A Comparison Strategy for Improving the Precision of Contour Error Estimation

Contour error estimation is one of the most important tasks in contour following control. The general way to estimate the contour error is by carrying out curve approximation at the current reference point. But it will suffer a loss of precision in large tracking lag condition. To improve the accuracy of estimation, iteration of the approximation process is usually inevitable. In this paper, a comparison strategy is proposed to ameliorate the accuracy of traditional contour error estimation. By searching the optimal reference point, then directly performing estimation near the neighbor of real contour error point, the estimation accuracy can be improved and the iteration process can be avoided. Principles and details of the proposed strategy are discussed by numerical simulations. The verification experiments are implemented by employing linear and circular based contour error estimation methods. The proposed strategy exhibits better universal estimation performance compared with several advanced algorithms and is easy to implement on external computer. The compensation results of ellipse path following task show the feasibility and efficiency of the proposed comparison strategy.