CN108832853A - A kind of DC brushless motor speed regulating method based on fuzzy PI-PD control - Google Patents

Abstract

The invention relates to a speed regulation method of a DC brushless motor based on fuzzy PI-PD control. Including the establishment of the model and the speed regulation method, the establishment of the model includes a two-level fuzzy controller, the first-level fuzzy control adjusts the parameters of the PI controller in real time, and the second-level fuzzy control adjusts the scaling factor of the output of the first-level fuzzy controller. The method of speed regulation is to first compare and calculate the actual speed n of the motor with the given speed n _r to obtain the final deviation e and the deviation change rate ec. After that, E and EC interact with the fuzzy controller to carry out inference work, so as to obtain the defuzzified k _1p and k _1i , use the same method in the fuzzy controller 2 to obtain k _2p and k _2i , and then combine the two fuzzy controllers Multiplied by the output of the controller, the result is input into the PI controller, and finally input into the brushless DC motor model through PD control adjustment, so as to achieve the purpose of controlling the motor speed. And the present invention adopts fuzzy control without relying on the precise mathematical model of the controlled motor, making it more stable in the control state, and can effectively suppress the non-linear situation of the controlled motor; in the control process, the fuzzy PI-PD Self-tuning can continuously monitor the changes of parameters and the real-time feedback of parameters to optimize the control effect.

Description

A Speed Regulation Method of Brushless DC Motor Based on Fuzzy PI-PD Control

technical field

The invention belongs to the technical field of DC motor speed regulation, and in particular relates to a DC brushless motor speed regulation method based on fuzzy PI-PD control.

Background technique

Brushless DC motors have been used in mechanical power equipment, electric vehicles, robots and other fields. However, the brushless DC motor is in a non-linear operating state during the speed regulation process, and the traditional PID control cannot be used to regulate the speed of the DC motor well.

Traditional control strategies, such as PID control, have the advantages of simple structure and easy implementation. Usually, better performance can be obtained in the case of parameter matching, but in the case of system parameter changes or load disturbances, it is often impossible to guarantee ideal closed-loop control. performance.

Contents of the invention

In order to solve the above technical problems, the present invention provides a method capable of stably controlling the controlled object: a speed regulation method of a DC brushless motor based on fuzzy PI-PD control. Including the establishment of the model and the speed regulation method, the establishment of the model includes a two-level fuzzy controller, the first-level fuzzy control adjusts the parameters of the PI controller in real time, and the second-level fuzzy control adjusts the scaling factor of the output of the first-level fuzzy controller. The method of speed regulation is to first compare and calculate the actual speed n of the motor with the given speed n _r to obtain the final deviation e and the deviation change rate ec. After that, E and EC interact with the fuzzy controller to carry out inference work, so as to obtain the defuzzified k _1p and k _1i , use the same method in the fuzzy controller 2 to obtain k _2p and k _2i , and then combine the two fuzzy controllers Multiplied by the output of the controller, the result is input into the PI controller, and finally input into the brushless DC motor model through PD control adjustment, so as to achieve the purpose of controlling the motor speed.

A kind of brushless DC motor speed regulation method based on fuzzy PI-PD control provided by the present invention, the steps of described model establishment are as follows:

Step 1: Set up two fuzzy controllers, define the fuzzy subsets of input values and output values of the two fuzzy controllers;

Step 2: Establish the membership function of the fuzzy subset and the fuzzy control model of each fuzzy controller;

Step 3: According to the membership function of the fuzzy subset and the fuzzy control model of each fuzzy controller, apply fuzzy synthetic reasoning to obtain the fuzzy matrix table of PI control parameters;

Step 4: Defuzzification is performed on the fuzzy subset by using the center of gravity method to obtain a clear amount for control.

The speed regulation method is to set up two fuzzy controllers according to the above-mentioned model, define the fuzzy subsets of the input value and the output value of the two fuzzy controllers, and also include: using the speed deviation and the deviation change rate as the two fuzzy subsets. The input values of two fuzzy controllers define the fuzzy subsets of the speed deviation and deviation change rate, and map the speed deviation and deviation change rate fuzzy subsets to the universe; the output values of the two fuzzy controllers are respectively multiplication, the result is used as the correction value of the proportional and integral control parameters of the traditional PI controller, defines the fuzzy subset of the output values of the two fuzzy controllers, and maps the fuzzy subset of the output values of the two fuzzy controllers to the domain.

The fuzzy matrix table of PI control parameters is calculated as follows:

k _p =k _2p ×k _1p +k _p0

k _i =k _2i ×k _1i +k _i0

Among them, k _p0 and k _i0 are the preset values of system parameters, k _1p and k _1i are the output values of fuzzy controller 1, k _2p and k _2i are the output values of fuzzy controller 2, which can be determined according to the state of the controlled object Automatically adjust the value of PI control parameters.

Compared with the prior art, the beneficial effect of the present invention is that the fuzzy control adopted by the present invention does not need to rely on the precise mathematical model of the controlled object, making it more stable in the control state, and can effectively suppress the nonlinearity of the controlled object In the control process, the self-tuning of fuzzy PI-PD can continuously monitor the changes of parameters and the real-time feedback of parameters, so that the control effect can be idealized.

Description of drawings

FIG. 1 is a schematic diagram of a model of a brushless DC motor speed regulation method based on fuzzy PI-PD control according to the present invention.

Fig. 2 shows the specific working flow chart of the brushless DC motor speed regulation method based on fuzzy PI-PD control in the present invention.

Detailed ways

The present invention will be described in detail below in conjunction with specific embodiments. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be regarded as isolated, and they can be combined with each other to achieve better technical effects.

The invention provides a speed regulation method of a DC brushless motor based on fuzzy PI-PD control. Including the establishment of the model and the speed regulation method, the establishment of the model includes a two-level fuzzy controller, the first-level fuzzy control adjusts the parameters of the PI controller in real time, and the second-level fuzzy control adjusts the scaling factor of the output of the first-level fuzzy controller. The method of speed regulation is to first compare and calculate the actual speed n of the motor with the given speed n _r to obtain the final deviation e and the deviation change rate ec. After that, E and EC interact with the fuzzy controller to carry out inference work, so as to obtain the defuzzified k _1p and k _1i , use the same method in the fuzzy controller 2 to obtain k _2p and k _2i , and then combine the two fuzzy controllers Multiplied by the output of the controller, the result is input to the PI controller, and finally the result adjusted by PD control is input to the brushless DC motor model to achieve the purpose of controlling the motor speed.

The model schematic diagram of the brushless DC motor speed regulation method based on fuzzy PI-PD control in the present invention is shown in Figure 1, and its specific modeling steps are as follows:

Step 1: Set up two fuzzy controllers, define the fuzzy subsets of input values and output values of the two fuzzy controllers;

Step 2: Establish the membership function of the fuzzy subset and the fuzzy control model of each fuzzy controller;

Step 3: According to the membership function of the fuzzy subset and the fuzzy control model of each fuzzy controller, apply fuzzy synthetic reasoning to obtain the fuzzy matrix table of PI control parameters;

Step 4: Defuzzification is performed on the fuzzy subset by using the center of gravity method to obtain a clear amount for control.

As shown in Figure 2, it is a specific work flow chart of the brushless DC motor speed regulation method based on fuzzy PI-PD control in the present invention, and the work flow is described in detail in conjunction with the steps of model establishment below:

Step 1: Set up two fuzzy controllers, define the fuzzy subsets of input values and output values of the two fuzzy controllers;

Taking the speed deviation and the deviation change rate as the input values of the two fuzzy controllers, define the fuzzy subsets {NB, NM, NS, ZO, PS, PM, PB} of the speed deviation and the deviation change rate, respectively representing Fuzzy subsets of input and output linguistic variables: negative large, negative medium, negative small, zero, positive small, positive medium, positive large, and map the fuzzy subsets of speed deviation and deviation change rate to the universe [-6, 6] ;

The output values of the two fuzzy controllers are multiplied respectively, and the result is used as the correction value of the proportional and integral control parameters of the traditional PI controller, and the fuzzy subset {NB, NM, NS, ZO, PS, PM, PB} represent the fuzzy subsets of input and output linguistic variables: negative large, negative medium, negative small, zero, positive small, positive medium, positive large, and the output values of the two fuzzy controllers The fuzzy subset of is mapped to the domain of discourse [-10, 10].

Step 2: Establish the membership function of the fuzzy subset and the fuzzy control model of each fuzzy controller;

Step 3: According to the membership function of the fuzzy subset and the fuzzy control model of each fuzzy controller, apply fuzzy synthetic reasoning to obtain the fuzzy matrix table of PI control parameters;

The fuzzy matrix table of PI control parameters is calculated as follows:

k _p =k _2p ×k _1p +k _p0

k _i =k _2i ×k _1i +k _i0

Among them, k _p0 and k _i0 are the preset values of system parameters, k _1p and k _1i are the output values of fuzzy controller 1, k _2p and k _2i are the output values of fuzzy controller 2, which can be determined according to the state of the controlled object Automatically adjust the value of PI control parameters.

The quality of control mainly depends on the rationality of the control parameter selection. Based on experience, considering the system response speed, stability, overshoot, steady-state accuracy, and the role of PID control parameters k _p , _ki and k _d , the corresponding deviation e and deviation change in the controlled process When the rate ec changes, the self-adjustment of the PI controller parameters k _p and _ki should meet the following adjustment principles;

(1) When the error E is large, in order to eliminate the error as soon as possible and improve the response speed, k _1p and k _2p take a large value, and k _1i and k _2i take a small value or zero; when the error E is small, in order to continue to eliminate the error, And to prevent oscillation caused by excessive overshoot, the values of k _1p and k _2p should be reduced, and k _1i and k _2i should be small. When the error E is small, in order to eliminate the static error and avoid the system from oscillating near the set value, use The system is stabilized as soon as possible, and the values of k _1p and k _2p continue to decrease, and the values of k _1i and k _2i remain unchanged or slightly larger.

(2) When E and EC have the same sign, the controlled quantity changes in the direction of deviating from the given value, and the control effect should be strengthened to make the error change in the direction of decreasing, and k _1i and k _2i should be smaller; when E and EC are different When the number is , the controlled quantity changes towards the given value, so when the error E is large, take a smaller value of k _1p , k _2p or zero to speed up the dynamic process of control.

(3) The larger the EC is, the smaller the values of k _1p and k _2p are, and the larger the values of k _1i and k _{2i are} .

Step 4: Defuzzification is performed on the fuzzy subset by using the center of gravity method to obtain a clear amount for control.

Defuzzification is to transform the output language variables into precise numerical values. The fuzzy controller of the present invention adopts the center of gravity method to defuzzify fuzzy subsets. The defuzzification results are obtained by weighting the average of the membership function of fuzzy subsets of the control role on the control role discourse domain. The result of defuzzification is input into the brushless DC motor model to achieve the purpose of controlling the speed of the motor.

The present invention is a brushless DC motor speed regulation method based on fuzzy PI-PD control. Because the fuzzy control does not need to rely on the precise mathematical model of the controlled object, the motor is more stable in the control state and can effectively suppress the controlled object. In the control process, the self-tuning of fuzzy PI-PD can continuously monitor the changes of parameters and the real-time feedback of parameters, so that the effect of controlling the motor can be optimized.

Although some embodiments of the present invention have been given herein, those skilled in the art should understand that the embodiments herein can be changed without departing from the spirit of the present invention. The above-mentioned embodiments are only exemplary, and the embodiments herein should not be used as limitations on the scope of rights of the present invention.

Claims (6)

1. a kind of DC brushless motor speed regulating method based on fuzzy PI-PD control, which is characterized in that building including Controlling model Vertical and motor speed regulating method, the foundation of Controlling model include two-stage fuzzy controller, and level-one fuzzy control adjusts PI control in real time Device parameter, two pole fuzzy controls adjust the zoom factor of level-one fuzzy controller output.Motor speed regulating method is first to motor Actual speed n and given rotating speed n_rIt is compared calculating, final deviation e and deviation variation rate ec is obtained, in fuzzy controller 1 It is middle to be blurred above-mentioned two deviations, give fuzzy controller to carry out reasoning work the E and EC after blurring, To obtain the k after defuzzification_1pAnd k_1i, k is obtained using same method in fuzzy controller 2_2pAnd k_2i, then by two A fuzzy controller output is multiplied, and is as a result input in PI controller, is finally input to brushless dc by PD control adjusting In machine model, achieve the purpose that control motor speed.

2. a kind of DC brushless motor speed regulating method based on fuzzy PI-PD control according to claim 1, feature exist In：The modeling procedure of the Controlling model is：

Step1：Two fuzzy controllers are established, the input value of described two fuzzy controllers and the fuzzy son of output valve are defined Collection；

Step2：Establish the subordinating degree function of the fuzzy subset and the fuzzy control model of each fuzzy controller；

Step3：According to the subordinating degree function of the fuzzy subset and the fuzzy control model of each fuzzy controller, using fuzzy Compositional rule of inference obtains the fuzzy matrix table of PI control parameter；

Step4：Anti fuzzy method is carried out to the fuzzy subset using gravity model appoach, obtains the clear amount for control.

3. a kind of DC brushless motor speed regulating method based on fuzzy PI-PD control according to claim 2, feature exist In：The motor speed regulating method be on the basis of established Controlling model, to the fuzzy rules of two fuzzy controllers into Row definition.

4. a kind of DC brushless motor speed regulating method based on fuzzy PI-PD control according to claim 3, feature exist In：Described establishes two fuzzy controllers, using revolving speed deviation and deviation variation rate as the defeated of described two fuzzy controllers Enter value, defines the fuzzy subset { NB, NM, NS, ZO, PS, PM, PB } of the revolving speed deviation and deviation variation rate, respectively represent defeated Enter the fuzzy subset of output language variable：In negative big, negative, bear it is small, zero, it is just small, center, honest, and by revolving speed deviation and deviation The fuzzy subset of change rate is mapped on domain [- 6,6]；The output valve of two fuzzy controllers is multiplied respectively, as a result conduct Ratio, the correction value of integration control parameter of conventional PI control device, define the fuzzy son of described two fuzzy controller output valves Collect { NB, NM, NS, ZO, PS, PM, PB }, the fuzzy subset of representative input and output linguistic variable, and will be described with above-mentioned subset The fuzzy subset of two fuzzy controller output valves is mapped on domain [- 10,10].

5. a kind of DC brushless motor speed regulating method based on fuzzy PI-PD control according to claim 3, feature exist In：The fuzzification process is according to the subordinating degree function for establishing the fuzzy subset and the fuzzy control of each fuzzy controller Model obtains the fuzzy matrix table of PI control parameter using fuzzy synthetic reason；The fuzzy matrix table of PI control parameter is as the following formula It is calculated：

k_p=k_2p×k_1p+k_p0

k_i=k_2i×k_1i+k_i0

Wherein, k_p0、k_i0It is the preset value of system parameter, k_1p、k_1iIt is the output valve of fuzzy controller 1, k_2p、k_2iIt is fuzzy control The output valve of device 2, can be according to the value of the state adjust automatically PI control parameter of controlled motor.

6. a kind of DC brushless motor speed regulating method based on fuzzy PI-PD control according to claim 2, feature exist In：Described carries out anti fuzzy method to the fuzzy subset using gravity model appoach, exactly converts the linguistic variable of output to accurately Numerical value, control action fuzzy subset's subordinating degree function is weighted and averaged as weight coefficient using the point on control action domain and is asked Anti fuzzy method is obtained as a result, the result of anti fuzzy method is input in brshless DC motor model, reaches the mesh of control electric machine speed regulation 's.