Semi-active reaction force compensation for a linear motor motion stage

Abstract

Acceleration and deceleration of a mover excite unwanted vibration to the system base, causing a significant reduction of life and productivity to manufacturing equipment. The system base vibration of a linear motor motion stage can be reduced with a passive reaction force compensation (RFC) mechanism. However, the passive RFC mechanism cannot provide the capability to adjust its stiffness and damping coefficient in real-time. Therefore, resonance may occur if the frequency of the passive RFC mechanism accidentally matches with the frequency components of applied motion profile. This paper presents a semi-active RFC method for a linear motor motion stage using an additional fixed coil. The semi-active RFC mechanism can adjust damping coefficient by changing the resistor load or switching the period of the additional fixed coil. The semi-active RFC mechanism also does not require an additional amplifier or control axis. Mathematical analysis of the semi-active RFC is presented to demonstrate the adjustable damping capability by changing the load resistor. Finally, the effectiveness of the proposed semi-active RFC mechanism is verified via simulations and experiments.