Dynamic Decoupling Compensation for Six Degrees of Freedom Maglev Planar Motor Based on Nonlinear Extended State Observer

The fine motion system is a key component of precision IC manufacturing equipment such as lithography machines. It is essentially a six degrees of freedom (DOF) maglev planar motor, which is driven by voice coil motor (VCM), can achieve high-precision step scanning movement and leveling and focusing movement. However, due to the inherent thrust fluctuation of VCM and the inevitable error caused in the process of equipment manufacturing and installation, the decoupling of the motor system is not complete, and crosstalk exists between each DOF, which reduces the performance indicators of the motor system. In order to solve the problem of incomplete decoupling among the various DOF, this paper firstly describes the static decoupling control strategy for the six DOF maglev planar motor system, and then proposes a control strategy using the nonlinear extended state observer (NLESO) to estimate the total disturbance and dynamically compensate. Both simulation and experimental results indicate that the proposed control strategy can effectively suppress disturbance and improve the dynamic response and tracking accuracy of the system.