Design of a Controlled Spatial Curve Trajectory for Robot Manipulations

Abstract

For integrating different constraints from robot’s tasks, such as geometry, kinematics, and dynamics, with trajectory planning and robot motion control, a two-layer robot trajectory planning structure is proposed. The structure decomposes the trajectory planning problem into path geometry planning and motion speed planning. By separating speed planning from path geometry planning, two different problems can be solved. The first problem is to incorporate geometric changes of a robot task into both translational and orientational path plannings. By solving it, various spatial curve paths can be planned and the difficulty of predicting rotational motions in the Cartesian space can be removed. The second problem is to incorporate motion constraints into the trajectory planning, such as the constraint of maintaining a desired constant robot speed along any planned geometric path. Through the proposed structure, different robot motion requirements along various spatial curves can be controlled by different speed control functions. To demonstrate the proposed scheme, examples are given.