A Hydraulic Energy Efficient Fast Positioning Actuator Exploiting a Hydraulic Spring Concept

For some applications industry is searching for very fast, powerful and energy efficient actuators. Fast positioning actuators can be used, e.g. for a punching process or for operating large and fast hydraulic switching valves. One system which is based on a fast switching actuator is Hoerbigers’s so called “HydroCom” [4], which opens and closes suction valves of huge compressors. In contrast to classical non return valve concepts, these active suction valves provide additional control which can be utilised in several ways. In this paper a novel actuation concept is discussed (see Figure 3), the basic idea of which was already presented by N. Krimbacher [2,3]. Functionally, it features a mass spring oscillator with a latch. The spring is realised by the compressibility of hydraulic fluid in a cavity, the latch by a fast hydraulic switching main valve 1V1. We will report about the examination of the concept by a test rig (see Figure 6). It comprises the main components as shown in Figure 3 and additional valves for replenishing leakage and for energy supply, additional pressure and displacement transducers, and flow rate sensors. Control and data recording is provided by a digital signal processing system. The measurement results affirm the basic functioning and the robustness of the system. The effect of several imperfections of the system, such as leakage, fluid friction, parasitic hydraulic capacities in control lines on the system performance will be discussed. The experimental results will be compared with those of extensive simulation studies. All numerical computations have been carried out with MATLAB/SIMULINK and we have used MAPLEV for deriving analytical results. To control and monitor the test rig a digital signal processor unit (dSPACE) was used.