Adaptive robust synchronous control with dynamic thrust allocation of dual drive gantry stage

H-type dual drive gantry structure is usually set up with dual mechanically coupled linear motors to provide higher power density. It has the potential to yield high speed motion and positioning accuracy at the same time. This paper addresses the dynamics and synchronous control of a H-type gantry stage. The mechanical coupling between the dual drives is analyzed. Adaptive robust control (ARC) algorithm is developed to deal with the effect of parametric uncertainties and uncertain nonlinearities of the linear motor system. A synchronous control scheme with thrust allocation is proposed to regulate the internal force at the same time. The proposed dynamic thrust allocation is also able to handle the significant change of load distribution due to the head motion. Experiments are carried out on a dual drive industrial gantry stage. The results suggest that, with the proposed control scheme, the motion performance is guaranteed and the two drives are appropriately coordinated and synchronized as well, validating the effectiveness and the performance improvement of the proposed dynamic thrust allocation approach.