Dynamics and Control of a Self-Reconfiguring Sphere Leading to the Design of a Spherical Mobile Robot

本研究项目是设计和开发一种独特的球形移动机器人，该机器人具有球形外骨骼、内部自推进机构和各种运动控制和侦察传感器。该机器人系统的独特特点包括可伸缩摄像机、可伸缩机械手和可伸缩肢体。手臂和四肢在机器人休息时展开，用于操作和支撑，在机器人恢复运动之前收回。该机器人能够进行快速机动，并相对轻松地在崎岖的地形上移动。在球形机器人系统的发展过程中，需要解决动力学、控制和机械系统设计三个基本问题。第一个问题涉及非完整系统的非线性反馈控制策略的发展，主要应用于滚动球。针对球面的重构问题，提出了一种光滑时不变控制器。尽管非完整控制系统取得了重大进展，但滚动球体的重构仍然是一个悬而未决的问题。本研究的第二个问题是设计一个球体的内部自推进机构，并构造一个闭环控制器使该机构有效运行。该机构为球体提供了加速、匀速运动或在一点上随动的能力。最后一个问题是球形移动机器人的发展，希望通过传感和控制的协调来实现自主。该问题涉及桁架的设计，传感器的选择和放置，以及通过上述两个控制器的集成来设计整个控制系统。作为本研究的一部分，非完整控制策略被纳入密歇根州立大学机械工程系的高级控制系统课程。球体自推进的内部机制和球形移动机器人的设计在许多研究生和本科生的设计、结构、力学和控制课程中被用作激励例子。

This research project deals with the design and development of a unique spherical mobile robot having a spherical exo- skeleton, an internal mechanism for self-propulsion, and a variety of sensors for motion control and reconnaissance. Unique Features of the robotic system include its retractable camera, retractable manipulators, and telescopic limbs. The arms and limbs are deployed for manipulation and support when the robot is at rest and retracted before the robot resumes its motion. The robot is able to perform rapid maneuvers and move over rough terrain with relative ease. In the process of development of the spherical robotic system, three fundamental problems in the areas of dynamics, control, and design of mechanical systems are addressed. The first problem relates to the development of a nonlinear feedback control strategy for nonholonimic systems with primary application to the rolling sphere. A smooth and time- invariant controller will be developed for the reconfiguration of the sphere. Despite significant progress in nonholonomic control systems, the reconfiguration of the rolling sphere is still an open problem. The second problem of this research is to design an internal mechanism for self- propulsion of the sphere and to construct a closed loop controller for the effective operation of the mechanism. The mechanism provides the sphere with the capability to accelerate, move with constant velocity, or servo at a point. The final problem relates to the development of the spherical mobile robot, which is expected to achieve autonomy thorough coordination between sensing and control. This problem deals with design of the truss, choice and placement of sensors, and design f the overall control system through integration of the two controllers mentioned above. The nonholonomic control strategy, developed as a part of this research, is incorporated in the Advanced Control Systems course, offered in the Department of Mechanical Engineering at Michigan State University. The internal mechanism for self-propulsion of the sphere and the design of the spherical mobile robot are used as motivational examples in a number of graduate and undergraduate courses in design, structures, mechanics, and controls.