Minimum-time Control for the Transport of Flexible Loads by Two Manipulators

The minimum-time pointwise motion of two manipu-lators grasping the same exible object is examined in this paper. We model the object as a spring with an associated damping factor. The coordinated motion is accomplished through the speciication of the trajectory for the mid-point between the two manipulators. The separate trajectories for each manipulator are not relevant per se, since they only need to preserve the desired motion of the mid-point. This freedom in the motion together with the presence of the exible material causes the minimum time to be less than the minimum time required to move two manipulators with a rigid link between them. This result shows the advantage of exploiting the exibility of the material being worked by two manipulators.