Accession Number : ADA198131

Title :   The Effect of Transmission Design on Force-Controlled Manipulator Performance.

Descriptive Note : Technical rept.,

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE ARTIFICIAL INTELLIGENCE LAB

Personal Author(s) : Towsend, William

PDF Url : ADA198131

Report Date : Apr 1988

Pagination or Media Count : 109

Abstract : The concept of manipulator force control and a corresponding emphasis on the choice of appropriate servo implementation have been developing for many years. However, the selection of appropriate mechanical hardware may ultimately be the limiting performance factor in force control. Mechanism properties, such as contact compliance, actuator-to-joint compliance, torque ripple, and highly nonlinear dry friction, affect, and often degrade, manipulator performance in force-controlled systems. This thesis describes a set of requisites for good performance, analyzes the effects of transmission-mechanism properties on force-controlled manipulators, and recommends mechanical-design strategies to improve performance. While much of the analysis applies to a broad class of transmissions, a special control-volume analysis quantities a limit on the power efficiency of tension-element drives. A single-degree-of-freedom transmission testbed was constructed and used to confirm the predicted effect of Coulomb friction on robustness; design of a cable-driven, four-degree-of-freedom, whole-arm manipulator illustrates the recommended mechanical-design strategies. (kr)

Descriptors :   *MANIPULATORS, *SERVOMECHANISMS, *SYSTEMS ENGINEERING, CONTROL, DEGREES OF FREEDOM, EFFICIENCY, FRICTION, LIMITATIONS, MECHANICAL PROPERTIES, POWER, RIPPLES, TEST BEDS, TORQUE, TRANSMITTANCE

Subject Categories : Cybernetics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE