U-024

Thermodynamic Treatment of Tug-&-Twist Technology Part 2: Thermodynamic Twistor Design

Authors: Henry M. Paynter and Joseph M. Juarez, Jr.
Affiliation: Henry M. Paynter, Lecturer and Professor Emeritus, MIT and Joseph M. Juarez, Jr., Member, ASME

Abstract
Various jointed-arm or jointed-leg robots called Arthrobots can use the new technical field variously called Rubber-tronics or Pneumo-elastics and designated here as Tug-&-Twist technology. Part 1 of this paper was concerned only with Linear Tension Actuators or Tuggers[1]. A thermodynamic treatment in Part 1 inter-related all existing Tugger designs through an Enthalpy relation H(P,x). Now by establishing an analogous angular Enthalpy H(P,a), one may conceive and construct a new class of Twistors. Part 2 of this paper introduces a transforming transducer, in the form of a fluid-driven torsional device called a Twistor actuator. Analysis for this device is based upon the application of thermodynamic principles and in particular, the use of this Enthalpy function. Volume measurements then show that the thermodynamic treatment leads to an approximate model that predicts output torque taking into account the effect of shell stretch due to pressure.

Joseph Juarez
Joseph.Juarez@CAS.honeywell.com