Real-time accurate hand path tracking and joint trajectory planning for industrial robots (I)

Abstract

Previously, researchers raised the accuracy for a robot’s hand to track a specified path in Cartesian space mainly through increasing the number of knots on the path and the number of the path’s segments, which results in the heavier online computational burden for the robot controller. Aiming at overcoming this drawback, the authors propose a new kind of real-time accurate hand path tracking and joint trajectory planning method. Through selecting some extra knots on the specified hand path by a certain rule and introducing a sinusoidal function to the joint displacement equation of each segment, this method can greatly raise the path tracking accuracy of robot’s hand and does not change the number of the path’s segments. It also does not increase markedly the computational burden of robot controller. The result of simulation indicates that this method is very effective, and has important value in increasing the application of industrial robots.

Keywords

industrial robots / real-time / accurate / hand path tracking / joint trajectory planning / extra knot

References

[1] TonduB, BazazA. The three-cubic method: an optimal online robot joint trajectory generator under velocity, acceleration, and wandering constraints[J]. The International Journal of Robotics Research, 1999, 18(9): 893-901

[2] GalickiM. The planning of robotic optimal motions in the presence of obstacles[J]. The International Journal of Robotics Research, 1998, 17(3): 248-259

[3] TanGuan-zheng, LiTan. Optimum motion planning for CS-I industrial robot with two manipulators[A]. Proceedings of IEEE 1997 International Conference on Intelligent Processing Systems [C], 1997, Beijing, Computer Department of Tsinghua University: 1287-1291

[4] LinC S, ChangP R, LuhJ Y S. Formulation and optimization of cubic polynomial joint trajectories for mechanical manipulators[J]. IEEE Transactions on Automatic Control, 1983, 28(12): 1066-1078

[5] ChandS, Dotyk L. On-line polynomial trajectories for robot manipulators [J]. The International Journal of Robotics Research, 1985, 4(2): 38-48

[6] BobowJ E, DubowskyS, GibsonJ S. Time-optimal control of robotic manipulators along specified paths[J]. The International Journal of Robotics Research, 1985, 4(3): 3-17

[7] AkenL V, BrusselH V. On-line robot trajectory control in joint coordinates by means of imposed acceleration profiles [J]. Robotica, 1988, 6(2): 185-195

[8] LuhJ Y S, LinC S. Approximate joint trajectories for control of industrial robots along Cartesian path[J]. IEEE Transactions on Systems, Man, and Cybernetics, 1984, 14(3): 444-450