Patent US 4,338,672

Teach assist apparatus is provided for a programmable manipulator arm to precompute a projected fixed path solution during an initial teaching operation. The projected fixed path solution represents a desired series of manipulator arm work operations to be performed with respect to a workpiece in the minimum execution time while the workpiece is moving at a projected velocity. During the teaching operation, the manipulator arm is moved to various teach positions corresponding to the desired series of work operations relative to the workpiece. The teach assist apparatus computes the minimum execution time on the basis of the maximum dynamic capabilities of the manipulator arm being taught. The precomputed path data is stored and control apparatus is provided to reconstruct the precomputed fixed path solution in a playback work cycle in accordance with dynamic movement of the workpiece. The precomputation performed by the teach-assist apparatus is also useful to perform work operations on a stationary workpiece. In a preferred arrangement, the teach-assist apparatus determines the minimum execution time for each controlled manipulator axis for each step; the axis requiring the largest execution time being utilized to determine the minimum execution time.