Je. Bobrow et al., TIME-OPTIMAL CONTROL OF 2 ROBOTS HOLDING THE SAME WORKPIECE, Journal of dynamic systems, measurement, and control, 115(3), 1993, pp. 441-446
An algorithm given which minimizes the time for two robots holding the
same workpiece to move along a given path. The unique feature of thes
e systems is that they have more actuators than degrees of freedom. Th
e method can be applied to any constrained robot system, including the
case where one robot arm moves in contact with a surface. In addition
to finding the optimum torque histories, the algorithm determines the
optimum contact force between the each robot and the workpiece throug
hout the motion. Constraints on these internal forces are easily intro
duced into the algorithm.