阅读说明：本技术 一种多关节串联型工业机器人的谐振抑制方法 (Resonance suppression method of multi-joint series industrial robot ) 是由 李玉霞 黄梁松 于 2019-10-23 设计创作，主要内容包括：本发明公开了一种多关节串联型工业机器人的谐振抑制方法,具体涉及机器人控制领域。该方法通过每个关节的伺服驱动器对关节连续施加正反转的位置阶跃信号,使得机器人产生低频阶跃摆动,再利用安装在机器人末端的六维加速度传感器测量关节的振动频率,然后针对每个关节设计双T型陷波滤波器,将测量得到的振动频率作为陷波滤波器的谐振频率。利用人工蜂群算法对陷波滤波器的陷波深度和陷波宽度进行寻优,最终得到每个关节的最优的陷波滤波器参数,实现对多关节串联型工业机器人谐振抑制的最优化,该方法简单可靠且便于实现,对于多关节串联型工业机器人的轨迹控制精度和重复定位精度有重要的意义。(The invention discloses a resonance suppression method of a multi-joint series industrial robot, and particularly relates to the field of robot control. The method comprises the steps of continuously applying forward and reverse rotating position step signals to joints through a servo driver of each joint to enable a robot to generate low-frequency step swing, measuring the vibration frequency of the joints by using a six-dimensional acceleration sensor installed at the tail end of the robot, designing a double-T-shaped notch filter for each joint, and taking the measured vibration frequency as the resonance frequency of the notch filter. The artificial bee colony algorithm is utilized to optimize the notch depth and the notch width of the notch filter, the optimal notch filter parameter of each joint is finally obtained, the optimization of the multi-joint series industrial robot resonance suppression is realized, the method is simple, reliable and convenient to realize, and the method has important significance for the track control precision and the repeated positioning precision of the multi-joint series industrial robot.)

1. A resonance suppression method of a multi-joint series industrial robot is characterized by comprising the following steps:

the method comprises the following steps of firstly, starting from a basic coordinate joint of the robot, sequentially measuring the mechanical resonance frequency of each joint of the robot, specifically:

1-1, setting the serial number of the joints of the robot, wherein the serial number of the joints of a robot base coordinate is 1, the serial numbers of the joints sequentially increase along the direction from the base coordinate to a tail end coordinate, and the serial number of the tail end joint is the maximum value of the serial number;

1-2, for the nth joint of the robot, n is more than or equal to 1, firstly, manually adjusting the posture of the robot through a demonstrator of the robot, and enabling the adjusted postures of all joints with joint numbers more than n to be the largest when the adjusted postures are used as the load of the nth joint;

step two, starting from the basic coordinate joint of the robot, designing a notch filter of each joint of the robot in sequence, specifically:

selecting a double T-shaped filter as a notch filter, wherein the transfer function expression of the double T-shaped filter is shown as formula (1):

where f is the notch center frequency, ζ is the notch depth, and K is the notch width.

2. A resonance suppression method of an industrial robot of a multi-joint series type according to claim 1, wherein said step one further comprises:

locking all joints except the nth joint by using a band-type brake device in a robot servo system, applying a forward and reverse rotation position step signal to the nth joint for 1 time by using a servo driver of the nth joint so that the nth joint of the robot generates step swing with the period not less than 10 seconds, and measuring the vibration frequency f in the motion direction of the nth joint by using a six-dimensional acceleration sensor arranged at the tail end of the robot_n0And the time t for the vibration to decay to 2% of the initial amplitude_nrAccording to the method, the resonant frequency and the vibration attenuation time of the other joints are measured in sequence.

3. The resonance damping method of an industrial robot of the multi-joint series type according to claim 2, wherein the vibration frequency f of the nth joint measured in the step one is measured for the nth joint_n0For the notch center frequency of the notch filter of the nth joint, an artificial bee colony algorithm is adopted to search the optimal zeta and K parameter values of the nth joint, and the specific process is as follows:

setting the target function of the artificial bee colony algorithm of the nth joint as follows:

f_n＝0.1t_ni(2)

I. initializing a bee colony, initializing 100 employed bees and observation bees, corresponding to 100 honey sources, wherein the dimension of a solution corresponding to each honey source is two, and the two solutions respectively represent zeta and K;

II. The bee colony searches for a new honey source, and the hiring bee corresponding to the ith honey source searches for the new honey source according to the formula (3), namely a new solution:

x′_id＝x_id+φ_id(x_id-x_kd) (3)

where i is 1, 2.. 100, d is 1,2,. phi_idIs a random number, phi_idIn the interval [ -1,1 [)]And i ≠ k, and the found new honey source is X'_i＝{x′_i1,x′_i2}；

III, x 'of New Honey Source'_i1,x′_i2Respectively corresponding to currently searched zeta value and K value, bringing zeta value and K value into formula (1) to obtain notch filter of current joint, and filtering with notch filterThe output signal of a speed loop in a servo driver of the joint is filtered to be a command signal of a current loop, positive and negative rotation position step signals with the period not less than 10 seconds are applied to the joint for 10 times, the time when the vibration amplitude in the motion direction of the joint is attenuated to 2 percent of the initial value is measured through a six-dimensional acceleration sensor arranged at the tail end of a robot, and the average value t is obtained_ni；

IV, updating the honey source, and mixing the new honey source X_iFound t_niValue and original honey source X_i-1Found t_ni-1Comparing, updating the honey source according to the formula (4),

therein, fit_iIs to solve X_iThe expression is shown in formula (5):

v, detecting bees, in step IV, the employed bees corresponding to the discarded honey sources become detecting bees, and searching new honey sources according to the formula (6),

wherein r is₁∈[0,1]，

VI, memorizing the optimal honey source, memorizing the position of the optimal honey source, namely the optimal solution, and repeating II-VI for 100 times;

VII, finishing the searching of the honey source, and when 100 cycles are finished or the honey source reaching the expected fitness is found, stopping optimizing and outputting the optimal solution of zeta and K values of the notch filter of the joint.

Technical Field

The invention relates to the field of robot control, in particular to a resonance suppression method for a multi-joint series industrial robot.

Background

The multi-joint serial industrial robot is the most common structural form in the industrial machine at present. Because the joint adopts flexible devices such as a speed reducer or a synchronous transmission belt, the flexible effect of the joint and the connecting rod of the multi-joint serial industrial robot can be increased when the multi-joint serial industrial robot moves, mechanical resonance occurs to the body structure of the robot, residual vibration at the tail end of the robot can be prolonged, and the repeated positioning precision of the robot is reduced. Especially, when the multi-joint serial industrial robot is applied to industries such as 3C with higher requirements on speed and precision, the deformation of the joints of the robot is more obvious due to the inertia greatly changed in the high-speed motion process, and the mechanical resonance is easier to generate. Mechanical resonance not only can influence the stability of a robot servo system, the control precision of the tail end track of the robot and the repeated positioning precision, but also can damage mechanical parts and reduce the service life of the robot, so that how to effectively inhibit the mechanical resonance is important research content in the field of industrial robots at present.

Disclosure of Invention

The invention aims to provide a scheme for suppressing mechanical resonance of a multi-joint series industrial robot.

The invention specifically adopts the following technical scheme:

a resonance suppression method of a multi-joint series industrial robot includes the following steps:

the method comprises the following steps of firstly, starting from a basic coordinate joint of the robot, sequentially measuring the mechanical resonance frequency of each joint of the robot, specifically:

1-1, setting the serial number of the joints of the robot, wherein the serial number of the joints of a robot base coordinate is 1, the serial numbers of the joints sequentially increase along the direction from the base coordinate to a tail end coordinate, and the serial number of the tail end joint is the maximum value of the serial number;

1-2, for the nth joint of the robot, n is more than or equal to 1, firstly, manually adjusting the posture of the robot through a demonstrator of the robot, and enabling the adjusted postures of all joints with joint numbers more than n to be the largest when the adjusted postures are used as the load of the nth joint;

step two, starting from the basic coordinate joint of the robot, designing a notch filter of each joint of the robot in sequence, specifically:

selecting a double T-shaped filter as a notch filter, wherein the transfer function expression of the double T-shaped filter is shown as formula (1):

where f is the notch center frequency, ζ is the notch depth, and K is the notch width.

Preferably, the first step further comprises:

locking all joints except the nth joint by using a band-type brake device in a robot servo system, applying a forward and reverse rotation position step signal to the nth joint for 1 time by using a servo driver of the nth joint so that the nth joint of the robot generates step swing with the period not less than 10 seconds, and measuring the vibration frequency f in the motion direction of the nth joint by using a six-dimensional acceleration sensor arranged at the tail end of the robot_n0And the time t for the vibration to decay to 2% of the initial amplitude_nrAccording to the method, the resonant frequency and the vibration attenuation time of the other joints are measured in sequence.

Preferably, for the nth joint, the vibration frequency f of the nth joint measured in the step one_n0For the notch center frequency of the notch filter of the nth joint, an artificial bee colony algorithm is adopted to search the optimal zeta and K parameter values of the nth joint, and the specific process is as follows:

setting the target function of the artificial bee colony algorithm of the nth joint as follows:

f_n＝0.1t_ni(2)

I. initializing a bee colony, initializing 100 employed bees and observation bees, corresponding to 100 honey sources, wherein the dimension of a solution corresponding to each honey source is two, and the two solutions respectively represent zeta and K;

II. The bee colony searches for a new honey source, and the hiring bee corresponding to the ith honey source searches for the new honey source according to the formula (3), namely a new solution:

x′_id＝x_id+φ_id(x_id-x_kd) (3)

where i is 1, 2.. 100, d is 1,2,. phi_idIs a random number, phi_idIn the interval [ -1,1 [)]And i ≠ k, and the found new honey source is X'_i＝{x′_i1,x′_i2}；

III, x 'of New Honey Source'_i1,x′_i2Respectively corresponding to currently searched zeta value and K value, taking zeta value and K value into formula (1) to obtain notch filter of current joint, and notchingThe filter filters an output signal of a speed loop in a servo driver of the joint, the filtered output signal is a command signal of a current loop, a positive and negative rotation position step signal with the period not less than 10 seconds is applied to the joint for 10 times, the time when the vibration amplitude in the motion direction of the joint is attenuated to 2% of an initial value is measured through a six-dimensional acceleration sensor arranged at the tail end of the robot, and the average value t is obtained_ni；

IV, updating the honey source, and mixing the new honey source X_iFound t_niValue and original honey source X_i-1Found t_ni-1Comparing, updating the honey source according to the formula (4),

therein, fit_iIs to solve X_iThe expression is shown in formula (5):

v, detecting bees, in step IV, the employed bees corresponding to the discarded honey sources become detecting bees, and searching new honey sources according to the formula (6),

wherein r is₁∈[0,1]，

And

the upper and lower bounds of the solution, respectively;

VI, memorizing the optimal honey source, memorizing the position of the optimal honey source, namely the optimal solution, and repeating II-VI for 100 times;

VII, finishing the searching of the honey source, and when 100 cycles are finished or the honey source reaching the expected fitness is found, stopping optimizing and outputting the optimal solution of zeta and K values of the notch filter of the joint.

The invention has the following beneficial effects:

firstly, measuring mechanical resonance frequency of each joint of the robot, then designing a double-T-shaped notch filter aiming at the resonance frequency of each joint, and optimizing the parameters of each notch filter by utilizing an artificial bee colony algorithm to realize optimization of multi-joint series type industrial robot resonance suppression;

the method is simple, reliable and convenient to implement, and has important significance for the track control precision and the repeated positioning precision of the multi-joint serial industrial robot.

Detailed Description

The following embodiments are further illustrated in the following description:

a resonance suppression method of a multi-joint series industrial robot includes the following steps:

the method comprises the following steps of firstly, starting from a basic coordinate joint of the robot, sequentially measuring the mechanical resonance frequency of each joint of the robot, specifically:

1-1, setting the serial number of the joints of the robot, wherein the serial number of the joints of a robot base coordinate is 1, the serial numbers of the joints sequentially increase along the direction from the base coordinate to a tail end coordinate, and the serial number of the tail end joint is the maximum value of the serial number;

1-2, for the nth joint of the robot, n is more than or equal to 1, firstly, manually adjusting the posture of the robot through a demonstrator of the robot, and enabling the adjusted postures of all joints with joint numbers more than n to be the largest when the adjusted postures are used as the load of the nth joint;

locking all joints except the nth joint by using a band-type brake device in a robot servo system, applying a forward and reverse rotation position step signal to the nth joint for 1 time by using a servo driver of the nth joint so that the nth joint of the robot generates step swing with the period not less than 10 seconds, and measuring the vibration frequency f in the motion direction of the nth joint by using a six-dimensional acceleration sensor arranged at the tail end of the robot_n0And the time t for the vibration to decay to 2% of the initial amplitude_nrAccording to the method, the resonant frequency and vibration of the other joints are measured in sequenceThe decay time.

Step two, starting from the basic coordinate joint of the robot, designing a notch filter of each joint of the robot in sequence, specifically:

selecting a double T-shaped filter as a notch filter, wherein the transfer function expression of the double T-shaped filter is shown as formula (1):

where f is the notch center frequency, ζ is the notch depth, and K is the notch width.

For the nth joint, the vibration frequency f of the nth joint measured in the step one_n0For the notch center frequency of the notch filter of the nth joint, an artificial bee colony algorithm is adopted to search the optimal zeta and K parameter values of the nth joint, and the specific process is as follows:

setting the target function of the artificial bee colony algorithm of the nth joint as follows:

f_n＝0.1t_ni(2)

I. initializing a bee colony, initializing 100 employed bees and observation bees, corresponding to 100 honey sources, wherein the dimension of a solution corresponding to each honey source is two, and the two solutions respectively represent zeta and K;

II. The bee colony searches for a new honey source, and the hiring bee corresponding to the ith honey source searches for the new honey source according to the formula (3), namely a new solution:

x′_id＝x_id+φ_id(x_id-x_kd) (3)

where i is 1, 2.. 100, d is 1,2,. phi_idIs a random number, phi_idIn the interval [ -1,1 [)]And i ≠ k, and the found new honey source is X'_i＝{x′_i1,x′_i2}；

III, x 'of New Honey Source'_i1,x′_i2Respectively corresponding to currently searched zeta value and K value, taking zeta value and K value into formula (1) to obtain notch filter of current joint, filtering out output signal of speed loop in servo driver of the joint by notch filter, applying cycle to the jointPositive and negative rotation position step signals of not less than 10 seconds are measured for 10 times, the time when the vibration amplitude in the joint motion direction is attenuated to 2% of the initial value is measured through a six-dimensional acceleration sensor arranged at the tail end of the robot, and the average value t is obtained_ni；

IV, updating the honey source, and mixing the new honey source X_iFound t_niValue and original honey source X_i-1Found t_ni-1Comparing, updating the honey source according to the formula (4),

therein, fit_iIs to solve X_iThe expression is shown in formula (5):

v, detecting bees, in step IV, the employed bees corresponding to the discarded honey sources become detecting bees, and searching new honey sources according to the formula (6),

wherein r is₁∈[0,1]，

Andthe upper and lower bounds of the solution, respectively;

VI, memorizing the optimal honey source, memorizing the position of the optimal honey source, namely the optimal solution, and repeating II-VI for 100 times;

VII, finishing the searching of the honey source, and when 100 cycles are finished or the honey source reaching the expected fitness is found, stopping optimizing and outputting the optimal solution of zeta and K values of the notch filter of the joint.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.