Performance Analysis And Experimental Research On 2D Digital Valve Of Adjustable Area Gradient

Hydraulic valve is an essential functional unit in the hydraulic system. The optimization and upgrading of hydraulic system need to rely on the hydraulic valve to improve its performance. Nowadays, hydraulic valve have been developed fast in many aspects, such as performance improvement, energy consumption, manufacturing process technology, intellig -ent technology and so on. With the combination of hydraulic system, IT, electronics and network technology, there is a trend that hydraulic valve should be digital.The new strategies that area gradient of orifice can be adjusted and 2D flow control are proposed after reviewing research achievement of domestic and international digital valves. Then a new structure of 2D digital valve of variable-area gradient is designed, which is driven by two stepper motors to control spool two-dimensional movement that can adjust the hydraulic system flow. The simulation of the internal flow field is processed with software Fluent and the pressure distribution of the internal flow field in 2D digital valve is gained. Then the hydraulic clamping caused by radial force is studied and the spool friction compensation with dither signal is proposed. The static and dynamic characteristics of the 2D digital valve of variable-area gradient are investigated by utilizing the simulation software Matlab. Building the experiment platform on this basis, to verify the compensation effects of dither signal and test the performance of the digital valve. The experiment result shows that the friction of system is smoothed with the effect of dither signal, the hysteresis nonlinearity caused by friction is eliminated and the performance of valve is improved. The main tasks of this dissertation are listed as followed:In chapter 1, the history and trend of electro-hydraulic control technology is summed up, then current research situation of domestic and international digital valves are reviewed. At last, the meaning, purpose and the main tasks of this thesis are given.In chapter 2, the structure and working principle of 2D digital valve are introduced first. Then the way of two-dimensional flow control is proposed. And main mechanical components are designed in detail.In chapter 3, the hydraulic clamping caused by radial force was studied and the simulation of the internal flow field is processed with software Fluent. Then the pressure distribution of the internal flow field in 2D digital valve is gained. By analysis of the reason of the radial force, the spool friction compensation with dither signal is carried out to avoid the hydraulic clamping.In chapter 4, the mathematical model of 2D digital valve of variable-area gradient is established. The static and dynamic characteristics are analyzed and researched based on the environment of the software Matlab.In chapter 5, a experiment system is built to analyze the compensation effects of dither signal and the static and dynamic characteristics.In chapter 6, the summarization of this dissertation and the prospect of this research are given.