The Research Of Direct Drive Proportional Cartridge Valve

The electro-hydraulic proportional/servo valve is widely used in the field of electro-hydraulic control.Proportional/servo cartridge valves basically have two or three grades of structures with a high-performance servo valve as its pilot stage.The structure of such valves is more complicated and the cost is more High,and also high requirements on oil cleanliness.In recent years,with the rapid development of permanent magnet synchronous motor servo control system,its application is also more and more widely.In the field of electro-hydraulic control,AC servo motor is considered as a good electro-mechanical converter because of its advantages such as closed-loop control,high torque with low inertia and lower cost.Based on the previous research results,this paper developed a proportional cartridge valve with AC servo motor drive the spool of the valve directly,the following is the summary of the main contents of this article:The first chapter:through literature survey,the proportional/servo cartridge valve,direct-drive electro-hydraulic servo valve and servo motor direct drive-valve are analyzed.The main contents of this paper are pointed out,and paving the way for the following chapters.The second chapter:complete the design of direct-drive proportional cartridge valve.Determine the overall design of the valve,all parts of the valve have been carefully designed.Mainly include:determine the steady state hydraulic power of the spool through the theoretical research and simulation analysis;check the selection of servo motor and ball screw.The third chapter:established the mathematical model of direct-drive proportional cartridge valve.The servo motor and screw drive system are modeled in detail,their inherent principle and structure are analyzed,the differential equation is established,and then the mathematical model is established in the form of transfer function through the Laplace transform to prepare for the follow-up study.The fourth chapter:analyzed and designed the current loop,velocity loop and position loop of the controller.Then the model is reasonably simplified and the controller model is obtained through parameter identification.Then,the theoretical analysis and simulation research on the ratio optimization of direct-drive proportional cartridge valve were carried out.The fifth chapter:the no-load and load test of direct-drive proportional cartridge valve were carried out.Found the fact that the present control algorithm has load-sensitive issues through the test.The test results also show that the driving force provided by the servo motor is greater than the maximum axial load force exerted on the spool under the research conditions in this paper,which verifies the feasibility and rationality of the valve design.The sixth chapter:summarized the main contents of this paper,and analyzed the shortcomings of the current research and the prospect of follow-up research.