Int. J. Automation and Control, Vol. 6, No. 1, 2012 39 Copyright © 2012 Inderscience Enterprises Ltd. Optimal trajectory planning for industrial robot along a specified path with payload constraint using trigonometric splines Shital S. Chiddarwar* Department of Mechanical Engineering, Shri Ramdeobaba Kamla Nehru Engineering College, Ramdeo Tekadi, Katol Road, Nagpur 440013, Maharashtra, India E-mail: s.chiddarwar@gmail.com *Corresponding author N. Ramesh Babu Manufacturing Engineering Section, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, Tamil Nadu, India E-mail: nrbabu@iitm.ac.in Abstract: 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. Keywords: optimal trajectory planning; SQP; sequential quadratic programming; trigonometric spline; multi-objective optimisation; GA; genetic algorithm. Reference to this paper should be made as follows: Chiddarwar, S.S. and Babu, N.R. (2012) ‘Optimal trajectory planning for industrial robot along a specified path with payload constraint using trigonometric splines’, Int. J. Automation and Control, Vol. 6, No. 1, pp.39–65. Biographical notes: Shital S. Chiddarwar is a Mechanical Engineering Graduate from VNIT Nagpur. She completed her PhD from the Indian Institute of Technology Madras, Chennai, India. Her areas of interest are multiple robot motion planning, control of mobile manipulators, development of robot teaching techniques and soft computing methods for optimisation. She is