The Research Of High-performance Servo Based On Sliding Mode Control

In recent years, with the continuous development of power electronics, automatic controltechnology and the microelectronic technology, the servo systems in areas such as industrialcontrol and household electrical more widely used, people on the servo system is more and morehigh performance requirements.High performance digital signal processing chip as the core,permanent magnet synchronous motor for the implementation of the motor, the use of advancedcontrol strategies all-digital AC servo system has become the mainstream of developmenttrends.In the vast majority of closed-loop control of servo system, PID control are used as thesystem regulator, the traditional PID control, however, due to inherent limitations, may undercertain conditions can get good control effect, but when the load or the external environmentchanges, the system tracking error increases, the settling time longer, the performance will begreatly affected.Therefore, the need to find a more effective control technology to deal with theproblems encountered by PID control.This article analyzes the mathematical model of permanent magnet synchronous motor andthe basic principles of vector control, established a space vector pulse width modulation basedon the three closed-loop servo control system.Using MATLAB software to establish a completesystem simulation model,application of the traditional PID controller design method forengineering design, then simulation verify the correctness.After the shortcomings for the PIDcontrol is proposed,based on sliding mode control servo system position loop and speed loopregulator integrated design.Because of the chattering problem, the paper proposed the improvedconventional sliding mode controller, while MATLAB software with improved sliding modecontroller simulation results show that with traditional PID control compared the modifiedsliding mode controller has stronger resistance to load disturbances and the more accuratelocation tracking capabilities.Finally built using TMS320F2808-based control chip, digital servo system experimentplatform has been built.Describes the system hardware, including the specific design of the mainmodules, and software process design and implementation and the development ofcommunication protocols and so on.Based on the aforementioned theory to design a prototype,built from the system experiment platform and a series of performance tests of their experiments,including the current loop, velocity loop step response experiments, and rapid start and stop themotor position loop experiments,no-load and position with a large loda duty cycle signaltracking experiments and so on.Experimental results show that the actual machine the traditionalPID control with a big load in the system can not meet the performance indicatorsrequired,sliding mode control is necessary to introduce in order to improve system performance.