Trajectory modeling of robot manipulators in the presence of obstacles

This paper presents two different strategies for the problem of the optimal trajectory planning of robot manipulators in the presence of fixed obstacl es. The first strategy is related to the situation where the trajectory mus t pass through a given number of points. The second strategy corresponds to the case where only the initial and final points are given. The optimal tr aveling time and the minimum mechanical energy of the actuators are conside red together to build a multiobjective function. The trajectories are defin ed using spline functions and are obtained through offline computation for online operation. Sequential unconstrained minimization techniques (SUMT) h ave been used for the optimization. The obstacles are considered as three-d imensional objects sharing the same workspace performed by the robot. The o bstacle avoidance is expressed in terms of the distances between potentiall y colliding parts. Simulation results are presented and show the efficiency of the general methodology used in this paper.