Sole contact virtual variable stiffness device based on electrostatic adsorption principle

Abstract

A plantar contact virtual variable stiffness device based on an electrostatic adsorption principle belongs to the technical field of virtual reality, and comprises a plantar fixing piece used for supporting a foot; the brake comprises two electrode plates and a pair of bearing pieces capable of moving relatively; the swing rod assembly is rotationally connected with the sole fixing plate and the pair of bearing pieces respectively and used for driving the pair of bearing pieces to move relatively, the two electrode plates are arranged in an up-down spaced mode, a dielectric layer is arranged between the two electrode plates, and the two electrode plates are fixed to the pair of bearing pieces respectively and can move relatively under the action of the bearing pieces; alternating voltage is applied to the two electrode plates through the high-voltage alternating-current power supply, the brake is continuously adjusted to generate resistance for preventing the electrode plates from shifting, and the pressure feeling under the feet of a wearer in the walking process is constantly changed. The adjustable resistance is generated based on the electrostatic adsorption principle, the walking treading feeling simulating topographic changes is generated, and the requirement of users for VR immersion feeling is met.

Description

Technical Field

[0001] The present invention relates to a device capable of real-time simulating terrain walking interaction force, and particularly to a plantar contact virtual variable stiffness device based on the principle of electrostatic adsorption. It belongs to the field of virtual technology. Background Art

[0002] With the continuous improvement of people's living standards and the continuous development of virtual reality (VR) technology, people have more requirements for the flexibility and authenticity of VR devices. The ground of general VR venues is often cement floor, ceramic tile floor, wooden floor, carpet or synthetic material floor. However, there is a mismatch between the ordinary venue and the virtual environment in terms of vision, touch and spatial layout, which affects the immersion feeling. The ground design in the virtual environment is rich and diverse, such as sandy land, mountain land, etc., while the ground of the ordinary venue is simple and realistic, and the visual and tactile feelings are inconsistent with the virtual environment, resulting in limited immersion feeling, lack of real feedback, and affecting the experience of users. Summary of the Invention

[0003] In order to solve the problem that it is difficult for users to obtain a walking feeling that conforms to the changes in the virtual scene due to the simplification of the venue ground and the large difference from the virtual scene in the ordinary VR venue, the present invention proposes a plantar contact virtual variable stiffness device based on the principle of electrostatic adsorption. This device uses adjustable resistance generated based on the principle of electrostatic adsorption to generate a walking and stepping feeling simulating terrain changes, meeting the requirements of the user group for the VR immersion feeling.

[0004] A plantar contact virtual variable stiffness device based on the principle of electrostatic adsorption includes:

[0005] A plantar fixing member for supporting the foot;

[0006] A brake including two electrode plates and a pair of relatively movable carrier members;

[0007] A swing rod assembly is rotatably connected to the plantar fixing plate and a pair of carrier members respectively, and is used to drive the pair of carrier members to move relatively.

[0008] The two electrode plates are arranged at a distance from top to bottom and there is a dielectric layer between them. The two electrode plates are respectively fixed on a pair of carrier members and can move relatively under the action of the carrier members. An alternating voltage is applied to the two electrode plates through a high-voltage AC power supply to continuously adjust the resistance generated by the brake to prevent the misalignment of the electrode plates, so that the pressure feeling under the feet of the wearer changes continuously during walking.

[0009] Further, it further includes a return spring. One end face of one electrode plate is connected to one of the carrier members, the other end face of one electrode plate is connected to one end of the return spring, the other end of the return spring is connected to the other carrier member, and the other electrode plate is installed on the other carrier member.

[0010] Further, the swing rod assembly includes two first swing rods and two second swing rods; one first swing rod and one second swing rod are respectively arranged on opposite sides of the sole fixing member. One end of the first swing rod and one end of the second swing rod are both rotatably connected to the sole fixing member. The other end of the first swing rod on one side is rotatably connected to a bearing member, and the other end of the second swing rod is rotatably connected to another bearing member. The other end of the first swing rod on the other side is rotatably connected to another bearing member, and the other end of the second swing rod is rotatably connected to a bearing member.

[0011] Further, among the pair of bearing members, one bearing member is a guide bar bearing plate, and the other bearing member is a guide groove bearing plate, and the guide bar is in sliding fit with the guide groove.

[0012] Further, the materials of the sole fixing member, the swing rod assembly, and the pair of relatively movable bearing members are nylon.

[0013] Further, one of the electrode plates is a steel plate, and the other electrode plate is a copper plate.

[0014] The beneficial effects of the present invention compared with the prior art are as follows:

[0015] 1. The main body of the sole contact virtual variable stiffness device is made of lightweight nylon material, which is light in weight, highly tough and wear-resistant. The electrode plates use materials with a small thickness, and the total mass is less than 0.5 kg, and the consumption of the user's walking during wearing is not large.

[0016] 2. A brake based on the principle of electrostatic adsorption is adopted. By controlling the voltage and duty cycle of the high-voltage AC power supply, the resistance output by the brake can be controlled, and the stepping resistance that changes according to the demand can be generated in real time to simulate the walking feeling on different terrains.

[0017] The following further illustrates the solution of the application with reference to the drawings and embodiments: Brief Description of the Drawings

[0018] Figure 1 is a perspective view of the sole contact virtual variable stiffness device of the present application;

[0019] Figure 2 is a perspective view of the sole contact virtual variable stiffness device of the present application with one electrode plate removed;

[0020] Figure 3 is a perspective view of the sole contact virtual variable stiffness device of the present application viewed from another direction;

[0021] Figure 4 is an exploded view of the sole contact virtual variable stiffness device of the present application;

[0022] Figure 5Partial schematic diagram of the connection between the swing rod and the bearing member;

[0023] Figure 6 Working principle diagram of the sole contact virtual variable stiffness device of the present application;

[0024] Figure 7 Schematic diagram of a human foot stepping on the sole contact virtual variable stiffness device of the present application.

[0025] Accompanying drawings: 1. Sole fixing member, 2. Electrode plate, 3. Bearing member, 4. Swing rod assembly, 5. Return spring, 6. Pin, 7. Roller, 8. Anti-collision sponge pad, 9. Adjustable strap.

[0026] Embodiment: 21. First electrode plate, 22. Second electrode plate, 31. First bearing member, 32. Second bearing member, 41. First swing rod, 42. Second swing rod. Detailed implementation manners

[0027] The embodiments of the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the technical terms or scientific terms used in this application have the ordinary meanings understood by those skilled in the art.

[0028] Refer to Figure 1 , a sole contact virtual variable stiffness device based on the principle of electrostatic adsorption provided by the embodiment of the present application includes:

[0029] A sole fixing member 1 for supporting the foot;

[0030] A brake, including two electrode plates 2 and a pair of relatively movable bearing members 3;

[0031] A swing rod assembly 4, which is rotatably connected to the sole fixing member 1 and a pair of bearing members 3 respectively, and is used to drive a pair of bearing members 3 to move relatively;

[0032] The two electrode plates 2 are arranged at a distance from top to bottom and there is a dielectric layer between them. The two electrode plates 2 are respectively fixed to a pair of relatively movable bearing members 3 and can move relatively under the action of the bearing members 3. An alternating voltage is applied to the two electrode plates 2 through a high-voltage AC power supply to continuously adjust the resistance generated by the brake to prevent the misalignment of the electrode plates, so that the pressure feeling under the feet of the wearer changes continuously during walking. That is, when the electrode plates are connected to the high-voltage AC power supply, a changing electric field is formed between the two electrode plates 2, and a resistance to prevent the misalignment of the electrode plates will be generated between the two electrode plates 2. By changing the voltage of the AC power supply, the magnitude of this resistance is adjusted, and the resistance is transmitted to the sole of the foot through the swing rod assembly 4, generating a walking and stepping feeling simulating terrain changes.

[0033] Specifically, for the convenience of description, in this embodiment, a pair of carrier members 3 are respectively defined as a first carrier member 31 and a second carrier member 32; the swing rod assembly 4 includes two first swing rods 41 and two second swing rods 42; one first swing rod 41 and one second swing rod 42 are respectively arranged on opposite sides of the sole fixing member 1. One end of the first swing rod 41 and one end of the second swing rod 42 are both rotatably connected to the sole fixing member 1. The other end of the first swing rod 41 on one side is rotatably connected to the first carrier member 31 through a shaft and bearings, and the other end of the second swing rod 42 is rotatably connected to the second carrier member 32 through a shaft and bearings. The other end of the first swing rod 41 on the other side is rotatably connected to the second carrier member 32 through a shaft and bearings, and the other end of the second swing rod 42 is rotatably connected to the first carrier member 31 through a shaft and bearings.

[0034] In some other embodiments, the sole contact virtual variable stiffness device further includes a return spring 5. One end face of one electrode plate 2 is connected to one of the carrier members 3, the other end face of one electrode plate 2 is connected to one end of the return spring 5, the other end of the return spring 5 is connected to the other carrier member 3, and the other electrode plate 2 is installed on the other carrier member 3. For example, one end face of one electrode plate 2 is connected to the first carrier member 31, the other end face of one electrode plate 2 is connected to one end of the return spring 5, the other end of the return spring 5 is connected to the second carrier member 32, and the other electrode plate 2 is installed on the upper surface of the second carrier member 32.

[0035] Referring to Figure 3 and Figure 4 , in the pair of carrier members, the first carrier member 31 is a guide bar carrier plate, and the second carrier member 32 is a guide groove carrier plate, and the guide bar is in sliding fit with the guide groove.

[0036] In a specific embodiment, referring to Figure 4 , the sole fixing member 1 (such as a frame structure formed by plates) is connected to the guide bar carrier plate and the guide groove carrier plate through a shaft or a pin 6, the first swing rod 41, and the second swing rod 42. One end of the pin 6 is positioned by a snap ring, and bearings are added at the connection to make the device operate more smoothly during work, as Figure 5 shown. The two electrode plates 2 are respectively bonded to the two carrier plates and move along with the carrier plates. There is a layer of polyimide film between the two electrode plates 2 as a dielectric layer (as Figure 6 shown), referring to Figure 2 and Figure 4, one of the electrode plates 2 is located above the other electrode plate 2; for example, the electrode plate 2 located above is the first electrode plate 21, whose length is greater than that of the electrode plate 2 below, and the electrode plate below is the second electrode plate 22; one of the electrode plates 2 is a steel plate and the other electrode plate 2 is a copper plate. For example, the first electrode plate 21 is a steel plate and the second electrode plate 22 is a copper plate. The polyimide film is adhered to the smaller electrode plate (copper foil plate) 2 to avoid electrical conduction due to contact between the electrode plates 2 and also provide stable frictional resistance.

[0037] In some other embodiments, one end of the longer electrode plate 2 (such as the first electrode plate 21) is insulated and has an opening, and is connected to the pin 6 through the return spring 5. The return spring 5 can make the bearing plates on both sides return to the initial position when the user lifts the foot. A roller 7 is installed on the other bearing member 3 for controlling the distance between the two electrode plates 2. For example, a limiting groove and a roller 7 are provided on the second bearing member 32 (such as the guide groove bearing plate), as Figure 4 shown. The limiting groove can ensure the stable direction of the longer electrode plate during movement, and the roller 7 can ensure the stable distance between the two electrode plates 2 during operation, preventing sudden changes in frictional resistance caused by separation between the electrode plates. The roller 7 is fixed to the corresponding hole position of the second bearing member 32 (such as the guide groove bearing plate) using a nut.

[0038] In addition, the guide bar bearing plate and the guide groove bearing plate are slidably connected through the guide bar and the guide groove, as Figure 4 shown. A collision-proof sponge pad 8 is designed at one end of the guide groove, and a collision convex platform is provided on the guide bar, which can absorb the impact generated when the guide bar is quickly retracted and reduce noise.

[0039] As described above, the main body (the sole fixing member 1, the bearing member 3 and the swing rod assembly) is made of nylon material, and the electrode plates 2 of the brake are respectively made of steel sheets and copper foil electrodes. After the user wears the pedal, the resistance on the brake can be continuously adjusted by the alternating voltage applied by an external high-voltage AC power supply, so that the pressure feeling under the feet of the wearer changes continuously during walking. As long as the current on the pedal is adjusted in real time according to the VR scene, the terrain environment corresponding to the VR scene can be simulated, effectively reducing the problem of weak immersion of the user caused by the single ground environment and meeting the requirements of the user group for the VR immersion feeling.

[0040] The principle of the application scenario of the above implementation scheme is to add a brake based on the principle of electrostatic adsorption under the foot fixing member 1 and connect it with the swing rod assembly 4. The two electrode plates 2 are respectively fixed on the two bearing members 3 and can move parallel to each other under the action of the guide rails of the bearing members 3. The bearing members 3 are connected to the swing rod assembly 4 and finally connected to the foot fixing member 1. When a high-voltage AC power supply is connected to the electrode plates 2, a changing electric field will be formed between the two electrode plates 2. According to the principle of electrostatic adsorption, a resistance that hinders the misalignment of the electrode plates will be generated between the two electrode plates 2. By changing the voltage of the alternating current, the magnitude of this resistance can be adjusted. Finally, the resistance is transmitted to the human foot through the swing rod, generating a walking and stepping feeling that simulates terrain changes. The variable stiffness is mainly manifested in that the resistance between the two electrode plates is controlled by voltage during the working process, so that the force required to step on the pedal is different.

[0041] The theoretical principle of this application: The principle of electrostatic adsorption is adopted, and the schematic diagram is as Figure 7 , when no voltage is applied, the two electrode plates 2 are separated, and the magnitude of the frictional resistance can be ignored; when an alternating voltage is applied, an electrostatic adsorption force is generated between the two electrode plates (in the principle, the longer electrode plate above is defined as electrode plate A, and the shorter electrode plate below is defined as electrode plate B) and they are in close contact, and a frictional resistance opposite to the direction of motion is generated between the adsorbed electrode plates. According to the parallel plate capacitor model, the magnitude of the generated resistance can be expressed as:

[0042]

[0043] Among them: ε r represents the relative dielectric constant of the polyimide film, ε0 represents the dielectric constant of vacuum, A represents the contact area of the two electrode plates, μ is the friction coefficient, d represents the distance between the two electrode plates, and U is the voltage of the high-voltage AC power supply. According to the above expression, when the size of the electrode plates, the thickness of the dielectric layer, and the distance between the electrode plates are determined, the magnitude of the resistance can be controlled by the amplitude of the input voltage of the AC power supply. Ideally, continuous changes of any force value within the designed range can be achieved, realizing different stepping simulation effects.

[0044] Application scenario: Such as Figure 7As shown, the adjustable strap 9 binds and connects the user's shoe to the sole fixing member 1, and its length can be adjusted according to the user's situation to achieve flexible and adaptable fixation. The sole fixing member 1 is connected to a pair of bearing members 3 through a swing rod assembly 4. One operating frequency of this device is 10 Hz, and the input waveform of the voltage is a square wave. Below 10 Hz, the braking force of the device can effectively increase with the voltage, and the operating voltage range is 200 V - 1100 V. During use, two electrode plates are connected to an AC power supply. According to the visual terrain effect during user use, the resistance and variation law of the electrostatic adsorption brake can be continuously adjusted by changing the voltage amplitude and duty cycle of the high-voltage AC power supply, generating continuously changing sole pressures, thereby realizing the simulation of walking sensations on different terrains.

[0045] The present invention has been disclosed above with preferred embodiments. However, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-disclosed structure and technical content as equivalent embodiments of equivalent changes, and all still fall within the scope of the technical solution of the present invention.

Claims

1. A plantar contact virtual variable stiffness device based on the principle of electrostatic adsorption, characterized in that: Comprising: A sole fixing member for supporting the foot; A brake, comprising two electrode plates and a pair of relatively movable carrier members; A swing rod assembly, rotatably connected to the sole fixing plate and a pair of carrier members respectively, for driving the pair of carrier members to move relatively, The two electrode plates are arranged at a distance from each other vertically and there is a dielectric layer between them. The two electrode plates are respectively fixed on a pair of carrier members and can move relatively under the action of the carrier members. An alternating voltage is applied to the two electrode plates by a high-voltage AC power supply to continuously adjust the resistance generated by the brake to prevent the misalignment of the electrode plates, so that the pressure feeling under the feet of the wearer changes continuously during walking.

2. The virtual variable stiffness device for plantar contact based on the principle of electrostatic adsorption according to claim 1, wherein: It further comprises a return spring. One end face of one electrode plate is connected to one of the carrier members, the other end face of one electrode plate is connected to one end of the return spring, the other end of the return spring is connected to the other carrier member, and the other electrode plate is installed on the other carrier member.

3. The virtual variable stiffness device for sole contact based on the principle of electrostatic adsorption according to claim 1, characterized in that: The swing rod assembly comprises two first swing rods and two second swing rods; One first swing rod and one second swing rod are respectively arranged on opposite sides of the sole fixing member. One end of the first swing rod and one end of the second swing rod are both rotatably connected to the sole fixing member. The other end of the first swing rod on one side is rotatably connected to one carrier member, and the other end of the second swing rod is rotatably connected to the other carrier member. The other end of the first swing rod on the other side is rotatably connected to the other carrier member, and the other end of the second swing rod is rotatably connected to one carrier member.

4. The virtual variable stiffness device for plantar contact based on the principle of electrostatic adsorption according to claim 1, wherein: Among the pair of carrier members, one carrier member is a guide bar carrier plate, and the other carrier member is a guide groove carrier plate, and the guide bar is in sliding fit with the guide groove.

5. The sole contact virtual variable stiffness device based on the principle of electrostatic adsorption according to claim 1, characterized in that: One of the electrode plates is located above the other electrode plate.

6. The plantar contact virtual variable stiffness device based on the principle of electrostatic adsorption according to claim 4, wherein: A roller is installed on the other carrier member for controlling the distance between the two electrode plates.

7. The plantar contact virtual variable stiffness device based on the principle of electrostatic adsorption according to claim 4, wherein: One end of the guide groove is designed with an anti-collision sponge pad, and a collision boss is arranged on the guide bar.

8. The virtual variable stiffness device for plantar contact based on the principle of electrostatic adsorption according to claim 1, characterized in that: The materials of the sole fixing member, the swing rod assembly and the pair of relatively movable carrier members are all nylon.

9. The plantar contact virtual variable stiffness device based on the principle of electrostatic adsorption according to claim 5, characterized in that: One of the electrode plates is a steel plate, and the other electrode plate is a copper plate.

10. The sole contact virtual variable stiffness device based on the principle of electrostatic adsorption according to claim 1, characterized in that: The generated resistance is expressed as: Among them, ε r represents the relative dielectric constant of the polyimide film, ε0 represents the dielectric constant of vacuum, A represents the contact area of the two electrode plates, μ is the friction coefficient, d represents the distance between the two electrode plates, and U is the voltage of the high-voltage AC power supply.

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