Thermodynamic treatment of tug-&-twist technology. 2. Thermodynamic twistor design

Abstract

For pt. 1 see Japan-USA Symposium on Flexible Automation, Boston, MA, USA, p.111-17. 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. By establishing an angular enthalpy analogous to the enthalpy developed in the first part for linear tension actuators (tuggers), a new class of twisters is conceived and constructed. A transforming transducer, in the form of a fluid-driven torsional device called a twister actuator, is used. 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.