A switched inertance hydraulic system uses a fast switching valve to control flow or pressure and is potentially very efficient as it does not rely on dissipation of power by throttling. This article studies its performance using an analytical method which efficiently describes the system in the time domain and frequency domain. A lumped parameter model and a distributed parameter model have been used for investigation using different parameters and conditions. The analytical models have been validated in experiments and the results on a prototype device show a very promising performance. The proposed analytical models are effective for understanding, analysing and optimizing the characteristics and performance of a switched inertance hydraulic system.

The transmission line method is a very efficient technique for dynamic modelling of flow in pipelines, and uses delay elements to represent wave propagation. In this paper, an existing transmission line method is investigated and shown to have some deficiencies. Some adjustments are proposed to avoid these deficiencies and enhance the transient and steady-state accuracy. Very good agreement is obtained between this adjusted transmission line method and an analytical model. The method has been implemented in simulations of a number of highly dynamic systems, and has been found to be robust and reliable.

The transmission line method is a very efficient method for dynamic modelling of flow in pipelines and uses delay elements to represent wave propagation. In this article, an existing transmission line method model is investigated and shown to have some deficiencies. An alternative technique is introduced to enhance the transient and steady-state accuracy. Extremely good agreement is obtained between this new transmission line method and an analytical model. The model has been implemented in simulation of a number of highly dynamic systems and has been found to be robust and reliable.

This paper reports on theoretical and experimental investigations of a switched inertance device, which is designed to control the flow and pressure of a hydraulic supply. The device basically consists of a switching element, an inductance and a capacitance. It is able to boost the pressure or flow with a corresponding drop in flow or pressure respectively, analogous to a hydraulic transformer. In this paper, an enhanced analytical distributed parameter model in the frequency domain, which includes the effect of switching transition, non-linearity and leakage of the valve, is proposed and validated by simulation and experiments. A flow booster test rig is studied as a typical system. Simulated and experimental results show good performance, and accurate estimation of system pressure and dynamic flowrate can be obtained by using the enhanced analytical model. The model is very effective for understanding, analysing and optimising the characteristics and performance of a switched inertance device. It also can be used to aid in the design of a switched inertance hydraulic system.

This paper reports on experimental investigations of a switched inertance hydraulic system (SIHS), which is designed to control the flow and pressure of a hydraulic supply. The switched system basically consists of a switching element, an inductance (inertance), and a capacitance. Two basic modes, a flow booster and a pressure booster, can be configured in a three-port SIHS. It is capable of boosting the pressure or flow with a corresponding drop in flow or pressure, respectively. This technique makes use of the inherent reactive behavior of hydraulic components. A high-speed rotary valve is used to provide sufficiently high switching frequency and to minimize the pressure and flow loss at the valve orifice, and a small diameter tube is used to provide an inductive effect. In this paper, a flow booster is introduced as the switched system for investigation. The measured steady-state and dynamic characteristics of the rotary valve are presented, and the dynamics characteristics of the flow booster are investigated in terms of pressure loss, flow loss, and system efficiency. The speed of sound is measured by analysis of the measured dynamic pressures in the inertance tube. A detailed analytical model of an SIHS is applied to analyze the experimental results. Experimental results on a flow booster rig show a very promising performance for the SIHS.