Improving the Efficiency of Closed-Chain Robotic Systems by the Trajectory Energy Index

This paper deals with the analysis of the impact of the task location within the robot workspace on its energy consumption. The work presents a performance index, which can be used to estimate the most favorable location of a given motion task, regardless of its complexity. The proposed performance index, called Trajectory Energy Index (TEI), is based on the inertial and kinematic properties of the robot, and its computation provides a guideline for defining the minimum-energy position of a task within the robot workspace. The effectiveness in prediction of the TEI is tested for a simple rest-to-rest motion and for a more complex task, which are executed by a two-degree-of-freedom planar robot with closed-loop kinematics.