Improving the Efficiency of Time-Optimal Path-Following Algorithms

This communication presents a new method which significantly improves the computational efficiency of time-optimal path-following planning algorithms for robot manipulators with limited actuator torques. Characteristic switching points are identified and characterized analytically as functions of the single parameter defining the position along the path. Limit curves are then constructed from the characteristic switching points, in contrast with the so-called maximum velocity curve approach of existing methods. A new efficient algorithm is proposed which exploits the characteristics of the newly defined concepts. The algorithm can also account for viscous friction effects and smooth state-dependent actuator bounds. A numerical example, while showing the consistence of the algorithm with the existing techniques, demonstrates its potential for increasing computational efficiency by several orders of magnitude.