Research On Speed Control Strategy Of Two-Phase Hybrid Stepper Motor

Stepping motor is a special type of motor controlled by pulses.Its structure and operating principle are similar to synchronous motor,and it can be used as a low speed permanent magnet synchronous motor.Due to its superior performance,stepping motor is widely used in industrial and automation fields,so it is of great significance to study the drive control technology of stepping motor.In this paper,two-phase hybrid stepping motor is selected as the research object,and its open loop control technology and closed loop control technology are studied.There are many ways of open-loop control for stepper motors,and among all the open-loop control methods,the most classic is subdivision control.However,subdivision control highly relies on subdivision drive chips,and in recent years,there has been a certain degree of "chip shortage" globally,which has affected the production of foreign subdivision drive chip manufacturers and caused a certain shortage of subdivision drive chips in China,Therefore,it is urgent to develop a localized replacement solution for segmented driver chips.In response to the demand for domestic substitution of segmented driver chips,this article proposes a replacement scheme of main control module,current acquisition module,and driver module,as an alternative solution when there is a shortage of segmented driver chips.Firstly,the hardware design(including schematic design and PCB design)and hardware debugging work were completed;Secondly,the software program design was completed;Finally,experimental verification was conducted,and the subdivision control of the two-phase hybrid stepper motor was achieved using a self-designed experimental platform.The closed-loop control of stepper motors is mainly divided into two types: lead angle control and full closed-loop control.The lead angle control method cannot directly control the phase winding current,and the torque output performance and dynamic performance are average.Therefore,this article focuses on the research of full closed-loop control:The first method of full closed-loop control for stepper motors is to install a photoelectric encoder on the motor to collect rotor position/speed information.Aiming at the problem that two-phase hybrid stepper motors are susceptible to system uncertainties and other factors when tracking a given speed signal,resulting in reduced control accuracy of the speed closed-loop system,a fuzzy neural network sliding mode controller based on the sparrow search algorithm(SSA-FNNSMC)is proposed.Firstly,based on sliding mode control(SMC),fuzzy neural networks are used to approximate the equivalent and switched control terms of the sliding controller;Secondly,the Sparrow Search Algorithm(SSA)is used to replace the adaptive law to optimize the weights of the fuzzy neural network in real time.Finally,simulation experiments have verified that the designed fuzzy neural network sliding mode controller based on the Sparrow Search Algorithm has strong robustness and dynamic performance.The second method of full closed-loop control for stepper motors is to estimate the angle using the observation angle,which is a sensorless control method.In this paper,a two-phase hybrid stepping motor sensorless control system based on sliding mode observers is studied.Aiming at the chattering problem existing in traditional sliding mode observers,a novel sliding mode observer is proposed.Firstly,by introducing a new power reaching law,the problems of slow reaching speed and large buffeting in traditional reaching laws are solved;Secondly,in view of the problem that the traditional arctangent function will expand the high-frequency chattering in the sliding mode observer,this chapter uses a phase locked loop to replace it;Finally,simulation experiments verify the advantages of the new sliding mode observer designed in this paper.