Determining maximum payloads for cooperating robots under time-optimal control

This work presents an algorithm which evaluates the dynamic performance limit of a cooperating robotic system using movements planned for minimum time. Minimum-time movements characteristically require that a set of motors in the robot be driven at their maximum torque throughout the motion. These movements are limited by the combination of motor performance, mechanical advantage of the kinematic chain, and the location of the start and goal positions. By increasing the payload for a motion until a minimum-time solution is no longer feasible the payload limit of the system for the associated path is obtained. To illustrate the algorithm a detailed analysis of a robotic arm developed at Odetics Inc. is presented. The analysis includes numerical results for cooperating Odetics robotic arms using their maximum payload under time-optimal control. Furthermore, the maximum payload for the cooperating robotic system to perform the same motion with a 1 sec time constraint is determined.