Electromechanical coupling rotor system starting and vibration suppression method based on fuzzy PID control

Abstract

The invention relates to an electromechanical coupling rotor system starting and vibration suppression method based on fuzzy PID control, and belongs to the field of electromechanical coupling rotor systems. According to the method, an 8-degree-of-freedom rotor system mechanical dynamics model and an equivalent motor model are established through a finite element method, an electromechanical coupling rotor simulation model is established based on Matlab / Simulink, and then a fuzzy PID control module is established to be assembled with an electromechanical coupling rotor system. Finally, simulation analysis is conducted on the electromechanical coupling rotor assembled with the fuzzy PID control module and the normal PID control module, and the result shows that the fuzzy PID control module can effectively shorten the starting response time of the rotor system and the vibration amplitude during stable operation.

Description

Technical Field

[0001] The invention relates to a method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control, and belongs to the field of electromechanical coupling rotor systems. Background Art

[0002] Rotating machinery is the most widely used, earliest appeared and simplest mechanical system in engineering. The rotor system is a common system of rotating machinery. With the continuous development of science and technology, rotating machinery has appeared in manufacturing industries with higher precision requirements such as aerospace. The movement of the rotor system is mainly in the form of vortex motion. Under normal circumstances, the vibration of the rotor system is generally more prominent, and the reasons are also very complicated. Not only the buckling vibration and torsional vibration of the stator, but also the vibration of the parts on the shaft, the foundation vibration of the casing, and even vortex instability caused by fluid media and bearing oil layers.

[0003] At present, a large number of studies have shown that there are many factors that affect the dynamic characteristics of the rotor system, among which torsional vibration is the main one. This type of vibration formed in the shaft system will directly or indirectly affect the transmission accuracy of the shaft system, cause torsional deformation of the transmission shaft, and in severe cases damage the shaft system. There is an urgent need for a control method for vibration suppression of the electromechanical coupling rotor system. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control. By setting a fuzzy PID control algorithm, the stability of the motor starting process is improved, and vibration suppression during the operation of the electromechanical coupling rotor system is effectively achieved.

[0005] The technical solution of the present invention is: a method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control, the specific steps of which are:

[0006] Construct an electromechanically coupled rotor system;

[0007] Establish the rotor mechanical system dynamics model and the motor system equivalent circuit model;

[0008] Based on Matlab and Simulink, a mechanical system dynamics model and an equivalent circuit model of the motor system are combined to establish an electromechanical coupling simulation system. The electromechanical coupling rotor system is simulated based on the standard PID control algorithm to obtain the initial vibration time domain response curves during node startup and operation.

[0009] Build a fuzzy PID controller and combine it with an electromechanical coupled rotor system;

[0010] The combined electromechanical coupling rotor system is simulated based on the fuzzy PID control algorithm and the standard PID control algorithm to obtain the vibration time domain response curve of the combined node during startup and operation.

[0011] Compare the combined node vibration time domain response curve with the initial vibration time domain response curve;

[0012] Based on the comparison results, the control constraints in the simulation process are optimized until the comparison results meet the vibration suppression requirements.

[0013] Preferably, the establishing of the rotor mechanical system dynamic mathematical model comprises:

[0014] Based on the mechanical structure characteristics of the rotor, the finite element method is used to divide the rotor system into 7 shaft end units. Each unit contains two nodes, and each node has one torsional degree of freedom, a total of 8 degrees of freedom. The dynamic mathematical model of the rotor mechanical system is established.

[0015] Preferably, establishing the motor system equivalent circuit model comprises:

[0016] Firstly, the feedback decoupling and feedforward control methods are used to establish the dq-axis voltage control model of the motor rotor. Then, the electromagnetic characteristics of the motor are obtained in the two-phase synchronous rotating dq coordinate system. The motor equivalent circuit model is established by combining the current, inductance and flux of the motor d-axis and q-axis.

[0017] Preferably, the electromechanical coupling simulation system is established based on Matlab / Simulink combined mechanical dynamics model and motor equivalent circuit model;

[0018] Preferably, in the process of building a PID controller, the expression of the PID controller is:

[0019]

[0020] The transfer function of the PID controller is:

[0021]

[0022] Among them, U(t) is the controller output, e(t) is the controller input; K p , K i , K d are proportional factor, integral factor, differential factor, T i is the integration time constant, T d is the differential time constant, G(s) is the transfer function, U(s) and E(s) are the Laplace transforms of the output and input respectively, and s is the complex variable of the Laplace transform.

[0023] Preferably, in the process of using the fuzzy PID controller, the expressions of the proportional factor, the integral factor and the differential factor are:

[0024]

[0025] Among them, K p , K i , K d are the actual values ​​of the PID controller parameters, K p0 , K i0 , K d0 are the initial values ​​of the parameters, ΔK p , ΔK i , ΔK d They are the increments of fuzzy thrust parameters adjusted in real time.

[0026] Preferably, the construction of the fuzzy PID controller is specifically as follows:

[0027] The fuzzy PID controller takes the angular acceleration and the rate of change of the angular acceleration as input to establish a fuzzy PID control module.

[0028] Preferably, the vibration time domain response curve of the taken node is compared with the vibration time domain response curve before the fuzzy PID controller is not combined, specifically:

[0029] Compare and analyze the motor output torque and the time from startup to normal operation at the rotor end node, and use the fuzzy PID control algorithm to shorten the startup time;

[0030] The motor output torque is compared with the vibration amplitude at the rotor end node during normal operation, and the vibration suppression effect of the fuzzy PID control algorithm is analyzed.

[0031] Preferably, the comparison result satisfies the vibration suppression requirement specifically when the peak value of the vibration time domain response curve of the combined fuzzy PID controller is less than 60% of the working condition of the uncombined fuzzy PID controller, which satisfies the vibration suppression requirement.

[0032] The beneficial effects of the present invention are as follows: the present invention jointly builds an electromechanical coupling rotor system based on Matlab / Simulink, builds a fuzzy PID module and assembles it, obtains the vibration time domain response of the rotor system during startup and operation with and without the fuzzy PID control module, optimizes the motor startup rotor time and suppresses vibration during operation, and provides a method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control, which has the advantages of low cost, high efficiency, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0034] Figure 1 It is a flow chart of the steps of the present invention;

[0035] Figure 2 Schematic diagram of the rotor system model of the present invention;

[0036] Figure 3 It is a schematic diagram of the finite element division of the rotor system of the present invention;

[0037] Figure 4 Simulating Matlab / Simulink model for the electromechanical coupled rotor system of the present invention;

[0038] Figure 5 It is the structural diagram of the fuzzy PID controller of the present invention;

[0039] Figure 6 is the membership function graph of the present invention;

[0040] Figure 7 Simulate Matlab / Simulink model for the fuzzy PID control electromechanical coupling rotor system of the present invention;

[0041] Figure 8 This is a comparison diagram of the motor rotor system response under fuzzy PID and PID control at the motor output end of the present invention;

[0042] Fig. 9 This is a comparison diagram of the motor rotor system response under fuzzy PID and PID control at the end of the rotor system of the present invention;

[0043] Fig.10 This is a comparison diagram of the speed vibration response of the motor when it is running under fuzzy PID and PID control at the output end of the motor of the present invention;

[0044] Fig.11 This is a comparison diagram of the speed vibration response of the motor when it is running under fuzzy PID and PID control at the end of the rotor system of the present invention. DETAILED DESCRIPTION

[0045] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0046] Example 1: Figure 1 As shown, a method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control, the specific steps are:

[0047] Constructing a rotor system electromechanical coupling model, wherein the rotor system electromechanical coupling model includes a rotor system dynamics model and a motor model;

[0048] Establish the rotor system dynamics model and motor equivalent circuit model. The rotor system model is as follows: Figure 2 As shown;

[0049] Based on Matlab / Simulink joint establishment of electromechanical coupling simulation system Figure 4 As shown;

[0050] Based on Matlab / Simulink, fuzzy PID control module and electromechanical coupling simulation system are assembled, such as Figure 7 As shown;

[0051] Run the assembled fuzzy PID control module and the unassembled electromechanical coupling simulation system;

[0052] Detect the time domain signals of the motor output and the displacement at the end nodes of the rotor system during startup and operation under two working conditions;

[0053] The detected displacement time domain signal is converted into speed, and the vibration suppression effect of fuzzy PID on the rotor system during startup and operation is compared and analyzed. Figure 8 , Fig. 9 , Fig.10 , Fig.11 shown.

[0054] like Figure 2 As shown, the rotor system includes a rotor motor system 1 and a rotor mechanical system 2. The rotor mechanical system includes a bearing seat 21, a bearing seat 22, a bearing seat 23, a bearing seat 24, a coupling 25, a coupling 26, and a propeller 27. The propeller 27 is equivalent to a turntable unit. The motor system rotor is connected to the rotor mechanical system through a coupling to transmit torque.

[0055] The rotor mechanical system dynamics model includes:

[0056] The rotor to be tested is an 8-DOF model. The present invention uses the finite element method to perform dynamic modeling on the rotor mechanical system. The finite element division is as follows: Figure 3 As shown;

[0057] The rotor shaft system is divided into 7 shaft segments. The shaft segments adopt Timoshenko beam elements. Each shaft segment consists of two nodes. Each node includes a torsional degree of freedom. The torsional displacement of the shaft unit node is θ = {θ1, θ2}.

[0058] Kinetic energy of the shaft unit T i s With potential energy It can be expressed as:

[0059]

[0060] Where ρ is the material density of the shaft unit, J Ps is the moment of inertia of the shaft unit, Ω is the angular velocity of the rotating shaft segment, G is the shear modulus, θ s is the displacement of the shaft unit in the torsional direction.

[0061] The dynamic equation of the rotating axis is derived as:

[0062]

[0063] Where M b , G b , K b are the mass matrix, gyro matrix and stiffness matrix of the rotating axis respectively, Ω is the angular velocity of the rotating axis segment, T b is the overall vector matrix of the external load on the rotating axis, θ s is the displacement of the shaft unit in the torsional direction.

[0064] The coupling unit is equivalent to the shaft end unit;

[0065] The method and principle of disk dynamics modeling are the same as those of rotating axis dynamics modeling. The dynamics equation of the disk is:

[0066]

[0067] Where M d , G d are the disk mass matrix and gyro matrix, θ d is the torsional displacement of the disk unit, Ω is the angular velocity of the disk unit, T d is the external force vector matrix of the disk.

[0068] The total matrix of the rotor mechanical system dynamics equations is assembled according to the shaft unit matrix, coupling unit matrix and disk unit matrix:

[0069]

[0070] Where M is the overall mass matrix, G is the overall gyro matrix, K is the overall mass matrix, Ω is the rotor angular velocity, θ is the rotor torsional displacement, and T is the external force vector matrix of the rotor system.

[0071] The establishing of the motor system equivalent circuit model comprises:

[0072] Firstly, the feedback decoupling and feedforward control method is used to establish the voltage control model of the motor rotor dq axis, and the motor speed loop and current loop are used to establish the voltage control model of the motor rotor d axis and q axis. The model is as follows:

[0073]

[0074] In the formula, u d 、u q are the dq axis components of the stator voltage respectively; i d 、i q They are the dq axis components of the stator current respectively; They are the dq axis components of the rated stator current; ω e is the electrical angular velocity; L d , L q They are the dq axis inductance components respectively; ψ f is the permanent magnet flux; K pd , K pq is the proportional gain; K id , K iq is the integral gain; s is the complex variable of Laplace transform.

[0075] The purpose of establishing the motor system equivalent circuit model is to indirectly obtain the d-axis and q-axis currents in the subsequent motor equivalent circuit model. Then, the motor electromagnetic characteristics are obtained in the two-phase synchronous rotating dq coordinate system, and the motor equivalent circuit model is established by combining the motor d-axis and q-axis currents, inductance and flux.

[0076] Specifically, the electromagnetic characteristics of the generator are obtained in the two-phase synchronous rotating dq coordinate system, the generator rotor dq voltage control model is controlled according to the speed and current loop, and the motor equivalent circuit model is established by combining the inductance, current and flux of the motor stator and rotor. The model is as follows:

[0077]

[0078] In the formula, p n is the number of motor pole pairs; T e is the output torque of the first node motor output terminal; i d 、i q are the dq axis components of the stator current respectively; ω e is the electrical angular velocity; L d , L q They are the dq axis inductance components respectively; ψ f is the permanent magnet flux.

[0079] T e The output torque of the motor output end of the first node is added to the first degree of freedom in the rotor dynamics torque vector matrix T, and the load torque T is added to the eighth degree of freedom. L .

[0080] like Figure 4 As shown, the electromechanical coupling simulation system jointly established based on Matlab\Simulink includes:

[0081] The large-span rotor dynamics model of the electromechanical coupling system includes the rotor mechanical system part and the motor system part. According to the excitation effect of the motor electromagnetic torque on the rotor mechanical system dynamics model, the mechanical and motor parts are coupled to establish the rotor system electromechanical coupling system dynamics model.

[0082] The fuzzy PID controller design is as follows:

[0083] Fuzzy controller is a language controller that simulates human control characteristics. Fuzzy PID is based on the typical PID and applies fuzzy control to adjust parameters in real time to achieve better control effect and improve the robustness of the control system. The fuzzy controller in this paper takes angular acceleration and the rate of change of angular acceleration as input. The controller structure is as follows: Figure 5 As shown. Ratio K p , integral K i , differential K d , the calculation formula is:

[0084]

[0085] Among them, K p , K i , K d are the actual values ​​of the PID controller parameters, K p0 , K i0 , K d0 are the initial values ​​of the parameters, ΔK p , ΔK i , ΔK d They are the increments of fuzzy thrust parameters adjusted in real time.

[0086] First define the deviation E and the rate of change E c And output ΔK p , ΔK i , ΔK d The fuzzy sets and domains are as follows: E, E c , ΔK p , ΔK i , ΔK d The fuzzy set is {NB, NS, Z, PS, PB}, corresponding to {negative large, negative small, moderate, positive small, positive large}, deviation E and ΔK p , ΔK i , ΔK d The domain of the controller is [-6, 6]. Different membership functions have a great influence on the performance of the controller. The membership function selects a triangle. Based on Matlab\Simulink, the fuzzy PID control module and the electromechanical coupling simulation system are assembled, such as Figure 6 shown.

[0087] In order to verify the effectiveness of the strategy proposed in the present invention in reducing the startup response time and suppressing torsional vibration, the assembled fuzzy PID control module and the normal PID electromechanical coupling simulation system were started and run.

[0088] Set the rated speed of the motor to 1500r / min, set the load torque at the motor load end to a frequency of 100Hz and an amplitude of 10N·m; draw the motor output torque and the rotor end node to compare the assembled fuzzy PID control module and the normal PID speed startup curve, such as Figure 8-9 It can be seen that:

[0089] At the node between the motor output torque and the rotor end, the rotor system containing the standard PID module reaches the rated speed within 0.6s; the rotor system containing the fuzzy PID control module reaches the rated speed within 0.3s. It can be clearly seen that the fuzzy PID control module can shorten the time from startup to normal operation of the rotor system.

[0090] Extract the assembled fuzzy PID control module and the normal PID simulation speed data, and draw a comparison chart of the motor output torque and the speed under normal operation after the rotor end node reaches the rated speed, such as Figure 10-11 It can be seen that:

[0091] When the rotor system is operating normally, the speed vibration amplitude of the electromechanical coupled rotor system assembled with fuzzy PID at the motor output torque and the rotor end node is significantly smaller than the vibration amplitude under the standard PID working condition, verifying that the method of the present invention can significantly suppress the vibration of the rotor system.

[0092] The speed of the electromechanical coupled rotor system is controlled by a fuzzy PID control algorithm to adjust the parameters in real time, thereby shortening the start-up time and suppressing the vibration of the rotor system.

[0093] The specific implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control, characterized in that: Construct an electromechanically coupled rotor system; Establish the rotor mechanical system dynamics model and the motor system equivalent circuit model; Based on Matlab and Simulink, a mechanical system dynamics model and an equivalent circuit model of the motor system are combined to establish an electromechanical coupling simulation system. The electromechanical coupling rotor system is simulated based on the standard PID control algorithm to obtain the initial vibration time domain response curves during node startup and operation. Build a fuzzy PID controller and combine it with an electromechanical coupled rotor system; The combined electromechanical coupling rotor system is simulated based on the fuzzy PID control algorithm and the standard PID control algorithm to obtain the vibration time domain response curve of the combined node during startup and operation. Compare the combined node vibration time domain response curve with the initial vibration time domain response curve; Based on the comparison results, the control constraints in the simulation process are optimized until the comparison results meet the vibration suppression requirements.

2. A method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control according to claim 1, characterized in that: Constructing the electromechanical coupling rotor system specifically includes: the electromechanical coupling rotor system includes a rotor mechanical system and a motor system.

3. A method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control according to claim 1, characterized in that: The establishment of the rotor mechanical system dynamics model is specifically as follows: Based on the torsional degree of freedom and combined with the structural characteristics of the motor and rotor mechanical system, the finite element method is used to establish the mechanical dynamics model of the 8-degree-of-freedom rotor system.

4. The method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control according to claim 1, characterized in that: The establishment of the motor system equivalent circuit model is specifically as follows: Firstly, the feedback decoupling and feedforward control methods are used to establish the dq-axis voltage control model of the motor rotor. Then, the electromagnetic characteristics of the motor are obtained in the two-phase synchronous rotating dq coordinate system. The motor equivalent circuit model is established by combining the current, inductance and flux of the motor d-axis and q-axis.

5. The method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control according to claim 1, characterized in that: The specific steps of constructing the fuzzy PID controller are as follows: the fuzzy PID controller takes the angular acceleration and the rate of change of the angular acceleration as input to establish a fuzzy PID control module.

6. The method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control according to claim 1, characterized in that: Comparing the vibration time domain response curve of the node taken with the vibration time domain response curve before the fuzzy PID controller is combined is as follows: Compare and analyze the motor output torque and the time from startup to normal operation at the rotor end node, and use the fuzzy PID control algorithm to shorten the startup time; The motor output torque is compared with the vibration amplitude at the rotor end node during normal operation, and the vibration suppression effect of the fuzzy PID control algorithm is analyzed.

7. The method for starting and suppressing vibration of an electromechanical coupling rotor system based on fuzzy PID control according to claim 1, characterized in that: Specifically, the comparison result meets the vibration suppression requirement: the peak value of the vibration time domain response curve of the combined fuzzy PID controller is less than 60% of the working condition of the uncombined fuzzy PID controller, which meets the vibration suppression requirement.

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