Differential Geometry Soft Variable Structure Control of Magnetic Levitation Movement Stage

Background: It is easy to carry out a wide range of high-precision micro movement on the magnetic levitation stage which also turns to be suitable in precision manufacturing and ultra-precision measurement field. In view of the strong coupling and nonlinear characteristics of the dynamic model of the sandwich layer structure, the differential geometry soft variable structure control method is proposed. Method: Based on differential geometry theory, the study of state feedback linearization for dynamic model of the magnetic levitation movement stage is conducted, which implements the exact linearization and decoupling in the vertical and horizontal subsystems of the stage. The soft variable structure controller with variable saturation is designed according to the linear model of the subsystem. Result: The simulation results show that the control method is able to achieve better performance than the PID and sliding mode controller and satisfy the requirement of precision positioning.