Event-based motion planning and control for robotic systems

This thesis focuses on the issues related to the integration of event-based task space planning and real-time control of robotic systems. First, the theory of event-based planning and control is discussed. The key step is introducing the concept of motion reference variable. The equivalence of the event-based and time-based representations of nonlinear feedback has been shown. In addition, the overall system stability criterion has been obtained. The event-based planning and control scheme is exemplified by considering the single arm tracking problem. The time and energy optimal motion plans integrated with nonlinear feedback control are derived. The benefits of event-based planning and control scheme are further demonstrated by its ability to deal with unexpected obstacle. Furthermore, the event-based planning and control scheme is extended to multi-arm coordination. The event-based motion reference for multi-arm robotic system is introduced to drive the system so that it achieves the best possible coordination. Based on the combination of general task space with nonlinear feedback technique, hybrid position/force controllers are also designed. To improve the force control performance, the dynamics of joint motors is also considered in the force control. In the multi-arm coordination scheme, for a given task a task projection operator can be found for each robot with the consideration of redundancy management. The computational aspects of event-based planning and control, in particular for multi-arm systems, and several other important issues related to practical implementation are also addressed. Finally, the theoretical results are illustrated by experiments.