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Title: Parallel-coupled micro-macro actuators

Abstract

This paper presents a new actuator system consisting of a micro-actuator and a macro-actuator coupled in parallel via a compliant transmission. The system is called the parallel-coupled micro-macro actuator, or PaCMMA. In this system, the micro-actuator is capable of high-bandwidth force control owing to its low mass and direct-drive connection to the output shaft. The compliant transmission of the macro-actuator reduces the impedance (stiffness) at the output shaft, and increases the dynamic range of force. Performance improvement over single-actuator systems was expected in force control, impedance control, force distortion, and transient impact force reduction. Several theoretical performance limits are derived from the saturation limits of the system. A control law is presented. A prototype test bed was built and an experimental comparison was performed between this actuator concept and two single-actuator systems. A set of quantitative measures is proposed and the actuator system is evaluated against them with the following results: force bandwidth of 56 Hz, torque dynamic range of 800:1, peak torque of 1,040 mNm, and minimum torque of 1.3 mNm. Peak impact force, force distortion, and back-driven impedance of the PaCMMA system are shown to be better than either of the single-actuator configurations considered.

Authors:
;  [1]
  1. MIT Artificial Intelligence Lab., Cambridge, MA (United States)
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
665351
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Robotics Research; Journal Volume: 17; Journal Issue: 7; Other Information: PBD: Jul 1998
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; ACTUATORS; ROBOTS; CONTROL THEORY; COMPARATIVE EVALUATIONS; MOTION; PERFORMANCE

Citation Formats

Morrell, J.B., and Salisbury, J.K. Parallel-coupled micro-macro actuators. United States: N. p., 1998. Web. doi:10.1177/027836499801700707.
Morrell, J.B., & Salisbury, J.K. Parallel-coupled micro-macro actuators. United States. doi:10.1177/027836499801700707.
Morrell, J.B., and Salisbury, J.K. Wed . "Parallel-coupled micro-macro actuators". United States. doi:10.1177/027836499801700707.
@article{osti_665351,
title = {Parallel-coupled micro-macro actuators},
author = {Morrell, J.B. and Salisbury, J.K.},
abstractNote = {This paper presents a new actuator system consisting of a micro-actuator and a macro-actuator coupled in parallel via a compliant transmission. The system is called the parallel-coupled micro-macro actuator, or PaCMMA. In this system, the micro-actuator is capable of high-bandwidth force control owing to its low mass and direct-drive connection to the output shaft. The compliant transmission of the macro-actuator reduces the impedance (stiffness) at the output shaft, and increases the dynamic range of force. Performance improvement over single-actuator systems was expected in force control, impedance control, force distortion, and transient impact force reduction. Several theoretical performance limits are derived from the saturation limits of the system. A control law is presented. A prototype test bed was built and an experimental comparison was performed between this actuator concept and two single-actuator systems. A set of quantitative measures is proposed and the actuator system is evaluated against them with the following results: force bandwidth of 56 Hz, torque dynamic range of 800:1, peak torque of 1,040 mNm, and minimum torque of 1.3 mNm. Peak impact force, force distortion, and back-driven impedance of the PaCMMA system are shown to be better than either of the single-actuator configurations considered.},
doi = {10.1177/027836499801700707},
journal = {International Journal of Robotics Research},
number = 7,
volume = 17,
place = {United States},
year = {Wed Jul 01 00:00:00 EDT 1998},
month = {Wed Jul 01 00:00:00 EDT 1998}
}
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