Integrated strain type torque sensor based on harmonic reducer

Abstract

The invention discloses a harmonic reducer integration-based strain torque sensor, and relates to the technical field of sensors, the harmonic reducer integration-based strain torque sensor comprises an annular strain gauge and a signal acquisition module, and the annular strain gauge is electrically connected with the signal acquisition module; the annular strain gauge is mounted on the bottom surface of the flexible gear and is concentric with the flexible gear; the signal acquisition module is mounted outside the hollow inner shaft of the flexible gear; during working, when output power of the flexible gear is subjected to resistance, the bottom surface of the flexible gear generates strain, the annular strain gauge converts a strain signal into an analog voltage signal through a Wheatstone bridge formed by a resistance wire grid, the analog voltage signal is output to the signal acquisition module, and a force value signal is obtained after digital-to-analog conversion; by arranging the annular strain gauge on the bottom surface of the flexible gear, real-time detection of output torque is realized, extra flexible introduction of deformation of the peripheral surface of the flexible gear is avoided, structural deformation is reduced, interference of rotation of a wave generator on signals is effectively suppressed through a Wheatstone bridge design, and measurement precision and stability are ensured.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a strain gauge torque sensor based on a harmonic reducer integrated. Background Technology

[0002] As one of the most influential inventions of the 20th century, robotics has become an important indicator of a country's high-tech level and industrial automation. Sensing and perception technologies, as the core of robot automatic control and intelligent development, directly determine a robot's precise control and intelligent decision-making capabilities in complex environments. Researchers generally believe that logic algorithms and artificial intelligence can improve robot performance, but this still relies on high-quality sensor feedback. Therefore, the research and development of high-performance sensors has become a crucial foundation for promoting robot intelligence.

[0003] Harmonic drive, as a novel precision transmission technology, was first applied in the field of space science. Due to its advantages such as low backlash, large transmission ratio, small size, light weight, and high load-bearing capacity, it has been rapidly adopted in aerospace, radar, medical devices, and industrial robots. Especially in industrial robots and collaborative robots, harmonic reducers have become core components of small joints. However, to achieve robot force control, relying solely on multi-dimensional force sensors at the end effector leads to structural complexity and computational difficulties. Therefore, directly configuring torque sensors at the joints is a better solution. Furthermore, joint torque sensors can measure joint torque in real time and provide feedback to the control system, making them an indispensable core component for improving robot operational sensitivity and force perception.

[0004] The existing integration methods of torque sensors with harmonic reducers still have significant limitations. For example, among the published technical solutions, CN202110124625.9 proposes adding a torque detection structure at the output end of the harmonic reducer, but this method inevitably introduces additional flexible units, resulting in a decrease in overall stiffness and an increase in weight and complexity; CN109139856A constructs a Wheatstone bridge by arranging strain gauges on the surface of the flexible wheel, but the signal is easily affected by the rotation of the wave generator, resulting in poor output stability; CN119427427A prepares a sensitive unit at the end of the flexible wheel, which can improve the detection sensitivity, but the requirements for the flexible wheel material and process are too high, making it difficult to apply on a large scale.

[0005] Overall, existing solutions all have problems to varying degrees, such as the introduction of additional flexibility, significant signal interference, or high process complexity.

[0006] In summary, the existing technology has at least the following technical problems:

[0007] Existing torque sensors integrated into harmonic reducers have technical problems such as the introduction of additional flexibility, susceptibility to interference of the measurement signal, weakening of the overall stiffness of the reducer, and limitation of high-speed response capability. Summary of the Invention

[0008] The purpose of this invention is to provide a strain gauge torque sensor based on a harmonic reducer integration, in order to solve the technical problems of existing torque sensors integrated into harmonic reducers, such as the introduction of additional flexibility, susceptibility of measurement signals to interference, weakening of the overall stiffness of the reducer, and limitation of high-speed response capability.

[0009] The preferred technical solutions among the many technical solutions provided by this invention can produce a variety of technical effects, which are described in detail below.

[0010] To address the aforementioned technical problems, the present invention provides the following technical solution:

[0011] This invention provides a strain gauge torque sensor integrated with a harmonic reducer, comprising a ring strain gauge and a signal acquisition module. The ring strain gauge is electrically connected to the signal acquisition module. The ring strain gauge is mounted on the bottom surface of the flexible wheel to be used, and the ring strain gauge and the flexible wheel are arranged concentrically. The signal acquisition module is mounted outside the hollow inner shaft of the flexible wheel. When the rotation of the flexible wheel outputs power, the resistance hinders the motion tendency, causing the ring strain gauge to generate strain on the bottom surface of the flexible wheel. The ring strain gauge converts the strain signal into an analog voltage signal through a Wheatstone bridge built by its own resistance wire grid, and outputs it to the signal acquisition module for digital-to-analog conversion into a force signal output.

[0012] In one embodiment, the annular strain gauge is bonded to the bottom surface of the flexure.

[0013] In one embodiment, the annular strain gauge is bonded to the bottom surface of the flexible wheel via epoxy resin and cured at high temperature.

[0014] In one embodiment, a signal transmission hole is provided on the hollow inner shaft peripheral wall of the flexible wheel. The signal acquisition module is led out through the signal transmission hole via a communication cable to the outside of the harmonic reducer and connected to the host computer that receives the force signal.

[0015] In one embodiment, the annular strain gauge is provided with multiple pairs of resistance wire grids with an included angle of ±45°. The multiple pairs of resistance wire grids cover the annular strain gauge in a 360° alternating ring distribution and are connected to form a Wheatstone bridge.

[0016] In one embodiment, multiple pairs of resistance wire grids are uniformly and alternately distributed in a circular manner on the annular band of the annular strain gauge along the circumferential direction.

[0017] In one embodiment, the resistance wire grid on the annular strain gauge is divided into four groups, including a first wire grid group, a second wire grid group, a third wire grid group, and a fourth wire grid group, which are connected in a manner that forms a Wheatstone bridge.

[0018] In one embodiment, the first wire grid group and the second wire grid group occupy half of the annular band of the annular strain gauge, and the third wire grid group and the fourth wire grid group occupy the other half of the annular band of the annular strain gauge; the first wire grid group and the second wire grid group are alternately distributed, and adjacent resistance wire grids in the first wire grid group and the second wire grid group sequentially form a pair of resistance wire grids with an angle of ±45°; the third wire grid group and the fourth wire grid group are alternately distributed, and adjacent resistance wire grids in the third wire grid group and the fourth wire grid group sequentially form a pair of resistance wire grids with an angle of ±45°.

[0019] In one embodiment, the first wire grid group, the second wire grid group, the third wire grid group, and the fourth wire grid group each include a plurality of the resistor wire grids; the plurality of resistor wire grids included in the first wire grid group are connected in series sequentially; the plurality of resistor wire grids included in the second wire grid group are connected in series sequentially; the plurality of resistor wire grids included in the second wire grid group are connected in series sequentially; the plurality of resistor wire grids included in the second wire grid group are connected in series sequentially.

[0020] A harmonic reducer flexure wheel integrating a strain gauge torque sensor is also provided, including a ring strain gauge and a signal acquisition module of the strain gauge torque sensor, as well as a rigid wheel, a flexure wheel and a wave generator of the harmonic reducer; the rigid wheel is sleeved outside the flexure wheel, and the wave generator is sleeved inside the flexure wheel; the ring strain gauge and the signal acquisition module are installed on the flexure wheel, and the ring strain gauge is electrically connected to the signal acquisition module.

[0021] The strain gauge torque sensor based on a harmonic reducer integrated in this invention has the following advantages:

[0022] (1) Avoiding the introduction of additional flexibility and improving structural stiffness: In this invention, the annular strain gauge is directly installed on the bottom surface of the flexible wheel, and the strain distribution of the flexible wheel is evenly distributed on its bottom surface and arranged concentrically with the flexible wheel. The annular surface of the annular strain gauge matches the annular surface of the inner bottom surface of the flexible wheel. The signal acquisition module that matches the annular strain gauge is installed in the internal space of the flexible wheel and fixed on the hollow shaft of the flexible wheel. There is no need to add an additional detection structure on the end face of the harmonic reducer, which avoids the flexibility problem introduced by the additional detection unit in the existing solution, thereby maintaining the overall stiffness and stability of the reducer.

[0023] (2) Effectively suppress signal interference and improve measurement accuracy: The present invention adopts a specially designed ring strain gauge. The resistance wire grid distributed on the ring strain gauge forms a strain measurement circuit through a Wheatstone bridge. This design can accurately convert the strain signal caused by the torque of the flexure into a voltage signal, and then convert it into a force signal output through digital-analog conversion. This effectively eliminates the interference of the measurement signal caused by the deformation of the peripheral wall of the flexure caused by the rotation of the wave generator and the introduction of additional flexibility, so as to significantly improve the output stability and measurement accuracy of the force value.

[0024] (3) Maintaining lightweight characteristics without changing the basic structure of the reducer: The strain gauge torque sensor uses the flexible wheel body as the strain carrier, and the ring strain gauge and signal acquisition module are directly arranged on the bottom surface of the flexible wheel and the hollow inner shaft. The deformation of the bottom surface of the flexible wheel is directly sensed by the thin-film ring strain gauge as the strain sensing unit. It does not change the main structure and installation method of the harmonic reducer, nor does it increase the weight and volume too much, thus maintaining the advantages of miniaturization and lightweight of the harmonic reducer.

[0025] (4) Improve joint force control performance and adapt to high-speed response scenarios: Since the strain gauge torque sensor consists only of a ring strain gauge and a signal acquisition module, the structure and arrangement are reasonable, which ensures the structural stiffness of the harmonic reducer and the stability of the force signal output of the strain gauge torque sensor. It can stably acquire the torque information output by the joint driven by the harmonic reducer under high-speed response and fast movement conditions, providing high-precision feedback for the robot's real-time force control and force perception, and effectively breaking through the application limitations of the existing harmonic reducer torque detection scheme in dynamic scenarios.

[0026] In summary, while maintaining the original structural, rigidity, and weight advantages of the harmonic reducer, this invention achieves high-precision, anti-interference, and low-flexibility torque detection, significantly improving the force control capability and applicability of robot joints. Attached Figure Description

[0027] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a cross-sectional view of the strain gauge torque sensor integrated into the harmonic reducer of the present invention.

[0029] Figure 2 This is a front view schematic diagram of the strain gauge torque sensor integrated into the harmonic reducer of the present invention;

[0030] Figure 3This is a schematic diagram of the circuit structure connecting the first wire grid group, the second wire grid group, the third wire grid group, and the fourth wire grid group of the annular strain gauge of the present invention;

[0031] Figure 4 This is a front view schematic diagram of the annular strain gauge of the present invention.

[0032] The accompanying figure is labeled as follows:

[0033] 1. Strain gauge torque sensor;

[0034] 2. Circular strain gauge; 21. Resistance wire grid; 22. Circular belt; 23. First wire grid group; 24. Second wire grid group; 25. Third wire grid group; 26. Fourth wire grid group;

[0035] 3. Signal acquisition module; 31. Communication cable;

[0036] 4. Harmonic reducer;

[0037] 5. Flexible wheel; 51. Hollow inner shaft; 52. Signal transmission hole; 53. End face flange;

[0038] 6. Rigid wheel;

[0039] 7. Wave generator. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0041] A specific embodiment provides a strain gauge torque sensor integrated with a harmonic reducer. The strain gauge torque sensor includes a ring strain gauge and a signal acquisition module, with the ring strain gauge electrically connected to the signal acquisition module. The ring strain gauge is mounted on the bottom surface of the flexible wheel and arranged concentrically with the flexible wheel. The signal acquisition module is mounted outside the hollow inner shaft of the flexible wheel. During operation, when the flexible wheel is subjected to resistance while outputting power, strain is generated on its bottom surface. The ring strain gauge converts the strain signal into an analog voltage signal through a Wheatstone bridge composed of resistance wire grids and outputs it to the signal acquisition module. After digital-to-analog conversion, a force signal is obtained. The force signal is obtained through the strain gauge on the bottom surface of the flexible wheel. By incorporating a ring strain gauge, real-time detection of the output torque is achieved, avoiding the introduction of additional flexibility due to the deformation of the flexure wheel's circumferential surface and reducing structural deformation. Simultaneously, a well-designed bridge effectively suppresses interference from the wave generator's rotation, ensuring measurement accuracy and stability. This system boasts advantages such as simple structure, light weight, strong anti-interference capability, and suitability for high-speed response scenarios, significantly improving the force control performance and application range of robot joints. It effectively solves the technical problems of existing torque sensors integrated into harmonic reducers, including the introduction of additional flexibility, susceptibility to interference in the measurement signal, weakening of the overall stiffness of the reducer, and limitation of high-speed response capabilities.

[0042] The first embodiment of strain gauge torque sensor 1 is as follows: Figures 1 to 4 As shown, the device includes a ring strain gauge 2 and a signal acquisition module 3, which constitute a strain-type torque sensor 1. The ring strain gauge 2 and the signal acquisition module 3 are electrically connected. The ring strain gauge 2 is installed on the bottom surface of the flexible wheel 5 to be used, and the ring strain gauge 2 and the flexible wheel 5 are arranged concentrically. The signal acquisition module 3 is installed outside the hollow inner shaft 51 of the flexible wheel 5. When the flexible wheel 5 rotates, the output power is resisted by the resistance, which causes the ring strain gauge 2 to generate strain on the bottom surface of the flexible wheel 5. The ring strain gauge 2 converts the strain signal into an analog voltage signal through the Wheatstone bridge built by its own resistance wire grid 21, and outputs it to the signal acquisition module 3 for digital-to-analog conversion into a force signal output.

[0043] Specifically, the strain gauge torque sensor 1 integrated into the harmonic reducer 4 proposed in this technical solution has several technical advantages: avoiding the introduction of additional flexibility and improving structural rigidity: the technical solution directly installs the annular strain gauge 2 on the bottom surface of the flexible wheel 5, and the strain distribution of the flexible wheel 5 is evenly distributed on its bottom surface and arranged concentrically with the flexible wheel 5. The annular surface of the annular strain gauge 2 matches the annular surface of the inner bottom surface of the flexible wheel 5, and the signal acquisition module 3 matching the annular strain gauge 2 is installed in the internal space of the flexible wheel 5 and fixed on the hollow shaft of the flexible wheel 5. It is no longer necessary to add an additional detection structure on the end face of the harmonic reducer 4, avoiding the flexibility problem introduced by the additional detection unit in the existing solution, thereby maintaining the overall rigidity and stability of the reducer;

[0044] Effectively suppressing signal interference and improving measurement accuracy: The technical solution adopts a specially designed ring strain gauge 2. The resistance wire grid 21 distributed on the ring strain gauge 2 forms a strain measurement circuit through a Wheatstone bridge. This design can accurately convert the strain signal caused by the torque of the flexure wheel 5 into a voltage signal, and then convert it into a force signal output through digital-analog conversion. This effectively eliminates the interference of the measurement signal caused by the deformation of the peripheral wall of the flexure wheel 5 caused by the rotation of the wave generator 7 and the introduction of additional flexibility, so as to significantly improve the output stability and measurement accuracy of the force value.

[0045] Without changing the basic structure of the reducer and maintaining its lightweight characteristics: The strain torque sensor 1 uses the flexible wheel 5 as the strain carrier, and the ring strain gauge 2 and signal acquisition module 3 are directly arranged on the bottom surface of the flexible wheel 5 and the hollow inner shaft 51. The thin-film ring strain gauge 2 is used as the strain sensing unit to directly sense the deformation of the bottom surface of the flexible wheel 5. This does not change the main structure and installation method of the harmonic reducer 4, nor does it increase the weight and volume too much, thus maintaining the advantages of miniaturization and lightweight of the harmonic reducer 4.

[0046] Enhancing joint force control performance and adapting to high-speed response scenarios: Since the strain gauge torque sensor 1 consists only of a ring strain gauge 2 and a signal acquisition module 3, its structure and arrangement are reasonable, which ensures the structural rigidity of the harmonic reducer 4 and the stability of the force signal output of the strain gauge torque sensor 1. It can stably acquire the torque information output by the joint driven by the harmonic reducer 4 under high-speed response and rapid movement conditions, providing high-precision feedback for the robot's real-time force control and force perception, and effectively breaking through the application limitations of the existing harmonic reducer 4 torque detection scheme in dynamic scenarios.

[0047] In summary, while maintaining the original structural, rigidity, and weight advantages of the harmonic reducer 4, the technical solution achieves high-precision, anti-interference, and low-flexibility torque detection, significantly improving the force control capability and applicability of the robot joints.

[0048] As one alternative implementation method:

[0049] Regarding the manner in which the annular strain gauge 2 is fixed to the bottom surface of the flexible wheel 5, this embodiment is, for example... Figure 1 As shown, the annular strain gauge 2 is bonded to the bottom surface of the flexible wheel 5.

[0050] Among them, the annular strain gauge 2 is bonded to the bottom surface of the flexible wheel 5 by epoxy resin and high temperature curing.

[0051] In application, the high bonding strength and fatigue resistance of epoxy resin after curing enable the annular strain gauge 2 to be stably attached to the area with uniform strain distribution on the bottom surface of the flexible wheel 5 for a long period of time, thereby ensuring that the sensor can maintain a stable signal output under repeated loading and unloading conditions; and improve the bonding between the annular strain gauge 2 and the bottom surface of the flexible wheel 5, so that the annular strain gauge 2 can follow the strain generated by the bottom surface of the flexible wheel 5 with higher sensitivity, thereby improving the sensitivity and accuracy of the strain-type torque sensor 1 in detecting the torque of the harmonic reducer 4.

[0052] This method solves the problem that traditional mechanical fastening methods can easily lead to strain gauge position displacement or additional stress, effectively improving the accuracy and long-term reliability of signal acquisition.

[0053] Depending on the specific working conditions, two-component high-performance adhesives can be used to replace epoxy resins.

[0054] Furthermore, before bonding the annular strain gauge 2 to the bottom of the flexible wheel 5, pretreatment processes such as surface sandblasting and plasma cleaning are used to change the microstructure of the bottom surface of the flexible wheel 5 and improve the roughness of the bottom surface of the flexible wheel 5. This improves the adhesion of the adhesive to the bottom surface of the flexible wheel 5, thereby increasing the bonding force between the annular strain gauge 2 and the bottom surface of the flexible wheel 5, and further improving the environmental adaptability and durability of the strain torque sensor 1.

[0055] Regarding the connection method between the aforementioned ring strain gauge 2 and the signal acquisition module 3, this implementation is as follows: Figure 1 As shown, the hollow inner shaft 51 of the flexible wheel 5 is provided with a signal transmission hole 52 on its peripheral wall. The signal acquisition module 3 is led out through the signal transmission hole 52 via the communication cable 31 to the outside of the harmonic reducer 4 and connected to the host computer that receives the force value signal.

[0056] In application, the ring strain gauge 2 and the signal acquisition module 3 are electrically connected by a cable, so that the analog voltage signal output by the ring strain gauge 2 can be transmitted without loss to the signal acquisition module 3 inside the flexible wheel 5. Then, through the digital-to-analog conversion by the signal acquisition module 3, the force signal value is transmitted without loss to the host computer outside via the communication cable 31, thereby realizing real-time feedback of torque data.

[0057] This structure ensures the stability of torque signal transmission, avoids the problems of easy interference or wear and breakage caused by external mechanical movement in traditional exposed wiring methods, and improves the stable operation capability of strain gauge torque sensor 1.

[0058] A sealing sleeve or stress buffer ring is provided at the edge of the signal transmission hole 52 to prevent stress concentration during cable vibration or bending, thereby extending the overall service life of the sensor; a shielding tube or corrugated tube is fitted on the cable that electrically connects the annular strain gauge 2 and the signal acquisition module 3 to prevent the annular strain gauge 2 from being interfered with by electronic and electrical signals generated by the movement of the flexible wheel 5 and the wave generator 7 during the transmission of analog voltage signals to the signal acquisition module 3.

[0059] Furthermore, an optional wireless signal transmission module can be added to replace wired transmission methods and meet the cableless requirements in special application scenarios.

[0060] Regarding the distribution structure of the resistance wire grid 21 of the aforementioned annular strain gauge 2, this embodiment, for example... Figure 3 and Figure 4 As shown, the annular strain gauge 2 is provided with multiple pairs of resistance wire grids 21 with an included angle of ±45°. The multiple pairs of resistance wire grids 21 cover the annular strain gauge 2 in a 360° annular alternating distribution and are connected to form a Wheatstone bridge.

[0061] Specifically, multiple pairs of resistance wire grids 21 are uniformly and alternately distributed in a circular manner on the annular band 22 of the annular strain gauge 2 along the circumferential direction.

[0062] Furthermore, the resistance wire grid 21 on the annular strain gauge 2 is divided into four groups, including the first wire grid group 23, the second wire grid group 24, the third wire grid group 25 and the fourth wire grid group 26. The first wire grid group 23, the second wire grid group 24, the third wire grid group 25 and the fourth wire grid group 26 are connected in a way that forms a Wheatstone bridge.

[0063] Among them, the first wire grid group 23 and the second wire grid group 24 occupy half of the annular band 22 of the annular strain gauge 2, and the third wire grid group 25 and the fourth wire grid group 26 occupy the other half of the annular band 22 of the annular strain gauge 2.

[0064] The first wire grid group 23 and the second wire grid group 24 are alternately distributed. The adjacent resistance wire grids 21 in the first wire grid group 23 and the second wire grid group 24 form a pair of resistance wire grids 21 with an included angle of ±45°.

[0065] The third wire grid group 25 and the fourth wire grid group 26 are distributed alternately. The adjacent resistance wire grids 21 in the third wire grid group 25 and the fourth wire grid group 26 form a pair of resistance wire grids 21 with an included angle of ±45°.

[0066] Each of the first wire grid group 23, the second wire grid group 24, the third wire grid group 25, and the fourth wire grid group 26 contains a plurality of resistance wire grids 21; the plurality of resistance wire grids 21 contained in the first wire grid group 23 are connected in series; the plurality of resistance wire grids 21 contained in the second wire grid group 24 are connected in series; the plurality of resistance wire grids 21 contained in the second wire grid group 24 are connected in series; the plurality of resistance wire grids 21 contained in the second wire grid group 24 are connected in series.

[0067] Specifically, such as Figure 3 The pins U+, U-, S+, and S- shown are the positive power supply, negative power supply, positive signal, and negative signal, respectively.

[0068] In application, multiple pairs of resistance wire grids 21 with an angle of ±45° are evenly distributed in a ring-alternating manner on the annular strain gauge 2 and divided into four groups. The resistance wire grids 21 in each group are connected in series to form a complete Wheatstone bridge. This ensures that the strain of the flexible wheel 5 under torsion can be effectively collected in different directions, and the interference caused by external non-torsional loads or the rotation of the wave generator 7 is eliminated through bridge circuit complementarity. Moreover, this ring-alternating array distribution structure makes the output signal more stable and the sensitivity higher, solving the problems of insufficient signal drift and anti-interference ability in the existing technology.

[0069] The resistance wire grid 21 can be a metal foil strain gauge, or it can be replaced with a semiconductor strain gauge to further improve the sensitivity, depending on the different accuracy requirements.

[0070] In addition, a temperature compensation resistor element can be introduced into the Wheatstone bridge formed on the annular strain gauge 2 to suppress the influence of ambient temperature changes on measurement accuracy, thereby expanding the applicability of the sensor in complex environments.

[0071] Based on the above embodiments of the strain gauge torque sensor 1, a harmonic reducer 4 with a flexible wheel 5 integrating the strain gauge torque sensor 1 is provided, such as... Figures 1 to 4As shown, the device includes a ring strain gauge 2 and a signal acquisition module 3 of a strain-type torque sensor 1, as well as a rigid wheel 6, a flexible wheel 5 and a wave generator 7 of a harmonic reducer 4; the rigid wheel 6 is fitted outside the flexible wheel 5, and the wave generator 7 is fitted inside the flexible wheel 5; the ring strain gauge 2 and the signal acquisition module 3 are installed on the flexible wheel 5, and the ring strain gauge 2 and the signal acquisition module 3 are electrically connected.

[0072] Among them, the end flange 53 of the flexible wheel 5 is connected to the actuator to be executed, and is used to output power to the actuator;

[0073] When applied, the wave generator 7 rotates to drive the flexible wheel 5 to deform, which in turn drives the flexible wheel 5 to mesh with the rigid wheel 6 in a relatively staggered manner. The flexible wheel 5 outputs power to the actuator, and the motion tendency is hindered by the resistance of the actuator, causing the annular strain gauge 2 to generate strain on the bottom surface of the flexible wheel 5. The annular strain gauge 2 converts the strain signal into an analog voltage signal through its own built-in Huishitong electric bridge and outputs it to the signal acquisition module 3, which converts it into a force signal for digital-analog conversion.

[0074] Specifically, the end flange 53 of the flexible wheel 5 is connected to the actuator to realize power output; the rotation of the wave generator 7 causes the flexible wheel 5 to undergo periodic elastic deformation and form a relative staggered tooth meshing with the rigid wheel 6 to complete the power transmission. During this process, under the action of the feedback resistance of the actuator, the bottom surface of the flexible wheel 5 generates strain that varies with torque; the annular strain gauge 2 is fixed to the bottom surface of the flexible wheel 5, and converts the strain signal into an analog voltage signal in real time through a Wheatstone bridge structure, which is then processed by the signal acquisition module 3 and converted from digital to analog to force signal output, thereby realizing high-precision detection of the joint output torque.

[0075] In practical applications, this solution not only ensures the normal transmission function of the harmonic reducer 4, but also realizes the synchronous output of torque and force information, avoiding the problem of increasing flexibility and weakening rigidity caused by traditional external torque sensors, and effectively improving the force control performance and stability of robot joints under high-speed movement and dynamic response.

[0076] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described.

Claims

1. A strain gauge torque sensor based on a harmonic reducer integration, characterized in that, The device includes a ring strain gauge and a signal acquisition module that form a strain-type torque sensor, wherein the ring strain gauge is electrically connected to the signal acquisition module. The annular strain gauge is mounted on the bottom surface of the flexible wheel to be used, and the annular strain gauge and the flexible wheel are arranged concentrically. The signal acquisition module is installed outside the hollow inner shaft of the flexible wheel; The rotation of the flexible wheel outputs power, but the resistance hinders the motion trend, causing the annular strain gauge to generate strain on the bottom surface of the flexible wheel. The annular strain gauge converts the strain signal into an analog voltage signal through a Wheatstone bridge built by its own resistance wire grid, and outputs it to the signal acquisition module for digital-to-analog conversion into a force signal output.

2. The strain gauge torque sensor according to claim 1, characterized in that, The annular strain gauge is bonded to the bottom surface of the flexible wheel.

3. The strain gauge torque sensor according to claim 2, characterized in that, The annular strain gauge is bonded to the bottom surface of the flexible wheel via epoxy resin and cured at high temperature.

4. The strain gauge torque sensor according to claim 1, characterized in that, The hollow inner shaft of the flexible wheel is provided with a signal transmission hole. The signal acquisition module is led out through the signal transmission hole to the outside of the harmonic reducer via a communication cable and connected to the host computer that receives the force signal.

5. The strain gauge torque sensor according to claim 1, characterized in that, The annular strain gauge is provided with multiple pairs of resistance wire grids with an included angle of ±45°. The multiple pairs of resistance wire grids cover the annular strain gauge in a 360° alternating ring distribution and are connected to form a Wheatstone bridge.

6. The strain gauge torque sensor according to claim 5, characterized in that, Multiple pairs of resistance wire grids are uniformly and alternately distributed in a ring on the annular band of the annular strain gauge along the circumferential direction.

7. The strain gauge torque sensor according to any one of claims 5 or 6, characterized in that, The resistance wire grid on the annular strain gauge is divided into four groups, including a first wire grid group, a second wire grid group, a third wire grid group, and a fourth wire grid group. The first wire grid group, the second wire grid group, the third wire grid group, and the fourth wire grid group are connected in a manner that forms a Wheatstone bridge.

8. The strain gauge torque sensor according to claim 7, characterized in that, The first wire grid group and the second wire grid group occupy half of the annular band of the annular strain gauge, and the third wire grid group and the fourth wire grid group occupy the other half of the annular band of the annular strain gauge; The first wire grid group and the second wire grid group are alternately distributed, and the adjacent resistance wire grids in the first wire grid group and the second wire grid group are sequentially formed into a pair of resistance wire grids with an included angle of ±45°. The third wire grid group and the fourth wire grid group are distributed alternately, and the adjacent resistance wire grids in the third wire grid group and the fourth wire grid group are sequentially arranged to form a pair of resistance wire grids with an included angle of ±45°.

9. The strain gauge torque sensor according to claim 8, characterized in that, Each of the first wire grid group, the second wire grid group, the third wire grid group, and the fourth wire grid group contains a plurality of the resistor wire grids; The first wire grid group comprises a plurality of resistance wire grids connected in series in sequence; The second wire grid group comprises a plurality of resistance wire grids connected in series in sequence; The second wire grid group comprises a plurality of resistance wire grids connected in series in sequence; The second wire grid group comprises multiple resistance wire grids connected in series.

10. A harmonic reducer flexspline with an integrated strain gauge torque sensor, comprising the strain gauge torque sensor as described in claims 1-9, characterized in that, Includes a ring strain gauge and signal acquisition module for strain-type torque sensors, as well as a rigid wheel, flexible wheel, and wave generator for a harmonic reducer; The rigid wheel is fitted outside the flexible wheel, and the wave generator is fitted inside the flexible wheel; The annular strain gauge and the signal acquisition module are mounted on the flexible wheel, and the annular strain gauge is electrically connected to the signal acquisition module.

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