A Global Optimisation of a Switched Inertance Hydraulic System based on Genetic Algorithm

Abstract

The switched inertance hydraulic system (SIHS) is a novel high-bandwidth and energy-efficient device which can adjust or control flow and pressure by a means that does not rely on throttling the flow and dissipation of power. The three-port SIHS usually consists of a high-speed switching valve, an inertance tube and an accumulator. The device can provide an efficient step-up or stepdown of pressure or flow rate by using a digital control technique. The existing analytical models of an SIHS can effectively predict the flow response, pressure loss, system characteristics and efficiency. The optimal switching frequency and ratio of an SIHS can also be accurately estimated by using the analytical models. However, there is no study related to the 'optimal inertance tube', which considers the optimal tube diameter and length corresponding to different system operating frequencies and ratios. In other words, there is inertia and resistance balance of the system. This paper investigates the global optimisation of an SIHS based on genetic algorithm. The energy cost function is proposed, and the optimal solutions are presented. Numerical simulation models are used to validate the results. It provides a general guidance of the SIHS design and its parameter optimisation.

A Review of Switched Inertance Hydraulic Converter Technology1

“…The group also developed a time-domain cavitation pipeline model of a pressure booster to effectively predict the condition resulting in cavitation [44]. Pan optimised the diameter and length of the inertance tube using a genetic algorithm and found global optimal parameters for designing an SIHC for maximum efficiency [45]. The approach is based on a constant delivery flow rate and could be expanded to a varying loading condition.…”

Investigation of suction flow characteristic in the inertance hydraulic converters for efficiency improvement

“…With the assistance of the theoretical model, 13,14 Pan utilized a genetic algorithm to attain a group of optimized parameters of the inertance pipe. 15 This group of parameters is used for designing an active inertance hydraulic converter driven by an equivalent 2/3 way fast switching valve to achieve maximum efficiency. Normally, the suction flow characteristic induced by fluid inertance is assumed as a time-invariant or well-performing contribution term for system efficiency.…”