Title: Improvement of energy efficiency of servo pneumatic cylinders by optimising velocity profiles

Authors: Jia Ke, Jihong Wang

Addresses: Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ, UK. ' Department of Electrical Engineering and Electronics, University of Liverpool, Brownlow Hill, Liverpool L69 3GJ, UK

Abstract: The authors| previous simulation study indicated that different quantities of compressed air will be consumed by a servo-controlled pneumatic cylinder with different velocity profiles under the same control strategy. This motivated the authors to investigate if there is the most energy-efficient profile, which leads the system to use the least amount of compressed air. To avoid solving a set of complicated non-linear differential equations, the non-linear system is linearised through input/output state feedback, then energy efficient optimal control theory is applied to the linearised system. An optimal control strategy is derived with respect to the transformed states of the linear system model. The solution of the state trajectory results in an energy efficient profile. Simulation study has been conducted using both the linearised and original non-linear system models and the simulation results indicated that the profiles obtained in this paper are more energy efficient.

Keywords: pneumatic actuators; optimal control; nonlinear systems; energy efficiency; servo pneumatic cylinders; velocity profiles; compressed air.

DOI: 10.1504/IJMIC.2006.012618

International Journal of Modelling, Identification and Control, 2006 Vol.1 No.4, pp.301 - 307

Published online: 27 Feb 2007 *

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