Mechatronic Design of an Active Two-body Vibration Isolation System

Structural modes as for example decoupling of a mechanical subsystem are in general unwanted effects in high precision positioning systems. This paper proposes a well designed decoupling mechanism as a design choice to improve the energy efficiency of an active vibration isolation system that needs to position a structure comprising a high and low precision subsystem. Experimental setups of a single DoF system with a rigid and a decoupling mechanical system structure are developed and analyzed. PD and a PID controllers are designed for the rigid and the equivalent decoupling structure, respectively, resulting in the same disturbance rejection performance for the high precision subsystem. Experiments demonstrate that disturbances of 12.4 µm rms amplitude are reduced to below 118 nm rms for both systems and that the rms energy consumption of the decoupling structure can be reduced by 68% as compared to the rigid system structure.