Quadruped robot foot end three-dimensional force pressure sensor

Abstract

The application discloses a kind of four-legged robot foot end three-dimensional force sensor, including spherical silica gel foot end, thin film pressure sensor, five surface support, five-way signal conversion module, fixed bolt.Thin film pressure sensor is installed on the surface of five surface support, and is mutually matched with the inner surface of spherical silica gel foot end Assembly.Five surface support is fastened in calf end by bolt.Five-way signal switching module inside includes five amplification circuits, respectively with five thin film pressure sensor by line connection.The application utilizes front-back symmetry, left-right symmetry, and ground total five thin film pressure sensors, so that the included angle formed by four-legged robot and ground in its leg portion can be acquired three-dimensional force size on foot end when moving in arbitrary normal action angle range.The application is simple to install, and has strong applicability, light quality, high measurement accuracy, low cost, convenient and effective.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and specifically to a three-dimensional force and pressure sensor device for the foot end of a quadruped robot. Background Technology

[0002] With their strong adaptability to complex terrains, quadruped robots have become a hot research topic in mobile robotics, and the design of foot sensors is fundamental to achieving quadrupedal walking. Foot-end three-dimensional force and pressure sensors achieve foot control based on force control, combining force feedback signals with position control input signals, and using relevant force-position hybrid algorithms to achieve overall motion control of the quadruped robot.

[0003] Foot pressure sensors are widely used detection devices for acquiring force signals from the foot. A well-designed foot sensor can make quadruped robots walk more easily and adapt to more complex terrains.

[0004] However, currently available foot pressure sensors can generally only detect forces perpendicular to the ground, and they suffer from problems such as complex installation, low accuracy, heavy weight, and high cost. Summary of the Invention

[0005] The purpose of this invention is to design a three-dimensional force and pressure sensor device for the foot to solve the problems existing in the background art.

[0006] To achieve the above objectives, 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-channel signal conversion module, and fixing bolts;

[0007] The spherical silicone foot is made by mixing silicone and curing liquid. It is formed by pouring the mixture of silicone and curing liquid into the internal space formed by the foot mold and the five-sided support body. This effectively reduces the impact of the foot touching the ground and prevents slipping.

[0008] The thin-film pressure sensor is mounted on the five bottom surfaces of the five-sided support and is assembled in conjunction with the inner surface of the spherical silicone foot.

[0009] The five-sided support is manufactured by 3D printing and is connected to the end of the lower leg by fixing bolts;

[0010] The five-channel signal conversion module includes five amplification circuits, which are connected to five thin-film pressure sensors via wires. Each amplification circuit includes a sliding rheostat. The surface of the thin-film pressure sensor is covered with silicone. The thickness of the silicone directly affects the amount of pressure applied to the surface of the thin-film pressure sensor. The amplification factor can be adjusted by changing the resistance value of the sliding rheostat.

[0011] Optionally, the angle between the four front, back, left, and right sides of the five-sided support and the bottom surface is designed to be 45 degrees, so that the foot can obtain the pressure value in three directions when the foot is subjected to force.

[0012] Optionally, the voltage output of the five-channel 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 the output voltage value of the foot sensor and the magnitude of the three-dimensional force on the sole of the foot are acquired through a data acquisition card.

[0013] Optionally, the relationship between the voltage values ​​output by the five thin-film pressure sensors and the three-dimensional force on the sole of the foot is calibrated using Gaussian process regression to find the mapping relationship between the output voltage signal of the foot sensor and the three-dimensional force on the sole of the foot, and to reliably estimate the three-dimensional force on the sole of the foot.

[0014] The beneficial effects of this invention are as follows:

[0015] The three-dimensional force pressure sensor at the foot of the quadruped robot of the present invention is reasonably designed, simple in structure, lightweight, low in cost, and highly accurate, enabling the quadruped robot to obtain the magnitude of the three-dimensional force at the foot end within any range of normal movement angles formed by its legs and the ground. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a three-dimensional force and pressure sensor at the foot of a quadruped robot in one embodiment of the present invention;

[0017] Figure 2 This is a 3D circuit model diagram of a five-channel signal conversion module in one embodiment of the present invention;

[0018] Figure 3 This is a cross-sectional view of the spherical silicone foot end in one embodiment of the present invention;

[0019] Figure 4 This is a cross-sectional view of the five-sided support structure in one embodiment of the present invention;

[0020] Figure 5 This is a top view of a five-sided support body in one embodiment of the present invention;

[0021] In the diagram: 1. Spherical silicone foot tip; 2. Thin-film pressure sensor; 3. Five-sided support body; 4. Five-channel signal conversion module; 5. Lower leg; 6. Fixing bolt; 11. Outer surface of the bottom of the silicone foot tip; 12. Inner surface of the bottom of the silicone foot tip; 13. Through hole of the silicone foot tip; 31. Outer surface of the five-sided support body; 32. Inner surface of the five-sided support body; 33. Through hole of the five-sided support body; 41. Amplification circuit. Detailed Implementation

[0022] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0023] The working process of this invention is as follows:

[0024] like Figure 1 As shown, the three-dimensional force pressure sensor at the foot of the quadruped robot includes an external spherical silicone foot end 1, a thin-film pressure sensor 2, a five-sided support body 3, a five-channel signal conversion module 4, and fixing bolts 6.

[0025] like Figure 3-5 As shown, the spherical silicone foot 1 is made of silicone with a Shore hardness of 50 and curing liquid mixed in a ratio of 10:1. It is formed by pouring the mixture of silicone and curing liquid into the internal space formed by the foot mold and the outer surface 31 of the five-sided support body, which effectively reduces the impact of the foot touching the ground and prevents slipping.

[0026] like Figure 1 As shown, the material of the thin-film pressure sensor 2 includes polyester film with excellent comprehensive mechanical properties, highly conductive material and nano-level pressure-sensitive material; since the Z-direction force changes between 0 and 60 N during the movement of the quadruped robot, the model of the thin-film pressure sensor 2 is selected as RP-C18.3-ST, with a sensing range between 0 and 260 N; the RP-C pressure sensor is installed on the five bottom surfaces of the five-sided support 3 and is assembled with the inner surface of the spherical silicone foot 1.

[0027] like Figures 3-5 As shown, the thin-film pressure sensor 2 is mounted on the outer surface 31 of the five-sided support body and is assembled with the inner surface 12 of the bottom of the silicone foot. The end of the lower leg 5 is fitted with the inner surface 32 of the five-sided support body.

[0028] The outer surface 11 at the bottom of the silicone foot is designed as a hemispherical shape, while the upper part is designed according to the calf model. The two silicone foot through holes 13 on the upper part are connected to the end of the calf 5 and the through holes 33 of the five-sided support body by fixing bolts 6.

[0029] like Figure 4 As shown, the five-sided support 3 is 3D printed from polylactic acid material and is connected to the end of the lower leg 5 by fixing bolts 6. The bottom of the five-sided support 3 is a five-sided prism with five faces: front, back, left, right, and bottom. Five thin-film pressure sensors 2 are respectively centered and attached to the surfaces of the five faces.

[0030] like Figure 5 As shown, the thin-film pressure sensor 2 is attached to the center of each of the five faces of the five-faced support 3.

[0031] like Figures 2-3As shown, the five-channel signal conversion module 4 contains five amplifier circuits 41, each outputting a voltage in the range of 0.13V-3V. The five amplifier circuits 41 are connected to five thin-film pressure sensors 2 via wires, and the five-channel signal conversion module 4 is connected to a microcontroller. Each amplifier circuit 41 includes a sliding rheostat. The surface of the thin-film pressure sensor 2 is covered with silicone; the thickness of the silicone directly affects the pressure applied to the surface of the thin-film pressure sensor 2. By adjusting the sliding rheostat, the resistance value is changed, thereby adjusting the amplification factor and amplifying the voltage variation to the range of 0.1V-0.3V.

[0032] The angle between the four sides of the five-sided support 3 (front, back, left, right) and the bottom surface is designed to be 45 degrees, so that the spherical silicone foot 1 can obtain the pressure value in three directions when under force.

[0033] The five-channel signal conversion module 4 outputs a voltage in the range of 0.13V-3V. The pressure value is obtained through a three-dimensional force sensor of model LZ-SWF90, and the output voltage value of the foot sensor and the magnitude of the three-dimensional force on the sole of the foot are obtained through a data acquisition card of model NI USB-6009.

[0034] The relationship between the voltage values ​​output by the five thin-film pressure sensors 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 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.

[0035] This invention is reasonably designed, has a simple structure, low cost, and high precision, enabling the quadruped robot to obtain the magnitude of three-dimensional force on its feet when moving within any range of normal operating angles formed by its legs and the ground.

Claims

1. A three-dimensional force sensor at the foot of a quadruped robot, characterized in that: Includes spherical silicone foot, thin-film pressure sensor, five-sided support, five-channel signal conversion module, and fixing bolts; The spherical silicone foot is made by mixing silicone and curing liquid. It is formed by pouring the mixture of silicone and curing liquid into the internal space formed by the foot mold and the five-sided support body. This effectively reduces the impact of the foot touching the ground and prevents slipping. The thin-film pressure sensor is mounted on the five bottom surfaces of the five-sided support and is assembled in conjunction with the inner surface of the spherical silicone foot. The five-sided support is manufactured by 3D printing and is connected to the end of the lower leg by fixing bolts; The five-channel signal conversion module includes five amplification circuits, which are connected to five thin-film pressure sensors via wires. Each amplification circuit includes a sliding rheostat. The surface of the thin-film pressure sensor is covered with silicone. The thickness of the silicone directly affects the amount of pressure applied to the surface of the thin-film pressure sensor. The amplification factor is adjusted by changing the resistance value of the sliding rheostat.

2. The three-dimensional force sensor at the foot of a quadruped robot according to claim 1, characterized in that: The angle between the four sides (front, back, left, and right) of the five-sided support and the bottom surface is designed to be 45 degrees, so that the foot can receive pressure values ​​in three directions when it is under force.

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

4. The three-dimensional force sensor at the foot 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 on the sole of the foot is determined by using Gaussian process regression to calibrate the three-dimensional force on the sole of the foot, find the mapping relationship between the output voltage signal of the foot 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.

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