The unified gain tuning approach to the PID position control with minimal overshoot, position stiffness, and robustness to load variance for linear machine drives in machine tool environment

In this paper, the authors present the unified gain tuning approach to the PID position control for a linear machine drive in machine tools with minimal overshoot and robustness to load variance. This approach unifies state-feedback and reference feed-forward loop. This unification of the traditional position PID (proportional integral and differential) controller gains give perfect freedom in the design of suitable control architecture for linear machine drives. To prove the feasibility and the dynamic characteristics of the proposed approach, various experimental studies based on laboratory test system are performed. Through the test results, it is revealed that the proposed algorithm with unified gain tuning approach has rare sensitivity to the load mass variation when the load mass varied from -100% to 100% of its original known value. And, in the test for high stiffness, it is shown that the value of the stiffness can be increased to 10/sup 8/ order when the whole mass of the moving parts is 100 kg, and this result satisfy the requirement of the actual field.