Robust disturbance compensation method for servo motor
阅读说明：本技术 一种伺服电机鲁棒扰动补偿方法 (Robust disturbance compensation method for servo motor ) 是由 傅平 于 2021-09-09 设计创作，主要内容包括：本发明提出一种伺服电机鲁棒扰动补偿方法,所述补偿方法中,电机的控制系统包括电机控制器；电机动力系统中,电机一侧的输出轴测量端(3)与光电编码器(1)相连接,另一侧的输出轴动力端(6)与用于模拟电机扰动负载的飞轮惯性负载相连；所述飞轮惯性负载的输出轴经弹性联轴器(9)与力矩传感器(10)相连；所述电机控制器经光电编码器采集电机输出轴的角速度,经力矩传感器采集飞轮惯性负载的摩擦力矩,以根据采集数据调整电机工况来进行鲁棒扰动补偿；本发明能有效的增进系统的控制效能,并进一步减少电机控制系统对于不确定性的影响程度。(The invention provides a robust disturbance compensation method for a servo motor, wherein in the compensation method, a control system of the motor comprises a motor controller; in the motor power system, an output shaft measuring end (3) at one side of a motor is connected with a photoelectric encoder (1), and an output shaft power end (6) at the other side of the motor is connected with a flywheel inertial load for simulating motor disturbance load; the output shaft of the flywheel inertial load is connected with a torque sensor (10) through an elastic coupling (9); the motor controller collects the angular speed of the output shaft of the motor through a photoelectric encoder, and collects the friction torque of the inertia load of the flywheel through a torque sensor so as to adjust the working condition of the motor according to the collected data to perform robust disturbance compensation; the invention can effectively improve the control efficiency of the system and further reduce the influence degree of the motor control system on the uncertainty.)
1. A robust disturbance compensation method for a servo motor is characterized by comprising the following steps: in the compensation method, a control system of the motor comprises a motor controller; in the motor power system, an output shaft measuring end (3) at one side of a motor is connected with a photoelectric encoder (1), and an output shaft power end (6) at the other side of the motor is connected with a flywheel inertial load for simulating motor disturbance load; the output shaft of the flywheel inertial load is connected with a torque sensor (10) through an elastic coupling (9); the motor controller collects the angular speed of the output shaft of the motor through the photoelectric encoder, and collects the friction torque of the inertia load of the flywheel through the torque sensor, so that the working condition of the motor is adjusted according to the collected data to perform robust disturbance compensation.
2. The robust disturbance compensation method for the servo motor according to claim 1, wherein: the motor is an ultrasonic motor (4) arranged on the base (12).
3. The robust disturbance compensation method for the servo motor according to claim 2, wherein: the motor controller comprises an ultrasonic motor drive control circuit (29), the ultrasonic motor drive control circuit comprises a control chip circuit (13) and a drive chip circuit (14), the signal output end of the photoelectric encoder is connected with the corresponding input end of the control chip circuit, and the output end of the control chip circuit is connected with the corresponding input end of the drive chip circuit so as to drive the drive chip circuit;
the driving frequency adjusting signal output end of the driving chip circuit and the driving half-bridge circuit adjusting signal output end are respectively connected with the corresponding input ends of the ultrasonic motor; the driving chip circuit generates a driving frequency adjusting signal and a driving half-bridge circuit adjusting signal, controls the frequency, the phase and the on-off of A, B two-phase PWM output by the ultrasonic motor, and controls the starting and stopping of the ultrasonic motor by switching on and off the output of PWM waves; the optimal operation state of the motor is adjusted by adjusting the frequency of the output PWM wave and the phase difference of the two phases.
4. The robust disturbance compensation method for the servo motor according to claim 2, wherein: the motor power system forms a pre-sliding friction force model, and the friction effect of the pre-sliding friction force model is expressed as a formula
J(dω/dt)＝Tm-Tf-B ω formula one;
j is total moment of inertia, ω is motor angular velocity, TmIs the torque of the motor, TfIs friction torque, B is viscous resistanceCoefficient of damping, TmExpressed as:
Tm＝(VA-VB)(KT/R)＝(KAu-KBomega) formula two;
VAis the output of a voltage amplifier, VBCounter electromotive voltage of, KTIs the torque constant of the motor, R is the armature resistance, KAIs the gain of the voltage amplifier, u is the control voltage, KBIs the back electromotive force constant;
in the pre-sliding friction model, the formula for modeling the parameter uncertain system is
A formula III;
whereinIn the term of formula three, "^" added to the letter represents the nominal parameter, and "Δ" represents the variation in the parameter;
a nominal transfer function ofExpressed as:
wherein the model uncertainty function is defined as:
in the formula:
p(s) and Δ P(s) are unknowns,the identification quantity of the system acquisition information is obtained;
when non-linear friction torque TfFor unknown interference values, T is usedefInstead of TfNamely, the formula three is expressed as:
when T isefWhen the value is estimated, the compensation functionThe method can be used for eliminating the influence of friction torque and model uncertainty;
when the angular velocity of the output shaft of the motor is expressed by the following formula
At this time
Compensation functionIs composed of
Where g is the non-negative gain of the integral term and F(s) is a low pass filter of high cut-off frequency; the filter F(s) in the formula ninth is used for filtering high-frequency measurement noise;
when there is uncertainty in the model, the parametric error function ρ(s) is defined by the formula:
the ninth formula can be expressed as
In the formula eleven, the first step is carried out,is equal to the equivalent function Tef(s) and a parametric error function ρ(s), ρ(s) having a high gain g; when the gain g is designed to be a larger value, the tracking effect of the model is improved, namely the influence of the friction torque and the parameter error function on the motor system is reduced through the compensation function;
after adding the compensation function, the formula six is expressed as:
in the model, the remaining perturbation d(s) is defined by the formula:
wherein d is1(s) and d2(s) represents the uncertainty disturbance to the motor power system of the residual friction and residual model.
5. The robust disturbance compensation method for the servo motor according to claim 4, wherein: when the residual friction force and the equation incomplete compensation in the simulation scheme model cannot be completely eliminated, the traditional controller is combined to restrain model uncertainty caused by the residual friction force and the equation incomplete compensation;
combining a formula twelve and a formula thirteen, the dynamic equation of the motor is expressed by the following formula;
in the above formula, the first and second carbon atoms are,
b＝(KAKT) Sixty (RJ) formula;
for a known non-negative constant δ1And delta2Interference d1(t) and d2(t) having:
d1(t)＜δ1，d2(t)＜δ2seventeen, a formula;
when the dynamic parameter f (t) in equation fourteen cannot be completely determined, the interference δ1And delta2Is bounded;
dynamic parameter f (t) and estimated valueThe estimation error therebetween is determined by the following known function:
the control gain of parameter b in equation fourteen is an unknown quantity with a known boundary, bmax、bminAs boundary maximum and minimum values, i.e.
bmax≥b≥bminMore than 0 formula nineteen;
estimation of control gainThe geometric mean given by the formula nineteen:
the boundary is formulated as:
in the formula twenty-one
When the time-varying state vector is defined as x (t) [ [ theta (t) ] omega (t) ]]TWhen the formula is twenty-three, the reaction is carried out,
the desired time-varying state is defined as xd(t)＝[θd(t) ωd(t)]TTwenty-four of the formula;
the tracking error vector is defined as:
the switching state s (t) of the compensation method, defined in the state space of the model as:
wherein λ is a strictly normal number;
control law of compensation method
Wherein
Where eta is a strictly normal number,
Technical Field
The invention relates to the technical field of motor control, in particular to a robust disturbance compensation method for a servo motor.
Background
The existing ultrasonic motor servo control system can find that the model is highly nonlinear according to the property of the pre-friction model, and that obtaining all state information including the state of the reversal point is physically impossible.
Furthermore, since unknown friction and modeling in such systems cannot be completely eliminated, if the control scheme can be combined with a conventional controller, it helps to suppress model uncertainty caused by residual friction and incomplete equation compensation.
Disclosure of Invention
The invention provides a robust disturbance compensation method for a servo motor, which can effectively improve the control efficiency of a system and further reduce the influence degree of a motor control system on uncertainty.
The invention adopts the following technical scheme.
A servo motor robust disturbance compensation method is provided, in the compensation method, a control system of a motor comprises a motor controller; in the motor power system, an output shaft measuring end (3) at one side of a motor is connected with a photoelectric encoder (1), and an output shaft power end (6) at the other side of the motor is connected with a flywheel inertial load for simulating motor disturbance load; the output shaft of the flywheel inertial load is connected with a torque sensor (10) through an elastic coupling (9); the motor controller collects the angular speed of the output shaft of the motor through the photoelectric encoder, and collects the friction torque of the inertia load of the flywheel through the torque sensor, so that the working condition of the motor is adjusted according to the collected data to perform robust disturbance compensation.
The motor is an ultrasonic motor (4) arranged on the base (12).
The motor controller comprises an ultrasonic motor drive control circuit (29), the ultrasonic motor drive control circuit comprises a control chip circuit (13) and a drive chip circuit (14), the signal output end of the photoelectric encoder is connected with the corresponding input end of the control chip circuit, and the output end of the control chip circuit is connected with the corresponding input end of the drive chip circuit so as to drive the drive chip circuit;
the driving frequency adjusting signal output end of the driving chip circuit and the driving half-bridge circuit adjusting signal output end are respectively connected with the corresponding input ends of the ultrasonic motor; the driving chip circuit generates a driving frequency adjusting signal and a driving half-bridge circuit adjusting signal, controls the frequency, the phase and the on-off of A, B two-phase PWM output by the ultrasonic motor, and controls the starting and stopping of the ultrasonic motor by switching on and off the output of PWM waves; the optimal operation state of the motor is adjusted by adjusting the frequency of the output PWM wave and the phase difference of the two phases.
The motor power system forms a pre-sliding friction force model, and the friction effect of the pre-sliding friction force model is expressed as a formula
J(dω/dt)＝Tm-Tf-B ω formula one;
j is total moment of inertia, ω is motor angular velocity, TmIs the torque of the motor, TfIs the friction torque, B is the viscous damping coefficient, TmExpressed as:
Tm＝(VA-VB)(KT/R)＝(KAu-KBomega) formula two;
VAis the output of a voltage amplifier, VBCounter electromotive voltage of, KTIs the torque constant of the motor, R is the armature resistance, KAIs the gain of the voltage amplifier, u is the control voltage, KBIs the back electromotive force constant;
in the pre-sliding friction model, the formula for modeling the parameter uncertain system is
WhereinIn the term of formula three, "^" added to the letter represents the nominal parameter, and "Δ" represents the variation in the parameter; a nominal transfer function ofExpressed as:
wherein the model uncertainty function is defined as:
in the formula:
p(s) and Δ P(s) are unknowns,the identification quantity of the system acquisition information is obtained;
when non-linear friction torque TfFor unknown interference values, T is usedefInstead of TfNamely, the formula three is expressed as:
when T isefWhen the value is estimated, the compensation functionThe method can be used for eliminating the influence of friction torque and model uncertainty;
when the angular velocity of the output shaft of the motor is expressed by the following formula
At this time
Compensation functionIs composed of
Where g is the non-negative gain of the integral term and F(s) is a low pass filter of high cut-off frequency; the filter F(s) in the formula ninth is used for filtering high-frequency measurement noise;
when there is uncertainty in the model, the parametric error function ρ(s) is defined by the formula:
the ninth formula can be expressed as
In the formula eleven, the first step is carried out,is equal to the equivalent function Tef(s) and a parametric error function ρ(s), ρ(s) having a high gain g; when the gain g is designed to be a larger value, the tracking effect of the model is improved, namely the influence of the friction torque and the parameter error function on the motor system is reduced through the compensation function;
after adding the compensation function, the formula six is expressed as:
in the model, the remaining perturbation d(s) is defined by the formula:
wherein d is1(s) and d2(s) represents the uncertainty disturbance to the motor power system of the residual friction and residual model.
When the residual friction force and the equation incomplete compensation in the simulation scheme model cannot be completely eliminated, the traditional controller is combined to restrain model uncertainty caused by the residual friction force and the equation incomplete compensation;
combining a formula twelve and a formula thirteen, the dynamic equation of the motor is expressed by the following formula;
in the above formula, the first and second carbon atoms are,
b＝(KAKT) Sixty (RJ) formula;
for a known non-negative constant δ1And delta2Interference d1(t) and d2(t) having:
d1(t)＜δ1，d2(t)＜δ2seventeen, a formula;
when the dynamic parameter f (t) in equation fourteen cannot be completely determined, the interference δ1And delta2Is bounded;
dynamic parameter f (t) and estimated valueThe estimation error therebetween is determined by the following known function:
the control gain of parameter b in equation fourteen is an unknown quantity with a known boundary, bmax、bminAs boundary maximum and minimum values, i.e.
bmax≥b≥bminMore than 0 formula nineteen;
estimation of control gainThe geometric mean given by the formula nineteen:
the boundary is formulated as:
in the formula twenty-one
When the time-varying state vector is defined as x (t) [ [ theta (t) ] omega (t) ]]TWhen the formula is twenty-three, the reaction is carried out,
the desired time-varying state is defined as xd(t)＝[θd(t) ωd(t)]TTwenty-four of the formula;
the tracking error vector is defined as:
the switching state s (t) of the compensation method, defined in the state space of the model as:
wherein λ is a strictly normal number;
the control law u (t) of the compensation method is
Wherein
Where eta is a strictly normal number,
compared with the prior art, the invention has the following beneficial effects:
the invention uses the ultrasonic motor servo control system based on the pre-sliding friction force model to effectively improve the dynamic performance of the system, further reduce the influence degree of the system on the uncertainty, improve the control accuracy and obtain better dynamic characteristics. In addition, the device has the advantages of reasonable design, simple and compact structure, low manufacturing cost, strong practicability and wide application prospect.
Drawings
The invention is described in further detail below with reference to the following figures and detailed description:
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic diagram of the control circuit of the present invention;
in the figure: 1-a photoelectric encoder; 2-photoelectric encoder fixed bolster; 3-output shaft measuring end; 4-ultrasonic motor; 5-fixing the bracket by the ultrasonic motor; 6-power end of output shaft; 7-flywheel inertial load; 8-flywheel inertial load output shaft; 9-an elastic coupling; 10-a torque sensor; 11-a torque sensor fixing support; 12-a base; 13-control chip circuit; 14-a driver chip circuit;
15. 16, 17-A, B, Z phase signal output by photoelectric encoder; 18. 19, 20, 21-driving frequency adjusting signal generated by the driving chip circuit; 22-driving half-bridge circuit regulation signals generated by the driving chip circuit; 23. 24, 25, 26, 27, 28 — signals generated by the control chip circuit to drive the chip circuit; 29-ultrasonic motor drive control circuit.
Detailed Description
As shown in the figure, a robust disturbance compensation method for a servo motor is provided, wherein in the compensation method, a control system of the motor comprises a motor controller; in the motor power system, an output shaft measuring end 3 at one side of a motor is connected with a photoelectric encoder 1, and an output shaft power end 6 at the other side of the motor is connected with a flywheel inertial load 7 for simulating motor disturbance load; an output shaft 8 of the flywheel inertial load is connected with a torque sensor 10 through an elastic coupling 9; the motor controller collects the angular speed of the output shaft of the motor through the photoelectric encoder, and collects the friction torque of the inertia load of the flywheel through the torque sensor, so that the working condition of the motor is adjusted according to the collected data to perform robust disturbance compensation.
The motor is an ultrasonic motor 4 arranged on a base 12.
In this example, the photoelectric encoder is fixed at the photoelectric encoder fixing bracket 2, and the torque sensor is fixed at the torque sensor fixing bracket 11.
The motor controller comprises an ultrasonic motor drive control circuit 29, the ultrasonic motor drive control circuit comprises a control chip circuit 13 and a drive chip circuit 14, the signal output end of the photoelectric encoder is connected with the corresponding input end of the control chip circuit, A, B, Z phase signals 15, 16 and 17 output by the photoelectric encoder are received by the control chip circuit, the output end of the control chip circuit is connected with the corresponding input end of the drive chip circuit to drive the drive chip circuit, and specifically, signals 23, 24, 25, 26, 27 and 28 of the drive chip circuit generated by the control chip circuit are driven;
the driving frequency adjusting signal output end of the driving chip circuit and the driving half-bridge circuit adjusting signal output end are respectively connected with the corresponding input ends of the ultrasonic motor; the driving chip circuit generates driving frequency adjusting signals 18, 19, 20 and 21 and driving half-bridge circuit adjusting signals 22, controls the frequency, the phase and the on-off of A, B two-phase PWM output by the ultrasonic motor, and controls the starting and stopping of the ultrasonic motor by switching on and off the output of PWM waves; the optimal operation state of the motor is adjusted by adjusting the frequency of the output PWM wave and the phase difference of the two phases.
The motor power system forms a pre-sliding friction force model, and the friction effect of the pre-sliding friction force model is expressed as a formula
J(dω/dt)＝Tm-Tf-B ω formula one;
j is total moment of inertia, ω is motor angular velocity, TmIs the torque of the motor, TfIs the friction torque, B is the viscous damping coefficient, TmExpressed as:
Tm＝(VA-VB)(KT/R)＝(KAu-KBomega) formula two;
VAis the output of a voltage amplifier, VBCounter electromotive voltage of, KTIs the torque constant of the motor, R is the armature resistance, KAIs the gain of the voltage amplifier, u is the control voltage, KBIs the back electromotive force constant;
in the pre-sliding friction model, the formula for modeling the parameter uncertain system is
WhereinIn the term of formula three, "^" added to the letter represents the nominal parameter, and "Δ" represents the variation in the parameter; a nominal transfer function ofExpressed as:
wherein the model uncertainty function is defined as:
in the formula:
p(s) and Δ P(s) are unknowns,the identification quantity of the system acquisition information is obtained;
when non-linear friction torque TfFor unknown interference values, T is usedefInstead of TfNamely, the formula three is expressed as:
when T isefWhen the value is estimated, the compensation functionThe method can be used for eliminating the influence of friction torque and model uncertainty;
when the angular velocity of the output shaft of the motor is expressed by the following formula
At this time
Compensation functionIs composed of
Where g is the non-negative gain of the integral term and F(s) is a low pass filter of high cut-off frequency; the filter F(s) in the formula ninth is used for filtering high-frequency measurement noise;
when there is uncertainty in the model, the parametric error function ρ(s) is defined by the formula:
the ninth formula can be expressed as
In the formula eleven, the first step is carried out,is equal to the equivalent function Tef(s) and a parametric error function ρ(s), ρ(s) having a high gain g; when the gain g is designed to be a larger value, the tracking effect of the model is improved, namely the influence of the friction torque and the parameter error function on the motor system is reduced through the compensation function;
after adding the compensation function, the formula six is expressed as:
in the model, the remaining perturbation d(s) is defined by the formula:
wherein d is1(s) and d2(s) represents the uncertainty disturbance to the motor power system of the residual friction and residual model.
When the residual friction force and the equation incomplete compensation in the simulation scheme model cannot be completely eliminated, the traditional controller is combined to restrain model uncertainty caused by the residual friction force and the equation incomplete compensation;
combining a formula twelve and a formula thirteen, the dynamic equation of the motor is expressed by the following formula;
in the above formula, the first and second carbon atoms are,
b＝(KAKT) Sixty (RJ) formula;
for a known non-negative constant δ1And delta2Interference d1(t) and d2(t) having:
d1(t)＜δ1，d2(t)＜δ2seventeen, a formula;
when the dynamic parameter f (t) in equation fourteen cannot be completely determined, the interference δ1And delta2Is bounded;
dynamic parameter f (t) and estimated valueThe estimation error therebetween is determined by the following known function:
the control gain of parameter b in equation fourteen is an unknown quantity with a known boundary, bmax、bminAs boundary maximum and minimum values, i.e.
bmax≥b≥bminMore than 0 formula nineteen;
estimation of control gainThe geometric mean given by the formula nineteen:
the boundary is formulated as:
in the formula twenty-one
When the time-varying state vector is defined as x (t) [ [ theta (t) ] omega (t) ]]TWhen the formula is twenty-three, the reaction is carried out,
the desired time-varying state is defined as xd(t)＝[θd(t) ωd(t)]TTwenty-four of the formula;
the tracking error vector is defined as:
the switching state s (t) of the compensation method, defined in the state space of the model as:
wherein λ is a strictly normal number;
the control law u (t) of the compensation method is
Wherein
Where eta is a strictly normal number,
the above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.