Design and control of redundant-actuated Six-DOF micropositioning stage with magnetic gravity compensation

Abstract The performance of ultra-precision positioning stages is particularly critical in the field of ultra-precision manufacturing. This paper presents the design of an eight-actuator redundant six-degree-of-freedom micropositioning stage with magnetic suspension gravity compensation (6-DOF RDMS). All drives are electromagnetic direct-drive systems based on voice coil motors (VCMs). The vertical motors incorporate a Halbach array and a magnetic suspension gravity compensation structure. A mathematical model and a finite element model are established for the designed positioning stage. The models are utilized for magnetic field and magnetic force analysis, thermal analysis, and analysis of the dynamic force-induced deformation of stator to ensure operational stability. A decoupling control system for the six-degree-of-freedom micropositioning stage is developed, mapping the six degrees of freedom to the control loops of the eight actuators to achieve high-precision positioning. Finally, a prototype was constructed, validating the effectiveness and feasibility of the structural design and the decoupling control system.