Sliding-mode Control with Multi-sensor Fusion for orientation of Spherical Motion Platform

摘要

This paper presents control system design for multi-degree-of-freedom (DOF) motion platform referred here to as spherical motion platform (SMP) based on compliant spherical wheels. The SMP is capable of providing smooth unlimited rotational motions along all axes and three DOFs translational motions. The various motion platforms have been explored and applied to industry for virtual reality. However, existing motion platforms have limited motion range and motion coupling. In this paper, the full-scaled SMP is developed as practical applications for virtual reality. In addition, the compliant mechanism of spherical wheels helps the SWMP controlled without slipping between a cockpit sphere and the spherical wheels. In addition, for orientation measurement, sensor fusion of both an optical sensor and an inertial measurement unit (IMU) is utilized to control the cockpit rotation without mechanical contact and compensates accumulated error of the IMU. A sliding mode controller with active driving control is designed to deal with disturbances including uncertain dynamic model and coupling effect, respectively. Finally, the experimental results show the sensing and control operation are successfully implemented using the real scale SMP and can be applied to virtual reality simulation as motion simulator.