Studies On Variable Parameters Hydraulic Accumulator

Hydraulic accumulator is the most direct and effective components to store energy, absorb shock and reduce vibration in hydraulic control system. It plays the key role to reduce energy consumption, reduce noise, extend the life of components and systems, and improve system performance. The conventional accumulator have the mistakes that its basic theory is not detailed, structure is too single, and working parameters can not be changed, which restricts its using results. Therefore, aimed to the status quo, the follow research work is completed in this article:Firstly, study on the basic theory section is to be finished. Aimed at two major shortcomings of traditional accumulator, design thought about variable parameters hydraulic accumulator prototype and its computer control system is proposed, its working principle is determined, and concrete engineering design is finished. Then, follow in-depth theoretical research is carried out.(1)Combined with single degree of freedom system vibration theory, the hydraulic system vibration mathematical model its vibration mechanism are studied, and the impact of damping, mass block and the spring coefficient upon the hydraulic system vibration is analyzed.(2)Based on the theory that the change of gas parameters may have great influence on the performance of accumulator, gas parameters on-line adjusting device that is driven by valve-controlled asymmetric cylinder is designed, its state-space model based on gas load characteristics is established by the mechanism analytical method.(3) Based on the research results about MRFD (magneto-rheological fluid damper), MRF (magneto-rheological fluid) working chamber fitted to the prototype is designed. On the base of the mechanical mechanism of MRF and the computation theory about damping force, the mathematical model of MRF working chamber is finished.(4)Based on the study on the damping effect of accumulator oil port, semi-active damping regulatory adjustment derived by servo motor is designed. Then, the mathematical models of servo motor, axial rotation part and the linear motion part are established separately, and the overall state space mathematical model of semi-active damping regulatory adjustment is established by furthermore study.(5)Based on the analysis the working principle, mathematical model and performance of traditional piston-type accumulator and bladder-type accumulator, the structure advantage of the two kinds of accumulator is integrated, variable parameters accumulator unit is designed with air cavity, MRF cavity and the oil cavity. Its mechanical model is established and analyzed, then its state space mathematical model is established too.Secondly, simulation work is to be finished. Based on the various parts of mathematical models, the controllability and observe ability of them is analyzed, and the dynamic performance of every parts is studied by simulating. For gas parameters on-line adjusting device, the influence upon the dynamic performance of valve-controlled asymmetric cylinder is studied when the initial gas equivalent, the initial inflated size and the location of cylinder are changed. For semi-active damping regulatory adjustment derived by servo motor, its dynamic performance is mainly researched by simulating. For variable parameters accumulator unit, the influence upon its dynamic performance is studied when the initial gas equivalent, the initial inflated size and the oil inlet area is changed by simulating. Then, aimed to the closed-loop control system for valve-controlled asymmetric cylinder and semi-active damping regulatory adjustment separately, the system dynamic performance is studied when the PID control strategy and fuzzy PID control strategy are used. The simulation plays the auxiliary function for the design of prototype, at the same time it provides some guidance and help for research.Thirdly, the prototype and computer system are to be built. Combined with the study results of basic theory and simulation, the prototype is designed and made. Two stages computer hardware systems mainly controlled by"PC+DSP"is designed and established. In the LabVIEW (Laboratory Virtual Instrument Engineering) and CCS3.3 (Code Computer Studio IDE) programming environment, the upper and lower computer software control procedures are prepared.Finally, experiments are to be finished. Combined the results of theoretical study and simulation, many experiments are finished against the prototype. During the experiments, the prototype is installed into two-channel load-simulation system, and working conditions of the system is changed real-timely. The dynamic response capabilities of valve-controlled asymmetric cylinder and semi-active damping regulatory adjustment are studied by experiments. At the same time, the, the influence upon dynamic performance of variable parameters accumulator unit is studied when the gas parameters, the oil inlet structure parameters and MRF electromagnetic coil current. Which will verify whether the prototype structure design is proper, and the the mathematical models is correct.The research results will build the study base that the variable parameters accumulator may be controlled by adaptive control.