This thesis describes a novel, general methodology for designing a Passive Assist Device (PAD) (e.g., spring) to augment an actuated system using optimization based on a known maneuver of the active system. Implementation of the PAD can result in an improvement in system performance with respect to efficiency, reliability, and/or safety. The methodology is experimentally demonstrated with a parallel, torsional spring designed to minimize energy consumption of a prototypical, single link unmanned ground vehicle (UGV) robot arm. The method is extended to series systems as well as dual PAD systems that contain both a series and a parallel component. We show that the proposed method is not limited to robot manipulator joints, can be applied to multi-DOF systems, and can be used to design PADs that are robust against variation in the maneuver. Furthermore, for certain situations a significant increase in performance can be realized if the maneuver is redesigned considering that a PAD will be added to the system. The addition of properly designed energy minimizing springs can lead to a decrease in energy consumption, as shown in various engineering examples, by as much as 60–80% while also improving reliability and/or safety.
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