Optimal trajectory planning for industrial robot along a specified path with payload constraint using trigonometric splines

This paper presents a general methodology for the offline planning of trajectory of a six axis serial robot along a specified path. The objective of trajectory planning is to minimise a cost function when subjected to joint angles, joint velocities, acceleration, jerks, torques and gripping force constraints by considering dynamic of the robot. A trigonometric spline is used to represent the trajectory. This non-linear constrained optimisation problem consists of 6 objectives, 67 constraints and 48 variables. The cost function is a weighted balance of travelling time, actuator torques, singularity avoidance, joint jerks, joint accelerations and gripping force. The optimisation problem is solved by using two methods, namely sequential quadratic programming and genetic algorithm. The proposed methodology is implemented for trajectory planning of six degree of freedom industrial robot and results obtained with two optimisation techniques are compared.