Joint torque sensor for intelligent medical robot

Abstract

The joint torque sensor for the intelligent medical robot comprises an elastic body, a strain circuit, a flexible circuit board and a silica gel protective layer, the elastic body is of a hollow cylindrical structure, and the strain circuit is a Wheatstone bridge composed of four half-bridge strain gauges. The four half-bridge strain gauges are arranged on the inner surface of a shaft cavity of the elastic body in the circumferential direction of the elastic body, the flexible circuit board is arranged in the shaft cavity of the elastic body and located on the inner sides of the four half-bridge strain gauges, and the silica gel protection layer is arranged in the shaft cavity of the elastic body and located on the inner side of the flexible circuit board. The loading end and the fixed end of the sensor are concentric cylinders, so that unstable output signals of the sensor caused by non-concentric installation of the two ends of the sensor are avoided, and inaccurate torsion signals provided for a control system due to deviation of output analog signals of the sensor are avoided. Meanwhile, the input resistance and the output resistance of the Wheatstone bridge are 2000 ohms, the resistance is large, the energy consumption is low, the power consumption of the battery is greatly reduced, the working time of the robot after being charged once is prolonged, and the charging frequency is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of sensors, and in particular relates to a joint torque sensor for an intelligent medical robot. Background Art

[0002] With the advent of the intelligent era, intelligent medical robots have also emerged. In the field of medical robots, the application of intelligent medical robots is also particularly important, and the scope of application is also very wide, such as rehabilitation, treatment and surgery. Intelligent medical robots can replace manual labor to avoid some medical risks caused by improper human intervention, and the flexible, precise and continuous movements of the robot arm are inseparable from the real-time force measurement monitoring of the sensor. The torque sensor transmits the measured torque value to the main control system in real time in the form of an analog signal. The control system processes the analog signal through calculation and then adjusts and controls the robot arm in time, which can avoid damage to the robot arm due to excessive force. Intelligent medical robots can also greatly reduce medical costs by replacing manual labor.

[0003] The existing intelligent medical robot torque sensor is very small, and the strain gauge and other components are assembled in the sensor cavity. The sensor can be installed in the joint of the robot arm and can measure the torque of the robot arm in all directions when it rotates in real time. The intelligent robot control system can control the flexible, continuous and precise movement of the robot arm through the analog signal output by the sensor, without the need for human operator intervention. The existing sensor has no temperature compensation and cannot be used in an environment with large temperature changes. It can only be used in a constant temperature and humidity environment. Utility Model Content

[0004] In order to solve the defects in the prior art, the utility model provides a joint torque sensor for an intelligent medical robot.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] The utility model provides a joint torque sensor for an intelligent medical robot, comprising an elastomer, a strain circuit, a flexible circuit board, and a silicone protective layer, wherein the elastomer is a hollow cylindrical structure, the strain circuit is a Wheatstone bridge composed of four half-bridge strain gauges, the four half-bridge strain gauges are arranged on the inner surface of the axial cavity of the elastomer along the circumferential direction of the elastomer, the flexible circuit board is arranged in the axial cavity of the elastomer and is located on the inner side of the four half-bridge strain gauges, and the silicone protective layer is arranged in the axial cavity of the elastomer and is located on the inner side of the flexible circuit board.

[0007] Preferably, an axial cavity with one end open is provided inwardly on any axial end face of the elastic body, and the four half-bridge strain gauges are arc-surface structures, and the four half-bridge strain gauges are arranged on the inner surface of the axial cavity.

[0008] Preferably, a flange boss structure is provided on the end face of the elastomer close to the opening end of the shaft cavity, and a mounting hole is provided on the outer end face of the flange boss structure; a rectangular groove is provided on the end face of the elastomer away from the opening end of the shaft cavity, and a threaded hole connected to the shaft cavity is provided at the center of the bottom of the rectangular groove, and two opposite sides of the rectangular groove are open structures, and the axis center of the threaded hole and the axis center of the mounting hole are on the same straight line as the axis center of the elastomer.

[0009] Preferably, a notch for the cable assembly to pass through is also provided on the side surface of the flange boss structure, and the flexible circuit board is connected to an external plug through the cable assembly.

[0010] Preferably, a groove is further provided on the outer end surface of the flange boss structure and located outside the mounting hole.

[0011] Preferably, the elastomer is made of 17-4PH stainless steel.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] The loading end and the fixed end of the sensor of the utility model are concentric cylinders, which avoids the unstable output signal of the sensor due to the eccentric installation of the two ends of the sensor, and avoids the deviation of the output analog signal of the sensor and provides inaccurate torque signal to the control system. At the same time, the input and output resistance of the Wheatstone bridge is 2000Ω, which has large resistance and low energy consumption, greatly reducing the battery power consumption, extending the working time of the robot after one charge, and reducing the number of charging times. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the exploded structure of a joint torque sensor for an intelligent medical robot of the utility model;

[0015] Figure 2 This is a cross-sectional view of a joint torque sensor for an intelligent medical robot of the utility model;

[0016] Figure 3 This is a right view of a joint torque sensor for an intelligent medical robot of the utility model;

[0017] Figure 4 This is a left view of a joint torque sensor for an intelligent medical robot of the utility model;

[0018] Figure 5 The utility model discloses a circuit diagram of a Wheatstone bridge in a joint torque sensor for an intelligent medical robot. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0020] In the description of the present invention, it should be understood that the terms "left" and "right" indicate directions or positional relationships based on the drawings in the specification. Figure 1 The orientation or positional relationship shown is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] like Figures 1 to 5 As shown, this embodiment provides a joint torque sensor for an intelligent medical robot, including an elastic body 1, a strain circuit 2, a flexible circuit board 3, and a silicone protective layer 4. The elastic body 1 is a hollow cylindrical structure, and an axial cavity 11 with an opening at the right end is opened inward on the right axial end face of the elastic body 1. A flange boss structure 12 is provided on the end face of the elastic body 1 close to the opening end of the axial cavity, and a mounting hole 13 is provided on the outer end face of the flange boss structure 12; a rectangular groove 14 is provided on the end face of the elastic body 1 away from the opening end of the axial cavity, and a threaded hole 15 connected to the axial cavity is provided at the center of the bottom of the rectangular groove 14, and two opposite sides of the rectangular groove 14 are open structures, and the axis of the threaded hole 15 and the axis of the mounting hole 13 are on the same straight line as the axis of the elastic body 1. A notch 16 for the cable assembly to pass through is also provided on the side of the flange boss structure 12, and the flexible circuit board 3 is connected to the external plug of the cable assembly through the cable assembly. The loading end and the fixed end of the sensor are concentric cylinders, which avoids the instability of the sensor output signal caused by the eccentric installation of the two ends of the sensor, and avoids the deviation of the output analog signal of the sensor and providing inaccurate torque signals to the control system.

[0023] Specifically, the strain circuit 2 is a Wheatstone bridge composed of four half-bridge strain gauges, the four half-bridge strain gauges are arc-shaped structures, and the four half-bridge strain gauges are arranged on the inner surface of the axial cavity of the elastic body along the circumferential direction of the elastic body. The flexible circuit board 3 is arranged in the axial cavity of the elastic body 1 and is located on the inner side of the four half-bridge strain gauges, and the silicone protective layer 4 is arranged in the axial cavity of the elastic body and is located on the inner side of the flexible circuit board. The input and output resistances of the Wheatstone bridge are 2000Ω, with large resistance and low energy consumption, which greatly reduces the battery power consumption, prolongs the working time of the robot after one charge, and reduces the number of charging times.

[0024] Specifically, a groove 17 is further provided on the outer end surface of the flange boss structure 12 and located outside the mounting hole 14. Adding the groove improves the tightness of the connection between the loading end and other parts of the robot, reduces data deviation, and also improves the structural strength of the product.

[0025] Specifically, the elastomer 1 is made of 17-4PH stainless steel, which improves the service life and overload capacity of the sensor.

[0026] The working principle of this embodiment is further explained below: the joint torque sensor described in this embodiment is installed in the joint of the robotic arm of the intelligent medical robot. The robotic arm will generate torque during the torsional operation process. The sensor elastomer is elastically deformed due to the torsion of the robotic arm. The strain gauge in the elastomer changes its resistance due to the deformation. The bridge circuit converts the sensor voltage change and outputs an analog signal. The subsequent circuit control system of the robot then converts the voltage output analog signal into torque output, and the control system makes various action instructions to the robotic arm.

[0027] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A joint torque sensor for an intelligent medical robot, characterized in that: The invention comprises an elastic body (1), a strain circuit (2), a flexible circuit board (3), and a silicone protective layer (4), wherein the elastic body (1) is a hollow cylindrical structure, the strain circuit (2) is a Wheatstone bridge composed of four half-bridge strain gauges, the four half-bridge strain gauges are arranged on the inner surface of the axial cavity of the elastic body along the circumferential direction of the elastic body, the flexible circuit board (3) is arranged in the axial cavity of the elastic body (1) and is located on the inner side of the four half-bridge strain gauges, and the silicone protective layer (4) is arranged in the axial cavity of the elastic body and is located on the inner side of the flexible circuit board.

2. A joint torque sensor for an intelligent medical robot according to claim 1, characterized in that: An axial cavity (11) with one end open is provided inwardly on any axial end surface of the elastic body (1); the four half-bridge strain gauges are of an arc-shaped structure; the four half-bridge strain gauges are arranged on the inner surface of the axial cavity (11).

3. A joint torque sensor for an intelligent medical robot according to claim 2, characterized in that: The end surface of the elastic body (1) close to the opening end of the shaft cavity is provided with a flange boss structure (12), and the outer end surface of the flange boss structure (12) is provided with a mounting hole (13); the end surface of the elastic body (1) away from the opening end of the shaft cavity is provided with a rectangular groove (14), and the center of the groove bottom of the rectangular groove (14) is provided with a threaded hole (15) connected to the shaft cavity, and two opposite side surfaces of the rectangular groove (14) are open structures, and the axis center of the threaded hole (15) and the axis center of the mounting hole (13) are on the same straight line as the axis center of the elastic body (1).

4. A joint torque sensor for an intelligent medical robot according to claim 3, characterized in that: A notch (16) for the cable assembly to pass through is also provided on the side surface of the flange boss structure (12), and the flexible circuit board (3) is connected to an external plug through the cable assembly.

5. The joint torque sensor for an intelligent medical robot according to claim 3, characterized in that: A groove (17) is also provided on the outer end surface of the flange boss structure (12) and located outside the mounting hole (13).

6. The joint torque sensor for an intelligent medical robot according to claim 2, characterized in that: The elastomer (1) is made of 17-4PH stainless steel.

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