The Characteristics Of The Motor Drive System Modeling Method And Studying Much

With the servo-system applied in the high precision, high dynamic performance, large inertia and high power occasion more and more widely, the demand of multi-motor servo-system is more and more urgent. In the background of demand, the multi-motor driving servo-system of gear drive is taken as the research object and the application of the characteristic model approach for multi-motor driving servo-system is explored.First, according to the existing backlash nonlinearity and friction nonlinearity factors in the mechanical system inevitably, the mechanism modeling method is used. Starting with the single-motor driving servo-system, the dynamic models with backlash nonlinearity and friction nonlinearity of double-motor driving servo-system and four-motor driving servo-system are established respectively. In order to further depict the dynamic and static characteristics of the friction in the multi-motor driving servo-system, the friction torque is described by the dynamic LuGre friction model.Second, according to the double-motor driving servo-system and four-motor driving servo-system with backlash nonlinearity and friction nonlinearity, the fixed bias torque is applied to eliminate the backlash nonlinearity. The friction nonlinearity is compensated by dynamic LuGre friction model which is identified by genetic algorithm. Then combined with the requirements of control performance, characteristic models in the form of second-order time-varying difference equations are established for double-motor and four-motor driving servo-system. And then, the dynamic models of double-motor driving servo-system and four-motor driving servo-system are taken as standard models respectively. By comparing the model errors between standard model and its corresponding characteristic model which is identified by recursive least square method with forgetting factor, the validity of characteristic models is verified.Third, based on the characteristic model of double-motor driving servo-system, all-coefficient adaptive control which is simple and has less adjustable parameters is designed. When double-motor driving servo-system is required to track the sine signal which includes speed and acceleration information, the tracking accuracy is low. According to the problem, a new algorithm which includes feedforward control and all-coefficient adaptive control is proposed. The simulation results show that the proposed controller is robust and has high control accuracy, well anti-interference ability. Both double-motor driving servo-system and four-motor driving servo-system controlled by feedforward control and all-coefficient adaptive controller have good dynamic and steady-state performance.