Torque sensor for robot joint and articulated robot

Abstract

The utility model discloses a torque sensor for a robot joint, which comprises a circular sheet-shaped elastic body and a strain gauge, the sheet-shaped elastic body comprises a fixed mounting surface, the upper side and the lower side of the fixed mounting surface are respectively provided with a strain groove with a side wall and a bottom wall, and the strain grooves are connected through a through groove. The through groove comprises first grooves which are arranged on two sides of the strain groove and extend along the radial direction of the sheet-shaped elastic body and second grooves which are connected with two adjacent first grooves in a penetrating mode and extend along the circumferential direction of the sheet-shaped elastic body, the width of the through groove is 0.8-1.0 mm, and the strain gauge is arranged on the bottom wall of the strain groove. The torque sensor is compact in structure and easy to install and maintain, stress can be effectively released, the influence of bending moment on the measurement precision of the sensor is remarkably reduced, sensitivity is high, measurement signals are more stable, and the torque sensor is more suitable for high-precision and high-reliability articulated robots.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of sensor, especially be related to a torque sensor for robot joint place. BACKGROUND

[0002] The statements in this section merely provide background information related to the utility model and can not constitute the prior art.

[0003] Torque sensor, also known as moment sensor, torsion sensor, torque sensor or torque meter, its core function is to accurately perceive and detect the torsional moment on the rotating or non-rotating mechanical parts. Through the built-in circuit mechanism, the sensor can accurately convert the physical change of torque into an electrical signal. Torque sensor is mainly divided into dynamic and static two categories, one of the key types of static torque sensor operates according to the resistance strain principle, which can convert the strain effect caused by torque into corresponding electrical signal output.

[0004] In the technical system of robot joints, torque sensor plays a vital monitoring role and is integrated into each joint unit of the robot. For robots pursuing excellent performance, it is crucial to select torque sensors with high precision matching, stable and reliable performance, wide measurement range and compact installation size. However, the current market torque sensors of the same kind generally have problems such as insufficient sensitivity, complex structure, weak bending moment resistance and easy drift of detection signal.

[0005] In view of the above challenges, an innovative structural design scheme is proposed to comprehensively improve the overall performance and practicality of torque sensor, which has extremely important significance. CONTENT OF THE UTILITY MODEL

[0006] In view of the deficiencies of the prior art, the utility model solves the technical problem of providing a torque sensor for robot joints.

[0007] To achieve the above purpose, the utility model provides the following technical scheme:

[0008] A torque sensor for robot joints, comprising a circular sheet-shaped elastic body and a strain gauge, characterized in that the sheet-shaped elastic body comprises a fixed mounting surface, the upper and lower sides of the fixed mounting surface are provided with strain grooves with side walls and bottom walls, each strain groove is connected through a through groove, the through groove comprises a first groove extending along the radial direction of the sheet-shaped elastic body and a second groove extending along the circumferential direction of the sheet-shaped elastic body connecting the first grooves of adjacent two, the width of the through groove is 0.8-1.0 mm, and the strain gauge is arranged on the bottom wall of the strain groove.

[0009] Further, the sheet-shaped elastic body comprises a loading installation surface, the second grooves are arranged circumferentially along the loading installation surface, and the through grooves are arranged for releasing stress and arranging lines.

[0010] Further, the strain grooves are uniformly distributed along the horizontal direction of the fixed installation surface, the width of the strain grooves is greater than the width of the through grooves, and the width of the first grooves and the second grooves is the same.

[0011] Further, the sheet-shaped elastic body is in a stepped flange shape, and the fixed installation surface, the loading installation surface and the centering structure are sequentially arranged according to the order of increasing thickness.

[0012] Further, the fixed installation surface, the loading installation surface and the centering structure are arranged on different horizontal planes in a decreasing diameter order.

[0013] Further, the strain grooves are uniformly distributed along the horizontal direction of the fixed installation surface.

[0014] Further, a plurality of threaded holes are arranged on the fixed installation surface and the loading installation surface, the threaded holes are uniformly distributed along the horizontal direction of the centering structure, and are staggered with the strain grooves.

[0015] Further, the through grooves are processed by milling or water jet processing.

[0016] Further, the material of the sheet-shaped elastic body is one or more of amorphous alloy, stainless steel, titanium alloy, high-entropy alloy and aluminum alloy.

[0017] A joint robot comprises the torque sensor.

[0018] In the torque sensor, stress can be effectively released when a bending moment is borne at a joint of the robot, the influence of the bending moment on the measurement accuracy of the sensor is significantly reduced, the sensitivity is high and the measurement signal is more stable, and the torque sensor is more suitable for a mechanical arm of a joint robot with high precision and high reliability. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application.

[0020] Fig. 1 A perspective view of the torque sensor according to one embodiment of the present application is shown.

[0021] Fig. 2 A front view of the torque sensor according to one embodiment of the present application is shown.

[0022] Fig. 3 A cross-sectional view of a torque sensor according to one embodiment of the present application is shown.

[0023] The meanings of the various reference numerals in the drawings are as follows:

[0024] Sheet-shaped elastomer-1; fixed mounting surface-2; strain groove-3; strain gauge-4; second groove-5; loading mounting surface-6; centering structure-7; threaded hole-8; first groove-9. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below with reference to the drawings. It should be noted that the embodiments given by the present application are only for illustration, and do not limit the protection scope of the present application.

[0026] As shown in Figs. 1-3 A torque sensor according to one embodiment of the present application is shown. The sheet-shaped elastomer 1 is a circular sheet-shaped structure, and includes a fixed mounting surface 2. The upper and lower sides of the fixed mounting surface 2 are each provided with a strain groove 3 having a side wall and a bottom wall. Each strain groove 3 is connected by a through groove. The through groove includes a first groove 9 extending in the radial direction of the sheet-shaped elastomer 1 and provided on both sides of the strain groove 3, and a second groove 5 extending in the circumferential direction of the sheet-shaped elastomer 1 and connecting the first grooves 9 of adjacent two. The width of the through groove is 0.8-1.0 mm. A strain gauge 4 is provided on the bottom wall of the strain groove 3.

[0027] Specifically, the second groove 5 connects the adjacent first grooves 9 to form a ring-shaped or partial ring-shaped structure. The first grooves 9 are uniformly arranged along the direction of the circular sheet-shaped elastomer 1, thereby realizing the connectivity between the through groove and the strain groove 3. In some embodiments, the width of the through groove is 0.8-1.0 mm. The narrower through groove can reduce the stress concentration phenomenon and avoid structural damage caused by excessive local stress. When the torque sensor bears a bending moment, the through groove can isolate most of the bending moment, significantly reducing the interference of the bending moment on the torque measurement accuracy of the torque sensor. In addition, the torque sensor structure proposed by the present application is compact, which enhances the stiffness and use range of the sheet-shaped elastomer 1. When the torque sensor is loaded with a torque, the strain grooves 3 on the fixed mounting surface 2 can produce a larger and uniform elastic strain, thereby improving the sensitivity of the torque sensor and the stability of the measurement signal.

[0028] In some embodiments, the sheet-shaped elastomer 1 includes a loading mounting surface 6. The second grooves 5 are uniformly arranged along the circumferential direction of the loading mounting surface 6. The through groove is provided for stress release and wiring arrangement.

[0029] In some embodiments, the strain grooves 3 are uniformly distributed along the horizontal direction of the fixed mounting surface 2, and the width of the strain grooves 3 is greater than the width of the through grooves, and the widths of the first grooves 9 and the second grooves 5 are the same. The wider strain grooves 3 can better withstand external loads, reducing the risk of damage due to local stress concentration, while also helping to improve the accuracy of the measurement.

[0030] In some embodiments, as shown in FIG. 1, the sheet-shaped elastic body 1 is in the shape of a stepped flange, and is sequentially provided with a fixed mounting surface 2, a loading mounting surface 6, and a centering structure 7 in order of increasing thickness. The centering structure 7 is designed in the shape of a stepped boss and is arranged on the loading mounting surface 6 to achieve precise centering. The centering structure 7 can ensure that the torque sensor is precisely connected with the mechanical arm. Therefore, the above structure not only ensures the cooperation accuracy of the torque sensor and the mechanical arm, but also effectively avoids torque eccentricity. Fig. 2

[0031] In some embodiments, the fixed mounting surface 2, the loading mounting surface 6, and the centering structure 7 are arranged on different horizontal planes in order of decreasing diameter. This not only simplifies the assembly process of the torque sensor, but also avoids the influence of the pre-tightening force of the bolts on the measurement accuracy of the torque sensor during the installation process.

[0032] In some embodiments, the strain gauges 4 are uniformly distributed along the horizontal direction of the fixed mounting surface 2. The strain gauges 4 are used to obtain measurable strain signals and convert them into analog signals.

[0033] In some embodiments, the strain gauges 4 are preferably resistance strain gauges.

[0034] In some embodiments, the strain gauges 4 are selected from one or more of the following: straight strain gauges, T-shaped strain gauges, V-shaped strain gauges, double-bridge strain gauges, three-grid strain gauges, and full-bridge strain gauges. Preferably, the strain gauges 4 are V-shaped strain gauges, which have good resistance to bending moment crosstalk and can provide higher measurement sensitivity and accuracy.

[0035] In some embodiments, a strain gauge 4 is arranged on the bottom wall of each strain groove 3, and each strain gauge 4 is connected by a signal line to form a Wheatstone bridge circuit. This not only improves the accuracy of the measurement, but also enhances the stability of the signal. Through the balance of the Wheatstone bridge, reliable torque measurement results can be obtained under various working conditions. In addition, this design also allows individual calibration of each strain gauge 4, further improving the measurement accuracy and flexibility of the torque sensor.

[0036] In some embodiments, the strain gauges 4 can be fixed to the surface of the sheet-shaped elastic body 1, and preferably, the strain gauges 4 are fixed to the bottom wall of the strain grooves 3 of the sheet-shaped elastic body 1.

[0037] ​In some embodiments, a plurality of threaded holes 8 are formed on the fixed mounting surface 2 and the loading mounting surface 6, and are uniformly distributed along the horizontal direction of the centering structure 7 and staggered with the strain grooves 3. Preferably, the number of threaded holes on the fixed mounting surface 2 and the loading mounting surface 6 is 6-12.

[0038] In some specific embodiments, 6 threaded holes 8 are uniformly arranged on the fixed mounting surface 2 to ensure the connection strength of the sheet-shaped elastic body 1 and the mechanical arm.

[0039] In some specific embodiments, 6 strain grooves 3 are uniformly arranged on the upper and lower sides of the fixed mounting surface 2, respectively, and are staggered with the threaded holes 8. In this way, staggered arrangement can disperse stress, reduce local stress level, and maintain the overall strength and stability of the fixed mounting surface 2.

[0040] In some specific embodiments, 6 threaded holes 8 are uniformly arranged on the loading mounting surface 6 to connect the sheet-shaped elastic body 1 and the robot joint by bolts. It can better withstand and disperse the force and torque generated by the movement of the robot joint, allowing the articulated robot to perform precise motion control in different directions, improving the flexibility and adaptability of the robot.

[0041] In some embodiments, the through groove is processed by milling or water jet machining process. It effectively avoids the change of material performance caused by high temperature in the wire cutting process.

[0042] In some embodiments, the material of the sheet-shaped elastic body 1 is one or more of amorphous alloy, stainless steel, titanium alloy, high-entropy alloy, and aluminum alloy. Preferably, the material of the sheet-shaped elastic body 1 is amorphous alloy.

[0043] In some embodiments, the thickness of the sheet-shaped elastic body 1 is 0.01mm-10.0mm, preferably 1.0mm-10.0mm, and more preferably 5.0mm-7.0mm.

[0044] In some embodiments, the sensitivity of the torque sensor is 1.0mV / (N·m)-10.0mV / (N·m), preferably 4.0mV / (N·m)-6.0mV / (N·m), and most preferably 5.0mV / (N·m).

[0045] In some embodiments, the articulated robot includes a torque sensor. Specifically, when the torque sensor is used with the robot, the torque sensor can detect the change in torque due to external load or internal power during the movement of the robot joint. When the robot moves quickly or is impacted, the torque sensor can also quickly respond to the sudden change in torque to achieve effective force control and ensure the safe operation of the robot when it is impacted or subjected to accidental overload.

[0046] Although the utility model has been described through the embodiment, however, the utility model is not limited to the embodiment described here, still includes the various changes and changes made without departing from the scope of the utility model.

Claims

1. A torque sensor for use at a joint of a robot, comprising a circular sheet of elastomer and a strain gauge, characterised in that, The sheet-shaped elastic body comprises a fixed mounting surface, both upper and lower sides of the fixed mounting surface are provided with strain grooves with side walls and bottom walls, each of the strain grooves is connected through a through groove, the through groove comprises a first groove extending along the radial direction of the sheet-shaped elastic body arranged on both sides of the strain groove and a second groove extending along the circumferential direction of the sheet-shaped elastic body connecting the first grooves of two adjacent strain grooves, the width of the through groove is 0.8-1.0mm, and the strain gauge is arranged on the bottom wall of the strain groove.

2. The torque sensor of claim 1, wherein, The sheet-shaped elastic body comprises a fixed mounting surface, both upper and lower sides of the fixed mounting surface are provided with strain grooves with side walls and bottom walls, each of the strain grooves is connected through a through groove, the through groove comprises a first groove extending along the radial direction of the sheet-shaped elastic body arranged on both sides of the strain groove and a second groove extending along the circumferential direction of the sheet-shaped elastic body connecting the first grooves of two adjacent strain grooves, the width of the through groove is 0.8-1.0mm, and the strain gauge is arranged on the bottom wall of the strain groove.

3. The torque sensor of claim 1, wherein, The strain grooves are uniformly distributed along the horizontal direction of the fixed mounting surface, the width of the strain groove is greater than the width of the through groove, and the width of the first groove and the second groove is the same.

4. The torque sensor of claim 1, wherein, The sheet-shaped elastic body is in the shape of a stepped flange, and the fixed mounting surface, the loading mounting surface and the centering structure are sequentially arranged according to the order of increasing thickness.

5. The torque sensor of claim 4, wherein, The fixed mounting surface, the loading mounting surface and the centering structure are arranged on different horizontal planes with diameters decreasing in sequence.

6. The torque sensor of claim 1, wherein, The strain gauges are uniformly distributed along the horizontal direction of the fixed mounting surface.

7. The torque sensor of claim 4, wherein, A plurality of threaded holes are arranged on the fixed mounting surface and the loading mounting surface, the threaded holes are uniformly distributed along the horizontal direction of the centering structure and are staggered with the strain grooves.

8. The torque sensor of claim 1, wherein, The through groove is processed by milling or water jet processing.

9. The torque sensor of claim 1, wherein, The material of the sheet-shaped elastic body is one or more of amorphous alloy, stainless steel, titanium alloy, high-entropy alloy and aluminum alloy.

10. An articulated robot, characterized in that The articulated robot comprises the torque sensor according to any one of claims 1-9.

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