Kinematic characterization of manipulators: an approach to defining optimality

Some basic issues in kinematic optimization have been examined. Using the concept of the velocity and force ellipsoids, the author studies the relationships between the transmission ratios and manipulator performance characteristics. The transmission ratio has traditionally been viewed as a measure of manipulability. It is shown that the transmission ratio is also a direct measure of error amplification. The implication of this result is that manipulability must be obtained at the expense of accuracy, and vice versa. The author characterizes optimality as an appropriate compromise between manipulability and accuracy in the velocity and force domain. Approaches for both general optimization and task-oriented optimization are discussed