COORDINATED-MOTION CONTROL OF HEAVY-DUTY INDUSTRIAL MACHINES WITH REDUNDANCY

An implementation of a real-time scheme suitable for coordinated-motio n control of a class of teleoperated industrial machines with redundan cy is presented. An efficient gradient projection technique is adopted for the numerical solution. The scheme utilizes the redundancy to avo id the joint limits by minimizing a hyperbolic function of the joint d istances from the mid-range. This new performance criterion is shown t o be advantageous over similar criteria; both the joint-limit avoidanc e capability and the resulting joint velocity profiles can be adjusted by the appropriate choice of parameters introduced in the criterion. Previous criteria are shown to be special cases of the new criterion. Furthermore, the scheme includes a novel algorithm which incorporates the bounded joint velocities. The joint motions are determined conside ring both the required task in terms of the desired end-effector speed and the dynamic considerations, such as hydraulic circuit interdepend ency and power limitations. The feasibility and effectiveness of the i mplementation of the scheme is first tested through simulations of a K aiser Spyder-like excavator machine on a PC-486 micro-computer. The ro bustness and real-time response of the scheme are then validated on a real-time excavator-based graphics simulator interfaced to a human ope rator through a joystick.