NONHOLONOMIC PATH PLANNING OF SPACE ROBOTS VIA A BIDIRECTIONAL APPROACH

A free-flying space vehicle with manipulators is conceived to perform various tasks for construction and maintenance of space structures. Such a space robot system has different kinematic and dynamic features from those on the earth. The nonholonomic mechanical structure is one such feature. This paper discusses the path planning of nonholonomic motion of space robot systems. A space vehicle with a 6-DOF manipulator is described as a nine-variable system with six inputs. It is shown that, by carefully utilizing the nonholonomic mechanical structure, the vehicle orientation in addition to the joint variables of the manipulator can be controlled by actuating only the joint variables. In this paper, the nonholonomic mechanical structure of space robot systems is shown. Next, a mathematical proof of the nonholonomic mechanical structure is given. A method for the nonholonomic motion planning is then developed by using a Lyapunov function.