In order to improve the contour accuracy of precision direct drive XY platform in the process of complex trajectory machining

this paper proposes an adaptive super twisting time varying sliding mode control (ASTSMC) contour control scheme based on reduced order disturbance observer (RODOB). Firstly

the dynamic model containing uncertainty factors and contour error model of the direct drive XY platform are established

which can provide a model foundation for the control of the direct drive XY platform. Secondly

a robust ASTSMC contour tracking method is designed to address factors such as parameter changes and load disturbances in the system. In ASTSMC

the nonlinear time-varying sliding surface is used instead of the traditional linear sliding surface

and the adaptive super twisting control law is introduced as the switching control law of the system

which can significantly reduce chattering and improve the response speed of the system. Due to the overestimation of the upper bound of the total uncertainty in the ASTSMC control law during the selection process

resulting in excessive chattering

a RODOB is designed to estimate and feedforward compensate for it in the control law

thereby further enhancing the robustness of the system. Finally

the direct drive XY platform is controlled to track different position reference trajectories under conditions such as no-load

load disturbance

and parameter changes

and the experimental performance comparisons are analyzed. The results show that the proposed method can enhance the robustness of the system and meet the requirements of high-precision contour tracking.