This article presents to develop a robust control system of spherical motion platform (SMP) capable of controlling six-degree-of-freedom motion, particularly unlimited rotational motion for better virtual reality. The SMP is the new design of a motion manipulator/simulator driven by the frictional force between a set of spherical wheels and cockpit sphere. However, it has intrinsic difficulties in control due to numerous uncertainties, including slipping motion between spherical wheels and cockpit sphere. Inaccurate motion control may degrade human perception as well as tracking performance. In this article, sliding mode control based on a disturbance observer is developed for the SMP to achieve precise motion tracking performance and provide a more realistic environment regardless of kinematic and dynamic uncertainties. Numerical simulation and experimental results with proportional-integral-differential and the robust controllers are compared for step and sinusoidal inputs to demonstrate the feasibility of motion control and tracking performance in spite of uncertainties. Finally, the SMP is operated using two representative flight maneuvers as a flight simulator. The results show that the SMP with the control system can be utilized to provide motion cue for a human on board for virtual reality.

中文翻译：

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虚拟现实球面运动平台的鲁棒跟踪控制


本文提出开发一种鲁棒的球形运动平台（SMP）控制系统，能够控制六自由度运动，特别是无限旋转运动，以获得更好的虚拟现实。 SMP 是一种新设计的运动操纵器/模拟器，由一组球形轮和驾驶舱球体之间的摩擦力驱动。然而，由于存在许多不确定性，包括球轮和驾驶舱球体之间的滑动运动，它在控制方面存在固有的困难。不准确的运动控制可能会降低人类感知和跟踪性能。在本文中，为 SMP 开发了基于扰动观测器的滑模控制，以实现精确的运动跟踪性能，并提供更真实的环境，而不受运动学和动态不确定性的影响。对于阶跃和正弦输入，比例积分微分和鲁棒控制器的数值模拟和实验结果进行了比较，以证明运动控制和跟踪性能的可行性，尽管存在不确定性。最后，SMP 使用两个代表性的飞行动作作为飞行模拟器进行操作。结果表明，带有控制系统的 SMP 可用于为虚拟现实中的人员提供运动提示。