Improving dynamic performance of bi-articularly actuated robot arms by using infinity norm based actuation redundancy resolution

Bi-articular actuators, actuators spanning two joints, are gaining popularity for solving the known limitations of conventional robot arms. Actuator redundancy resulting from the presence of bi-articular actuators increases stability, transfers mechanical energy from proximal to distal joints, and decreases the non-linearity of the end effector force as a function of force direction. In this paper, advantages of infinity norm optimization criteria for actuator redundancy resolution of bi-articularly actuated robot arms is investigated under dynamic conditions. The infinity norm approach with closed form solution is compared with the pseudo inverse matrix based methods by simulation means. When using the infinity norm based approach, under the same robot arm dynamics, the required maximum joint actuator is reduced; and under the same joint actuator limitations the achievable maximum end effector acceleration is increased.