the actuator is disposed in the internal space.

8. The grip reaction force presentation device according to claim 3 , wherein the elastic body and / or the actuator is disposed in the internal space.

9. A grip reaction force presentation device system comprising: the grip reaction force presentation device according to claim 6; a power supply unit; and a display unit that displays the grip reaction force.

10. A reaction force control method that uses the grip reaction force presentation device described in claim 1 and adjusts the tensile force to provide any reaction force equal to or less than the displacement of the elastic body and / or the restoring force.

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