CN112179551B - Method and device for synchronizing test method and device of joint motor torque coefficient and friction force of robot - Google Patents

Abstract

The invention provides a method and device for synchronizing the torque coefficient and friction force of a joint motor of a robot. The method includes: calculating an analytical expression of the driving torque of the driving joint of the robot according to the dynamic model of the robot and the structural parameters of the robot; The experimental data is input into the analytical expression of the driving torque to obtain the forward torque and reverse torque, and the driving current is fitted to obtain the slope and intercept of the fitted linear function at different experimental positions; combined with the ratio of the reduction ratio of the joint to be tested, the test is obtained. The motor torque coefficient when the joint is moving forward and reverse, take the opposite number of the intercept to get the friction coefficient when the joint to be tested is moving forward and reverse; calculate the difference between the motor torque coefficient and friction coefficient at different experimental positions The average value is obtained to obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion. Thereby, the synchronous test of the torque coefficient of the joint motor and the coefficient of forward and reverse friction force is realized, and the test accuracy is improved.

Description

Method and device for synchronizing test method and device of joint motor torque coefficient and friction force of robot

technical field

The invention discloses a method and device for synchronizing the torque coefficient and friction force of a joint motor of a robot, and particularly relates to the technical field of industrial robot dynamics and control.

Background technique

Industrial robots are important equipment widely used in various industrial manufacturing fields. They can achieve efficient and accurate operation in dangerous and harsh working environments, and are the cornerstone of automated production. In order to improve the comprehensive performance of industrial robots, there are high requirements for the accuracy of the electromechanical system model of the robot "control-drive-motor-mechanism" in the aspects of robot performance evaluation, optimization design, control algorithm development, and parameter tuning. Some of the key parameters that cannot be directly obtained or are not accurate enough need to be tested to obtain accurate values.

From the perspective of electromechanical coupling, industrial robots are complex multi-axis coupled electromechanical systems. There is a coupling effect between the mechanical subsystem and the control subsystem. The key process is that the armature current of the driving motor is affected in the magnetic field. The force produces the driving torque, and the conversion coefficient between the two, the torque coefficient, is the key parameter of the electromechanical coupling system. The design value of the motor torque coefficient is generally marked on the motor nameplate, but when the robot is used in industrial scenarios such as surface spraying and machining, the operating environment is relatively harsh, and it is affected by factors such as dust, temperature and humidity changes, and mechanical structure assembly quality. , the torque coefficient of the joint motor often has a certain deviation from the design value, and the different running directions of the motor may also bring changes.

The driving torque is the force that drives the operation of the mechanical structure, which can be obtained by modeling the robot dynamics theory. The related methods are relatively mature. However, because the friction force during the actual operation of the joint is difficult to obtain accurately through theoretical modeling, the actual dynamics of the robot is difficult to obtain. There is a big gap between the behavior and the theoretical dynamic model, and the friction coefficient of the joint should also be tested before applying the dynamic model.

Usually, a dynamometer can be used to measure the torque coefficient of the motor before it is installed, and then the friction model of the robot joint after installation is tested based on the coefficient and the dynamic model, but this method does not consider the mechanical The influence of the assembly and operating environment on the motor parameters, and the steps are cumbersome, which cannot meet the needs of the rapid correction of the parameters of the robot after installation and operation for a period of time or after the working environment changes.

At present, there is still a lack of relevant research on the test and correction of the torque coefficient of the drive motor for industrial robots in practical applications. The rapid test of the motor torque coefficient and joint friction for the robot body needs to be improved. In order to meet the needs of accurate modeling of electromechanical systems , it is urgent to propose a robot-oriented joint motor torque coefficient and friction synchronous test method.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

Therefore, the purpose of the present invention is to propose a method and device for synchronizing the torque coefficient and friction force of the joint motor of a robot. Simultaneous test of coefficient and positive and negative friction coefficient to improve test accuracy.

The method for synchronizing the torque coefficient and friction force of the joint motor of the robot according to the present invention includes:

Establish a dynamic model of the robot based on the principle of virtual work, obtain the mechanical structure parameters of the robot, and calculate the analytical expression of the driving torque of each driving joint of the robot according to the dynamic model and the mechanical structure parameters; obtain the pre-stored experimental data, among which the experimental data Including: the angle, angular velocity, angular acceleration and driving current of each joint to be tested, and storing the experimental data in two arrays according to the direction of the angular velocity; respectively inputting the experimental data in the two arrays at different experimental positions into the driving torque analysis The forward torque and reverse torque are obtained from the expression, and the forward torque, reverse torque and driving current are fitted to obtain the slope and intercept of the fitted linear function at different experimental positions; The ratio of the reduction ratio of the joint to be tested is used to obtain the motor torque coefficient of the joint to be tested in the forward and reverse motions, and the inverse of the intercept of the fitted linear function is obtained to obtain the frictional force of the joint to be tested in the forward and reverse motions Calculate the average value of the motor torque coefficient and friction coefficient at different experimental positions, and obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion.

In addition, the joint motor torque coefficient and friction synchronization test method of the robot according to the present invention may also have the following additional technical features:

According to some embodiments of the present invention, it may also include determining different experimental positions and joints to be tested; keeping other joints still, and controlling the joints to be tested to perform trapezoidal acceleration and deceleration reciprocating motions at different experimental positions, wherein, the joints to be tested are in the uniform motion stage. There is a positive correlation between the speed and the angular velocity of the joint to be tested in actual work. Acquire experimental data at different experimental locations.

According to some embodiments of the present invention, obtaining experimental data at different experimental positions includes obtaining the angle of the joint to be tested through an absolute encoder; obtaining the speed of the joint to be tested through a grating encoder; The angular acceleration of the joint; the drive current of the joint to be tested is obtained through the Hall sensor.

According to some embodiments of the present invention, the analytical expression of the driving torque is:

为驱动力矩中的惯性力分量，

为驱动力矩中的离心力与科氏力分量，G(θ)g为驱动力矩中的重力分量。另外，使用待测试关节的正向运动时的实验数据计算获得的为正向运动时的理论驱动力矩；使用待测试关节的反向运动时的实验数据计算获得的为反向运动时的理论驱动力矩。Among them, τ is the real-time driving torque of the joint to be tested,

is the inertial force component in the driving torque,

are the centrifugal force and Coriolis force components in the driving torque, and G(θ)g is the gravity component in the driving torque. In addition, using the experimental data during the forward motion of the joint to be tested is the theoretical driving torque during the forward motion; using the experimental data during the reverse motion of the joint to be tested is the theoretical drive during the reverse motion. moment.

According to some embodiments of the present invention, the formula used for fitting is:

Among them, K _t is the torque coefficient of the joint motor to be tested, I _q is the drive current of the joint motor to be tested, f is the friction force of the joint to be tested, and i is the reduction ratio of the joint to be tested. τ is the theoretical driving torque of the joint to be tested, including the theoretical driving torque of the joint to be tested in the forward motion and the theoretical driving torque of the reverse motion. When the theoretical driving torque of the joint to be tested is used in the forward motion, the The function obtained by fitting is the forward motion fitting function; when the theoretical driving torque of the joint to be tested is used in the reverse motion, the function obtained by fitting is the reverse motion fitting function.

According to some embodiments of the present invention, controlling the joint to be tested to perform trapezoidal acceleration and deceleration reciprocating motion at different experimental positions is included in the preset working space of the robot, and uniformly selects the coordinate positioning of several robot end effectors with equal spacing to generate Different experimental positions; control the joints to be tested in different experimental positions to implement the same motion stroke and the same speed plan.

In order to achieve the above purpose, the embodiment of the second aspect of the present invention proposes a synchronous test device for the torque coefficient and friction force of a joint motor of a robot, including: a modeling module, an acquisition module, a first calculation module, a second calculation module, a third Three calculation modules, wherein the modeling module is used to establish a dynamic model of the robot based on the principle of virtual work, obtain the mechanical structure parameters of the robot, and calculate the analytical expression of the driving torque of each driving joint of the robot according to the dynamic model and the mechanical structure parameters; The acquisition module is used for acquiring pre-stored experimental data, wherein the experimental data includes: the angle, angular velocity, angular acceleration and driving current of each joint to be tested, and the experimental data are stored in two arrays respectively according to the direction of the angular velocity; the first The calculation module is used to input the experimental data in the two arrays of different experimental positions into the analytical expression of the driving torque respectively to obtain the forward torque and reverse torque, and fit the forward torque, reverse torque and driving current to obtain different values. The slope and intercept of the fitted linear function of the experimental position; the second calculation module is used to obtain the motor torque when the joint to be tested moves forward and backward according to the ratio of the slope of the fitted linear function to the reduction ratio of the joint to be tested The coefficient of friction is obtained by taking the inverse of the intercept of the fitted linear function to obtain the friction coefficient of the joint to be tested in forward and reverse motion; the third calculation module is used to calculate the average of the motor torque coefficient and friction coefficient at different experimental positions value to obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion.

In addition, the joint motor torque coefficient and friction force synchronization test device of the robot according to the above-mentioned embodiment of the present invention may also have the following additional technical features:

Further, in a possible implementation manner of the embodiment of the present application, it may also include:

A determination module for determining different experimental positions and joints to be tested;

The experimental module is used to keep other joints still, and control the joint to be tested to perform trapezoidal acceleration and deceleration reciprocating motion at different experimental positions. The speed of the joint to be tested in the uniform motion stage is positively correlated with the angular velocity of the joint to be tested in actual work. .

The recording module is used to obtain experimental data at different experimental locations.

Further, in a possible implementation manner of the embodiment of the present application, the recording module is specifically configured to obtain the angle of the joint to be tested through an absolute value encoder, obtain the speed of the joint to be tested through a grating encoder, and obtain the speed of the joint to be tested through an absolute value encoder. Do differential to obtain the angular acceleration of the joint to be tested, and obtain the drive current of the joint to be tested through the Hall sensor.

Further, in a possible implementation manner of the embodiment of the present application, the first calculation module is used to calculate the analytical expression of the driving torque as follows:

为驱动力矩中的惯性力分量，

为驱动力矩中的离心力与科氏力分量，G(θ)g为驱动力矩中的重力分量。另外，使用待测试关节的正向运动时的实验数据计算获得的为正向运动时的理论驱动力矩；使用待测试关节的反向运动时的实验数据计算获得的为反向运动时的理论驱动力矩。Among them, τ is the real-time driving torque of the joint to be tested,

is the inertial force component in the driving torque,

are the centrifugal force and Coriolis force components in the driving torque, and G(θ)g is the gravity component in the driving torque. In addition, using the experimental data during the forward motion of the joint to be tested is the theoretical driving torque during the forward motion; using the experimental data during the reverse motion of the joint to be tested is the theoretical drive during the reverse motion. moment.

The method for synchronizing the torque coefficient and friction force of the joint motor of the robot provided by the embodiment of the present invention may include the following beneficial effects:

Establish a dynamic model of the robot based on the principle of virtual work, obtain the mechanical structure parameters of the robot, and calculate the analytical expression of the driving torque of each driving joint of the robot according to the dynamic model and the mechanical structure parameters; obtain the pre-stored experimental data, among which the experimental data Including: the angle, angular velocity, angular acceleration and driving current of each joint to be tested, and storing the experimental data in two arrays according to the direction of the angular velocity; respectively inputting the experimental data in the two arrays at different experimental positions into the driving torque analysis The forward torque and reverse torque are obtained from the expression, and the forward torque, reverse torque and driving current are fitted to obtain the slope and intercept of the fitted linear function at different experimental positions; The ratio of the reduction ratio of the joint to be tested is used to obtain the motor torque coefficient of the joint to be tested in the forward and reverse motions, and the inverse of the intercept of the fitted linear function is obtained to obtain the frictional force of the joint to be tested in the forward and reverse motions Calculate the average value of the motor torque coefficient and friction coefficient at different experimental positions, and obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion. Therefore, under the condition of fully considering the influence of mechanical structure and working environment on key electromechanical parameters, the synchronous test of the torque coefficient of joint motor and the coefficient of forward and reverse friction force is realized, and the test accuracy is improved.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a schematic flowchart of a method for synchronizing the torque coefficient and friction force of a joint motor of a robot according to an embodiment of the present invention;

2 is a schematic structural diagram of a six-axis hybrid spraying robot suitable for the present invention;

Fig. 3 is a comparison diagram of the drive current curve of the joint to be tested and the angular velocity curve of the joint to be tested of the six-axis hybrid spraying robot;

Fig. 4 is the calculated driving torque curve diagram of the joint test experiment of the six-axis hybrid spraying robot;

Figure 5 is a scatter diagram of the actual drive current in the forward motion stage of the six-axis hybrid spraying robot;

Figure 6 is a scatter diagram of the calculated driving torque in the forward motion stage of the six-axis hybrid spraying robot;

Fig. 7 is the linear fitting schematic diagram of the actual drive current and the calculated drive torque in the forward motion stage of the six-axis hybrid spraying robot;

Figure 8 is a scatter diagram of the actual drive current in the reverse motion stage of the six-axis hybrid spraying robot;

Figure 9 is a scatter diagram of the calculated driving torque in the reverse motion stage of the six-axis hybrid spraying robot;

Figure 10 is a schematic diagram of the linear fitting of the actual drive current and the calculated drive torque in the reverse motion stage of the six-axis hybrid spraying robot;

Figure 11 is a comparison diagram of the predicted driving current and the actual driving current of the joint verification experiment of the six-axis hybrid spraying robot;

FIG. 12 is a schematic structural diagram of a device for synchronizing the torque coefficient and friction force of a joint motor of a robot according to an embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

The purpose of the invention is to fully consider the influence of the mechanical structure and the working environment on the key electromechanical parameters, realize the synchronous test of the torque coefficient of the joint motor and the positive and negative friction coefficient, and improve the test accuracy.

The following describes the method and device for synchronizing the torque coefficient and friction force of the joint motor of the robot according to the embodiments of the present invention with reference to the accompanying drawings.

FIG. 1 is a schematic flowchart of a method for synchronizing the torque coefficient and friction force of a joint motor of a robot according to an embodiment of the present invention. As shown in Figure 1, the joint motor torque coefficient and friction synchronization test method of the robot includes:

Step 101 , establishing a dynamic model of the robot based on the virtual work principle, obtaining mechanical structure parameters of the robot, and calculating an analytical expression for the driving torque of each driving joint of the robot according to the dynamic model and the mechanical structure parameters.

Among them, robots can be understood as industrial robots, etc. Different types of industrial robots will be used in different working environments. Due to different working environments, the operating parameters of the robots will be different or changed.

Specifically, the robot is regarded as a multi-rigid linkage mechanism, its theoretical dynamic model is established based on the principle of virtual work, the 3D model of the robot is established in 3D software, and the mass, length, and moment of inertia of each component of the robot are collected through the 3D software. and other parameters, brought into the theoretical dynamic model based on the virtual work principle, and obtained the analytical expression of the driving torque of each joint of the robot. The three-dimensional software may be Solidworks, Creo (Pro/E), and the like.

Step 102: Acquire pre-stored experimental data, wherein the experimental data includes: the angle, angular velocity, angular acceleration and driving current of each joint to be tested, and the experimental data is stored in two arrays according to the direction of the angular velocity.

Among them, the pre-stored experimental data can be understood as the joints to be tested determined in advance. In the preset working space of the robot, the coordinate positioning of several robot end effectors are evenly selected with equal spacing to generate different experimental positions. In the experimental position, keep other joints still, and control the joints to be tested to do trapezoidal acceleration and deceleration reciprocating motion, so as to obtain experimental data of multiple groups of joints to be tested in different experimental positions. The experimental data includes: the angle, angular velocity, angular acceleration and driving current of the joint to be tested. The method of obtaining each experimental data may be to obtain the angle of the joint to be tested through an absolute value encoder; to obtain the speed of the joint to be tested through a grating encoder; to obtain the angular acceleration of the joint to be tested by differentiating the instantaneous speed; Obtain the drive current of the joint to be tested. In addition, in the experimental data of multiple groups of joints to be tested at different experimental positions, they will also be divided into two arrays according to the direction of angular velocity. At the same time, the speed of the joint to be tested in the uniform motion stage has a positive correlation with the angular velocity of the joint to be tested in actual work.

Specifically, from the multiple sets of experimental data obtained according to the joints to be tested at different experimental positions, two arrays of one set of experimental data are selected, and the angles of the joints to be tested recorded in advance through the experimental process are obtained from the two arrays , angular velocity, angular acceleration and experimental data of driving current.

Step 103: Input the experimental data in the two arrays of different experimental positions into the driving torque analytical expression respectively to obtain the forward torque and reverse torque, and perform fitting processing on the forward torque, reverse torque and driving current to obtain different experiments. The slope and intercept of the fitted linear function of position.

Among them, the analytical expression of the driving torque is formula (1):

为驱动力矩中的惯性力分量，

为驱动力矩中的离心力与科氏力分量，G(θ)g为驱动力矩中的重力分量，另外，使用待测试关节的正向运动时的实验数据计算获得的为正向运动时的理论驱动力矩；使用待测试关节的反向运动时的实验数据计算获得的为反向运动时的理论驱动力矩。另外，在工业机器人中，对于没有高速运动需求的轻型机器人，在其驱动力矩中，惯性分量与重力分量将占据主要地位，因此后续计算可以忽略离心力与科氏力分量。Among them, τ is the real-time driving torque of the joint to be tested,

is the inertial force component in the driving torque,

is the centrifugal force and Coriolis force components in the driving torque, G(θ)g is the gravity component in the driving torque, in addition, the theoretical driving in the forward movement is calculated using the experimental data during the forward movement of the joint to be tested. Torque; the theoretical driving torque during reverse movement is calculated using the experimental data of the joint to be tested during reverse movement. In addition, in industrial robots, for light robots without high-speed motion requirements, inertial and gravitational components will occupy the dominant position in the driving torque, so centrifugal force and Coriolis force components can be ignored in subsequent calculations.

In addition, the formula used for fitting is formula (2):

Among them, K _t is the torque coefficient of the joint motor to be tested, I _q is the drive current of the joint motor to be tested, f is the frictional force of the joint to be tested, i is the reduction ratio of the joint to be tested, and τ is the joint to be tested. The theoretical driving torque of the joint, including the theoretical driving torque in the forward motion of the joint to be tested and the theoretical driving torque in the reverse motion, when using the theoretical driving torque in the forward motion of the joint to be tested, the function obtained by fitting is the forward motion fitting function; when the theoretical driving torque of the joint to be tested is used in the reverse motion, the function obtained by fitting is the reverse motion fitting function.

Specifically, the obtained multiple pre-stored angle, angular velocity, and angular acceleration data of the joint to be tested at different experimental positions are substituted into the analytical expression of the driving torque of the joint to be tested according to the direction of the angular velocity, and it is calculated that the joint to be tested is at Forward driving torque and reverse driving torque for different experimental positions and different motion directions.

Then, the forward driving torque in the forward driving torque and the reverse driving torque of the joint to be tested at different experimental positions are calculated and the collected motor driving current of the joint to be tested is linearly fitted by the least square method, and the results obtained in different experiments are obtained by linear fitting. The forward motion of the position fits the slope and intercept of a linear function.

Then, calculate the forward driving torque and the reverse driving torque of the joint to be tested at different experimental positions and the collected driving current of the joint motor to be tested. The inverse motion of the position fits the slope and intercept of a linear function.

Step 104, obtain the motor torque coefficient when the joint to be tested is moving forward and backward according to the ratio of the slope of the fitted linear function and the reduction ratio of the joint to be tested, and take the inverse of the intercept of the fitted linear function to obtain the value to be tested. Coefficient of friction for joint forward and reverse motion.

Specifically, the ratio of the slope of the forward fitting linear function, the slope of the backward fitting linear function and the reduction ratio of the joint to be tested at different experimental positions of the joint to be tested is taken as the motor torque when the joint to be tested moves forward Coefficient and motor torque coefficient during reverse motion, the intercept of the forward fitting linear function of the joint to be tested at different experimental positions and the opposite number of the intercept of the reverse fitting linear function as the forward motion of the joint to be tested The coefficient of friction at time and the coefficient of friction at the time of reverse motion.

Step 105: Calculate the average value of the motor torque coefficient and friction coefficient at different experimental positions, and obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion.

Specifically, calculate the respective average values of the motor torque coefficient and friction coefficient of the joint to be tested during the forward and reverse motions at different experimental positions, and obtain the target torque of the joint to be tested during the forward motion and the reverse motion. Coefficient and target friction value.

For example, taking the six-axis hybrid spraying robot shown in Figure 2 as an example, the six-axis hybrid spraying robot includes six joints in total, and its main body is composed of a first rotating joint 1, a second rotating joint 2, a third rotating joint The rotating joint 3 drives the spray gun 7 to move through each connecting rod to form a plane parallel mechanism 8 . In addition, the fourth rotating joint 4 realizes the rotation of the plane parallel mechanism 8 around the vertical axis, the fifth rotating joint 5 realizes the rotation of the fourth rotating joint 4 and the plane parallel mechanism 8 around the horizontal axis, and the sixth rotating joint 6 realizes the fifth rotation The rotation of the joint 5, the fourth rotating joint 4 and the plane parallel mechanism 8 around the vertical axis.

Firstly, the dynamic model of the robot is established based on the principle of virtual work, and it is written in the standard dynamic equation form as shown in formula (3):

为驱动力矩中的惯性力分量，

为驱动力矩中的离心力与科氏力分量，G(θ)g为驱动力矩中的重力分量，另外，使用待测试关节的正向运动时的实验数据计算获得的为正向运动时的理论驱动力矩；使用待测试关节的反向运动时的实验数据计算获得的为反向运动时的理论驱动力矩。由于该喷涂机器人不是有高速运动需求的轻型机器人，在其驱动力矩中，惯性分量与重力分量将占据主要地位，因此后续计算忽略离心力与科氏力分量。Among them, τ is the real-time driving torque of the joint to be tested,

is the inertial force component in the driving torque,

is the centrifugal force and Coriolis force components in the driving torque, G(θ)g is the gravity component in the driving torque, in addition, the theoretical driving in the forward movement is calculated using the experimental data during the forward movement of the joint to be tested. Torque; the theoretical driving torque during reverse movement is calculated using the experimental data of the joint to be tested during reverse movement. Since the spraying robot is not a light robot with high-speed motion requirements, inertial and gravitational components will occupy the dominant position in its driving torque, so centrifugal force and Coriolis force components are ignored in subsequent calculations.

In this embodiment, the joint 1 of the six-axis hybrid spraying robot, that is, the big arm drive joint, is used as the joint to be tested to perform the test steps, and the six-axis hybrid spraying robot is modeled in the three-dimensional software. The mechanical parameters such as the mass, length, moment of inertia of the robot read in the software are substituted into formula (3), and the analytical expression of the driving torque of joint 1 to be tested is obtained as formula (4):

分别为待测试关节1、2、3的角加速度(单位：rad/s²)，τ_d1为待测试关节1的驱动力矩(单位：N·m)。Among them, θ ₁ , θ ₂ , θ ₃ are the angles of joints 1, 2, and 3 to be tested (unit: rad), respectively,

are the angular accelerations of the joints 1, 2 and 3 to be tested (unit: rad/s ² ), respectively, and τ _d1 is the driving torque of the joint 1 to be tested (unit: N·m).

Figure 3 is the joint drive current and joint angular velocity curve recorded in the experiment for the joint 1 to be tested. The drive current value circled in the semi-transparent dashed box is originally a positive value. Considering the reverse driving torque at this time, the collected motor The current can only be a positive value, and the absolute value processing is performed here. It can be seen from the experimental results that when the speed of the joint to be tested changes from negative to positive, there is a positive sudden change in the value of the driving current. When the speed of the joint to be tested changes from positive to negative, the value of the driving current exists. The reverse mutation of the same magnitude is caused by the change in the direction of the speed of the joint to be tested and the change in the direction of the friction force on the joint to be tested.

Figure 4 is the driving torque curve obtained by substituting the data of the joint 1 to be tested in the experiment, such as angle, angular velocity, angular acceleration, etc. into equation (4).

Figure 5, Figure 6, Figure 8, Figure 9 are the actual driving current and calculated driving torque curves of the joint to be tested during forward and reverse operation obtained by implementing data packet storage according to the direction of the angular velocity of the joint to be tested.

Figure 7 and Figure 10 are schematic diagrams of linear fitting of the actual drive current and calculated drive torque of the joint to be tested in forward and reverse operation by the least squares method, where the abscissa is the actual drive current, and the ordinate is the calculated drive moment, the linear fitting effect of the two is good, the black solid line is the linear fitting result, and its expression is formula (5):

where τ _d+ is the driving torque of joint 1 to be tested in forward running (unit: N m), τ _d- is the driving torque in reverse running, and I _q+ is the driving current in forward running (unit: A ), and I _q- is the drive current during reverse operation. The unit of the slope of the linear fitting result expression is N·m/A, and the unit of the intercept is N·m.

In addition, in this embodiment, the reduction ratio of the joint to be tested of the six-axis hybrid spraying robot is set by the manufacturer to 121 when the six-axis hybrid spraying robot leaves the factory, and in other embodiments, the six-axis hybrid spraying robot is set to 121 by the manufacturer. The reduction ratio of the joint to be tested of the joint spraying robot can also be set to other specified values by the manufacturer. Therefore, in this embodiment, combined with the joint reduction ratio 121 to be tested, according to formula (2), the experimental test result of the motor torque coefficient and friction force can be obtained as formula (6):

Among them, K _t+ is the torque coefficient of the motor of joint 1 to be tested when it is running in the forward direction, K _t- is the torque coefficient of the motor of the joint 1 to be tested when it is running in reverse, and f ₊ is the motor of joint 1 to be tested when it is running in the forward direction. The friction force value of the joint to be tested during operation, f _- is the friction force value of the joint to be tested when the motor of the joint 1 to be tested is running in the reverse direction.

Repeat 6 groups of test experiments at different experimental positions of the robot, and take the average of the experimental results to obtain the predicted expression of the driving current I _q of the joint 1 to be tested as formula (7):

为根据上述步骤得到的待测试关节电机正向转矩系数测试结果，

为根据上述步骤得到的待测试关节电机反向转矩系数测试结果，

为根据上述步骤得到的待测试关节正向摩擦力数值，

为根据上述步骤得到的待测试关节反向摩擦力数值，ω₁为待测试关节角速度，其正值表示待测试关节正向运行，负值表示反向运行。in,

is the test result of the forward torque coefficient of the joint motor to be tested obtained according to the above steps,

is the test result of the reverse torque coefficient of the joint motor to be tested obtained according to the above steps,

is the positive friction force value of the joint to be tested obtained according to the above steps,

is the value of the reverse friction force of the joint to be tested obtained according to the above steps, ω ₁ is the angular velocity of the joint to be tested, a positive value of which indicates that the joint to be tested is running in the forward direction, and a negative value indicates that it is running in the reverse direction.

FIG. 11 is a verification result of applying the current prediction model of the joint to be tested 1 in formula (7) to another group of motion experiments of the joint to be tested. Among them, the actual driving current is the driving current curve of the joint to be tested collected in the experiment, and the predicted driving current is the predicted driving current curve obtained by substituting the position, velocity and angular velocity data of the joint to be tested collected in the experiment into formula (7), It can be seen from the figure that the two curves are well fitted, which proves that the method proposed by the present invention has completed the accurate test of the motor torque coefficient and friction force of the joint 1 to be tested of the robot in this embodiment.

It can be seen from the above that, in the embodiment of the present invention, the joint motor torque coefficient and friction force synchronization test method of the robot of the present invention establishes the dynamic model of the robot based on the principle of virtual work, obtains the mechanical structure parameters of the robot, and according to the dynamics The model and mechanical structure parameters are used to calculate the analytical expression of the driving torque of each driving joint of the robot; the pre-stored experimental data are obtained, wherein the experimental data includes: the angle, angular velocity, angular acceleration and driving current of each joint, and the direction of the angular velocity. The experimental data are stored in two arrays respectively; the experimental data in the two arrays at different experimental positions are respectively input into the analytical expression of the driving torque to obtain the forward torque and reverse torque, and the forward torque, reverse torque and driving current are calculated. Fitting process to obtain the slope and intercept of the fitted linear function at different experimental positions; according to the ratio of the slope of the fitted linear function to the reduction ratio of the joint to be tested, the motor torque of the joint to be tested is obtained during forward and reverse motions Take the inverse of the intercept of the fitted linear function to obtain the friction coefficient of the joint to be tested in the forward and reverse motions; calculate the average value of the motor torque coefficient and friction coefficient at different experimental positions to obtain the forward The target torque coefficient and target friction value of the joint to be tested during reverse motion. Therefore, under the condition of fully considering the influence of mechanical structure and working environment on key electromechanical parameters, the synchronous test of the torque coefficient of joint motor and the coefficient of forward and reverse friction force is realized, and the test accuracy is improved.

In order to realize the above embodiments, the present application also proposes a device for synchronizing the torque coefficient and friction force of a joint motor of a robot.

FIG. 12 is a schematic structural diagram of a device for synchronizing the torque coefficient and friction force of a joint motor of a robot according to an embodiment of the present invention.

As shown in FIG. 12 , the apparatus includes: a modeling module 1201 , an acquisition module 1202 , a first calculation module 1203 , a second calculation module 1204 , and a third calculation module 1205 .

The modeling module 1201 is used to establish a dynamic model of the robot based on the virtual work principle, obtain the mechanical structure number of the robot, and calculate the analytical expression of the driving torque of each driving joint of the robot according to the dynamic model and the mechanical structure parameters;

The acquisition module 1202 is used to acquire pre-stored experimental data, wherein the experimental data includes: the angle, angular velocity, angular acceleration and driving current of each joint, and the experimental data is stored in two arrays respectively according to the direction of the angular velocity;

The first calculation module 1203 is used to input the experimental data in the two arrays of different experimental positions respectively into the driving torque analytical expression to obtain the forward torque and reverse torque, and fit the forward torque, reverse torque and driving current processing to obtain the slope and intercept of the fitted linear function at different experimental positions;

The second calculation module 1204 is configured to obtain the motor torque coefficients of the joint to be tested in forward and reverse motions according to the ratio of the slope of the fitted linear function to the reduction ratio of the joint to be tested, and to take the intercept of the fitted linear function as The opposite number obtains the friction coefficient of the joint to be tested in forward and reverse motions;

The third calculation module 1205 is used to calculate the average value of the motor torque coefficient and friction coefficient in different experimental positions, and obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion.

Further, in a possible implementation manner of the embodiment of the present application, it further includes: a determination module 1206, an experiment module 1207, and a recording module 1208, wherein,

a determination module 1206 for determining different experimental positions and joints to be tested;

The experimental module 1207 is used to keep other joints still, and control the joint to be tested to perform trapezoidal acceleration and deceleration reciprocating motion at different experimental positions, wherein the speed of the joint to be tested in the uniform motion stage is positively correlated with the angular velocity of the joint to be tested in actual work. relation.

The recording module 1208 is used to acquire experimental data at different experimental locations.

Further, in a possible implementation of the embodiment of the present application, the recording module 1208 is specifically configured to obtain the angle of the joint to be tested through an absolute encoder; obtain the speed of the joint to be tested through a raster encoder; The angular acceleration of the joint to be tested is obtained by the speed difference; the driving current of the joint to be tested is obtained through the Hall sensor.

Further, in a possible implementation manner of the embodiment of the present application, the first calculation module 1203 is used to calculate the analytical expression of the driving torque as:

为驱动力矩中的惯性力分量，

为驱动力矩中的离心力与科氏力分量，G(θ)g为驱动力矩中的重力分量，另外，使用待测试关节的正向运动时的实验数据计算获得的为正向运动时的理论驱动力矩；使用待测试关节的反向运动时的实验数据计算获得的为反向运动时的理论驱动力矩。Among them, τ is the real-time driving torque of the joint to be tested,

is the inertial force component in the driving torque,

is the centrifugal force and Coriolis force components in the driving torque, G(θ)g is the gravity component in the driving torque, in addition, the theoretical driving in the forward movement is calculated using the experimental data during the forward movement of the joint to be tested. Torque; the theoretical driving torque during reverse movement is calculated using the experimental data of the joint to be tested during reverse movement.

It should be noted that the foregoing explanations of the method embodiment are also applicable to the apparatus of this embodiment, and details are not repeated here.

The joint motor torque coefficient and friction force synchronization test device of the robot in the embodiment of the present invention, the modeling module establishes the dynamic model of the robot based on the virtual work principle, obtains the mechanical structure parameters of the robot, and calculates the robot according to the dynamic model and the mechanical structure parameters. The analytical expression of the driving torque of each driving joint; the acquisition module acquires the pre-stored experimental data, wherein the experimental data includes: the angle, angular velocity, angular acceleration and driving current of each joint to be tested, and the experimental data is divided according to the direction of the angular velocity. Stored in two arrays; the first calculation module inputs the experimental data in the two arrays at different experimental positions into the driving torque analytical expression respectively to obtain the forward torque and reverse torque, and the forward torque, reverse torque and drive current are calculated. Perform the fitting process to obtain the slope and intercept of the fitted linear function at different experimental positions; the second calculation module obtains the forward and reverse motions of the joint to be tested according to the ratio of the slope of the fitted linear function to the reduction ratio of the joint to be tested The friction coefficient of the joint to be tested in forward and reverse motions is obtained by taking the inverse of the intercept of the fitted linear function; the third calculation module calculates the motor torque coefficient and friction force at different experimental positions The average value of the coefficients is used to obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion. Therefore, under the condition of fully considering the influence of mechanical structure and working environment on key electromechanical parameters, the synchronous test of the torque coefficient of joint motor and the coefficient of forward and reverse friction force is realized, and the test accuracy is improved.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

Any process or method description in the flowcharts or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing custom logical functions or steps of the process , and the scope of the preferred embodiments of the invention includes alternative implementations in which the functions may be performed out of the order shown or discussed, including performing the functions substantially concurrently or in the reverse order depending upon the functions involved, which should It is understood by those skilled in the art to which the embodiments of the present invention belong.

The logic and/or steps represented in flowcharts or otherwise described herein, for example, may be considered an ordered listing of executable instructions for implementing the logical functions, may be embodied in any computer-readable medium, For use with, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch instructions from and execute instructions from an instruction execution system, apparatus, or apparatus) or equipment. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport the program for use by or in conjunction with an instruction execution system, apparatus, or apparatus. More specific examples (non-exhaustive list) of computer readable media include the following: electrical connections with one or more wiring (electronic devices), portable computer disk cartridges (magnetic devices), random access memory (RAM), Read Only Memory (ROM), Erasable Editable Read Only Memory (EPROM or Flash Memory), Fiber Optic Devices, and Portable Compact Disc Read Only Memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program may be printed, as may be done, for example, by optically scanning the paper or other medium, followed by editing, interpretation, or other suitable means as necessary process to obtain the program electronically and then store it in computer memory.

It should be understood that various parts of the present invention may be implemented in hardware, software, firmware or a combination thereof. In the above-described embodiments, various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented by any one of the following techniques known in the art, or a combination thereof: discrete with logic gates for implementing logic functions on data signals Logic circuits, application specific integrated circuits with suitable combinational logic gates, Programmable Gate Arrays (PGA), Field Programmable Gate Arrays (FPGA), etc.

Those of ordinary skill in the art can understand that all or part of the steps carried by the methods of the above embodiments can be completed by instructing the relevant hardware through a program, and the program can be stored in a computer-readable storage medium, and when the program is executed, Include one or a combination of the steps of a method embodiment.

In addition, each functional unit in each embodiment of the present invention may be integrated into one processing module, or each unit may exist physically alone, or two or more units may be integrated into one module. The above-mentioned integrated modules can be implemented in the form of hardware, and can also be implemented in the form of software function modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

The above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, and the like. Although the embodiments of the present invention have been shown and described above, it should be understood that the above-mentioned embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (10)

1. the joint motor torque coefficient of a robot and the friction force synchronization test method, it is characterized in that, comprise: Establish a dynamic model of the robot based on the principle of virtual work, obtain the mechanical structure parameters of the robot, and calculate the analytical expression of the driving torque of each driving joint of the robot according to the dynamic model and the mechanical structure parameters; Acquiring pre-stored experimental data, wherein the experimental data includes: the angle, angular velocity, angular acceleration and driving current of each joint to be tested, and the experimental data is stored in two arrays respectively according to the direction of the angular velocity; Input the experimental data in the two arrays at different experimental positions into the driving torque analytical expression to obtain the forward torque and the reverse torque, and carry out the forward torque, the reverse torque and the driving current. Fitting processing, obtaining the slope and intercept of the fitting linear function of described different experimental positions; According to the ratio of the slope of the fitted linear function and the reduction ratio of the joint to be tested, the motor torque coefficient of the joint to be tested is obtained when the forward and reverse motions are performed, and the intercept of the fitted linear function is taken to be the opposite number to obtain the Describe the friction coefficient when the joint to be tested moves forward and backward; Calculate the average value of the motor torque coefficient and the friction coefficient at the different experimental positions, and obtain the target torque coefficient and target friction value of the joint to be tested during forward and reverse motion. 2. The method according to claim 1, characterized in that, before said acquiring the pre-stored experimental data, further comprising: determining the different experimental positions and the joint to be tested; Keep other joints still, and control the joint to be tested to do trapezoidal acceleration and deceleration reciprocating motion at the different experimental positions, wherein the speed of the joint to be tested in the uniform motion stage is the same as the angular velocity of the joint to be tested in actual work. a positive correlation; Acquire the experimental data at the different experimental locations. 3. The method of claim 2, wherein the acquiring the experimental data at the different experimental positions comprises: Obtain the angle of the joint to be tested through an absolute value encoder; Obtain the speed of the joint to be tested by using a raster encoder; Obtain the angular acceleration of the joint to be tested by differentiating the instantaneous velocity; The drive current of the joint to be tested is acquired through a Hall sensor. 4. The method according to claim 1, wherein the analytical expression of the driving torque is:

Wherein, τ is the real-time driving torque of the joint to be tested,

is the inertial force component in the driving torque,

is the centrifugal force and the Coriolis force component in the driving torque, G(θ)g is the gravity component in the driving torque, and is calculated using the experimental data of the joint to be tested in the forward motion. is the theoretical driving torque during forward motion; the theoretical driving torque during reverse motion is calculated and obtained by using the experimental data during reverse motion of the joint to be tested. 5. The method of claim 1, wherein the formula used for fitting is:

Wherein, K _t is the torque coefficient of the joint motor to be tested, I _q is the drive current of the joint motor to be tested, f is the friction force experienced by the joint to be tested, and i is the friction force of the joint motor to be tested. The reduction ratio of the test joint, τ is the theoretical driving torque of the joint to be tested, including the theoretical driving torque of the joint to be tested during the forward motion and the theoretical driving torque of the reverse motion. When using all When using the theoretical driving torque of the joint to be tested in the forward motion, the function obtained by fitting is a forward motion fitting function; when using the theoretical driving torque of the joint to be tested in the reverse motion When , the function obtained by fitting is the inverse kinematic fitting function. 6. The method of claim 2, wherein the joint to be tested is controlled to do trapezoidal acceleration and deceleration reciprocating motion at the different experimental positions, comprising: In the preset working space of the robot, evenly select the coordinate positioning of several end effectors of the robot with equal spacing to generate the different experimental positions; At the different experimental positions, the joints to be tested are controlled to implement the same motion stroke and the same speed planned motion. 7. A joint motor torque coefficient and friction force synchronization test device of a robot, comprising: The modeling module is used to establish a dynamic model of the robot based on the virtual work principle, obtain the mechanical structure parameters of the robot, and calculate the driving torque analysis of each driving joint of the robot according to the dynamic model and the mechanical structure parameters. expression; The acquisition module is used to acquire pre-stored experimental data, wherein the experimental data includes: the angle, angular velocity, angular acceleration and driving current of each joint to be tested, and the experimental data are respectively stored in the direction of the angular velocity according to the direction of the angular velocity. in two arrays; The first calculation module is used to input the experimental data in the two arrays of different experimental positions respectively into the driving torque analytical expression to obtain a forward torque and a reverse torque, and the forward torque and the reverse torque are calculated. The torque and the drive current are fitted to obtain the slope and intercept of the fitted linear function at the different experimental positions; The second calculation module is configured to obtain the motor torque coefficient of the joint to be tested in forward and reverse motions according to the ratio of the slope of the fitted linear function to the reduction ratio of the joint to be tested, The intercept takes the opposite number to obtain the friction coefficient when the joint to be tested moves forward and backward; The third calculation module is used to calculate the average value of the motor torque coefficient and the friction coefficient of the different experimental positions, and obtain the target torque coefficient and target torque coefficient of the joint to be tested during forward and reverse motion. Friction value. 8. The apparatus of claim 7, further comprising: a determination module for determining the different experimental positions and the joint to be tested; The experimental module is used to keep other joints still, and control the joint to be tested to perform trapezoidal acceleration and deceleration reciprocating motion at the different experimental positions, wherein the speed of the joint to be tested in the uniform motion stage is the same as that of the joint to be tested. The angular velocity during work is positively correlated; a recording module for acquiring the experimental data at the different experimental positions. 9. The device according to claim 8, the recording module is specifically used for: Obtain the angle of the joint to be tested through an absolute value encoder; Obtain the speed of the joint to be tested by using a raster encoder; Obtaining the angular acceleration of the joint to be tested by differentiating the instantaneous velocity; The drive current of the joint to be tested is acquired through a Hall sensor. 10. The device according to claim 9, wherein the first calculation module is used to calculate the analytical expression of the driving torque as:

Wherein, τ is the real-time driving torque of the joint to be tested,

is the inertial force component in the driving torque,

is the centrifugal force and the Coriolis force component in the driving torque, G(θ)g is the gravity component in the driving torque, and is calculated using the experimental data of the joint to be tested in the forward motion. is the theoretical driving torque during forward motion; the theoretical driving torque during reverse motion is calculated and obtained by using the experimental data during reverse motion of the joint to be tested.

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