Globally rigid formation of n-link doubly nonholonomic mobile manipulators

This paper provides a new framework for the collective motion control of a team of n-link doubly nonholonomic mobile manipulators in a constrained environment. A continuous decentralized motion planner is proposed. It guarantees the establishment and strict maintenance of a team formation using the Lyapunov-based control scheme (LbCS), which takes into account all the practical limitations, and the constraints due to fixed obstacles, nonholonomy and globally rigid formation requirements. The control scheme inherently utilizes artificial potential fields within an overarching leader-follower framework to mobilize the prescribed globally rigid formation. The designated leader of the team is modeled as a moving reference point, referred to as the virtual leader. With its protective polygonal region, it directs the motion of the team and manipulate the geometry of the formation. It is the authors' belief that this navigation and globally rigid formation control problem of n-link doubly nonholonomic mobile manipulators is treated for the first time with the use of continuous time-invariant control laws within the framework of LbCS and a variant of the leader-follower scheme. The effectiveness of the motion planner and the resulting acceleration-based control laws are demonstrated via computer simulations.