Research Of Linear Servo Dual Position Loops Synchronous Drive Control Method

Based on the Shenyang Science and Technology Project named "Research on Dual Linear Motors Synchronous Micro Feed Technology of Gantry Moving Type Computerized Numerical Control Machine (No. 1071201-1-00)", the problem of the linear servo dual position loops synchronous drive control is researched in the paper, which has an important and pervasive significance for solving multitude motors high precision feed and synchronous control. Considered the characters of the controlled object, based on the decoupling control theory and internal model control theory, two control strategies are proposed to reduce the synchronous error of dual linear motors synchronous drive system.The synchronous drive system based on decoupling-internal model control strategy, firstly, uses decoupling control technology to eliminate or counteract the mechanical coupling effect, and improve the synchronous control precision of dual linear motors. The ideal decoupling controller is designed for mechanical coupling, so that the system decoupled can be treated as two independent single input single output systems. Then, the proposed two-degree-of-freedom internal model control scheme for single motor position servo system can guarantee high response ability for the reference signals, high restraint ability for the model perturbations and the external disturbances.For the characters of gantry moving type milling machine, the decoupling control and internal model control are combined in internal model decoupling control strategy. The feed forward diagonal decoupling principle and the multivariable internal model control are employed here to design the internal model decoupling controller, which has the characters both decoupling controller and internal model controller synchronously, then it is able to conquer the effect which imprecise decoupling bring to the system.The theory analysis and results of simulation indicate that the proposed schemes based on decoupling control theory and internal model control theory have strong robustness, rapid response, and small dynamical synchronous error, thus the demand for the high precision synchronization control can be satisfied. Because the internal model decoupling control strategy avoids the imprecise decoupling in dynamic machining of decoupling-internal model control strategy, it has the superior dynamic performance and synchronous precision.