Feed-forward Control Research For Non-circular Piston CNC Turning System

The machining of noncircular section is one of the key working procedures of piston machining. The tracking capability of servo tool plays an important role in machining accuracy of noncircular section. On the base of ensuring the closed loop feedback accuracy in most extent, taking feed-forward control method can further improve the machining accuracy. How to apply this control method to the machine practice is discussed in this dissertation, and it includes such contents as follows:1. Introducing the whole configuration of piston machining system, and making a particular analysis on closed loop feedback control system of servo tool and err tracking model.2. Achieving the continuous model of the closed loop feedback control system, and then getting the discrete model function according to the different discrete time. This supplies a basic condition for the next step.3. Taking zero phase err track controller for the discrete system identified previously. Based on piston machining characters putting forward the technique"linear- phase-separating- identification"to design the feed-forward controller, that carving out the use of the zero phase err track controller.Simulation and actual machining proved that using the feed-forward controller can improve the machining accuracy of the noncircular section.