Rigid-flexible Coupling Positioning Stage Driven by Ball Screw with Dual Feedback Based on Active Disturbance Rejection Control

Friction is a high-frequency nonlinear disturbance, especially static friction. There are few effective compensation methods. The friction dead zone aroused by the switch between dynamic and static friction is bad to the stage’s position errors. Therefore, the precision of the mechanical-bearing-guided motion stage is limited. To solve the problems about friction disturbance, this paper proposes a rigid-flexible coupling stage driven by ball screw, which based on the idea about total disturbances of active disturbance rejection control (ADRC). The stage has two parts, a working platform and a frame, which are connected by flexible hinges. The flexible hinges can isolate the friction of the frame. On the one hand, this structure converts the frictional disturbance into the elastic deformation disturbance of the flexible hinge. On the other hand, a dual-feedback design is proposed to measure the deformation and deformation speed of the flexure hinges, which can be used to establish a model of flexure hinges. This work changes the composition of the total disturbances, and reduces the burden of ESO. Experimental results show that the maximum tracking errors are reduced by 90.17%, compared to the result without the model of flexure hinges’ deformation.