Torque detection method of harmonic speed reducer and harmonic speed reducer

Abstract

The invention relates to the technical field of speed reducers, in particular to a torque detection method of a harmonic speed reducer and the harmonic speed reducer, and solves the problem that the harmonic speed reducer cannot realize torque detection. According to the torque detection method of the harmonic speed reducer, the rotation angle of the wave generator and the measurement data of the strain gauge at the same time node are determined firstly, then the torque of the harmonic speed reducer is determined based on the preset function relation, the rotation angle and the measurement data, and torque detection of the harmonic speed reducer is achieved. In addition, the whole calculation process of the torque detection method of the harmonic speed reducer is simple and reliable, required parameters are few, and the calculation amount is small. Besides, according to the torque detection method of the harmonic speed reducer provided by the embodiment of the invention, the torque of the harmonic speed reducer can be calculated according to the measurement data of the strain gauge and the rotation angle of the wave generator only by attaching the strain gauge to the flexible gear, so that the harmonic speed reducer is simple in structure and low in cost.

Description

Technical Field

[0001] The present application relates to the technical field of speed reducers, and in particular to a torque detection method for a harmonic speed reducer and a harmonic speed reducer. Background Art

[0002] Harmonic reducers have the remarkable characteristics of small size, light weight, large reduction ratio, small backlash, simple structure, etc. They are widely used in the fields of robots, automation equipment, medical equipment, etc., especially for forming the rotary joints of robots. At present, harmonic reducers only have the function of deceleration, but not the function of torque detection.

[0003] However, in some special fields, such as flexible robot rotary joints and human-friendly robots, torque control is required. The existing harmonic reducers cannot realize torque detection and cannot meet the needs of torque control. Summary of the invention

[0004] In view of this, an embodiment of the present application provides a torque detection method for a harmonic reducer and a harmonic reducer, which solves the problem that the harmonic reducer cannot realize torque detection.

[0005] In a first aspect, an embodiment of the present application provides a torque detection method for a harmonic reducer, which is applied to a harmonic reducer, wherein the harmonic reducer includes a rigid wheel, a flexible wheel, a wave generator and a strain gauge, and the strain gauge is attached to the flexible wheel; wherein the torque detection method for the harmonic reducer includes: determining the rotation angle of the wave generator and the measurement data of the strain gauge at the same time node, wherein the rotation angle is the angle at which the wave generator rotates relative to the flexible wheel; determining the torque of the harmonic reducer based on a preset functional relationship, the rotation angle and the measurement data, wherein the preset functional relationship is used to characterize a functional relationship with the torque of the harmonic reducer as a dependent variable and the rotation angle and the measurement data as independent variables.

[0006] In some embodiments, before determining the torque of the harmonic reducer based on the preset functional relationship, the rotation angle and the measurement data, it also includes: determining the rotation angles at multiple same time nodes and a first variable coefficient of the first measurement data of the strain gauge when the harmonic reducer is unloaded, the first variable coefficient is used to characterize the association relationship between the rotation angles at multiple same time nodes and the first measurement data when the harmonic reducer is unloaded; when the harmonic reducer is loaded with a preset torque and the rotation angle is zero, determining the correlation coefficient between the second measurement data of the strain gauge and the preset torque, wherein when the first end of the wave generator along the long axis direction of the wave generator points to the strain gauge, the rotation angle is zero; determining the preset functional relationship based on the first variable coefficient and the correlation coefficient.

[0007] In some embodiments, determining the first variable coefficient of the rotation angle and the first measurement data of the strain gauge when the harmonic reducer is unloaded includes: determining the rotation angle and the first measurement data of multiple same time nodes when the harmonic reducer is unloaded; determining the first variable coefficient based on the rotation angle and the first measurement data by a fitting method, the first variable coefficient being a function that characterizes the change in the measurement data of the strain gauge caused by the change in the rotation angle when the harmonic reducer is unloaded.

[0008] In some embodiments, when the preset torque is loaded on the harmonic reducer and the rotation angle is zero, determining the correlation coefficient between the second measurement data of the strain gauge and the preset torque includes: when the preset torque is loaded on the harmonic reducer and the rotation angle is zero, determining the second measurement data; and determining the correlation coefficient based on the proportional relationship between the second measurement data and the preset torque.

[0009] In some embodiments, the preset functional relationship includes: torque of the harmonic reducer = (measured data - first variable coefficient) ÷ correlation coefficient.

[0010] In some embodiments, the measurement data of the strain gauge includes any one of the following data: a resistance value of the strain gauge, a voltage value of the strain gauge, a processed resistance value of the strain gauge, and a processed voltage value of the strain gauge.

[0011] In the second aspect, an embodiment of the present application provides a harmonic reducer, comprising: a housing; a flexible wheel fixedly connected to the housing; a rigid wheel capable of meshing with at least part of the teeth of the flexible wheel; a wave generator mounted on the inner ring of the flexible wheel and capable of rotating relative to the flexible wheel; a strain gauge attached to the flexible wheel, wherein the strain gauge can output measurement data; an encoder disposed on the wave generator and configured to detect the rotation angle of the wave generator; wherein the strain gauge and the encoder can be communicatively connected to a processor, the processor can receive the measurement data and the rotation angle, and determine the torque of the harmonic reducer based on the torque detection method of the harmonic reducer described in the first aspect.

[0012] In some embodiments, the flexible wheel includes: a fixing ring fixedly connected to the housing, wherein the strain gauge is attached to the first end face of the fixing ring, and the first end face of the fixing ring is the end face of the first end of the fixing ring; a transmission sleeve, wherein the first end of the transmission sleeve is coaxially connected to the second end of the fixing ring, and at least part of the teeth at the second end of the transmission sleeve are meshed with the rigid wheel.

[0013] In some embodiments, the first end face of the fixing ring includes a central area close to the inner ring of the fixing ring, an edge area close to the outer ring of the fixing ring, and a middle area between the central area and the edge area; wherein the fixing ring is fixedly connected to the shell through the edge area, and the strain gauge is attached to the middle area.

[0014] In some embodiments, the first end surface of the fixing ring is a stepped surface, and a first vertical distance between the middle area and the second end of the fixing ring is smaller than a second vertical distance between the edge area and the second end of the fixing ring.

[0015] The torque detection method of the harmonic reducer provided in the embodiment of the present application first determines the rotation angle of the wave generator and the measurement data of the strain gauge at the same time node, and then determines the torque of the harmonic reducer based on a preset functional relationship, the rotation angle and the measurement data, thereby realizing the torque detection of the harmonic reducer.

[0016] In addition, the entire calculation process of the torque detection method of the harmonic reducer is simple and reliable, requiring few parameters and less calculation.

[0017] In addition, the torque detection method of the harmonic reducer provided in the embodiment of the present application only needs to attach a strain gauge on the flexible pulley, and the torque of the harmonic reducer can be calculated according to the measurement data of the strain gauge and the rotation angle of the wave generator, so that the structure of the harmonic reducer is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] By describing the embodiments of the present application in more detail in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present application will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the drawings, the same reference numerals generally represent the same components.

[0019] Figure 1 Shown is a schematic structural diagram of a harmonic reducer provided in one embodiment of the present application.

[0020] Figure 2 The figure is a flow chart of a torque detection method for a harmonic reducer provided in one embodiment of the present application.

[0021] Figure 3 Shown is a flow chart of a torque detection method for a harmonic reducer provided in another embodiment of the present application.

[0022] Figure 4 Shown is a flow chart of a torque detection method for a harmonic reducer provided in another embodiment of the present application.

[0023] Figure 5 Shown is a flow chart of a torque detection method for a harmonic reducer provided in another embodiment of the present application.

[0024] Figure 6 The present invention provides an embodiment of the present invention. Figure 1 The harmonic reducer shown is a partial enlarged view along the A area.

[0025] Figure 7 FIG. 1 is a schematic structural diagram of a flexible wheel provided in an embodiment of the present application.

[0026] Figure 8 Shown is a front view of a flexible wheel provided in one embodiment of the present application.

[0027] Fig. 9 The present invention provides an embodiment of the present invention. Figure 8 A cross-sectional view of the flexible wheel along the BB direction.

[0028] Fig.10 FIG. 1 is a schematic diagram of finite element analysis results of a flexible spline provided in an embodiment of the present application.

[0029] Fig.11 FIG. 1 is a schematic diagram of finite element analysis results of a flexible pulley provided in another embodiment of the present application.

[0030] Reference numerals:

[0031] 1. Harmonic reducer; 11. Rigid wheel; 12. Flexwheel; 121. Fixed ring; 1211. First end of fixed ring; 1212. Second end of fixed ring; 1213. First end face of fixed ring; 1214. Central area; 1215. Edge area; 1216. Middle area; 122. Transmission sleeve; 1221. First end of transmission sleeve; 1222. Second end of transmission sleeve; 13. Wave generator; 14. Strain gauge; 15. Housing; 16. Encoder; 17. Processor; 18. Output flange; 19. Flexible bearing; 20. Rigid bearing; 21. Sealing pad; 22. Retaining ring; D1. First vertical distance; D2. Second vertical distance. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] Figure 1 Shown is a schematic structural diagram of a harmonic reducer provided in one embodiment of the present application. Figure 2 FIG. 1 is a flow chart of a torque detection method for a harmonic reducer provided in an embodiment of the present application. Figure 1 As shown, the harmonic reducer 1 includes a rigid wheel 11, a flexible wheel 12, a wave generator 13 and a strain gauge 14. The rigid wheel 11 can mesh with at least part of the teeth of the flexible wheel 12. The wave generator 13 is sleeved on the inner ring of the flexible wheel 12 and can rotate relative to the flexible wheel 12. The strain gauge 14 is attached to the flexible wheel 12.

[0034] like Figure 2 As shown, the torque detection method of the harmonic reducer 1 includes the following steps.

[0035] Step 200, determining the rotation angle of the wave generator 13 and the measurement data of the strain gauge 14 at the same time node.

[0036] Specifically, the rotation angle is the angle at which the wave generator 13 rotates relative to the flexspline 12 .

[0037] Exemplarily, the rigid wheel 11 is mounted on the outer ring of the flexible wheel 12 and meshes with part of the teeth of the flexible wheel 12. The wave generator 13 is an elliptical structure. In the long axis direction of the elliptical structure, the end of the wave generator 13 squeezes the flexible wheel 12 so that at least part of the teeth of the flexible wheel 12 mesh with the rigid wheel 11. The wave generator 13 rotates one circle relative to the flexible wheel 12, and the rotation angle is 360 degrees. At the time point when one end of the wave generator 13 points to the strain gauge 14, the rotation angle can be considered to be zero degrees.

[0038] Exemplarily, determining the rotation angle of the wave generator 13 and the measurement data of the strain gauge 14 at the same time node may be to detect the rotation angle in real time, and the strain gauge 14 outputs the measurement data in real time, thereby obtaining a one-to-one corresponding rotation angle and measurement data in real time, which facilitates the subsequent real-time acquisition of the torque of the harmonic reducer 1.

[0039] Exemplarily, to determine the rotation angle of the wave generator 13 and the measurement data of the strain gauge 14 at the same time node, the rotation angle of the wave generator 13 can be detected at a first time node, and the strain gauge 14 outputs the measurement data at the first time node; then, the rotation angle of the wave generator 13 is detected at a second time node, and the strain gauge 14 outputs the measurement data at the second time node; and so on, a plurality of one-to-one corresponding rotation angles and measurement data at the same time node are obtained, so as to facilitate the subsequent acquisition of the torque of the harmonic reducer 1 at different time nodes.

[0040] In some embodiments, the measurement data of the strain gauge 14 includes any one of the following data: the resistance value of the strain gauge 14, the voltage value of the strain gauge 14, the processed resistance value of the strain gauge 14, and the processed voltage value of the strain gauge 14. Exemplarily, the processed resistance value of the strain gauge 14 may be a preprocessed resistance value. For example, the processed resistance value of the strain gauge 14 may be a filtered resistance value of the strain gauge 14, or it may be a denoised resistance value of the strain gauge 14. Exemplarily, the processed voltage value of the strain gauge 14 may be a preprocessed voltage value. For example, the processed voltage value of the strain gauge 14 may be a filtered voltage value of the strain gauge 14, or it may be a denoised voltage value of the strain gauge 14.

[0041] Step 600, determining the torque of the harmonic reducer 1 based on a preset functional relationship, a rotation angle and measurement data.

[0042] Specifically, the preset functional relationship is used to characterize the functional relationship with the torque of the harmonic reducer 1 as the dependent variable and the rotation angle and the measurement data as the independent variables.

[0043] Exemplarily, the preset functional relationship can be a functional relationship obtained by calculation and analysis based on experimental data. In other words, the preset functional relationship is a known functional relationship. Since the preset functional relationship is known, the rotation angle and the measurement data are obtained through step 200. Therefore, by substituting the rotation angle and the measurement data into the preset functional relationship, the torque of the harmonic reducer 1 can be calculated, thereby realizing the torque detection of the harmonic reducer 1.

[0044] In addition, the entire calculation process of the torque detection method of the harmonic reducer 1 is simple and reliable. Only two parameters, namely the rotation angle and the measurement data, are needed to calculate the torque of the harmonic reducer 1. Fewer parameters are required, less calculation is required, and the calculation efficiency is high.

[0045] In addition, the torque detection method of the harmonic reducer 1 provided in the embodiment of the present application only needs to attach a strain gauge 14 to the flexible pulley 12, and the torque of the harmonic reducer 1 can be calculated according to the measurement data of the strain gauge 14 and the rotation angle of the wave generator 13, so that the structure of the harmonic reducer 1 is simple and the cost is low. It is understandable that in order to further improve the detection accuracy, multiple strain gauges 14 can also be attached to the flexible pulley 12, and then the measurement data for calculating the torque of the harmonic reducer 1 can be calculated by calculating the average value or weighted value of the measurement data corresponding to each of the multiple strain gauges 14. In other words, the measurement data used in step 600 can be the average value or weighted value of the measurement data corresponding to each of the multiple strain gauges 14.

[0046] Figure 3 FIG. 1 is a flow chart of a torque detection method for a harmonic reducer provided in another embodiment of the present application. Figure 2 The present application is extended based on the embodiment shown Figure 3 The embodiment shown is described below in detail. Figure 3 The embodiment shown and Figure 2 The differences and similarities of the illustrated embodiments are not described in detail.

[0047] like Figure 3 As shown, before determining the torque of the harmonic reducer 1 based on the preset functional relationship, the rotation angle and the measurement data, the torque detection method of the harmonic reducer 1 also includes the following steps.

[0048] Step 300 , when the harmonic reducer 1 is unloaded, determining the rotation angles of a plurality of nodes at the same time and the first variable coefficient of the first measurement data of the strain gauge 14 .

[0049] Specifically, the first variable coefficient is used to characterize the association relationship between the rotation angles of multiple same time nodes and the first measurement data when the harmonic reducer 1 is unloaded. Exemplarily, the association relationship between the rotation angle of the same time node and the first measurement data can be a functional relationship, that is, the first measurement data can be a function of the rotation angle. In other words, the association relationship between the rotation angle of the same time node and the first measurement data can be a functional relationship with the rotation angle as the independent variable and the first measurement data as the dependent variable, that is, when the harmonic reducer 1 is unloaded, the first measurement data changes with the change of the rotation angle. Exemplarily, the first variable coefficient can be a one-to-one mapping relationship between multiple rotation angles and multiple first measurement data. That is, for each time node, there is a corresponding rotation angle and a first measurement data.

[0050] The inventors have found that the main sources of deformation of the flexible wheel 12 during the transmission process are two parts. The first part of the deformation is that the elliptical wave generator 13 squeezes the flexible wheel 12 during the rotation process, resulting in the deformation of the flexible wheel 12; the second part of the deformation is that the rigid wheel 11 drives the load to rotate during the process of the flexible wheel 12 driving the steel wheel to rotate, and the rigid wheel 11 generates a reaction force on the flexible wheel 12, thereby causing the rigid wheel 11 to cause deformation of the tooth surface of the flexible wheel 12 that is meshing with each other. Therefore, when the rigid wheel 11 does not drive the load to rotate (that is, the harmonic reducer 1 is unloaded), it can be considered that the second part of the deformation is close to zero. At this time, the deformation of the flexible wheel 12 is mainly the first part of the deformation.

[0051] The inventors have found that the first partial deformation is related to the rotation angle of the wave generator 13. Specifically, by recording the rotation angle at the same time node and the first measurement data of the strain gauge 14 when the harmonic reducer 1 is unloaded, and then analyzing the correlation between the rotation angle at the same time node and the first measurement data of the strain gauge 14, the first variable coefficient can be obtained. Exemplarily, the correlation between the rotation angle at the same time node and the first measurement data of the strain gauge 14 can be analyzed by regression analysis. Regression analysis can be linear regression analysis, nonlinear regression analysis, univariate regression analysis, multivariate regression analysis, etc.

[0052] Step 400 , when a preset torque is loaded on the harmonic reducer 1 and the rotation angle is zero, determine the correlation coefficient between the second measurement data of the strain gauge 14 and the preset torque.

[0053] Specifically, when the first end of the wave generator 13 along the long axis direction of the wave generator 13 points to the strain gauge 14 , the rotation angle is zero.

[0054] The inventors have found that when the rotation angle of the wave generator 13 is zero, the deformation of the flexible wheel 12 is mainly related to the load of the harmonic reducer 1, that is, the deformation of the second part is mainly related to the load of the harmonic reducer 1. Therefore, the harmonic reducer 1 is loaded with a preset torque, and the second measurement data is recorded when the rotation angle of the wave generator 13 is zero, so that a plurality of preset torques and a plurality of second measurement data corresponding to each other can be obtained. The correlation coefficient can be obtained by analyzing the correlation between the plurality of preset torques corresponding to each other and the plurality of second measurement data. The regression analysis method can also be used to analyze the correlation between the plurality of preset torques corresponding to each other and the plurality of second measurement data. The regression analysis can be linear regression analysis, nonlinear regression analysis, univariate regression analysis, multivariate regression analysis, etc.

[0055] Step 500: Determine a preset functional relationship based on the first variable coefficient and the correlation coefficient.

[0056] Specifically, the preset functional relationship can be analyzed by taking the torque of the harmonic reducer 1 as the dependent variable, the rotation angle and the measurement data as the independent variables, and the first variable coefficient and the correlation coefficient as parameters.

[0057] For example, if a univariate regression analysis method is used, the following formula (1) can be obtained:

[0058] Preset torque = a × second measurement data + b (1)

[0059] Parameters a and b can be obtained through one-to-one correspondence between multiple preset torques and multiple second measurement data.

[0060] By using the regression analysis method, we can also get the following formula (2):

[0061] First measurement data = f(β)(2)

[0062] Wherein, β represents the rotation angle, that is, the first measurement data is a function that changes with the rotation angle.

[0063] When the torque is applied to the harmonic reducer 1 and the rotation angle is not necessarily zero, the following formula (3) can be obtained:

[0064] Measurement data = first measurement data + second measurement data (3)

[0065] That is, from formula (3), it can be seen that the second measurement data is equal to the measurement data minus the first measurement data.

[0066] Therefore, by combining formulas (1), (2) and (3), we can obtain formula (4):

[0067] Preset torque = a × (measured data - f (β)) + b (4)

[0068] According to formula (4), when the measured data and the rotation angle can be detected, the preset torque can be inferred. In other words, when the preset torque is unknown, the preset torque can be calculated according to formula (4), the measured data and the rotation angle. Therefore, the preset function relationship can be the following formula (5):

[0069] Torque of harmonic reducer = a × (measured data - f (β)) + b (5)

[0070] In formula (5), parameters a and b are correlation coefficients, parameters a and b are known parameters, and f(β) is the first variable coefficient. The torque of the harmonic reducer 1 can be calculated based on the measured data and the rotation angle.

[0071] In some embodiments, the preset functional relationship may also be the following formula (6):

[0072] Torque of harmonic reducer = (measured data - f(β)) ÷ a (6)

[0073] Wherein, f(β) is the first variable coefficient, and a is the correlation coefficient. a can be calculated using the method of univariate regression analysis.

[0074] The above formula for calculating the torque of the harmonic reducer 1 has few parameters, simple and accurate calculation, and high efficiency. In some embodiments, different regression methods can also be used to calculate the first variable coefficient and the correlation coefficient, thereby obtaining different formulas for calculating the torque of the harmonic reducer 1.

[0075] Figure 4 FIG. 1 is a flow chart of a torque detection method for a harmonic reducer provided in another embodiment of the present application. Figure 3 The present application is extended based on the embodiment shown Figure 4 The embodiment shown is described below in detail. Figure 4 The embodiment shown and Figure 3 The differences and similarities of the illustrated embodiments are not described in detail.

[0076] like Figure 4 As shown, when the harmonic reducer 1 is unloaded, determining the first variable coefficient of the rotation angle and the first measurement data of the strain gauge 14 includes the following steps.

[0077] Step 310: when the harmonic reducer 1 is unloaded, determine the rotation angles and first measurement data of multiple nodes at the same time.

[0078] Step 320, using a fitting method, based on the rotation angle and the first measurement data, determine a first variable coefficient, the first variable coefficient being a function for characterizing a change in the measurement data of the strain gauge 14 caused by a change in the rotation angle when the harmonic reducer 1 is unloaded.

[0079] Exemplarily, the fitting method may be linear fitting, nonlinear fitting, etc., which is not specifically limited in this application. Exemplarily, the first variable coefficient may be the above-mentioned f(β). Exemplarily, f(β) may be equal to β, or may be equal to a multiple of β, the square of β, etc. The specific representation of f(β) may vary according to different fitting methods, which is not specifically limited in this application.

[0080] By fitting the first variable coefficient based on the rotation angle and the first measurement data, the discrete experimental measurement value can be expressed as a functional relationship, so that the discrete value can be expressed as a continuous value, which is convenient for calculating the torque of the harmonic reducer 1.

[0081] Figure 5 FIG. 1 is a flow chart of a torque detection method for a harmonic reducer provided in another embodiment of the present application. Figure 3 The present application is extended based on the embodiment shown Figure 5 The embodiment shown is described below in detail. Figure 5 The embodiment shown and Figure 3 The differences and similarities of the illustrated embodiments are not described in detail.

[0082] like Figure 5 As shown, when a preset torque is loaded on the harmonic reducer 1 and the rotation angle is zero, determining the correlation coefficient between the second measurement data of the strain gauge 14 and the preset torque includes the following steps.

[0083] Step 410: Determine second measurement data when a preset torque is applied to the harmonic reducer 1 and the rotation angle is zero.

[0084] Step 420: Determine a correlation coefficient based on a proportional relationship between the second measurement data and the preset torque.

[0085] Exemplarily, the correlation coefficient may be a fixed value. For example, the correlation coefficient may be a ratio of the second measurement data to the preset torque. For another example, the correlation coefficient may be a multiple of the ratio of the second measurement data to the preset torque.

[0086] Based on the proportional relationship between the second measurement data and the preset torque, the correlation coefficient is determined, the calculation method is simple and the calculation efficiency is high.

[0087] Figure 6 The present invention provides an embodiment of the present invention. Figure 1The harmonic reducer shown is a partial enlarged view along the A area. Figure 7 FIG. 1 is a schematic diagram of the structure of a flexible wheel provided in an embodiment of the present application. Figure 1 , Figure 6 and Figure 7 As shown, the harmonic reducer 1 includes a housing 15 , a rigid wheel 11 , a flexible wheel 12 , a wave generator 13 , a strain gauge 14 and an encoder 16 .

[0088] Specifically, the flexible wheel 12 is fixedly connected to the housing 15. The rigid wheel 11 can mesh with at least part of the teeth of the flexible wheel 12. The wave generator 13 is mounted on the inner ring of the flexible wheel 12 and can rotate relative to the flexible wheel 12. The strain gauge 14 is attached to the flexible wheel 12. The strain gauge 14 can output measurement data. The encoder 16 is provided on the wave generator 13. The encoder 16 is configured to detect the rotation angle of the wave generator 13.

[0089] Specifically, the strain gauge 14 and the encoder 16 can be connected to the processor 17. The processor 17 can receive the measurement data and the rotation angle, and determine the torque of the harmonic reducer 1 based on the torque detection method of the harmonic reducer 1 provided in any of the above embodiments.

[0090] For example, there may be a plurality of strain gauges 14 , and the plurality of strain gauges 14 may be disposed around the circumference of the flexible wheel 12 .

[0091] Exemplarily, the harmonic reducer 1 may include a processor 17. Exemplarily, the processor 17 may not belong to the harmonic reducer 1, for example, the processor 17 may be a computer, a mobile phone, a tablet, etc.

[0092] For example, Figure 6 As shown, the harmonic reducer 1 further includes an output flange 18. The output flange 18 is connected to the rigid wheel 11, and the load of the harmonic reducer 1 acts on the output flange 18, and then the output flange 18 transfers the load to the rigid wheel 11, and the rigid wheel 11 transfers the load to the flexible wheel 12.

[0093] For example, Figure 6 As shown, a flexible bearing 19 is further provided between the wave generator 13 and the flexible wheel 12 , so as to reduce the friction between the wave generator 13 and the flexible wheel 12 .

[0094] For example, Figure 6 As shown, the rigid wheel 11 rotates relative to the housing 15 , and a rigid bearing 20 may be provided between the rigid wheel 11 and the housing 15 , so as to reduce the friction between the rigid wheel 11 and the housing 15 .

[0095] For example, Figure 6As shown, the harmonic reducer 1 may further include a sealing gasket 21 , which is disposed between the rigid wheel 11 and the housing 15 and on a side of the rigid bearing 20 away from the flexible wheel 12 , so as to seal the rigid bearing 20 .

[0096] For example, Figure 6 The harmonic reducer 1 may further include a retaining ring 22 , which is mounted on the wave generator 13 and disposed on a side of the flexible bearing 19 away from the flexible wheel 12 to block the flexible bearing 19 and prevent the flexible bearing 19 from falling off the wave generator 13 .

[0097] Figure 8 Shown is a front view of a flexible wheel provided in one embodiment of the present application. Fig. 9 The present invention provides an embodiment of the present invention. Figure 8 A cross-sectional view of the flexible wheel along the BB direction. Figures 7 to 9 As shown, the flexible wheel 12 includes a fixing ring 121 and a transmission sleeve 122 .

[0098] The fixing ring 121 is fixedly connected to the housing 15. The strain gauge 14 is attached to the first end surface 1213 of the fixing ring. The first end surface 1213 of the fixing ring is the end surface of the first end 1211 of the fixing ring.

[0099] The first end 1221 of the transmission sleeve is coaxially connected to the second end 1212 of the fixing ring. At least part of the teeth of the second end 1222 of the transmission sleeve are meshed with the rigid wheel 11.

[0100] For example, Figures 7 to 9 As shown, the fixing ring 121 is a flat ring structure, and the transmission sleeve is a tubular structure. Attaching the strain gauge 14 to the first end face 1213 of the fixing ring can be understood as attaching the strain gauge 14 to a plane, rather than a curved surface. Due to the measurement principle limitation of the strain gauge 14, the strain gauge 14 measures the deformation on the plane more accurately. Therefore, attaching the strain gauge 14 to the first end face 1213 of the fixing ring can make the measurement data of the strain gauge 14 more accurate.

[0101] In some embodiments, the first end surface 1213 of the fixing ring includes a central region 1214 close to the inner ring of the fixing ring 121, an edge region 1215 close to the outer ring of the fixing ring 121, and a middle region 1216 between the central region 1214 and the edge region 1215. The fixing ring 121 is fixedly connected to the housing 15 via the edge region 1215, and the strain gauge 14 is attached to the middle region 1216.

[0102] Fig.10 FIG. 1 is a schematic diagram of finite element analysis results of a flexible spline provided in an embodiment of the present application. Fig.11FIG. 1 is a schematic diagram of the finite element analysis results of a flexible wheel provided by another embodiment of the present application. Fig.10 and Fig.11 As shown, different colors are used to represent the size of the deformation of the flexible wheel 12, and the colors representing the deformation from large to small are red, dark yellow, light yellow, green, light blue, and dark blue. Since the fixing ring 121 is fixedly connected to the housing 15 through the edge area 1215, the deformation of the edge area 1215 is very small, and the central area 1214 is close to the transmission sleeve 122, so the force on the central area 1214 may include both torsional force and force causing plane deformation, and the force situation is complicated. The deformation of the middle area 1216 is between the deformation of the central area 1214 and the deformation of the edge area 1215, that is, the deformation of the middle area 1216 will not be too large or too small. Therefore, attaching the strain gauge 14 to the middle area 1216 can make the deformation sensed by the strain gauge 14 neither too large nor too small, which is convenient for analysis and calculation, and the deformation amount is more accurate.

[0103] In some embodiments, the first end face 1213 of the fixing ring is a stepped surface, and a first vertical distance D1 between the middle region 1216 and the second end 1212 of the fixing ring is smaller than a second vertical distance D2 between the edge region 1215 and the second end 1212 of the fixing ring, thereby forming a gap between the middle region 1216 and the shell 15, and the strain gauge 14 is arranged in the gap to prevent the shell 15 from squeezing the strain gauge 14, thereby improving the accuracy of the measurement data of the strain gauge 14.

[0104] Exemplarily, the strain gauge 14 forms a circuit with the electronic component through the wire harness, and outputs the measurement data through the circuit. The electronic component may include a resistor component, a voltage component, etc. The circuit may be a Huygens circuit, a simple voltage resistor circuit, etc. The flexible wheel 12 is fixedly connected to the housing 15, and the strain gauge 14 is attached to the flexible wheel 12. During the operation of the harmonic reducer 1, the strain gauge 14 does not need to move, so it is convenient to connect the strain gauge 14 to the electronic component through the wire harness, and will not cause the wire harness to be entangled and messy.

[0105] In the embodiments of the present application, if the connection form is not clearly defined, the connection form may be a detachable connection form such as bolts and nuts, screws, buckles, magnets, etc. If there is no special requirement for a non-detachable connection form in some connections, a non-detachable connection may be made by welding, bonding, etc.

[0106] The phrases "one embodiment", "an embodiment", etc. mentioned in the specification indicate that the embodiment described may include a specific feature, structure or characteristic, but not every embodiment may include the specific feature, structure or characteristic. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments, whether explicitly or not explicitly described.

[0107] It should be understood that “on,” “above,” and “over” in this disclosure should be interpreted in the broadest manner, so that “on” not only means “directly on something,” but also includes the meaning of “on something” with intervening features or layers therebetween, and “above” or “over” not only includes the meaning of “above” or “over,” but also may include the meaning of “above” or “over something” with no intervening features or layers therebetween (i.e., directly on something).

[0108] Additionally, spatially relative terms, such as "below," "below," "beneath," "above," "above," etc., may be used herein for ease of description to describe the relationship of one component or feature to other components or features as shown in the figures. The spatially relative terms are intended to encompass different orientations of the component in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may likewise be interpreted accordingly.

[0109] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0110] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A torque detection method for a harmonic reducer, characterized in that: Applicable to a harmonic reducer, the harmonic reducer comprises a rigid wheel, a flexible wheel, a wave generator and a strain gauge, and the strain gauge is attached to the flexible wheel; Wherein, the torque detection method of the harmonic reducer includes: Determine the rotation angle of the wave generator and the measurement data of the strain gauge at the same time node, wherein the rotation angle is the angle at which the wave generator rotates relative to the flexspline; Based on a preset functional relationship, the rotation angle and the measurement data, the torque of the harmonic reducer is determined, wherein the preset functional relationship is used to characterize a functional relationship with the torque of the harmonic reducer as a dependent variable and the rotation angle and the measurement data as independent variables.

2. The torque detection method of the harmonic reducer according to claim 1, characterized in that: Before determining the torque of the harmonic reducer based on the preset functional relationship, the rotation angle and the measurement data, the method further includes: When the harmonic reducer is unloaded, determining a first variable coefficient of the rotation angles at multiple same time nodes and the first measurement data of the strain gauge, wherein the first variable coefficient is used to characterize the correlation between the rotation angles at multiple same time nodes and the first measurement data when the harmonic reducer is unloaded; Determine the correlation coefficient between the second measurement data of the strain gauge and the preset torque when the preset torque is loaded on the harmonic reducer and the rotation angle is zero, wherein when the first end of the wave generator along the long axis direction of the wave generator points to the strain gauge, the rotation angle is zero; The preset functional relationship is determined based on the first variable coefficient and the correlation coefficient.

3. The torque detection method of the harmonic reducer according to claim 2 is characterized in that: The step of determining the first variable coefficient of the rotation angle and the first measurement data of the strain gauge when the harmonic reducer is unloaded includes: When the harmonic reducer is unloaded, determining the rotation angle and the first measurement data at a plurality of same time nodes; The first variable coefficient is determined based on the rotation angle and the first measurement data using a fitting method. The first variable coefficient is used to characterize a function of changes in the measurement data of the strain gauge caused by changes in the rotation angle when the harmonic reducer is unloaded.

4. The torque detection method of the harmonic reducer according to claim 2, characterized in that: The step of determining the correlation coefficient between the second measurement data of the strain gauge and the preset torque when the preset torque is applied to the harmonic reducer and the rotation angle is zero includes: Determining the second measurement data when a preset torque is applied to the harmonic reducer and the rotation angle is zero; The correlation coefficient is determined based on a proportional relationship between the second measurement data and the preset torque.

5. The torque detection method of the harmonic reducer according to claim 4, characterized in that: The preset functional relationship includes: Torque of harmonic reducer = (measured data - first variable coefficient) ÷ correlation coefficient.

6. The torque detection method of a harmonic reducer according to any one of claims 1 to 5, characterized in that: The measurement data of the strain gauge includes any one of the following data: the resistance value of the strain gauge, the voltage value of the strain gauge, the processed resistance value of the strain gauge, and the processed voltage value of the strain gauge.

7. A harmonic reducer, characterized in that: include: case; A flexible wheel, fixedly connected to the housing; a rigid wheel capable of meshing with at least some of the teeth of the flexible wheel; A wave generator is mounted on the inner ring of the flexible wheel and can rotate relative to the flexible wheel; A strain gauge is attached to the flexible wheel, wherein the strain gauge is capable of outputting measurement data; an encoder, disposed on the wave generator and configured to detect a rotation angle of the wave generator; Wherein, the strain gauge and the encoder can be communicatively connected to a processor, and the processor can receive the measurement data and the rotation angle, and determine the torque of the harmonic reducer based on the torque detection method of the harmonic reducer described in any one of claims 1 to 6.

8. The harmonic reducer according to claim 7, characterized in that: The flexible wheel comprises: A fixing ring fixedly connected to the housing, wherein the strain gauge is attached to a first end face of the fixing ring, and the first end face of the fixing ring is an end face of a first end of the fixing ring; A transmission sleeve, wherein the first end of the transmission sleeve is coaxially connected to the second end of the fixing ring, and at least part of the teeth at the second end of the transmission sleeve are meshed with the rigid wheel.

9. The harmonic reducer according to claim 8, characterized in that: The first end surface of the fixing ring includes a central area close to the inner ring of the fixing ring, an edge area close to the outer ring of the fixing ring, and an intermediate area between the central area and the edge area; Wherein, the fixing ring is fixedly connected to the housing through the edge area, and the strain gauge is attached to the middle area.

10. The harmonic reducer according to claim 9, characterized in that: The first end surface of the fixing ring is a stepped surface, and a first vertical distance between the middle area and the second end of the fixing ring is smaller than a second vertical distance between the edge area and the second end of the fixing ring.

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