Design Of Closed-loop Control System Of Two-phase Hybrid Stepping Motor Based On Variable Structure PID Control

The stepping motor with the advantages of its simple control,reliable operation,low driver cost and high cost performance,is still widely used in industrial and automation fields.However,due to its inherent defect and traditional control methods,the application of stepping motor in the industry is limited to a certain extent.Because the cost of microprocessors and electronic components become lower,people propose higher requirement for the control system of stepping motor.How to make the control system of stepping motor achieve higher precision and better capacity of load in high-speed is the current research direction.It has great engineering practical value to deeply learn the control system of stepping motor to improve its control performance.Firstly,this thesis introduces the development status of stepping motor and the research status of its control system,and summarizes the working principle of the two-phase hybrid stepping motor.Through reasonable assumptions,a mathematical model of the two-phase hybrid stepping motor in the stationary coordinate system is deduced in detail,and the mathematical model in the d-q rotating coordinate system is obtained by coordinate transformation.Decoupling control of the stator current of the motor in a rotating coordinate system to achieve vector control of 4)=0.Secondly,this thesis designed a closed-loop control system of two-phase hybrid stepping motor.Based on the three-phase space voltage vector pulse width modulation(SVPWM),a two-phase space voltage vector pulse width modulation method is derived.A variable structure PID control is introduced in the current loop which is the key to the control system of stepping motor,and affects the control system to achieve higher precision and better capacity of load in high-speed.The PI control and PD control are switched by the speed limit,and the fuzzy switching rule is used to ensure that parameters in the control system of stepping motor are not abrupt when switching.The variable structure PID control preserves the advantages of PI control and PD control in the current loop.The speed loop provides speed parameters for the variable structure PID control and improves the control accuracy of the two-phase stepping motor control system.Finally,in order to prove the practicability and practicability of the variable structure PID control,the hardware circuit design of the closed-loop control system of two-phase hybrid stepping motor is completed with Infineon’s XMC1402 chip as the core.Use DAVE to complete the application layer configuration and programming of the software.At the same time,the experimental control platform was built and the variable structure PID control proposed in this thesis was compared with the traditional PI and PD control.The experimental results further showed that the variable structure PID control is more advantageous than the PI control and PD control in the closed-loop control of the two-phase hybrid stepping motor.