The Digital Design Of Control System Of Secondary Spring Electric Locomotive Load Leveling Test-bed

With development of the railway in the direction of high speed and heavy haul, uniform load distribution of locomotive wheels and axles has been an essential role in locomotive’s hauling and braking performance. Studies show that uniform load distribution of primary and secondary springs has made a decisive effect on the distribution of locomotive load. According to engineering application the requirements of our country’s large power locomotive two supporting leveling and load test, the paper has studied control algorithm of electro-hydraulic position servo system based on the technology of computer control, completed control system design of the testing equipment.The first part of this thesis has established the system theory model on the basis of the principle of electro hydraulic servo system. According to the requirement of the test, it has determined the hydraulic power mechanism parameters, and used Simulink to analyze electro-hydraulic servo system’s dynamic and static performance. In order to improve the static and dynamic performance of the system, a PID parameters self-tuning control method is proposed based on support vector machine (SVM-PID). This method uses that support vector machines can approximate any nonlinear function characteristics to establish the system’off-line SVM model, then takes instantaneous linear processing of the model output the optimization parameters of PID controller under the minimum variance. Simulation results show that using the SVM-PID method in designing the digital controller can meet the control requirements of test system, and effectively reduce the noise interference, optimize the dynamic performance of the system, improve the efficiency of system parameter tuning and adaptive capacity and reliability.The second part has completed the control system of soft, hardware design. Based on the technical requirements of the test system, this paper describes the design and implementation a compensation method of displacement sensor nonlinear in feedback control system. The application results show that the measurement error of the displacement sensor is less than0.01mm after calibration, which improves the precision of control system, guarantees the practicability and reliability.