Time-optimal and smooth joint path generation for robot manipulators

In this paper a new approach to smooth and time-optimal unconstrained trajectory planning (point to point) for robot manipulators is presented. The optimization process is divided into two phases. The first is to obtain smooth joint trajectories. The second is to scale the time intervals for the time-optimal joint trajectories by contracting the travelling time so that the resulting velocities, accelerations and jerks at some knots or between some knots of each joint trajectory are maximal with their limitations. The resulting joint trajectories are smooth, time-optimal and have a minimum-vibration with optimal velocity profile, which is suitable for motion of robot manipulators. The results are illustrated by simulations and experiments. The results presented here are suitable for the unconstrained joint trajectory planning of general robot manipulators although the illustrative example is for an RTX SCARA type robot.