Optimal Tuning of a Biaxial Servomechanism Using a Cross-coupled Controller and Disturbance Observers

In order to improve the contouring accuracy of a biaxial servomechanism and the robustness against disturbance, a cross-coupled controller with a disturbance observer is studied, as well as the optimal tuning based on the integrated design methodology is proposed. Strict mathematical modeling and identification process of a servomechanism are performed first. An optimal tuning problem is formulated as a nonlinear constrained optimization problem including the relevant controller parameters of a servomechanism. The objective of the optimal tuning procedure is to minimize both contour error and settling time while satisfying constraints, such as relative stability and overshoots, etc. The effectiveness of the proposed optimal tuning procedure is verified through experimental results.