CN115686090B - Corner position control method of limited corner torque motor - Google Patents
Corner position control method of limited corner torque motor Download PDFInfo
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Abstract
The invention relates to a corner position control method of a limited corner torque motor, which obtains a mathematical expression of a controlled object (the limited corner torque motor) by a mathematical analysis method and determines motor parameters needing to be obtained according to the expression; parameters which cannot be directly obtained in the expression are measured through experiments to obtain the relation of input and output so as to obtain the mathematical expression of the parameters; analyzing the obtained mathematical model of the specific controlled object, and correspondingly designing an improved controller structure: performing interpolation processing on a nonlinear part in a controlled object and transmitting the nonlinear part to a controller as a software compensation parameter; the high-order part in the controlled object is subjected to order reduction processing of the control system by a method of adding a closed loop to hardware; aiming at the fluctuation problem of the load of the controlled object, EKF observer software is designed to predict the acceleration and speed conditions of the controlled object at the next moment, and the dynamic characteristic of the control system is improved.
Description
Technical Field
The invention relates to the field of motor control, in particular to a corner position control method of a limited corner torque motor.
Background
A Limited Angle Torque Motor (LATM), as an electromechanical rotary actuator, has a Limited angular motion of generally less than ± 180 °, and has been widely used in precision servo systems, such as optical scanning systems, aerospace systems, and simple switching valves. LATMs offer advantages over conventional rotating electrical machines in terms of higher torque/power ratios, lower cost, greater reliability, and fewer mechanical connecting components. The servo valve composed of the limited corner torque motor directly drives the valve core through an eccentric mechanism arranged on a motor shaft, and has the advantages of simple and compact structure, small volume, light weight, good static and dynamic performance and good market prospect. The torque coefficient is an important index for evaluating the output characteristic of the limited-angle torque motor, the torque coefficient is equal to the torque output under unit current input, and the larger the torque coefficient is, the better the dynamic performance of the motor is.
The general design method of the existing control system of the limited-rotation-angle torque motor is to regard a control object as an approximate linear model and design a simple closed-loop position control system according to the model. On the controller structure, a single closed loop position control formed by a position sensor is generally adopted; on the hardware of the controller, a microprocessor is usually adopted to generate a driving control signal, and the driving control signal is amplified by a power amplification circuit and then directly drives a motor; on the control algorithm of the controller, a closed-loop control algorithm of PID is generally adopted.
The existing control system of the limited corner torque motor has the following design defects:
1) The control object model is established with a large deviation. The existing design method considers that: the torque coefficient of the limited angle torque motor is a fixed value, namely, under all working conditions, the input current and the output torque are in a strict linear relation. In practice, however, the motor model of the limited angle motor has many non-linear factors, such as armature inductance and flux linkage, and the non-linear deviation of the torque varies with the current and the position of the rotor. These non-linear factors will cause the torque coefficient to vary with input current and rotor angle. If the output non-linearity deviation is large, a serious torque ripple problem will be caused. That is, the motor is a nonlinear model mainly influenced by the rotor angle and the input current, and the deviation established by the model directly influences the performance of the control system. In high-precision and high-speed application occasions, the model deviation generated by regarding the nonlinear model as the linear model can greatly restrict the improvement of the control precision and the response of the control system.
2) The adopted PID control algorithm is not matched with the control object. The PID control algorithm is a control algorithm that is based on data driving and can be designed without the need for an accurate model of the controlled object. The PID control algorithm has a good control effect on linear systems within the second order. However, in the drive control of the limited rotation angle torque motor, the output of the rotation angle position input to the motor by the voltage of the processor terminal is actually a third-order controlled object, and the control of the PID cannot achieve a high control accuracy. Meanwhile, due to the existence of the nonlinear characteristic of the limited-rotation-angle torque motor, the controlled object is actually a nonlinear system, and when the nonlinear characteristic of the controlled object is obvious, a control system adopting a PID control algorithm is difficult to achieve a good control effect.
3) The load fluctuation problem of the controlled object. In practical applications, the load force on the motor is not a constant force, and the magnitude of the force varies with time. Meanwhile, disturbance forces such as vibration and friction force on application conditions exist, and fluctuation of the magnitude of the load force is also influenced. Under the application condition of large fluctuation of the load force, the motor control cannot respond to the change of the load in time, and the control response time is delayed. These problems may cause the response speed of the control system to be limited by the load force, and the high dynamic performance cannot be achieved.
Disclosure of Invention
In order to solve the problems, the invention provides the corner position control method of the limited corner torque motor, which has the advantages of good dynamic performance, high precision and strong stability.
The technical scheme adopted by the invention is as follows: a method for controlling the corner position of a limited corner torque motor is characterized in that: the method comprises the following steps:
s1: modeling and analysis of controlled objects
The motor model of the limited-angle torque motor can be divided into an electromagnetic force model and a dynamic model, and the dynamic model is mainly analyzed in the control analysis of motor driving. The dynamic model of the motor can be expressed by a motion equation set of the system, and the motion equation is mainly obtained by a piezoelectric balance equation, an electromagnetic force equation and a force balance equation of the motor;
the mathematical expression of the limited angle torque motor is as follows:
in the formula (I), the compound is shown in the specification,
is the port voltage of the motor and is,
is the input current of the motor and is,
is a winding resistor of the motor,
the winding inductance is used as the winding inductance of the motor,
is the magnetic flux of the motor
In the formula (I), the compound is shown in the specification,
is the torque coefficient of the motor, which follows the motor due to its non-linear characteristics
Is changed;
in the formula (I), the compound is shown in the specification,
is the moment of inertia of the rotor and the load on the rotor,
is the rotating angle of the rotor of the motor,
as a matter of time, the time is,
in order to obtain the coefficient of friction,
to apply the stiffness of the return spring in the system,
is the electromagnetic torque output by the motor,
is the load torque;
the formulas 1-1, 1-2 and 1-3 are mathematical expressions of an electric model, an electromagnetic force model and a mechanical model of the limited angle torque motor respectively, and in a position control system of the limited angle torque motor, the voltage at two ends of the motor needs to be controlled by a motor controller
The dynamic input control of the motor realizes the rotation angle of the rotor of the controlled motor
The accurate control of the system is realized; rotor corner
The accuracy of the output value of (a) affects the accuracy of the position control system;
acceleration of motor rotor
Determining response speed and acceleration of control system
The calculation formula of (2):
wherein the content of the first and second substances,
is the angular velocity of the rotor of the motor,
in a position control system of a limited rotation angle torque motor for acceleration of a motor rotor, if rapidity and stability of position response of position control are to be ensured
Needs to be guaranteed within a certain numerical range; when in use
When the value of (A) is small, a delay in response time is caused when
When the value of (b) is large, the stability of the position response is deteriorated;
s2: model parameter acquisition based on data driving:
according to the mathematical expression of the dynamic model of the limited corner torque motor, the method comprises the following steps: to obtain an accurate mathematical model, the parameters of the motor: motor winding resistor
Motor winding inductor
Rotor and moment of inertia of load on rotor
Coefficient of friction
Stiffness of return spring in application system
And torque coefficient of the motor
Accurate measurement is required; therein, in addition to
Besides the parameters, other parameters can be simply measured by the existing instrument, and higher measurement precision can be obtained; torque coefficient of motor
The parameters are influenced by various motor design parameters, and when the precision of the machining process cannot be ensured, the fluctuation quantity of the values cannot be effectively controlled;
aiming at parameters which cannot be directly obtained, input and output data of the motor can be obtained through a test by building a test experiment platform of the motor, and the parameter characteristics of the motor are described according to the analysis and processing of the data. With a data-based driving method: designing equipment capable of obtaining model parameters of a controlled object, obtaining a large amount of motor working condition data and motor actual output data through a certain test method, and obtaining a torque coefficient of a motor through a data processing means
The form of mathematical expression of (a); for the test platform, by controlling the electric motor
The input changes the working condition of the motor, and the torque under different input quantities is measured
And recording the above input and output data, and drawing by using a specific data processing method
Obtaining the relation curve of
Mathematics of (2)A function expression;
s3: model analysis based on model driving
By the method, the motor parameters in the mathematical expression can be measured with higher precision; therefore, a more accurate motor model can be described by the mathematical model parameters; in order to guide the design of the controller according to the motion equation, the equation needs to be subjected to Lass transformation, and the Lass transformation processing is carried out on the equation to obtain the following results after 1-1 and 1-2 are subjected to the Lass transformation processing:
according to the combination of 3-1,3-2, when the port voltage of the motor is used as an input quantity and the rotation angle position of the motor is used as an output quantity, the transfer function of the system is as follows:
from the analysis of the above transfer model, it can be seen that:
when neglecting the loading force
When the mathematical model is changed, the mathematical model is a three-order system; the traditional controller adopts a PID control algorithm, and the PID control algorithm is more suitable for a second-order linear control system. If the PID control algorithm is adopted for direct control, the order of the controlled object is higher, and the control precision cannot be guaranteed. At the same time, because the system exists
Due to the nonlinear function, the control effect of the PID is limited, and the control precision is further reduced.
When the control system has real-time variable load force
Acceleration of the rotor
Comprises the following steps:
due to load force
Will fluctuate and output electromagnetic force
Since stable control is difficult to achieve due to the nonlinear characteristic of the torque coefficient
The values of the terms are not stable and the acceleration is difficult to control effectively. When the fluctuation of the value of the acceleration is largely out of the controllable range, it may cause an insufficient response speed or an insufficient positional response stability of the system.
Preferably, the controller adopts a PID control algorithm aiming at the problem that the control system has a high order, so that the position control precision is reduced. The invention adds feedback quantity in a certain link in a position closed loop in a control system by introducing new closed loop feedback. Through the closed-loop control of the link, some links with complex orders in the system are changed into linear links after closed-loop feedback, so that the effect of reducing the order of the system is achieved; the current feedback is a feedback mode with low cost and high precision, the current feedback is introduced to reduce the three-order control system into a second-order control system, and the PID control can reach high precision;
by introducing a current closed loop, the original drive control of the motor is changed from voltage control to current control. The piezoelectric equation of equation 3-1 is reduced, and the controlled variable is the current of the motor, and the expression is:
at the moment, the model of the controlled object is changed from a third-order model to a second-order model, and the PID is adopted as the control algorithm of the position controller, so that higher control precision can be achieved, and the controller is not required to adopt an excessively high and excessively complex control algorithm; the specific implementation scheme is as follows: on the basis of a position drive controller of a traditional limited-angle torque motor, a current sensor is added to a motor control signal part output by a power module, so that the magnitude of a current signal of a drive motor output by the power module is detected and controlled.
Preferably, the problem that the response speed of the motor control system is insufficient or the stability is reduced due to a nonlinear coefficient and load fluctuation is solved. Because the load fluctuation quantity is unpredictable and the control system has larger nonlinear characteristics, the invention adopts an Extended Kalman (EKF) observer to predict the variation trend of the acceleration in position control, thereby improving the dynamic characteristics of the system;
the control system mainly comprises a controlled motor, a position sensor, a current sensor and a controller, wherein the current sensor and the position sensor form a double-closed-loop controller structure; the position controller adopts a PID control algorithm and plays a main role in the position control of the control system; the current controller adopts PI algorithm, and mainly plays a role in reducing the order (three-order to two-order) of a controlled object and providing effective information for an EKF observer. The EKF observer estimates the system acceleration value at the next moment through the system state at the previous moment by obtaining the motor rotor position and the motor current information of the current sensor and the position sensor, and takes the value as a feedforward parameter
Compensating to the system output to improve the dynamic characteristic of the system.
The beneficial effects obtained by the invention are as follows: obtaining a mathematical expression of a controlled object (a limited corner torque motor) by a mathematical analysis method, and determining motor parameters to be obtained according to the expression; parameters which cannot be directly obtained in the expression are subjected to output measurement to obtain a mathematical expression of the parameters; analyzing the obtained mathematical model of the specific controlled object: performing interpolation processing on a nonlinear part in a controlled object and transmitting the nonlinear part serving as a software compensation parameter to a controller; the high-order part in the controlled object is subjected to order reduction processing of the control system by a method of newly adding a closed loop; aiming at the fluctuation problem of the load of the controlled object, the acceleration and speed conditions of the controlled object at the next moment are predicted by designing an EKF observer, and the dynamic characteristic of the control system is improved.
According to the method, a more accurate control model of the controlled object is obtained through a data driving method, and a corresponding motor controller is designed by adopting a model driving method according to the established model of the controlled object. The control system designed according to the method realizes higher-precision model establishment, has a controller structure and an algorithm matched with the model establishment, and can achieve higher control precision and response speed. Aiming at the problem of load torque fluctuation, an extended Kalman EKF observer is adopted to predict the torque change at the next moment, so that a controller can adjust in advance, and the response speed of a control system is improved.
Drawings
FIG. 1 is a schematic diagram of the present invention;
FIG. 2 is a block diagram of a mathematical model of a limited-angle torque motor;
FIG. 3 is a schematic diagram of an apparatus for obtaining model parameters of a controlled object based on data driving;
FIG. 4 is a specific circuit block diagram of a limited-angle torque motor controller;
fig. 5 is a block diagram of a control structure of a limited-rotation-angle torque motor controller.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, the method for controlling the rotational angle position of a limited rotational angle torque motor of the present invention employs a model acquisition method based on data driving and a controller design method based on a model, and includes: establishing a mathematical model of a control object, measuring parameter values of the mathematical model of the control object in a data-driven mode, carrying out model analysis on the mathematical model of the control object and providing an improved controller hardware and software structure.
The method mainly comprises the steps of establishing a dynamic mathematical model of a control object, wherein the dynamic mathematical model mainly comprises a piezoelectric balance equation, an electromagnetic equation and a force balance equation in a motor dynamic model. After mathematical expressions of the three equations are obtained, the motion equation of the motor can be established in a combined mode.
The principle of the method is that the working state of a motor is continuously changed, and the motor output under different working states is measured, so that a large amount of motor state-motor output corresponding relation data are obtained, and a certain parameter characteristic of the motor is fitted. The method specifically refers to the steps of obtaining a large amount of data of motor current-motor rotor angle-motor torque output by continuously changing the working angle and the driving current of the motor and measuring the torque output of the motor in real time, and finally obtaining the nonlinear torque coefficient of the motor through the data
Is described in (1).
The mathematical model analysis of the control object mainly comprises the steps of carrying out Lass transformation on a motion equation of the control object, and jointly obtaining a Lass transformation expression of input and output of the control system, wherein the order of the system and a control algorithm required to be adopted can be analyzed through the expression. The position control algorithm adopts a PID algorithm, the order of a control object is three orders, and the PID algorithm cannot be adapted, so that the input quantity of the control object is changed into current by introducing a new current closed loop, the control object is changed into a second-order model, and the PID algorithm achieves a better control effect.
The hardware and software structure design of the controller is improved, and the hardware structure design mainly refers to improvement of a hardware structure of a control system, and comprises a newly added current closed loop structure and a specific implementation scheme. The software design mainly refers to the design of the software structure of the controller, including the design of a position controller, the design of a current controller, the design of an EKF observer, the relationship among the structures of the controller and signal transmission.
The invention relates to a method for controlling the corner position of a limited corner torque motor, which specifically comprises the following steps:
s1: modeling and analysis of controlled objects
The motor model of the limited-angle torque motor can be divided into an electromagnetic force model and a dynamic model, and the dynamic model is mainly analyzed in the control analysis of motor driving. The dynamic model of the motor can be expressed by a motion equation set of the system, and the motion equation is mainly obtained by a piezoelectric balance equation, an electromagnetic force equation and a force balance equation of the motor;
the mathematical expression of the limited angle torque motor is as follows:
in the formula (I), the compound is shown in the specification,
is the port voltage of the motor and is,
is the input current of the motor and is,
is a winding resistor of the motor,
is a winding inductor of a motor, and comprises a winding coil,
is the magnetic flux of the motor;
in the formula (I), the compound is shown in the specification,
is the torque coefficient of the motor, which follows the nonlinear characteristics of the motor
Is changed;
as shown in FIG. 2, the formulas 1-1, 1-2 and 1-3 are respectivelyThe mathematical expressions of an electric model, an electromagnetic force model and a mechanical model of the limited angle torque motor need to carry out voltage control on two ends of the motor through a motor controller in a position control system of the limited angle torque motor
The dynamic input control of the motor realizes the rotation angle of the rotor of the controlled motor
The accurate control of the system is realized; rotor corner
The accuracy of the output value of (a) affects the accuracy of the position control system;
acceleration of motor rotor
Determining response speed and acceleration of control system
The calculation formula of (2):
wherein the content of the first and second substances,
is the angular velocity of the rotor of the motor,
in a position control system of a limited rotation angle torque motor for acceleration of a motor rotor, if rapidity and stability of position response of position control are to be ensured
A certain range of values is required to be guaranteed; when the temperature is higher than the set temperature
When the value of (A) is small, a delay in response time is caused when
When the value of (b) is large, the stability of the position response is deteriorated;
s2: model parameter acquisition based on data driving:
according to the mathematical expression of the dynamic model of the limited corner torque motor, the method comprises the following steps: to obtain an accurate mathematical model, the parameters of the motor: motor winding resistor
Motor winding inductor
Rotor and moment of inertia of a load on the rotor
Coefficient of friction
Stiffness of return spring in application system
And torque coefficient of the motor
Accurate measurement is required; therein is except for
Besides the parameters, other parameters can be simply measured by the existing instrument, and higher measurement precision can be obtained; torque coefficient of motor
The parameters are influenced by various motor design parameters, and the precision of the machining processWhen the value cannot be guaranteed, the fluctuation amount of the value cannot be effectively controlled;
for parameters which cannot be directly obtained, input and output data of the motor can be obtained through a test by building a test experiment platform of the motor, and the parameter characteristics of the motor are described according to analysis and processing of the data. FIG. 3 is a device for obtaining model parameters of a controlled object based on a data-driven method, which obtains torque coefficients of a motor through a plurality of motor operating condition data and motor actual output data by a certain testing method and data processing means
The form of mathematical expression of (a); for the test platform, by controlling the electric motor
The input changes the working condition of the motor, and the torque under different input quantities is measured
And by recording the above input and output data, a specific data processing method is used to profile
Obtaining a relation curve of
The mathematical function expression of (1);
s3: model analysis based on model driving
The motor parameter values in the mathematical expression established by the method can be measured with higher precision, so that the more accurate motor model can be described by the mathematical model. In order to guide the design of the controller according to the motion equation, the equation needs to be subjected to Lass transformation, and the Lass transformation processing is carried out on the equation to obtain the following results after 1-1 and 1-2 are subjected to the Lass transformation processing:
according to the combination of 3-1,3-2, when the port voltage of the motor is used as an input quantity and the rotation angle position of the motor is used as an output quantity, the transfer function of the system is as follows:
from the analysis of the above transfer model, it can be seen that: when neglecting the loading force
When the mathematical model is changed, the mathematical model is a three-order system; the traditional controller adopts a PID control algorithm, and the PID control algorithm is more suitable for a second-order linear control system. If the PID control algorithm is adopted for direct control, the order of the controlled object is higher, and the control precision cannot be guaranteed. At the same time, because the system exists
Due to the nonlinear function, the control effect of the PID is limited, and the control precision is further reduced.
When the control system has real-time variable load force
Acceleration of the rotor
Comprises the following steps:
due to load force
Will fluctuate and output electromagnetic force
It is difficult to realize stable control due to the non-linear characteristic of the torque coefficient, thereby
The values of the terms are not stable and the acceleration is difficult to control effectively. When the fluctuation of the value of the acceleration is largely out of the controllable range, it may cause an insufficient response speed or an insufficient positional response stability of the system.
According to the model analysis of the control system, the reason that the accuracy and the response speed of the original control system are limited is obtained. For the reason, the improvement scheme of the original controller is as follows:
1. the hardware design of the controller aiming at the problem of over-high system order: as shown in fig. 4, for a higher order of the control system, the PID control algorithm adopted by the controller may cause a decrease in position control accuracy. The invention adds feedback quantity in a certain link in a position closed loop in a control system by introducing new closed loop feedback. Through the closed-loop control of the link, some links with complex orders in the system are changed into linear links after closed-loop feedback, so that the effect of reducing the order of the system is achieved; the current feedback is a feedback mode with low cost and high precision, the current feedback is introduced to reduce the three-order control system into a second-order control system, and the PID control can reach high precision;
by introducing a current closed loop, the original drive control of the motor is changed from voltage control to current control. The piezoelectric equation of equation 3-1 is reduced, and the controlled variable is the current of the motor, and the expression is:
at the moment, the model of the controlled object is changed from a third-order model to a second-order model, and the PID is adopted as the control algorithm of the position controller, so that higher control precision can be achieved, and the controller is not required to adopt a control algorithm with too high order and too complex order; the specific implementation scheme is as follows: on the basis of a position drive controller of a traditional limited-angle torque motor, a current sensor is added to a motor control signal part output by a power module, so that the magnitude of a current signal of a drive motor output by the power module is detected and controlled;
2. design of controller software for system response speed problem: the method aims at the problem that the motor control system has insufficient response speed or reduced stability due to non-linear coefficients and load fluctuation. Because the load fluctuation quantity is unpredictable and the control system has larger nonlinear characteristics, the invention adopts an Extended Kalman (EKF) observer to predict the variation trend of the acceleration in position control, thereby improving the dynamic characteristics of the system;
the control structure block diagram of the motor control system is shown in fig. 5, the control system mainly comprises a controlled motor, a position sensor, a current sensor and a controller, and the current sensor and the position sensor form a double-closed-loop controller structure; the position controller adopts a PID control algorithm and plays a main role in the position control of the control system; the current controller adopts PI algorithm, and mainly plays a role in reducing the order (three-order to two-order) of a controlled object and providing effective information for an EKF observer. The EKF observer estimates the system acceleration value at the next moment through the system state at the previous moment by obtaining the motor rotor position and the motor current information of the current sensor and the position sensor, and takes the value as a feedforward parameter
The compensation is carried out to the system output, thereby achieving the effect of improving the dynamic characteristic of the system.
The calculation process of the Extended Kalman (EKF) observer is divided into two steps, wherein the first step is prediction and the second step is data updating.
1. And (3) prediction:
in the formula, the first and second organic solvents are,
、 
the previous and current times of the variable that it is desired to predict, represented herein as an acceleration measure;
the state transition matrix is used for calculating the variable value of the next state according to the current state of the variable;
is a matrix of control quantities, in this case currents
Control and position
； 
Is a Jacobian matrix, with
Similar to the state prediction, but the matrix parameter values are unchanged;
knowing the actual model of the controlled object, the next state of the model can be inferred from the model formula, such as in equations 3-2 and 3-4:
suppose that under load moment
Under the condition of no change, the output torque of the motor can be measured in the formula 3-4
Directly calculates the acceleration
To do so
I.e. from current and position information, can be directly determined
。
But when the system has an indeterminate amount
And when changing, the prediction will deviate. Uncertainty of system
Having a relationship with the controlled variable, the relationship being a covariance
And (4) showing. The greater the degree of correlation of the relationship, the greater the degree of action directly on the variable.
The modification of the formula 3-2 can be obtained
The load torque and the current angle at a certain moment have a certain mathematical relationship, but the relationship is unstable; because of the load
Is uncertain at the next moment of time
、 
Is difficult to calculate and match with, and therefore at different times
、 
And with
Covariance of
Are not the same;
equation 5-2 is the covariance update equation at the current time, as measured at the previous time
、 
Data to update this changing covariance;
wherein
Is a matrix of the covariance,
is the state transition matrix of the above,
is a sensor measurement error matrix;
by the last momentObtaining the ideal observed quantity of the current moment
Simultaneously updating the covariance matrix at the current moment
。
2. Updating the prediction data:
calculate the ideal situation
After the value is obtained, because the load torque change at the next moment is not compensated, the difference value between the predicted value and the actual value is ensured, and the difference value is used as a Kalman coefficient
Compensation:
a compensation factor for the load variation is obtained
；
The compensation coefficient is compensated to the original ideal condition through calculation by the formula 5-4
In the value, the observed quantity acceleration approaching the next moment infinitely is reached
The effect of (1); the achieved effects are as follows: no matter how the load force changes, the change of the force does not suddenly change in time, and the force fluctuation trend at the previous moment is passedThe acceleration output at the next moment can be predicted and compensated, and the effect of outputting stable acceleration is achieved.
Equation 5-5, also updated into the covariance for use at the next time.
After the Kalman calculation is finished, through expanding Kalman filtering, the acceleration under an ideal condition is firstly calculated, and a basic value of acceleration output at the next moment is determined. The load at the next moment will change compared to the last moment, the change and
、 
the variation trend of the load force is related, so that a Kalman compensation coefficient is obtained by updating the covariance matrix, and the variation condition of the load force is compensated into the output of the acceleration. Finally, stable control of the acceleration is realized, so that the acceleration is not too high or too low, and the response speed and the stability of the system are ensured.
The invention relates to a method for controlling the corner position of a limited corner torque motor, which adopts a high-performance position controller, wherein the controller comprises a current controller, a position controller and an EKF observer.
The position controller adopts PID algorithm according to the target position signal
And position feedback value
Performing operation to obtain the acceleration control signal transmitted to the next stage
。
The current controller adopts PI algorithm and is based on the target acceleration signalSignal-scaled current signal
And current feedback value
Controlling the input current of the motor
。
Acceleration control signal
And input current
The expression for the signal is:
wherein
， 
， 
Respectively represents a proportional term, an integral term and a differential term in the PID,
and
all the values of (A) are [ -1,1 [)]。
The EKF observer is used for observing the collected EKFDeviation value of current signal and position signal at previous moment
And estimating the output torque fluctuation and the load torque fluctuation situation at the moment, and carrying out predictive reasoning on the acceleration signal at the next moment. The EKF observer obtains an acceleration control signal after operation
Feedforward correction value of
And performing feedforward correction on the signal to obtain an acceleration correction signal at the next moment
. Acceleration correction signal
After conversion, obtaining a motor current control signal
The signal can better deal with the output torque
And load torque
The effect of the change in acceleration control. The EKF observer can realize effective control on acceleration of the position controller, so that the response speed and the stability of the system are improved.
The shapes, sizes, ratios, angles, and numbers disclosed to describe aspects of the specification and claims are examples only, and thus, the specification and claims are not limited to the details shown. In the following description, when a detailed description of related known functions or configurations is determined to unnecessarily obscure the focus of the present specification and claims, the detailed description will be omitted.
Where the terms "comprising", "having" and "including" are used in this specification, there may be another part or parts unless otherwise stated, and the terms used may generally be in the singular but may also be in the plural.
It should be noted that although the terms "first," "second," "top," "bottom," "one side," "another side," "one end," "another end," and the like may be present and used in this specification to describe various components, these components and parts should not be limited by these terms. These terms are only used to distinguish one element or section from another element or section. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, with the top and bottom elements being interchangeable or switchable with one another, where appropriate, without departing from the scope of the present description; the components at one end and the other end may be the same or different in performance from one another.
In describing positional relationships, for example, when positional sequences are described as being "on.. Above", "over.. Below", "below", and "next", unless such words or terms are used as "exactly" or "directly", they may include cases where there is no contact or contact therebetween. If a first element is referred to as being "on" a second element, that does not mean that the first element must be above the second element in the figures. The upper and lower portions of the member will change depending on the angle of view and the change in orientation. Thus, in the drawings or in actual construction, if a first element is referred to as being "on" a second element, it can be said that the first element is "under" the second element and the first element is "over" the second element. In describing temporal relationships, unless "exactly" or "directly" is used, the description of "after", "subsequently", and "before" may include instances where there is no discontinuity between steps. The features of the various embodiments of the present invention may be partially or fully combined or spliced with each other and performed in a variety of different configurations as would be well understood by those skilled in the art. Embodiments of the invention may be performed independently of each other or may be performed together in an interdependent relationship.
Finally, it should be noted that the above embodiments are merely representative examples of the present invention. It is obvious that the invention is not limited to the above-described embodiments, but that many variations are possible. Any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention should be considered to be within the scope of the present invention.
Claims (3)
1. A method for controlling the corner position of a limited corner torque motor is characterized in that: the method comprises the following steps:
s1: modeling and analysis of controlled objects
The mathematical expression of the limited angle torque motor is as follows:
where u is the port voltage of the motor, i is the input current of the motor, R a Is a motor winding resistor, L a The induction is a motor winding inductance, and psi is the magnetic flux of the motor;
in the formula, K t (I, theta) is a torque coefficient of the motor, and the coefficient can change along with the change of the I and the theta due to the nonlinear characteristic of the motor;
in the formula, m J Is the moment of inertia of the rotor and the load on the rotor, theta is the motor rotor angle, t is the time, D J Is the coefficient of friction, K J For the stiffness of the return spring in the application system, M isElectromagnetic torque output by the motor, M load Is the load torque;
formulas 1-1, 1-2 and 1-3 are mathematical expressions of an electrical model, an electromagnetic force model and a mechanical model of the limited-angle torque motor respectively, and in a position control system of the limited-angle torque motor, the dynamic input control of voltage u at two ends of the motor needs to be carried out through a motor controller, so that the accurate control of the rotor angle theta of the controlled motor is realized; the accuracy of the output value of the rotor angle θ affects the accuracy of the position control system;
the acceleration a of the motor rotor determines the response speed of the control system, and the calculation formula of the acceleration a is as follows:
in a position control system of a limited rotation angle torque motor, if the rapidity and the stability of position response of position control are to be ensured, a needs to be ensured within a certain numerical range; when the value of a is small, the delay of the response time is caused, and when the value of a is large, the stability of the position response is deteriorated;
s2: model parameter acquisition based on data driving:
measuring parameters of the motor by an instrument: motor winding resistor R a Motor winding inductor L a Rotor and moment of inertia m of a load on the rotor J Coefficient of friction D J Stiffness K of return spring in application system J ；
The method comprises the steps of constructing a test experiment platform of the motor, testing on the platform to obtain input and output data of the motor, describing output parameter characteristics of the motor according to analysis and processing of the data, and obtaining a torque coefficient K of the motor t A mathematical expression of a nonlinear function of (I, θ);
s3: model analysis based on model driving
Lass transformation of expressions 1-1 and 1-2 yields:
according to the combination of 3-1,3-2, when the port voltage of the motor is used as an input quantity and the rotation angle position of the motor is used as an output quantity, the transfer function of the system is as follows:
2. the rotational angle position control method of a limited rotational angle torque motor according to claim 1, characterized in that: by introducing a current closed loop, the original drive control of the motor is changed from voltage control to current control, and at this time, the piezoelectric equation of the formula 3-1 is reduced, the controlled variable is the current of the motor, and the expression is as follows:
3. the rotational angle position control method of a limited rotational angle torque motor according to claim 2, characterized in that: when the control system has real-time changing load force M load(s) The acceleration a of the rotor is:
due to the load force M load Fluctuation occurs and stable control of the output electromagnetic force M is difficult due to the non-linear characteristic of the torque coefficient, whereby (M-M) load ) The values of the terms are unstable and acceleration is difficultThe effective control is obtained; when the fluctuation of the acceleration value is larger than the controllable range, the response speed of the system is insufficient or the position response stability is insufficient;
an extended Kalman observer is adopted to predict the variation trend of acceleration in position control, so that the dynamic characteristic of the system is improved, the extended Kalman observer estimates the acceleration value of the system at the next moment through the system state at the previous moment by acquiring the motor rotor position and the motor current information of a current sensor and a position sensor, and the value is used as a feedforward parameter E ″ (s) The compensation is carried out to the system output, thereby achieving the effect of improving the dynamic characteristic of the system.
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Denomination of invention: Corner position control method for finite angle torque motor Granted publication date: 20230407 Pledgee: Wuhan rural commercial bank Limited by Share Ltd. economic and Technological Development Zone Branch Pledgor: WUHAN ZHIQU POWER TECHNOLOGY Co.,Ltd. Registration number: Y2024980024712 |