Award Date

12-1-2014

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical Engineering

First Committee Member

David V. Lee

Second Committee Member

Brendan O'Toole

Third Committee Member

Mohamed Trabia

Fourth Committee Member

Hui Zhao

Fifth Committee Member

Edward Neumann

Number of Pages

103

Abstract

Actuators determine the performance of robotic systems at the most intimate of levels. As a result, much work has been done to assess the performance of different actuator systems. However, biomimetics has not previously been utilized as a pretext for tuning a series elastic actuator system with the purpose of designing an empirical testing platform. Thus, an artificial muscle tendon system has been developed in order to assess the performance of two distinct actuator types: (1) direct current electromagnetic motors and (2) ultrasonic rotary piezoelectric motors. Because the design of the system takes advantage of biomimetic operating principles such as co-contraction in an agonist-antagonist configuration, it exists as an ideal system for testing different actuators for implicit performance attributes that may or may not come closer to the physiological performance of biological muscle.

In order to assess the respective performances of the two actuator types, error and system efficiency were both measured simultaneously in an attempt to characterize the fidelity and efficacy of the force-feedback control system. Although both motor types were shown to perform competitively by torque error, the electromagnetic motors outperformed in terms of efficiency. It is ultimately concluded that either actuator type may perform more impressively than the other when operating under the appropriate context of application. Specifically, it remains the interpretation of this study that piezoelectric motors require a stiffer elasticity as well as an extremely fast controller frequency in order to fully take advantage of its ultra-fast response time characteristic for torque control.

Keywords

Actuators; Artificial muscle; Biomimetics; Co-contraction; Elasticity; Feedback control systems; Piezoelectric; Piezoelectric devices; Robotics; Series-elastic; Ultrasonic motors

Disciplines

Artificial Intelligence and Robotics | Biomechanical Engineering | Biomedical Devices and Instrumentation | Mechanical Engineering | Robotics

Language

English