Nonholonomic Behavior in Free-floating Space Manipulators and its Utilization

The kinematics and dynamics of free-floating manipulators are examined from a fundamental point of view. The dynamic coupling between an uncontrolled spacecraft and its manipulator can make a system dynamically singular at configurations which cannot be predicted by the system’s kinematic properties. Nonholonomic behavior is observed in free-floating systems, and is due to the nonintegrability of the angular momentum. A workspace point can be singular or not, depending on the path taken to reach it. Trouble-free Path Independent Workspaces are defined. Nonholonomy in space manipulators is utilized by planning techniques that permit the control of a spacecraft’s attitude by means of joint manipulator motions, the simultaneous control of the joint angles of a manipulator and of the attitude of its spacecraft, using joint motions only, and finally, the effective use of a system’s reachable workspace by planning paths that avoid dynamically singular configurations.