Analysis of energy characteristic and working performance of novel controllable hydraulic accumulator with simulation and experimental methods

Abstract Hydraulic accumulator is widely applied in various transmission systems for improving system performance such as installed power reduction, pressure variation absorption and energy efficiency improvement. However, the traditional hydraulic accumulator suffers from two major drawbacks: 1) limited energy storage capacity 2) passively matched system working condition with fixed working mode. To overcome these problems, this study proposed a novel hydraulic accumulator with larger energy storage capacity and high controllability, which mainly comprises a piston accumulator, a gas regulator, and several control valves. First, this paper introduced the working principle of the controllable accumulator and calculated the energy-storage indices. Then, the mathematic model of the controllable accumulator, comprising mechanical, hydraulic and pneumatic model, was established by using appropriate theory. Based on the mathematic model, the control principle of four-working modes and the co-simulation model of the controllable accumulator were presented. Finally, a test rig of the accumulator was carried out to verify its actual function. The research results show that 1) Compared to traditional accumulator, the energy-storage capacity of this novel accumulator can be improved by nearly 1.5 times in this case, which is increased linearly with the volume rate. The energy storage capacity can be further increased with the increment of volume rate, which breaks out the limitation of the traditional accumulator. 2) Using Fuzzy PID algorithm, the precharge pressure, output flow, output pressure and output power in simulation and experiment results can be controlled to match the target working performance indices with high precision. Hence, this novel controllable accumulator can be taken as the high precision hydraulic component and applied in these high-end devices, which shows great superiority when compared to the traditional one. Based on above disadvantages, this novel accumulator is especially suitable for these hydraulic transmission systems with demanded requirements of achieving high accuracy, large power and fast response simultaneously.