Improved task adaptability of open/closed chain mechanisms through continuous joint mode conversion

Presents a simple and effective way of improving the task adaptability of redundant open/closed chain mechanisms based on joint locking/unactuation and continuous joint mode conversion. The joint locking/unactuation in an open/closed chain mechanism is incorporated in the kinematics/statics of the mechanism, and the varying kinematic characteristics depending on the distribution of frozen/passive joints is analyzed. The discontinuity in joint velocity/torque of an open/closed chain mechanism, incurred when the joint mode switching is done abruptly, is described. Two methods of the continuous joint mode conversion for a short transition interval are proposed and compared. Finally, simulation results for a planar redundant open chain mechanism employing joint locking are given