Papers by Author: Xu Dong Pan

Abstract: Electro-hydraulic servo valve is the key component of an electro-hydraulic servo control system, and double nozzle flapper valve is the main type of electro-hydraulic servo valve. Nozzles are the important part of a double nozzle flapper valve, the pairing quality is directly related to the performance of the servo valve .Servo valve is of symmetrical structure, and the use of nozzles is also in pairs. The process of nozzles matched in pairs is called pairing process. Because the orifice diameter of the nozzle is only about 0.2 to 0.3 mm, it is difficult to pair with the method of direct measurements. Besides, as a kind of hydraulic components, nozzles are usually paired by flow rate measured under differential pressure. Two nozzles will be matched to a pair if their pressure-flow rate characteristic curve is within the allowed tolerance. To ensure the success rate of pairing, it usually needs a large number of machined nozzles to be sifted. According to the principle of clustering analysis, we propose a new paring algorithm which can match nozzles efficiently and automatically.

Abstract: Electrical energy directly converted into mechanical energy of linear motion by linear force motor, greatly enhancedthe rapid response ability and control precision of the feed system. The product quality of linear force motor can be effectively improved by design a performance test system of linear force motor. The paper designed a performance test system of linear force motor based on the Labview virtual instrument platform, and test project of linear force motor has been planned, the test method, the structure of the test device, power drive module, step motor load part, data acquisition and the software system all have been completed. The test system realized automatic and manual two different kinds of test methods, data acquisition and management and processing function and the good human-machine interface, the linear force motor dynamic and static parameter, including input current, output force and output displacement and the relationships between them have been tested.

Abstract: The disturbance torque which is caused by the interference of the motor position has observably impact on accuracy of the loading system. According to unstable loading channel and disturbance torque, this paper use a complex control algorithm of differential forward PID control and feed-forward compensation. At the end of this paper, the simulation analysis results show that the feed-forward compensation can observably eliminate the influence of the disturbance torque, and improve the accuracy of the loading system.

Abstract: In this paper, a mathematical model of the loading system is established. The characteristics of the loading channel and disturbance channel are analyzed through this mathematical model. Analysis results show that the loading channel is unstable and disturbance torque leading the input command. It directly impact on the output torque, serious affect the systems loading precision. Characteristics of the loading system are analyzed, and the results show that stiffnesss effect on the loading system is twofold, should be considered at the same time. Reduce the system's moment of inertia is good for the characteristics of the loading system.

Abstract: As a pressure regulating component, pneumatic control valve has been widely used in control system. The stability of its performance not only concerns the control precision, but also has direct influence on the systems normal operation. Thus, a test on the valves characteristics before putting into use is rather important. According to analysis of testing requirements, this paper determined the overall program of this pneumatic measurement system, designed the gas-circuit, provided specialized software for measurement, and developed an automatic test system. The experimental data shows the system is with high precision and can satisfy the needs of valve test well.

Abstract: During the processing of the servo valve spool machining, the overlap of valve spool's each edge should take zero grinding. The grinding processes including spool overlap test and grinding. In this paper, the authors used a new test method, which simulates working condition of servo valve. Hydraulic cylinder is used as the load of servo valve in this test method, and the hydraulic cylinder is in no-load operation. This test method realized the automatic switch of test valve, and it determined the amount of grinding through complete measuring four edges overlap values, furthermore, it realized measuring the total amount of overlap, thus reflect the flow characteristics of a valve. This is a new automatic method for measuring servo valve overlap.

Abstract: This paper describes a distributed control system, which is based on PIC microcomputers. The hardware of this system included industrial personal computer, RS232-RS485 converter, control circuit, motor driver and so on. The PIC microcomputers on control circuits are used as basic control chips. The software of system is developed by Visual C++, communicates through the RS485 bus. The human-machine interface is developed, which is intuitive and friendly. Test result shows that the control system is effective and reliable.

Abstract: This paper describes machining trajectory generation and simulation of miniature integral impeller. Taking into account the closed and miniature of integral impeller, and low stiffness of the micro-milling tool, in order to avoid interference in the processing, through reasonably division of the impeller blade surface, generate the miniature integral impeller machining trajectory. Then impeller machining NC code is generated, and is simulated in Vericut software. Simulation result shows that the machining programs generated in this paper are effective, and the simulation machined workpiece surface is relatively smooth.

Abstract: The curve intensity of deddendum plays a significant role in gear strength design. Due to the complicated shape of gears, traditional method utilizes the cantilever beam model adds the concentrated load at a fixed point and then revises it by coordinating with different factors so as to calculate the gears the curve intensity of deddendum. In this paper, based on evolute formulas, a methodology about finite element analysis was used for establishing the accurate tooth profile model of the evolute cylinder gear. The moving load was added by programming and the regularity that the amplitude of load changes with the position of the point of application in a tooth meshing cycle was determined. Based on proposed model, this paper provides the variation regularity of the magnitude of the stress of deddendum by simulation.

Abstract: This paper studies a load simulation system based on permanent magnet synchronous motor. Vector control principle of the loading motors vector control technology is analyzed, and using the strategy that direct-axis component of the stator current is zero, the mathematical model of load control is established. To analysis the control characteristics and lay a foundation for the control algorithm of the system, the control channel is divided into two channels, namely the forward load channel and disturbance channel, whose characteristics are analyzed, too. The torsional stiffness of the connecting link has an effect on the dynamics characteristics of the system. Therefore, the system dynamic characteristics under different torsional stiffness of forward load channel and disturbance channel are analyzed in the paper.