Research On The Trajectory Tracking Control And Trajectory Re-planning Of Permanent Magnet Spherical Actuator

Permanent magnet spherical actuators(PMSAs)have the advantages of compact structure,relatively large range of motion and rapid dynamic response.Given that the PMSA can provide three degree-of-freedom movement in one joint,this system is used in various applications in modern aerospace,robotics and other fields.However,as a typical multivariable,coupled,and time-varying nonlinear system,the PMSA faces challenges such as inaccuracy of modeling,friction,uncertain disturbances,and time delay,which would degrade the performance of PMSA control system.With the focus on the trajectory tracking control and trajectory replanning of PMSA,the contents of this paper are as follows:1.The structure of PMSA is introduced.Based on its structure,the dynamic model and electrifying strategy of PMSA is introduced.2.An adaptive sliding-mode controller with delay compensation is designed.Linear predictor is introduced to reduce the delay caused by computation.And Adaptive sliding-mode controller is designed to compensate for Centripetal and Coriolis forces,friction and uncertain disturbances.The performance of PMSA control system under modelling inaccuracy,friction,uncertain disturbances,and computation delay is validated through simulation and experiment3.To further improve the trajectory tracking performance of PMSA,A control strategy based on trajectory re-planning is proposed.By reconstructing a local trajectory,the PMSA can converge smoothly and rapidly to desired trajectory when it is subjected to substantial error,and the controller’s tracking precision is improved.The efficiency and stability of this control strategy is proved through simulation and experiment.4.The experiment platform of PMSA control system is established.The experiment of adaptive sliding-mode control with delay compensation and the experiment of trajectory tracking control based on trajectory re-planning are performed.The efficiency and stability of the proposed control strategy are validated.