Minimum cycle time location of a task in the workspace of a robot arm

Abstract

A novel approach to optimal placement of a prescribed task in the workspace of a robotic manipulator is presented. The cycle time for a specified set of minimum-time straight-line movements is used as the optimality criterion. These movements are point-to-point, and the arm starts from standstill at the initial point and stops at the final point. Local velocity patterns for minimum-time straight-line movements in the regions of interest are obtained. This information is used to choose a good initial location for the task. A step-and-test method is then used to find the minimum-cycle-time location for the considered task. Results of application of this method to a manipulator with two revolute joints are presented. The results indicate that proper positioning of the task in the workspace can considerably reduce the cycle time and therefore increase productivity.<>