Research On Hydraulic-feedback Proportional Cartridge Valve For Large Construction Machinery

On behalf of the high technology, high value and high-margin products in construction machinery industry, large construction machinery’s development is greatly supported by the nation. But as the core of large construction machinery, the large flow multi-way valve is still lack of a mature solution. To solve this problem, this study proposes a solution which uses hydraulic-feedback proportional valve (HPV for short) as the core to build the large flow multi-way valve system. The study will focus on the hydraulic-feedback principle and HPV, adopt a combining method of theoretical modeling, simulation and experiment, to uncover steady characteristic, dynamic characteristic and design key points of the valve, then design and optimize the valve according the working condition of construction machinery. On this basis, the study will focus on HPV’s application on building the large flow multi-way valve. The operating mode of the multi-way valve, the unit controller of pressure unit and flow unit will be studied respectively. Finally, the auxiliary function component of the large flow multi-way valve will be studied and designed. The main contents of the study are as follows:Chapter 1 introduces the background and significance of the research, reviews the current development of large flow proportional components and their application in construction machinery, then present the main task of the research.In chapter 2, the design, modeling and qualitative analysis of the HPV are performed. Based on the simplification of the detailed model, the opening amplifying and flow amplifying characteristic of the main stage is revealed, and the restriction relationship between the parameters and steady/dynamic characteristics are studied. With these relationship, the qualitative knowledge of the valve is clear and can be used to design the parameters primarily. By designing the experiment and simulation, the detailed model is verified in steady and dynamic level, can provide a basis for the quantitative analysis, optimization and controller design in sequence.In chapter 3, the quantitative analysis and optimization of the HPV are performed. The quantitative analysis is implemented according the root locus and pressure stiffness of the valve. Revealed that the valve’s characteristics have significant difference with different working point. Analyzed the influence of each structure parameter on the characteristics. According to the construction machinery working environment, an optimization of the valve is performed using an improved adaptive non-dominated sorting genetic algorithm. After the optimization, the bandwidth and pressure stiffness of the valve are significantly enhanced. On the basis of quantitative analysis and optimization results, design guideline of the valve is summed up.Chapter 4 focuses on the application study of HPV in large flow multi-way valve system. The structure of the working link using HPV as the core is designed, and the corresponding work modes according basic working conditions of construction machinery are established. On this basis, design the unit controller for the pressure unit and flow unit. Considering there exist many nonlinear uncertain factors in the controlled object, proposed active disturbance rejection control method based on reduced order extended state observer, which effectively reduces the uncertainty of the system, achieved a stable and robust controller. Considering the problems that the feedback flow rate value can’t be directly acquire in the flow unit and the HPV’s high temperature sensitivity, proposed a flow calculation module which combine flow rate look-up table and temperature compensation coefficient look-up table, achieved a high accurate feedback flow rate.Chapter 5 studies the auxiliary function components of the large flow multi-way valve system. First of all, analyzed the existing proportional flow valve and proportional relief valve based on hydraulic-feedback principle, points out the advantage of hydraulic-feedback principle in anti-interference. Combined with understanding of the hydraulic-feedback principle and study of load control valves, proposed a new hydraulic-feedback load control valve.Chapter 6 summarizes the research work and the innovations, and prospects the future research direction.