Path-Accurate Online Trajectory Generation for Jerk-Limited Industrial Robots

Abstract

Standard industrial controllers of robot arms define constraints on the velocity, the acceleration, and the jerk and abort execution in case any of them is violated. In addition to satisfying these constraints, the presented method tries to generate a trajectory that is path-accurate, i.e., that exactly tracks the 6-dof shape of the desired path in axis space. Furthermore, the computed trajectory is as close as possible to the original robot program. This is reached by forward scaling and backtracking until a feasible trajectory is obtained. In contrast to previous work, blending of subsequent segments of the desired path is prevented by interpolation of the arc length instead of direct position interpolation. Because of its time-efficiency the algorithm can be applied in each sampling step, e.g. every 4~ms for a standard KUKA robot with RSI interface. Experimental results demonstrate the approach.