Maneuver based design of a passive-assist device for augmenting linear motion drives

Abstract

A methodology for designing a parallel, passiveassist device to augment an active system using energy minimization based on a known maneuver is presented. Implementation of the passive-assist device can result in an improvement in system performance with respect to efficiency, reliability, and/or utility. In previous work we demonstrated this concept experimentally on a single link robot arm augmented with a torsional spring. Here we show that the concept can effectively be applied to other machines performing known periodic motions by simulating a reciprocating single axis machining table and an X-Y table performing a slot milling operation. The addition of optimized springs results in a decrease in energy consumption of 79% and significantly outperforms springs based on a state-of-the-art force-displacement curvefitting approach. Finally, we show that a significant increase in performance can be realized if the maneuver is redesigned considering that a passive-assist device will be added to the system.

Mechanical design and energy storage efficiency research of a variable stiffness elastic actuator

“…To increase the EOES of the robots, a variable stiffness elastic actuator (EA), realized by the variable length of linkage, has been designed by Visser and his team, 1,2 and the design theory of their mechanism has been verified with simulation and experiment. Brown has presented a passiveassist device, [3][4][5] which consisted of actuator and elastic element, and introduced the optimization method of the spring and the results of the experiments to verify that EOES of the parallel elastic actuator (PEA) is higher than other mechanisms. Mazumdar has designed a robotic joint with PEA, 6 which increased the EOES, according to the motion data of the walking robotic joint.…”