Research And Implementation Of The Test Platform For Electric Servo Loading System

The electric servo loading system,also known as the electric torque servo system or the electric load simulator,is mainly used to simulate the actual load of the load-bearing mechanism during the loading process,and is usually used in military defense,aerospace,rail transit and other fields.In order to test the performance of a series of steering gear,this paper designed a test platform of electric servo loading system based on LabVIEW.Firstly,starting from the overall structure of the electric servo loading system,the mathematical models of the loading mechanism with permanent magnet synchronous motor(PMSM)as the actuator and the bearing mechanism with DC servo motor as the actuator are established respectively.These two models are coupled to get the overall model of the electric servo loading system.Secondly,the influence of nonlinear backlash and surplus torque on the loading accuracy of the system is analyzed.Aiming at the backlash phenomenon existing in the system,the mechanism analysis method is used to model the backlash nonlinearity,and the compensation control strategy based on DOB is designed.Considering that the system will be interfered by the surplus torque during the loading process,the factors affecting the surplus torque are analyzed,and the angular velocity feedforward compensation control strategy is designed to suppress the surplus torque.Then,the control strategy of the load controller of the electric servo load system is studied.Aiming at the interference problems such as nonlinearity and surplus torque in the system,an improved ADRC control strategy is designed.Compared with the traditional PID control strategy,the improved ADRC control strategy has stronger anti-interference and better control effect.Finally,the test platform of the electric servo loading system is designed,including hardware structure design and system software development.The hardware structure part combines with the function analysis,completes the equipment selection,and formulates the corresponding design scheme of the test platform.In terms of software design,the software architecture of the system is analyzed.The design of the monitoring and display program of the upper computer is completed by using LabVIEW visual graphics programming method,and the real-time control program of the lower computer is designed by using virtual instrument technology with high real-time and expansibility.The actual test results show that the loading system is indeed affected by the backlash nonlinearity and the surplus torque.And under the corresponding control strategy,the designed electric servo loading system meets the requirements of loading performance index.