Investigation on the Dynamic Behavior of High-Velocity Feed System Directly Driven by a Linear Motor

High-velocity feed system directly driven by a thrustful linear motor is a novel driving style for CNC machining tool feed system. It eliminates all mechanical transmission elements. The linear motor´s primary and secondary parts are assembled into the worktable and the machine bed respectively to directly drive the machine table to realize linear feed. But this kind of transmission is very sensitive to disturbances. The cutting force and moving mass are both direct disturbances to the system. This paper analyzes the method to calculate the dynamic rigidity based on the system´s control model, discusses the factors which influence the behavior of the system, and presents main measures to improve dynamic behavior. Moving mass estimator is designed according to the system. The paper realizes the online mass estimation and compensation. Simulation on the practical system shows the online mass estimation and compensation takes an approving control effect for the system