CN111290262A

CN111290262A - Control method and device of electric steering engine

Info

Publication number: CN111290262A
Application number: CN202010170155.5A
Authority: CN
Inventors: 汤廷孝; 吴红兵
Original assignee: Jiangsu Kukade Industrial Intelligent Technology Co ltd
Current assignee: Jiangsu Kukade Industrial Intelligent Technology Co ltd
Priority date: 2020-03-12
Filing date: 2020-03-12
Publication date: 2020-06-16

Abstract

The invention provides a control method and a control device of an electric steering engine, wherein the control method comprises the following steps: carrying out second-order low-pass filtering on the control surface expected step position signal of the electric steering engine to obtain an actual expected position and speed signal; improving an expert PID algorithm according to the actual expected position and speed signals, and outputting a control signal; in the improved expert PID algorithm, input signals of proportional control are actual position output signals and actual expected position signals, and input signals of differential control are actual speed output signals and actual expected speed signals; the reference signal comprises a current actual position signal and a current actual speed signal; performing anti-saturation PI control according to the control signal and the motor torque current signal, and outputting a signal as a basis for generating PWM or SVPWM; and driving a motor of the electric steering engine to operate according to the PWM or SVPWM signal generated according to the signal to control the position. The control method provided by the embodiment of the invention has higher position control precision on the electric steering engine.

Description

Control method and device of electric steering engine

Technical Field

The invention relates to the technical field of motor drive control, in particular to a control method and a control device of a high-performance electric steering engine in a robot or an aircraft.

Background

The electric steering engine is a control actuating mechanism, mainly controls the position of a control plane, belongs to position servo drive control in motor drive control, and is widely applied to the fields of robots, aircrafts and the like. The electric steering engine feeds back the output position signal to the input end, and the driving control is carried out after the calculation of the controller, so that a position servo control system is formed. The requirement on the aspects of volume, power-to-weight ratio, control performance and the like of the electric steering engine is very strict, the speed, torque and the like in position change need to be stably controlled while the position is optimally controlled, the rotating speed is prevented from shaking, and the performance of the electric steering engine is improved, so that the problem to be solved urgently in the steering engine industry is solved.

Disclosure of Invention

Based on the foregoing technical defects, embodiments of the present invention provide a method and a device for controlling an electric steering engine, which can better solve the above technical problems.

In order to achieve the above object, the present invention provides the following technical solutions.

A control method of an electric steering engine comprises the following steps:

carrying out second-order low-pass filtering on the control surface expected step position signal of the electric steering engine to obtain an actual expected position signal and an actual expected speed signal;

improving an expert PID algorithm according to the actual expected position signal and the actual expected speed signal, and outputting a control signal; in the improved expert PID algorithm, input signals of proportional control are an actual position output signal and the actual expected position signal, and input signals of differential control are an actual speed output signal and the actual expected speed signal;

performing anti-saturation PI control according to the control signal and the motor torque current signal, and outputting a signal as a basis for generating PWM or SVPWM;

and driving a motor of the electric steering engine to operate according to the PWM or SVPWM signal generated according to the signal, and performing position control.

Preferably, in the improved expert PID algorithm, the control manner of the proportional element is as follows:

kp[e(k)-e(k-1)]=kp[(r'(k)- r'(k-1))-(y(k)-y(k-1))]；

wherein kp is a proportional adjustment coefficient; e (k) and e (k-1) are error values of the current sampling moment and the previous sampling moment respectively; r '(k) and r' (k-1) are respectively the actual expected positions of the current sampling moment and the previous sampling moment; y (k) and y (k-1) are actual positions at the current and previous sampling time, respectively.

Preferably, in the improved expert PID algorithm, the control manner of the differential element is as follows:

kd[(y(k)-y(k-1))/T-v'(k)]；

wherein T is a position sampling period; v' (k) is the actual desired velocity.

A control device for an electric steering engine, comprising:

the filtering module is used for carrying out second-order low-pass filtering on the control surface expected step position signal of the electric steering engine to obtain an actual expected position signal and an actual expected speed signal;

the improvement module is used for improving an expert PID algorithm according to the actual expected position signal and the actual expected speed signal and outputting a control signal; in the improved expert PID algorithm, input signals of proportional control are an actual position output signal and the actual expected position signal, and input signals of differential control are an actual speed output signal and the actual expected speed signal;

the anti-saturation PI operation module is used for carrying out anti-saturation PI control according to the control signal and the motor torque current signal and outputting a signal as a basis for generating PWM or SVPWM;

and the control module is used for driving the motor of the electric steering engine to operate according to the PWM or SVPWM signal generated according to the signal so as to control the position.

The invention has the following advantages and beneficial effects:

1. according to the invention, the step signal of the expected position of the control surface is subjected to second-order low-pass filtering, so that the position information and the speed information required by the actual system of the steering engine are separated, and the requirements of the actual inertia control system of the steering engine are met;

2. the invention ensures that the error of the proportion link does not generate mutation, and the differential of the steering engine has a comparative reference, thereby being more suitable for an actual steering engine system, and the steering engine control system has stable speed operation;

3. the position and speed information is fused into a whole, and the response is quick;

4. the method of the invention is easy to realize in digital circuit and analog circuit, and has low implementation cost and reliable use.

Specific embodiments of the present invention are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the invention may be employed. It should be understood that the embodiments of the invention are not so limited in scope.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.

Drawings

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes, the proportional sizes, and the like of the respective members in the drawings are merely schematic for facilitating the understanding of the present invention, and do not specifically limit the shapes, the proportional sizes, and the like of the respective members of the present invention. Those skilled in the art, having the benefit of the teachings of this invention, may choose from the various possible shapes and proportional sizes to implement the invention as a matter of case. In the drawings:

fig. 1 is a flowchart of a control method of an electric steering engine according to an embodiment of the present invention;

FIG. 2(a) is a graphical illustration of a desired position step signal r;

FIG. 2(b) is a graphical illustration of an actual desired position signal r' obtained by second order RC filtering of the desired position step signal r;

fig. 2(c) is a schematic graph of the actual desired position velocity v' obtained by second order RC filtering for the desired position step signal r;

fig. 3 is a block diagram of a control device of an electric steering engine according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art without any inventive work based on the embodiments in the present application are within the scope of protection of the present application.

The invention aims to solve the technical problems that the position control response of the conventional electric steering engine is slow, the speed in operation is jittered, and the differentiation in PID control has no practical physical significance, and provides a novel control method and a novel control device for the electric steering engine.

As shown in fig. 1, an embodiment of the present invention provides a method for controlling an electric steering engine, which may include the following steps:

improving an expert PID algorithm according to the actual expected position signal and the actual expected speed signal, and outputting a control signal; in the improved expert PID algorithm, input signals of proportional control are reference signals and actual expected position signals, and input signals of differential control are reference signals and actual expected speed signals; the reference signal comprises a current actual position output signal and a current actual speed output signal; specifically, the reference signal input in the proportional control is a current actual position signal, and the reference signal input in the differential control is a current actual speed output signal;

and driving a motor of the electric steering engine to operate according to the PWM or SVPWM signal generated according to the signal to control the position.

The control method of the embodiment of the invention comprises the following steps:

1. desired position step signal: the target position r set by the electric steering engine according to actual requirements is provided by an external bus digital signal or a pulse analog signal input as shown in fig. 2(a), and the expected position r is a variable quantity.

2. Low-pass filtering: the desired position signal r is second order low pass filtered, such as second order RC filtered, so that the desired position step signal r changes from a step signal to a continuous exponential curve signal r ', i.e. the actual desired position signal r' as shown in fig. 2 (b). The actual desired position signal r' does not abruptly change. The exponential curve position signal r 'is then differentiated to obtain the actual desired velocity curve v', as shown in fig. 2 (c).

As shown in fig. 2, a graph after second-order RC filtering is used. Fig. 2(b) is an actual expected position curve after second-order RC filtering, where the actual expected position curve is continuous and does not change suddenly, the curve changes slowly in the initial stage and quickly in the middle stage, and changes slowly when reaching the expected value. Fig. 2(c) is a curve of the actual desired speed after the second-order RC filtering, where the actual desired speed is changed from slow to fast and then from fast to slow. After the expected position signal r is subjected to second-order low-pass filtering, two process signals of an actual expected position curve and an actual expected speed curve are separated, and the two process signals accord with the actual physical characteristics that the steering engine cannot change suddenly due to inertia, position and speed, the speed changes slowly in the initial stage, the middle stage and finally the expected value. And filtering the step signal of the expected position signal r into a corresponding position signal r 'and a corresponding speed signal v' according to the actual demand curve of the steering engine. The length of the curve segment can be adjusted according to the actual system torque, and is usually set to be several milliseconds to hundreds of milliseconds.

3. Actual desired position signal, actual desired velocity signal: the position deviation signal r 'and the speed signal v' are separated after the step signal of the expected position signal r is subjected to second-order low-pass filtering.

4. Expert PID: the expert PID is a nonlinear PID integrated with the steering engine control data, and the traditional expert PID calculation formula is as follows: u (k) = u (k-1) + k1{ kp [ e (k) -e (k-1) ] + kie (k) + kd [ e (k) -2e (k-1) + e (k-2) ] }. Where k1 is a gain amplification factor, kp, ki, and kd are a proportional adjustment factor, an integral adjustment factor, and a differential adjustment factor, respectively, e (k), e (k-1), and e (k-2) respectively represent error values at the current, previous, and two previous sampling times, and e (k) = r-y (k), and y (k) represents an actual position at the current sampling time.

The conventional expert PID algorithm mainly has the following two disadvantages:

(1) for the proportional segment kp [ e (k) -e (k-1) ]: if at time k-1 the position desired input is r (k-1) and the actual output is y (k-1), then e (k-1) = r (k-1) -y (k-1). However, since the position expectation input r may be mutated, at time k, the position expectation input is mutated to r (k), which may be very different from v r (k-1); while the actual output y (k) cannot be abruptly changed due to the inertia of the steering engine system, y (k) is close to the value of y (k-1), and e (k) = r1-y (k). This results in a proportional element kp [ e (k) -e (k-1) ] = kp [ (r (k) -y (k)) - (r (k-1) -y (k-1)) ] = kp [ (r (k) -r (k-1)) - (y (k) -y (k-1)) ], since y (k) is similar to y (k-1), r (k) can differ greatly from r (k-1), so that the value of the proportional element kp [ e (k) -e (k-1) ], can be mutated. Further, the control system is vibrated, the speed is jittered, and the control performance of the system is seriously affected.

(2) Differential element kd [ e (k) -2e (k-1) + e (k-2) ]: the differential link is kd [ (e (k) -e (k-1)) - (e (k-1) -e (k-2)) ], is the difference between the current adjacent error signal difference and the last adjacent error signal difference, and has no expected speed information of a steering engine system, so that the differential link is disconnected from the actual system requirement.

Aiming at the problems of the traditional expert PID algorithm, the invention improves the expert PID of the electric steering engine on the basis of filtering the position expectation signal r to obtain an actual expectation position signal r 'and an actual expectation speed signal v' thereof as follows:

(1) and substituting the obtained actual expected position signal r ' into a proportion link, wherein kp [ e (k) -e (k-1) ] = kp [ (r ' (k) -r ' (k-1)) - (y (k) -y (k-1)) ]. Because r '(k), r' (k-1), y (k) and y (k-1) can not be mutated, the value of the proportion link kp [ e (k) -e (k-1) ] can not be mutated, the control system can not generate oscillation and is stable in control.

(2) And the differentiation link is kd [ e (k) -2e (k-1) + e (k-2) ], and the essence is the differentiation of the actual position y, namely the actual speed v (k) = e (k) -e (k-1) at the time is compared with the actual speed v (k-1) = e (k-1) -e (k-2) at the last time. The differential link is improved as follows: comparing the current actual speed v (k) = (y (k) — y (k-1))/T with an ideal actual expected speed v' (k), wherein T is a position sampling period; namely, the differential link is kd [ (y (k) -y (k-1))/T-v' (k) ], namely, the actual operating speed of the steering engine is controlled through an ideal speed, and the actual inertial system requirement of the steering engine is met.

(3) The improved expert PID integrates the position control and the speed control of the steering engine, the response bandwidth is improved by 3-5 times, the rotating speed control is more stable, and the position control sensitivity and the accuracy are higher.

5. And (3) anti-saturation PI: the output of expert PID and motor torque current signal are input to carry out PI control, and the output signal is used as the basis signal for generating drive PWM or SVPWM.

6. Driving: the motor is driven by PWM or SVPWM.

7. A motor: the motor body is usually a direct current brush motor, a brushless motor or a permanent magnet synchronous motor.

8. A sensor: the device comprises a position lip stem sensor and a current sensor; the position sensor is arranged at the position of an output main shaft of the electric steering engine and samples the steering engine rotation angle; the current sensor is arranged in the controller and samples a steering engine bus and three-phase current.

9. Actual desired position signal, actual desired velocity signal: and (3) acquiring an actual position by using a position sensor, and obtaining a time speed after differential filtering.

10. Actual output position signals and actual output speed signals are used as reference signals: is the signal of a specific target location point in the short term target signal. For example, the steering engine is intended to rotate from a current initial suspension position (perpendicular to the ground) to a target position at an angle of 60 ° to the ground. The movement track from the initial position to the target position is the long-term movement of the steering engine, and the target position is the long-term target. In practice, however, the motor driving the steering engine to move subdivides the long-term target into a plurality of (at least two) short-term targets under the control of the corresponding control method, so as to realize the subsection operation. For example, the steering engine is driven to 10 degrees and then to 60 degrees. Then, the target position of the steering engine at each stage is the short-term target signal. The short-term target signals can be set and input according to the reality, and position signals and speeds which are reached when the steering engine finishes a plurality of short-term target signals to be staged are used as reference signals. For example, the steering engine described above reaches a position and speed at a short target of 10 °.

The invention has the following advantages and beneficial effects:

The method can also be used in other position-controlled servo motors.

Based on the same concept, the embodiment of the application also provides a control device of the electric steering engine, and the control device is described in the following embodiment. The principle of solving the problems of the control device of the electric steering engine and the technical effects which can be obtained are similar to the control method of the electric steering engine, so the implementation of the control device of the electric steering engine can refer to the implementation of the control method of the electric steering engine, and repeated parts are not repeated. The term "module" used below may be implemented based on software, or based on hardware, or implemented by a combination of software and hardware.

As shown in fig. 3, the control device of an electric steering engine according to the embodiment of the present invention includes:

the filtering module 100 is used for performing second-order low-pass filtering on the control surface expected step position signal of the electric steering engine to obtain an actual expected position signal and an actual expected speed signal;

an improvement module 200, configured to improve an expert PID algorithm according to the actual expected position signal and the actual expected speed signal, and output a control signal; in the improved expert PID algorithm, input signals of proportional control are an actual position output signal and the actual expected position signal, and input signals of differential control are an actual speed output signal and the actual expected speed signal;

the anti-saturation PI operation module 300 is used for performing anti-saturation PI control according to the control signal and the motor torque current signal and outputting a signal as a basis for generating PWM or SVPWM;

and the control module 400 is used for driving the motor of the electric steering engine to operate according to the PWM or SVPWM signal generated according to the signal so as to control the position.

In the 90 s of the 20 th century, improvements in a technology could clearly distinguish between improvements in hardware (e.g., improvements in circuit structures such as diodes, transistors, switches, etc.) and improvements in software (improvements in process flow). However, as technology advances, many of today's process flow improvements have been seen as direct improvements in hardware circuit architecture. Designers almost always obtain the corresponding hardware circuit structure by programming an improved method flow into the hardware circuit. Thus, it cannot be said that an improvement in the process flow cannot be realized by hardware physical modules. For example, a Programmable Logic Device (PLD), such as a Field Programmable Gate Array (FPGA), is an integrated circuit whose Logic functions are determined by programming the Device by a user. A digital system is "integrated" on a PLD by the designer's own programming without requiring the chip manufacturer to design and fabricate application-specific integrated circuit chips. Furthermore, nowadays, instead of manually making an integrated circuit chip, such Programming is often implemented by "logic compiler" software, which is similar to a software compiler used in program development and writing, but the original code before compiling is written by a specific Programming Language, which is called Hardware Description Language (HDL), and HDL is not only one but many, such as abel (advanced Boolean Expression Language), ahdl (alternate Language Description Language), Confluence, pl (core universal Programming Language), HDCal, JHDL (Java Hardware Description Language), languai, Lola, HDL, laspam, hardward Description Language (rhydr Language), etc. The most commonly used are VHDL (Very-High-speed Integrated Circuit Hardware Description Language) and Verilog 2. It will also be apparent to those skilled in the art that hardware circuitry that implements the logical method flows can be readily obtained by merely slightly programming the method flows into an integrated circuit using the hardware description languages described above.

For convenience of description, the above devices are described as being divided into various modules by functions, and are described separately. Of course, the functionality of the various modules may be implemented in the same one or more software and/or hardware implementations as the present application.

From the above description of the embodiments, it is clear to those skilled in the art that the present application can be implemented by software plus necessary general hardware platform. Based on this understanding, the technical solutions of the present application may be embodied in the form of software products, which essentially or partially contribute to the prior art. In a typical configuration, a computing device includes one or more processors (CPUs), input/output interfaces, network interfaces, and memory. The computer software product may include instructions for causing a computing device (which may be a personal computer, a server, or a network device, etc.) to perform the methods described in the various embodiments or portions of embodiments of the present application. The computer software product may be stored in a memory, which may include forms of volatile memory in a computer readable medium, Random Access Memory (RAM) and/or non-volatile memory, such as Read Only Memory (ROM) or flash memory (flash RAM). Memory is an example of a computer-readable medium. Computer-readable media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), other types of Random Access Memory (RAM), Read Only Memory (ROM), Electrically Erasable Programmable Read Only Memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), Digital Versatile Discs (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include transitory computer readable media (transient media), such as modulated data signals and carrier waves.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the system/electronic device embodiment, since the software functions executed by the processor are substantially similar to those of the method embodiment, the description is simple, and for the relevant points, reference may be made to part of the description of the method embodiment.

Although the present application has been described in terms of embodiments, those of ordinary skill in the art will recognize that there are numerous variations and permutations of the present application without departing from the spirit of the application, and it is intended that the appended claims encompass such variations and permutations without departing from the spirit of the application.

Claims

1. A control method of an electric steering engine is characterized by comprising the following steps:

2. The control method according to claim 1, wherein in the improved expert PID algorithm, the proportional element is controlled as follows:

kp[e(k)-e(k-1)]=kp[(r'(k)-r'(k-1))-(y(k)-y(k-1))]；

3. The control method according to claim 1, wherein in the modified expert PID algorithm, the differentiation element is controlled as follows:

kd[(y(k)-y(k-1))/T-v'(k)]；

wherein T is a position sampling period; v' (k) is the actual desired velocity.

4. A control device of an electric steering engine is characterized by comprising: