Planar Motion Measurement of a Compliant Micro Stage: An Enhanced Microscopic Vision Approach

This paper presents an enhanced microscopic vision-based approach supporting fast and high-precision measurement on planar motions of a multi-degree of freedom (DOF) compliant stage with sub-micrometer motion accuracy. The proposed method is based on an improved particle swarm optimization (PSO) algorithm, including two phases. First, an inverted pyramid structure is employed to divide the solution space into a top-level solution space, such that the expected solution can be quickly located into a smaller range from bottom to top. Then, the spacial three search step (S-TSS) algorithm is applied to achieve an accurate result. The effectiveness of the proposed method is evaluated on a three-DOF micro stage with translational and rotational motions, where comparative studies with existing results are also conducted. The experimental results demonstrate significant improvement on algorithm efficiency without sacrificing the measurement accuracy, which indicates good potential for visual servo control of such micro stages with the proposed approach.