Foot end three-dimensional force pressure sensor of quadruped robot

Abstract

The invention discloses a foot end three-dimensional force sensor for a quadruped robot. The foot end three-dimensional force sensor comprises a spherical silica gel foot end, a thin film type pressure sensor, a five-face supporting body, a five-way signal conversion module and a fixing bolt. The film type pressure sensor is installed on the surface of the five-face supporting body and assembled with the inner surface of the foot end of the spherical silica gel in a matched mode. And the pentahedral support body is fastened at the tail end of the shank through a bolt. And the five-path signal switching module internally comprises five amplifying circuits which are respectively connected with the five film type pressure sensors through wires. According to the four-foot robot, five film type pressure sensors which are in front-back symmetry, left-right symmetry and ground symmetry are utilized, so that when the four-foot robot moves within the range that the included angle formed by the legs of the four-foot robot and the ground is any normal action angle range, the three-dimensional force at the foot ends can be obtained. The device is simple in installation, high in applicability, light in weight, high in measurement precision, low in cost, convenient and effective.

Description

Technical Field

[0001] The present invention relates to the field of sensor technology, and in particular to a three-dimensional force pressure sensor device at the foot end of a quadruped robot. Background Art

[0002] With its strong adaptability to complex terrain, quadruped robots have become a hot topic in mobile robot research today, and the design of foot-end sensors is the basis for realizing quadruped walking. The foot-end three-dimensional force pressure sensor realizes foot-end control based on force control, combines the force feedback model with the position control input signal, and realizes the overall motion control of the quadruped robot through the relevant force-position hybrid algorithm.

[0003] The foot pressure sensor is a widely used detection device used to obtain the foot force signal. A good foot sensor design can make the quadruped robot walk more conveniently and also enable it to adapt to more complex terrains.

[0004] However, the foot pressure sensors currently on the market can generally only obtain the force perpendicular to the ground, and have problems such as complex installation, low accuracy, heavy weight, and high cost. Summary of the invention

[0005] The purpose of the present invention is to design a foot-end three-dimensional force pressure sensor device to solve the problems existing in the above-mentioned background technology.

[0006] To achieve the above-mentioned object, the present invention provides a three-dimensional force sensor for the foot end of a quadruped robot, comprising a spherical silicone foot end, a thin film pressure sensor, a five-sided support body, a five-way signal conversion module, and a fixing bolt; The spherical silicone foot end is prepared by mixing silicone and curing liquid, and is formed by pouring the mixture of silicone and curing liquid into the internal space formed by the outer surface of the manufactured foot end mold and the five-sided support body, which effectively alleviates the impact caused by the foot end touching the ground and prevents slipping; The thin film pressure sensor is mounted on the five bottom surfaces of the five-sided support body and assembled in cooperation with the inner surface of the spherical silicone foot end; The five-sided support body is made by 3D printing and is connected to the end of the calf by fixing bolts; The five-way signal adapter module includes five amplifying circuits, which are respectively connected to five thin-film pressure sensors by wires. Each amplifying circuit includes a sliding rheostat. The surface of the thin-film pressure sensor is covered with silicone. The thickness of the silicone will directly affect the extrusion force on the surface of the thin-film pressure sensor. The resistance value is changed by adjusting the sliding rheostat to adjust the amplification factor.

[0007] Optionally, the angle formed by the four front, back, left and right surfaces of the five-sided support body and the lowest bottom surface is designed to be 45 degrees, so as to ensure that the pressure values ​​in three directions of the foot end when the foot end is subjected to force can be obtained in all directions of the foot end.

[0008] Optionally, the voltage value output by the five-way signal conversion module is in the range of 0.1V-3.3V, and the pressure value is obtained through a calibrated three-dimensional force sensor, and then the output voltage value of the foot sensor and the three-dimensional force of the sole are obtained through a data acquisition card.

[0009] Optionally, the relationship between the voltage values ​​output by the five thin-film pressure sensors and the three-dimensional force of the plantar foot is used to calibrate the three-dimensional force of the plantar foot using Gaussian process regression, find the mapping relationship between the output voltage signal of the foot-end sensor and the three-dimensional force of the plantar foot, and reliably estimate the three-dimensional force of the foot-end.

[0010] The beneficial effects of the present invention are: The three-dimensional force pressure sensor at the foot end of the quadruped robot of the present invention has a reasonable design, a simple structure, a light weight, a low cost and a high precision, so that the quadruped robot can obtain the three-dimensional force size on the foot end within any normal movement angle range when the angle formed by the legs of the quadruped robot and the ground is within. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the overall structure of a three-dimensional force pressure sensor at the foot end of a quadruped robot in one embodiment of the present invention; Figure 2 A circuit 3D model diagram of a five-channel signal conversion module in one embodiment of the present invention; Figure 3 It is a structural cross-sectional view of a spherical silica gel foot end in one embodiment of the present invention; Figure 4 It is a structural cross-sectional view of a five-sided support body in one embodiment of the present invention; Figure 5 A top view of a five-sided support body in one embodiment of the present invention; In the figure: 1. Spherical silicone foot; 2. Thin film pressure sensor; 3. Five-sided support; 4. Five-way signal conversion module; 5. Lower leg; 6. Fixing bolt; 11. Outer surface of the bottom of silicone foot; 12. Inner surface of the bottom of silicone foot; 13. Through hole of silicone foot; 31. Inner surface of five-sided support; 32. Inner surface of five-sided support; 33. Through hole of five-sided support; 41. Amplifying circuit. DETAILED DESCRIPTION

[0012] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0013] The working process of the present invention is as follows: like Figure 1As shown, the three-dimensional force pressure sensor at the foot end of a quadruped robot includes an external spherical silicone foot end 1, a thin film pressure sensor 2, a five-sided support body 3, a five-way signal conversion module 4, and a fixing bolt 6.

[0014] like Figure 3-5 As shown, the spherical silicone foot end 1 is made of silicone with a Shore hardness of 50 and a curing liquid in a ratio of 10:1. It is formed by pouring a mixture of silicone and curing liquid into the internal space formed by the manufactured foot end mold and the outer surface 31 of the five-sided support body, which effectively alleviates the impact caused by the foot end touching the ground and prevents slipping.

[0015] like Figure 1 As shown, the material of the thin film pressure sensor 2 includes polyester film with excellent comprehensive mechanical properties, high conductive material and nano-level pressure sensitive material; because the variation range of the Z-direction force is between 0.60N when the quadruped robot moves, the model of the thin film pressure sensor 2 is selected as RP-C18.3-ST, and the sensing range is between 0.260N; the RP-C pressure sensor is installed on the five bottom surfaces of the five-sided support body 3 and assembled with the inner surface of the spherical silicone foot end 1.

[0016] like Figure 3-Figure 5 As shown, the thin film pressure sensor 2 is mounted on the inner surface 31 of the five-sided support body, and is assembled with the inner surface 12 of the bottom of the silicone foot end, and the end of the calf 5 is matched with the inner surface 32 of the five-sided support body.

[0017] The outer surface 11 of the bottom of the silicone foot end is designed to be hemispherical, and the upper design is based on the calf model. The two silicone foot end through holes 13 on the upper side are connected to the end of the calf 5 and the five-sided support body through holes 33 through fixing bolts 6.

[0018] like Figure 4 As shown, the five-sided support body 3 is made of polylactic acid material by 3D printing, and is connected to the end of the shank 5 by a fixing bolt 6. The bottom of the five-sided support body 3 is a five-sided prism, with five faces, front and back, left and right, and bottom, and five thin-film pressure sensors 2 are respectively centered and attached to the surfaces of the five faces.

[0019] like Figure 5 As shown, the thin-film pressure sensor 2 is attached to the centers of the five surfaces of the five-sided support body 3 respectively.

[0020] like Figure 2-Figure 3As shown, the five-way signal adapter module 4 includes five amplifier circuits 41, and the voltage output by the amplifier circuit 41 is in the range of 0.13V-3V. The five amplifier circuits 41 are respectively connected to the five thin-film pressure sensors 2 through wires, and the five-way signal adapter module 4 is connected to the single-chip microcomputer. Each amplifier circuit 41 includes a sliding rheostat; the surface of the thin-film pressure sensor 2 is covered with silicone, and the thickness of the silicone will directly affect the size of the extrusion force on the surface of the thin-film pressure sensor 2. By adjusting the sliding rheostat to change the resistance value and then adjust the amplification factor, the voltage change is amplified to the range of 0.1V-0.3V.

[0021] The angle formed by the four front, back, left and right surfaces of the five-sided support body 3 and the bottom bottom surface is designed to be 45 degrees, so that the pressure values ​​of the spherical silicone foot end 1 in three directions when subjected to force can be obtained in all directions of the spherical silicone foot end 1.

[0022] The voltage value of the five-way signal conversion module 4 is in the range of 0.13V-3V. The pressure value is obtained through the three-dimensional force sensor of model LZ-SWF90, and then the output voltage value of the foot sensor and the three-dimensional force of the plantar are obtained through the data acquisition card of model NI USB-6009.

[0023] The relationship between the voltage values ​​output by the five thin-film pressure sensors 2 and the three-dimensional force on the sole of the foot is too complex to be analytically modeled. Gaussian process regression is used to calibrate the three-dimensional force on the sole of the foot, find the mapping relationship between the output voltage signal of the foot-end sensor and the three-dimensional force on the sole of the foot, and reliably estimate the three-dimensional force on the sole of the foot.

[0024] The invention has reasonable design, simple structure, low cost and high precision, so that the three-dimensional force on the foot end of the quadruped robot can be obtained when the angle formed by its legs and the ground is within any normal action angle range.

Claims

1. A three-dimensional force sensor at the foot end of a quadruped robot, characterized in that: It includes a spherical silicone foot end, a thin film pressure sensor, a five-sided support body, a five-way signal conversion module, and fixing bolts; The spherical silicone foot end is prepared by mixing silicone and curing liquid, and is formed by pouring the mixture of silicone and curing liquid into the internal space formed by the outer surface of the manufactured foot end mold and the five-sided support body, which effectively alleviates the impact caused by the foot end touching the ground and prevents slipping; The thin film pressure sensor is mounted on the five bottom surfaces of the five-sided support body and assembled in cooperation with the inner surface of the spherical silicone foot end; The five-sided support body is made by 3D printing and is connected to the end of the calf by fixing bolts; The five-way signal adapter module includes five amplifying circuits, which are respectively connected to five thin-film pressure sensors by wires. Each amplifying circuit includes a sliding rheostat. The surface of the thin-film pressure sensor is covered with silicone. The thickness of the silicone will directly affect the extrusion force on the surface of the thin-film pressure sensor. The resistance value is changed by adjusting the sliding rheostat to adjust the amplification factor.

2. The three-dimensional force sensor at the foot end of a quadruped robot according to claim 1, characterized in that: The angle formed by the four front, back, left and right surfaces of the five-sided support body and the bottom bottom surface is designed to be 45 degrees, so that the pressure values ​​of the foot end in three directions when the foot end is subjected to force can be obtained in all directions of the foot end.

3. A three-dimensional force sensor at the foot end of a quadruped robot according to claim 1, characterized in that: The voltage value output by the five-way signal conversion module is in the range of 0.1V-3.3V. The pressure value is obtained through a calibrated three-dimensional force sensor, and then the output voltage value of the foot sensor and the three-dimensional force of the sole are obtained through a data acquisition card.

4. The three-dimensional force sensor at the foot end of a quadruped robot according to claim 1, characterized in that: The relationship between the voltage values ​​output by the five thin-film pressure sensors and the three-dimensional force of the sole of the foot is obtained. The three-dimensional force of the sole of the foot is calibrated using Gaussian process regression, the mapping relationship between the output voltage signal of the foot-end sensor and the three-dimensional force of the sole of the foot is found, and the three-dimensional force of the foot-end is reliably estimated.

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