Research on control technology of the middle-convex and varying ellipse piston lathe system

A High-frequency and micro-positioning mechanism for the middle-convex and varying ellipse piston machining is developed in this paper. To satisfy the complex profile and high accuracy requirement in piston machining, it uses rolling guide and elastic block to support the linear motor. This mechanism has high rigidity, small damping and high dynamic accuracy. Considering the characteristic of high-frequency and micro-feeding (HFMF) mechanism, we proposes a double PID (Proportional plus Integral plus Derivative) and double feed-forward(velocity feedforward and Acceleration feed forward) control method for the linear motor, and develops the tool path control software base on these. The experiment verifies that the double PID and double feed-forward (DPDF) control methods improve the system dynamic positioning accuracy and tracking accuracy greatly.