Robot joint rotation angle measuring method and device and storage medium

Abstract

The embodiment of the invention relates to the technical field of robots, and discloses a robot joint rotation angle measuring method and device and a storage medium. According to the method, the rotation load of a joint is monitored in real time, and when the rotation load exceeds a preset threshold value, forward and reverse historical rotation data and direction switching frequency of the joint are obtained; and a real-time correction value is generated in combination with the rotation angle correction model, and finally the rotation angle of the output flange and the correction value are fused to obtain the actual rotation angle of the robot joint. According to the method, the data driving model is used for compensating the flexible deformation error, a hardware sensor does not need to be added, and the hardware transformation or redevelopment cost is reduced. The method is suitable for a scene of frequent dynamic load switching, and the measurement precision and the system reliability are improved while the cost efficiency is ensured.

Description

Technical Field

[0001] The present invention relates to the field of robotics technology, and in particular to a method, device and storage medium for measuring the rotation angle of a robot joint. Background Art

[0002] In many fields, including modern industrial manufacturing, intelligent logistics, rehabilitation medicine, and home services, robots, with their advantages of high efficiency, precision, and repeatability, are becoming a key force driving industrial upgrading and improving people's quality of life. As the core moving components of robots, precise measurement of the rotation angle of robot joints is fundamental to enabling robots to achieve complex and precise movements. This is directly related to the robot's motion performance, task execution accuracy, and overall reliability.

[0003] In related technologies, robot joints need to frequently withstand various loads, especially large external loads. For example, industrial robots need to handle the grasping and movement of workpieces of different weights when handling materials, and rehabilitation robots need to withstand the dynamic forces exerted by human limbs when assisting patients in training. In order to adapt to this complex and changing load environment and improve the service life and operational stability of the joints, many robot joint designs will be equipped with flexible buffers between the first joint body and the second joint body. Through its own elastic deformation characteristics, the flexible buffer can effectively absorb and cushion the impact loads on the joint during movement, reduce vibration and stress concentration caused by rigid collisions, thereby reducing the risk of wear and damage to joint components and extending the service life of the joint.

[0004] However, although the introduction of flexible buffers brings many benefits, it also brings new challenges to the accurate measurement of robot joint rotation angles. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method, device and storage medium for measuring the rotation angle of a robot joint, aiming to solve the technical problem of low accuracy in measuring the rotation angle of a robot joint in the prior art.

[0006] To achieve the above objectives, in a first aspect, an embodiment of the present application provides a method for measuring the rotation angle of a robot joint, wherein the robot joint includes a first joint body, a second joint body, and a joint module, wherein the joint module includes a drive body and an output flange, wherein the drive body is fixedly connected to the first joint body, and the output flange is fixedly connected to the second joint body via a flexible connector, and the method includes: Obtaining the current rotational load of the robot joint; When the current rotation load of the robot joint is greater than or equal to a load threshold, first rotation data, second rotation data, and a direction switching frequency of the robot joint are respectively acquired, wherein the first rotation data is historical rotation data of the robot joint along a first direction, and the second rotation data is historical rotation data of the robot joint along a second direction, wherein the first direction is opposite to the second direction; Inputting the first rotation data, the second rotation data and the direction switching frequency into a rotation angle correction model to obtain a rotation angle correction value; The actual rotation angle of the robot joint is determined according to the rotation angle of the output flange and the rotation angle correction value.

[0007] In one possible implementation, the drive body includes a drive housing, a motor output shaft disposed in the drive housing, and a harmonic reducer drivingly connected to the motor output shaft, the harmonic reducer being fixedly connected to the output flange, and before determining the actual rotation angle of the robot joint according to the rotation angle of the output flange and the rotation angle correction value, further comprising: Obtaining a rotation angle of the motor output shaft based on a detection signal of a magnetic encoder; The rotation angle of the output flange is determined according to the rotation angle of the motor output shaft and the stiffness coefficient of the harmonic reducer.

[0008] In a possible implementation, determining the rotation angle of the output flange according to the rotation angle of the motor output shaft and the stiffness coefficient of the harmonic reducer includes: Obtaining the load torque, operating temperature and current speed of the harmonic reducer in real time; According to the load torque, operating temperature and current speed, the real-time stiffness coefficient of the harmonic reducer is determined by querying a pre-calibrated nonlinear stiffness mapping table; The rotation angle of the output flange is determined according to the real-time stiffness coefficient and the rotation angle of the motor output shaft.

[0009] In a possible implementation, the first rotation data includes a historical accumulated value of rotational work of the robot joint along a first direction, and the second rotation data includes a historical accumulated value of rotational work of the robot joint along a second direction. Acquiring the first rotation data of the robot joint includes: Obtaining a torque variation curve during the rotation of the robot joint along a first direction to obtain a first torque variation curve; determining a historical accumulated value of rotational work of the robot joint along a first direction according to the first torque variation curve; The obtaining of the second rotation data of the robot joint includes: Obtaining a torque variation curve during the rotation of the robot joint along the second direction to obtain a second torque variation curve; The historical rotational work accumulation value of the robot joint along the second direction is determined according to the second torque variation curve.

[0010] In one possible implementation, the rotation angle correction model includes a first sub-model and a second sub-model, and inputting the first rotation data, the second rotation data, and the direction switching frequency into the rotation angle correction model to obtain a rotation angle correction value includes: Inputting the historical accumulated value of the rotational work of the robot joint along the first direction and the historical accumulated value of the rotational work of the robot joint along the second direction into the first sub-model to obtain the fatigue gain / loss coefficient of the flexible connection; The fatigue loss coefficient of the flexible connection and the direction switching frequency are input into the second sub-model to obtain a rotation angle correction value.

[0011] In a possible implementation, the first sub-model is a fatigue prediction model based on energy confrontation, and its output satisfies the following expression: *γ Where, is the fatigue loss coefficient, is the accumulated historical rotation work of the robot joint along the first direction, is the accumulated historical rotation work of the robot joint along the second direction, and γ is the material fatigue sensitivity factor.

[0012] In a possible implementation, determining the actual rotation angle of the robot joint according to the rotation angle of the output flange and the rotation angle correction value includes: Performing a secondary correction on the rotation angle correction value according to the current temperature value of the flexible connector to obtain a rotation angle correction target value; The actual rotation angle of the robot joint is determined according to the rotation angle of the output flange and the rotation angle correction target value.

[0013] In a possible implementation, performing a secondary correction on the rotation angle correction value according to the current temperature value of the flexible connector to obtain a rotation angle correction target value includes: Obtaining a mapping relationship of elastic moduli of the flexible connector at different temperatures; Obtaining a current elastic modulus of the flexible connector according to a current temperature value of the flexible connector and the mapping relationship; The rotation angle correction value is secondary corrected according to the current elastic modulus of the flexible connection to obtain a rotation angle correction target value.

[0014] In a possible implementation, the current rotational load includes the current output torque of the joint module, and obtaining the current rotational load of the robot joint includes: Obtaining a detection signal of the strain gauge on the output flange; The current output torque of the robot joint is determined according to the detection signal of the strain gauge on the output flange.

[0015] In one possible implementation, the flexible connector is made of a hard rubber material and is configured not to elastically deform when subjected to a torque below a load threshold. The method further includes: When the current rotation load of the robot joint is less than a load threshold, the actual rotation angle of the robot joint is determined according to the rotation angle of the output flange.

[0016] In a second aspect, an embodiment of the present application further provides a joint rotation angle measurement device, comprising: a memory and a processor, wherein the memory is used to store program code; and the processor is used to call the program code to execute the method described in the first aspect.

[0017] In a third aspect, an embodiment of the present application further provides a storage medium on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0018] Different from the prior art, the method for measuring the rotation angle of a robot joint provided in an embodiment of the present application first obtains the current rotation load of the robot joint. When the current rotation load is greater than or equal to the load threshold, the first rotation data, the second rotation data and the direction switching frequency of the robot joint are respectively obtained; the first rotation data, the second rotation data and the direction switching frequency are then input into the rotation angle correction model to obtain the rotation angle correction value; finally, the actual rotation angle of the robot joint is determined according to the rotation angle of the output flange of the joint module and the rotation angle correction value. That is, the technical solution of the present application monitors the rotation load of the joint in real time. When the rotation load exceeds the preset threshold, the historical rotation data and the direction switching frequency of the joint in both forward and reverse directions are obtained, and the real-time correction value is generated by combining the rotation angle correction model. Finally, the rotation angle of the output flange is merged with the correction value to obtain the actual rotation angle. This method uses a data-driven model to compensate for flexible deformation errors without adding hardware sensors. It is suitable for scenarios where dynamic loads are frequently switched, and improves measurement accuracy and system reliability while ensuring cost efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1 Schematic diagram of the three-dimensional structure of the robot joint in some embodiments of the present application; Figure 2 This is a schematic diagram of the connection structure of the robot joint components in some embodiments of the present application; Figure 3 This is a flow chart of a method for measuring the rotation angle of a robot joint in some embodiments of the present application; Figure 4 This is a flow chart of step S300 of a method for measuring a robot joint rotation angle in some embodiments of the present application; Figure 5 Schematic diagram of the hardware structure of the joint rotation angle measurement device in some embodiments of the present application.

[0021] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0024] In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0025] In many fields, including modern industrial manufacturing, intelligent logistics, rehabilitation medicine, and home services, robots, with their advantages of high efficiency, precision, and repeatability, are becoming a key force driving industrial upgrading and improving people's quality of life. As the core moving components of robots, precise measurement of the rotation angle of robot joints is fundamental to enabling robots to achieve complex and precise movements. This is directly related to the robot's motion performance, task execution accuracy, and overall reliability.

[0026] In related technologies, robot joints need to frequently withstand various loads, especially large external loads. For example, industrial robots need to handle the grasping and movement of workpieces of varying weights when handling materials, and rehabilitation robots must withstand the dynamic forces exerted by human limbs when assisting patients in training. To adapt to this complex and changing load environment and improve the service life and operational stability of joints, many robot joint designs incorporate flexible buffers between the first and second joint bodies. Through their own elastic deformation characteristics, flexible buffers can effectively absorb and cushion the impact loads on joints during movement, reduce vibration and stress concentration caused by rigid collisions, thereby reducing the risk of wear and damage to joint components and extending the service life of the joints.

[0027] However, although the introduction of flexible buffers brings many benefits, it also brings new challenges to the accurate measurement of robot joint rotation angles.

[0028] like Figure 1-2As shown, in the embodiment of the present application, the robot joint includes a first joint body 100, a second joint body 200 and a joint module 300, and the joint module 300 includes a driving body 310 and an output flange 320, the driving body 310 is fixedly connected to the first joint body 100, and the output flange 320 is fixedly connected to the second joint body 200 via a flexible connector 400. In this way, when the first joint body 100 is subjected to a large external load, the flexible connector 400 can absorb the impact energy by its own deformation, effectively buffering the torque directly transmitted to the second joint body 200, thereby preventing the internal precision components or connection structures of the second joint body 200 from being mechanically damaged due to overload. Directions A1 and A2 in the figure are clockwise and counterclockwise.

[0029] In the aforementioned robot joint structure, when the external load is high, the flexible connector elastically deforms due to the force, resulting in a dynamic deviation between the actual joint rotation angle and the angle measured by the output flange. As the load increases, the deformation of the flexible connector increases. If the output flange angle is directly used as the actual joint rotation angle, the error will also increase, affecting the accuracy of motion control.

[0030] It should be noted that in the embodiments of the present application, the flexible connector is made of a hard rubber material and is configured to not elastically deform when subjected to torque below a load threshold (e.g., a force of 20 kg). In other words, in the embodiments of the present application, when the current rotational load of the robot joint is less than the load threshold, the rotation angle of the output flange can be directly used as the actual rotation angle of the robot joint. However, when the flexible connector is subjected to torque exceeding the load threshold (e.g., a force of 20 kg), it will elastically deform. Based on this, the present application proposes the following technical solution to accurately detect the rotation angle of the robot joint.

[0031] like Figure 3-Figure 4 As shown, the following takes the method for measuring the robot joint rotation angle performed by the joint rotation angle measuring device as an example. It should be noted that although the logical order is shown in the flowchart, in some cases, the steps shown or described can be performed in a different order. Figure 3 The method includes the following steps S100 to S400: Step S100, obtaining the current rotation load of the robot joint; A rotational load can be the weight of the object a robot joint is required to manipulate. For example, in a robotic arm application, the weight of the object being manipulated can be considered the rotational load. A rotational load can also be the torque applied to a robot joint. As you can see, due to the mutual nature of forces, the torque applied to a robot joint is actually the torque output by the robot joint. Thus, the current rotational load is the weight of the object a robot joint is required to manipulate at the current moment, or the real-time torque currently being output by the output flange of the robot joint.

[0032] There are several ways to obtain the current rotational load on a robot joint. For example, strain gauges can be installed on the output flange and the deformation signal from these strain gauges can be used to determine the output torque of the output flange. Alternatively, the current data from the joint module can be monitored in real time, and the current value can be used to indirectly provide feedback on the current rotational load. A higher current value indicates a greater rotational load on the robot joint.

[0033] For example, a relationship model between motor current and torque may be pre-trained, and then the output torque may be indirectly estimated using the current current value of the driving motor and the relationship model (eg, a permanent magnet synchronous motor torque formula).

[0034] Step S200: When the current rotation load of the robot joint is greater than or equal to a load threshold, first rotation data, second rotation data, and a direction switching frequency of the robot joint are respectively obtained, wherein the first rotation data is historical rotation data of the robot joint along a first direction, and the second rotation data is historical rotation data of the robot joint along a second direction, wherein the first direction is opposite to the second direction; It can be understood that when the current rotational load of the robot joint is greater than or equal to the load threshold, it indicates that the robot joint is subject to a large external impedance, further indicating that the flexible connector will undergo a certain degree of elastic deformation. At this time, the embodiment of the present application will obtain the historical rotation data of the robot joint in both forward and reverse directions, as well as the forward and reverse switching frequency, thereby providing an accurate data basis for subsequent rotation angle correction.

[0035] In one embodiment, the first rotation data includes the accumulated value of the historical rotation work of the robot joint along the first direction, and the second rotation data includes the accumulated value of the historical rotation work of the robot joint along the second direction. The obtaining of the first rotation data of the robot joint includes: obtaining the torque change curve of the robot joint during the rotation along the first direction to obtain a first torque change curve; and determining the accumulated value of the historical rotation work of the robot joint along the first direction based on the first torque change curve.

[0036] The obtaining of the second rotation data of the robot joint includes: obtaining a torque change curve during the rotation of the robot joint in the second direction to obtain a second torque change curve; and determining a historical rotation work accumulated value of the robot joint in the second direction according to the second torque change curve.

[0037] The technical solution of this application establishes a dynamic correlation between deformation energy and load history by quantifying the energy accumulation effect of the joint in different motion directions. Specifically, the historical cumulative rotational work value in the first rotation data reflects the energy absorption and release of the flexible connector due to the cumulative force in a single direction when the joint moves in a first direction (e.g., clockwise). This can be achieved by recording the torque versus angle curve (a first torque variation curve) in real time during the clockwise rotation of the joint using a high-sampling rate sensor (e.g., a 1000Hz torque sensor). This curve is then integrated based on the mechanical work calculation formula (W=∫τ(θ)dθ, where τ is torque and θ is the rotation angle) to obtain the cumulative work value in that direction. This value quantifies the energy absorption and release characteristics of the flexible connector in the first direction (e.g., the hysteresis effect of rubber materials or the microplastic deformation of metal composites). A larger value indicates more significant fatigue damage accumulated in the flexible connector during deformation in the first direction and a higher risk of material performance degradation. Similarly, the second rotation data can quantify the energy absorption and release characteristics of the flexible material in the second direction. The larger the value, the more significant the accumulated fatigue damage of the flexible connector during deformation in the second direction, and the higher the risk of material elastic performance attenuation.

[0038] It's understandable that the frequency of forward and reverse switching in a robot's joints directly impacts the fatigue life of its flexible connectors. When the direction of motion switches frequently (e.g., three times per second during assembly), the flexible connectors experience alternating stress cycles during elastic deformation, accelerating the growth of microcracks within the material. The higher the switching frequency, the greater the number of stress cycles per unit time, increasing the probability of elastic degradation in the flexible connectors due to accumulated fatigue.

[0039] In this way, the first rotation data, the second rotation data, and the forward and reverse direction switching frequency can be fed back and quantified to determine the degree of elastic performance attenuation of the flexible connector through relevant data calibration.

[0040] When the embodiment of the present application detects that the robot joint is in a high-load condition (i.e., the current rotational load ≥ a preset threshold), bidirectional motion energy parameters and direction switching dynamic indicators are synchronously collected to provide multi-dimensional data support for angle error compensation.

[0041] Step S300: inputting the first rotation data, the second rotation data and the direction switching frequency into a rotation angle correction model to obtain a rotation angle correction value; Since the first rotation data, the second rotation data and the direction switching frequency can all provide feedback on the degree of elastic performance attenuation of the flexible connector, the rotation angle correction value can be obtained by inputting the first rotation data, the second rotation data and the direction switching frequency into a pre-trained rotation angle correction model.

[0042] In one embodiment, the rotation angle correction model of the present application includes a first sub-model and a second sub-model. Step S300: inputting the first rotation data, the second rotation data, and the direction switching frequency into the rotation angle correction model to obtain a rotation angle correction value includes: S310, inputting the historical accumulated value of the rotational work of the robot joint along the first direction and the historical accumulated value of the rotational work of the robot joint along the second direction into the first sub-model to obtain the fatigue gain / loss coefficient of the flexible connector; S320: Input the fatigue loss coefficient of the flexible connection and the direction switching frequency into the second sub-model to obtain a rotation angle correction value.

[0043] Specifically, the embodiment of the present application first inputs the historical accumulated rotational work values ​​of the robot joints along the first direction and the historical accumulated rotational work values ​​of the robot joints along the second direction into the first sub-model to obtain the fatigue gain / loss coefficient of the flexible connector. The fatigue gain / loss coefficient is used to characterize the elastic attenuation degree of the flexible connector. A larger fatigue gain / loss coefficient indicates a greater elastic attenuation degree of the flexible connector. After obtaining the fatigue gain / loss coefficient of the flexible connector, the fatigue gain / loss coefficient of the flexible connector and the direction switching frequency are input into the second sub-model to obtain the rotation angle correction value.

[0044] Exemplarily, the first sub-model of the present application is a fatigue prediction model based on energy confrontation, and its output satisfies the following expression: *γ. Where, is the fatigue loss coefficient, is the accumulated historical rotation work of the robot joint along the first direction, is the accumulated historical rotation work of the robot joint along the second direction, and γ is the material fatigue sensitivity factor.

[0045] Energy resistance refers to the fact that the greater the difference between the accumulated historical rotational work of the robot joint along the first direction and the accumulated historical rotational work along the second direction, the higher the probability of unidirectional deformation of the flexible connector. In other words, the more obvious the imbalance between forward and reverse rotation, the greater the elastic attenuation of the flexible connector. The material fatigue sensitivity factor refers to the material's sensitivity to torsional deformation. The larger the material fatigue sensitivity factor, the more sensitive the material fatigue of the flexible connector is to deformation, further indicating a greater probability of elastic damage due to torsion. For example, the material fatigue sensitivity factor can be obtained by querying the material property table. During the specific calculation process, other control parameters can also be introduced to control the final size of the fatigue gain / loss coefficient.

[0046] It can be understood that the greater the elastic attenuation of the flexible connector, the lower its tracking performance (which can be understood as the elastic body being loose inside and not utilizing force transmission), that is, the more obvious the angle hysteresis effect.

[0047] In an embodiment of the present application, the fatigue loss coefficient and direction switching frequency of multiple groups of flexible connectors can be collected in advance for experiments to obtain the angle difference between the joint rotation angle and the output flange, thereby forming a curve model (second sub-model). Using this curve model, the angle correction value (the angle difference between the joint rotation angle and the output flange) can be obtained based on the measured fatigue loss coefficient and direction switching frequency.

[0048] Step S400: determining the actual rotation angle of the robot joint according to the rotation angle of the output flange and the rotation angle correction value.

[0049] After the rotation angle correction value is obtained in step S300 , the actual rotation angle of the robot joint can be determined according to the rotation angle of the output flange and the rotation angle correction value.

[0050] For example, when the output flange rotates 5°, the joint can follow it by 4° under normal flexible connector conditions, resulting in an angle difference of 1°. However, due to the elasticity decay of the flexible connector, its tracking performance is reduced. The rotation angle correction model calculates an angle difference of 1.4°, meaning that the actual rotation angle of the joint is only 3.6°.

[0051] In order to further improve the detection value of the rotation angle of the robot joint, in one embodiment, the actual rotation angle of the robot joint is determined based on the rotation angle of the output flange and the rotation angle correction value, including: performing a secondary correction on the rotation angle correction value according to the current temperature value of the flexible connection to obtain a rotation angle correction target value; and determining the actual rotation angle of the robot joint based on the rotation angle of the output flange and the rotation angle correction target value.

[0052] Specifically, the elastic modulus mapping relationship of the flexible connector at different temperatures can be first obtained; then the current elastic modulus of the flexible connector is obtained based on the current temperature value of the flexible connector and the mapping relationship; finally, the rotation angle correction value is secondary corrected based on the current elastic modulus of the flexible connector to obtain the rotation angle correction target value.

[0053] For example, when the output flange rotates 5°, under normal conditions of the flexible connector, the joint can follow the rotation by 4°, and the angle difference is 1°. However, due to the elastic attenuation of the flexible connector (temperature is not considered at this time), its following performance is reduced, and the angle difference obtained by the rotation angle correction model is 1.4°. In an embodiment of the present application, the temperature parameter is further introduced to correct the rotation correction value to obtain the rotation angle correction target value. For example, when the current temperature of the flexible connector is higher than the temperature threshold, its elastic attenuation degree further increases, that is, the following performance is further reduced. The hysteresis angle obtained at this time is further increased relative to 1.4°, such as the rotation angle correction target value of 1.6°. In the end, the actual angle at which the joint can rotate is only 3.4°.

[0054] In one embodiment, the drive body includes a drive housing, a motor output shaft disposed in the drive housing, and a harmonic reducer drivingly connected to the motor output shaft, the harmonic reducer being fixedly connected to the output flange, and before determining the actual rotation angle of the robot joint based on the rotation angle of the output flange and the rotation angle correction value, further comprising: Obtaining a rotation angle of the motor output shaft based on a detection signal of a magnetic encoder; The rotation angle of the output flange is determined according to the rotation angle of the motor output shaft and the stiffness coefficient of the harmonic reducer.

[0055] Specifically, the embodiment of the present application installs a magnetic encoder on the motor output shaft to detect the rotation angle θ of the motor output shaft in real time. 电 Since the harmonic reducer has a certain elasticity, it can be regarded as an elastic body. Therefore, the rotation angle θ of the output flange can be determined according to the rotation angle of the motor output shaft and the stiffness coefficient of the harmonic reducer. 输 For example, we can use the formula θ 输 =K*θ 电 Calculate the output flange angle, where K is the stiffness coefficient of the harmonic reducer.

[0056] Because the stiffness coefficient of a harmonic reducer is not a fixed value, it is affected by various factors, such as temperature, load, and rotational speed. The flexspline of a harmonic reducer is typically made of alloy steel or composite materials. Rising temperature causes differences in the thermal expansion coefficients of the materials, changing the meshing clearance between the flexspline and the wave generator, thereby reducing transmission stiffness. Increased load exacerbates the elastic deformation of the flexspline. For example, under a load of 100 Nm, the stiffness may drop from the nominal value of 5000 Nm / rad to 4500 Nm / rad. Thus, load also has a certain impact on the stiffness coefficient. At high speeds (such as 3000 rpm), the dynamic stiffness of the harmonic reducer may decrease due to inertia and vibration effects.

[0057] Therefore, in one embodiment, the rotation angle of the output flange is determined according to the rotation angle of the motor output shaft and the stiffness coefficient of the harmonic reducer, including: acquiring the load torque, operating temperature and current speed of the harmonic reducer in real time; determining the real-time stiffness coefficient of the harmonic reducer by querying a pre-calibrated nonlinear stiffness mapping table according to the load torque, operating temperature and current speed; and determining the rotation angle of the output flange according to the real-time stiffness coefficient and the rotation angle of the motor output shaft.

[0058] For example, the stiffness coefficient K(τ, T, ω) under different loads, temperatures, and speeds can be pre-calibrated through experiments. The calibration data is then stored as a lookup table (LUT) or a mathematical model (such as a neural network or polynomial fitting). The real-time stiffness coefficient K_realtime is then calculated using the LUT or model based on the real-time acquired τ, T, and ω. Finally, the output flange rotation angle is determined based on the real-time stiffness coefficient and the rotation angle of the motor output shaft.

[0059] Based on this, the embodiment of the present application provides a method for measuring the rotation angle of a robot joint, which monitors the joint rotation load in real time. When the rotation load exceeds a preset threshold, the historical rotation data and direction switching frequency of the joint in both directions are obtained, and a real-time correction value is generated in combination with a rotation angle correction model. Finally, the rotation angle of the output flange is integrated with the correction value to obtain the actual rotation angle of the robot joint. This method uses a data-driven model to compensate for flexible deformation errors, without the need to add hardware sensors, reducing the cost of hardware modification or redevelopment. It is suitable for scenarios where dynamic loads are frequently switched, improving measurement accuracy and system reliability while ensuring cost efficiency.

[0060] like Figure 5 As shown, Figure 5This is a hardware structure diagram of the joint rotation angle measuring device in some embodiments of the present application. The joint rotation angle measuring device provided in the embodiments of the present application includes a memory 1000 and a processor 2000, wherein the memory 1000 is used to store computer-readable instructions, and the processor 2000 is used to call the computer-readable instructions to execute the robot joint rotation angle measurement method as described above.

[0061] Among them, the processor 2000 is used to provide computing and control capabilities to control the joint rotation angle measuring device to perform corresponding tasks, for example, controlling the joint rotation angle measuring device to perform the robot joint rotation angle measurement method in any of the above-mentioned method embodiments, the method comprising: obtaining the current rotation load of the robot joint; when the current rotation load of the robot joint is greater than or equal to the load threshold, respectively obtaining the first rotation data, second rotation data and direction switching frequency of the robot joint, the first rotation data being the historical rotation data of the robot joint along the first direction, and the second rotation data being the historical rotation data of the robot joint along the second direction, wherein the first direction is opposite to the second direction; inputting the first rotation data, the second rotation data and the direction switching frequency into the rotation angle correction model to obtain a rotation angle correction value; determining the actual rotation angle of the robot joint according to the rotation angle of the output flange and the rotation angle correction value.

[0062] Processor 2000 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof; it may also be a digital signal processing (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or any combination thereof. The PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0063] Memory 1000, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the robot joint rotation angle measurement method in the embodiments of the present application. Processor 2000 can implement the robot joint rotation angle measurement method in any of the above-described method embodiments by executing the non-transitory software programs, instructions, and modules stored in memory 1000.

[0064] Specifically, the memory 1000 may include a volatile memory (VM), such as a random access memory (RAM); the memory 1000 may also include a non-volatile memory (NVM), such as a read-only memory (ROM), a flash memory, a hard disk drive (HDD) or a solid-state drive (SSD) or other non-transitory solid-state storage device; the memory 1000 may also include a combination of the above types of memory.

[0065] In summary, the joint rotation angle measuring device of the present application adopts the technical solution of any of the above-mentioned robot joint rotation angle measurement method embodiments, and therefore, has at least the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0066] The present application also provides a computer-readable storage medium, such as a memory device including program code. The program code can be executed by a processor to implement the method for measuring the rotation angle of a robot joint in the above embodiment. For example, the computer-readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CDROM), a magnetic tape, a floppy disk, or an optical data storage device.

[0067] The present application also provides a computer program product comprising one or more program codes stored in a computer-readable storage medium. A processor of the early warning system reads the program code from the computer-readable storage medium and executes the program code to perform the steps of the method for measuring the rotation angle of a robot joint provided in the above embodiment.

[0068] Those skilled in the art will understand that all or part of the steps of implementing the above embodiments can be completed by hardware, or by hardware related to program code, and the program can be stored in a computer-readable storage medium. The above-mentioned storage medium can be a read-only memory, a disk or an optical disk, etc.

[0069] It should be noted that the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0070] Through the description of the above embodiments, it is clear to those skilled in the art that each embodiment can be implemented by means of software plus a general hardware platform, or of course by hardware. It is understood by those skilled in the art that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0071] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for measuring the rotation angle of a robot joint, characterized in that: The robot joint includes a first joint body, a second joint body, and a joint module, the joint module includes a drive body and an output flange, the drive body is fixedly connected to the first joint body, and the output flange is fixedly connected to the second joint body via a flexible connector, and the method includes: Obtaining the current rotational load of the robot joint; When the current rotation load of the robot joint is greater than or equal to a load threshold, first rotation data, second rotation data, and a direction switching frequency of the robot joint are respectively acquired, wherein the first rotation data is historical rotation data of the robot joint along a first direction, and the second rotation data is historical rotation data of the robot joint along a second direction, wherein the first direction is opposite to the second direction; Inputting the first rotation data, the second rotation data and the direction switching frequency into a rotation angle correction model to obtain a rotation angle correction value; The actual rotation angle of the robot joint is determined according to the rotation angle of the output flange and the rotation angle correction value.

2. The method for measuring the rotation angle of a robot joint according to claim 1, wherein: The driving body includes a driving housing, a motor output shaft disposed in the driving housing, and a harmonic reducer drivingly connected to the motor output shaft, wherein the harmonic reducer is fixedly connected to the output flange. Before determining the actual rotation angle of the robot joint according to the rotation angle of the output flange and the rotation angle correction value, the driving body further includes: Obtaining a rotation angle of the motor output shaft based on a detection signal of a magnetic encoder; The rotation angle of the output flange is determined according to the rotation angle of the motor output shaft and the stiffness coefficient of the harmonic reducer.

3. The method for measuring the rotation angle of a robot joint according to claim 2, wherein: Determining the rotation angle of the output flange according to the rotation angle of the motor output shaft and the stiffness coefficient of the harmonic reducer includes: Obtaining the load torque, operating temperature and current speed of the harmonic reducer in real time; According to the load torque, operating temperature and current speed, the real-time stiffness coefficient of the harmonic reducer is determined by querying a pre-calibrated nonlinear stiffness mapping table; The rotation angle of the output flange is determined according to the real-time stiffness coefficient and the rotation angle of the motor output shaft.

4. The method for measuring the rotation angle of a robot joint according to claim 1, wherein: The first rotation data includes a historical accumulated value of rotation work of the robot joint along a first direction, and the second rotation data includes a historical accumulated value of rotation work of the robot joint along a second direction. Acquiring the first rotation data of the robot joint includes: Obtaining a torque variation curve during the rotation of the robot joint along a first direction to obtain a first torque variation curve; determining a historical accumulated value of rotational work of the robot joint along a first direction according to the first torque variation curve; The obtaining of the second rotation data of the robot joint includes: Obtaining a torque variation curve during the rotation of the robot joint along the second direction to obtain a second torque variation curve; The historical rotational work accumulation value of the robot joint along the second direction is determined according to the second torque variation curve.

5. The method for measuring the rotation angle of a robot joint according to claim 4, wherein: The rotation angle correction model includes a first sub-model and a second sub-model. The first rotation data, the second rotation data, and the direction switching frequency are input into the rotation angle correction model to obtain a rotation angle correction value, including: Inputting the historical accumulated value of the rotational work of the robot joint along the first direction and the historical accumulated value of the rotational work of the robot joint along the second direction into the first sub-model to obtain the fatigue gain / loss coefficient of the flexible connection; The fatigue loss coefficient of the flexible connection and the direction switching frequency are input into the second sub-model to obtain a rotation angle correction value.

6. The method for measuring the rotation angle of a robot joint according to claim 5, wherein: The first sub-model is a fatigue prediction model based on energy confrontation, and its output satisfies the following expression: *c Where, is the fatigue loss coefficient, is the accumulated historical rotation work of the robot joint along the first direction, is the accumulated historical rotation work of the robot joint along the second direction, and γ is the material fatigue sensitivity factor.

7. The method for measuring the rotation angle of a robot joint according to claim 5, wherein: Determining the actual rotation angle of the robot joint according to the rotation angle of the output flange and the rotation angle correction value includes: Performing a secondary correction on the rotation angle correction value according to the current temperature value of the flexible connector to obtain a rotation angle correction target value; The actual rotation angle of the robot joint is determined according to the rotation angle of the output flange and the rotation angle correction target value.

8. The method for measuring the rotation angle of a robot joint according to claim 7, wherein: Performing a secondary correction on the rotation angle correction value according to the current temperature value of the flexible connector to obtain a rotation angle correction target value includes: Obtaining a mapping relationship of elastic moduli of the flexible connector at different temperatures; Obtaining a current elastic modulus of the flexible connector according to a current temperature value of the flexible connector and the mapping relationship; The rotation angle correction value is secondary corrected according to the current elastic modulus of the flexible connection to obtain a rotation angle correction target value.

9. The method for measuring the rotation angle of a robot joint according to claim 1, wherein: The current rotational load includes the current output torque of the joint module. Obtaining the current rotational load of the robot joint includes: Obtaining a detection signal of the strain gauge on the output flange; The current output torque of the robot joint is determined according to the detection signal of the strain gauge on the output flange.

10. The method for measuring the rotation angle of a robot joint according to claim 1, wherein: The flexible connector is made of a hard rubber material and is configured not to elastically deform when subjected to a torque below a load threshold. The method further comprises: When the current rotation load of the robot joint is less than a load threshold, the actual rotation angle of the robot joint is determined according to the rotation angle of the output flange.

11. A joint rotation angle measuring device, characterized in that: include: A memory and a processor, wherein the memory is used to store program codes; The processor is configured to call the program code to execute the method according to any one of claims 1 to 10.

12. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 10 are implemented.

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