Study Of Three-motor Synchronous Control System Based On Active Disturbances Rejection Control

With the improvement of modern industrial automation standard, mufti-motor synchronous system is widely applied in modern industrial production. The paper focuses on the multi-variable decoupling control of the multi-motor synchronous system. With the application of active disturbances rejection control method, the decoupling control between the speed and tension of the three-motor synchronous system composed of three AC induction motors and three transducers is studied.On the basis of mathematic model analysis of three-motor synchronous system, the master-slave following mode control strategy is determined. After analysis the advantages and disadvantages of traditional multi-motor control, three active disturbances rejection controllers (ADRC) are designed to control the speed of master motor and two tensions between motors respectively. Double channels compensation of extended state observer (ESO) is used and the coupling of speed and two tensions can be viewed as external disturbance. The extended nonlinear part is used to estimate and compensate the real-time action of external disturbance, that an approximate linearization and deterministic system is obtained and realize the decoupling control between the speed and tensions. With some nonlinear component in the typical ADRC model replaced by linear models, the structure of the model is simplified and its computation load is reduced, thus the practicability of ADRC is greatly enhanced.Siemens S7-300 PLC and Siemens upper computer software WinCC are applied to construct the experimental platform. PROFIBUS-DP network are connected to realize the communication between PLC and transducers. WinCC is applied in establishing monitoring picture of multi-motor system and MPI data communication between WinCC and PLC is established to realize the long-distance intellectualized control for three-motor synchronous system in real-time. In addition, the active disturbances rejection control algorithm program, PROFIBUS-DP communication program and data archiving program are compiled in STEP7 by the structural programming idea.Lots of experiments are performed on the platform of three-motor synchronous system and contrast with traditional PID control, results indicate that: the system under ADRC can realize the decoupling control between the speed and tensions with better dynamic response speed and static precision, has great robust to the load disturbance, and can trance any defined route. Therefore, the method presented in the paper with simple algorithm and strong practicality can meets the requirements of many industrial control environments, and has good application prospects.