An Energy Efficient Manipulator Design Approach: Application to a Leg in Swing Phase

Abstract

The importance of energy efficiency of a robotic manipulator is clearly evident when the manipulator has to use on-board power. With miniature machines, this issue is even more important since the size and the weight guides the performance of the design. In this paper, a design methodology is proposed which may allow a robot to follow desired trajectories approximately without actuator inputs. Actuator inputs can be used to further modify the trajectories. The design philosophy has the following key elements: (i) the inertia matrix of the device is suitably altered using mass distribution, (ii) compliant elements are introduced to take away the gravity terms, and (iii) additional springs are used to create certain periodic gait motion. If the generated motion is the desired motion, then no external inputs are needed. Otherwise, actuators can be added to get the desired motion. The energy efficiency with this design philosophy is compared using an example of a two degree-of-freedom leg executing a swing motion.