Research On Nonlinear Control Method Of Electro-hydraulic Load Simulation Device

The electro-hydraulic load simulator is the key device to the missile hardware-in-the-loop simulation,which is used for the steering gear performance testing or the flight control closed-loop simulation,and whether its performance is good or not directly affects the confidence coefficient of the measured object.The device is usually implemented by the electro-hydraulic servo device,and it may be realized difficultly that how to design a reasonable control strategy not only can effectively restrain the redundant force caused by the steering gear movement,but also can improve the dynamic property of the electro-hydraulic force(torque)servo system.According to the key control problems of the device,the main research work is conducted in the following several aspects:1.Aimed at the inherent nonlinear characteristics,such as the pressure-flow nonlinearity of the servo valve,the structure nonlinearity of the differential equation,the friction nonlinearity,etc.,existing in the electro-hydraulic force(torque)servo system,through the friction identification,establish the nonlinear mathematical model which contains the continuously differentiable friction model,in order to provide the theoretical basis in designing the high-performance and high-precision control strategy of the electro-hydraulic load simulator.2.In addition to the inherent nonlinear characteristics,the system also has various model uncertainties.Against uncertainty nonlinearities existing in the system,such as unmodeled disturbances,leakages,frictions,etc.,design an integral robust controller,which classifies the parameter error,the modeling error,the unmodeled dynamics and external disturbances into the system uncertainty nonlinearities,and implements the asymptotic stability of the system without using the high gain feedback.At the same time,on the basis of the integral controller,integrated with the adaptive control ideology,design the gain self-adjustment law to adjust online the ? value of the controller robust gain.It can effectively solve potential problems,such as the conservatism,the randomness,the limitation and the high gain feedback of gain adjustment of the symbol function,existing in the traditional error sign integral robust control strategy.3.In view of the system parameter uncertainties and unmodeled disturbances,merged together with the compensation scheme in eliminating the redundant force,based on the nonlinear adaptive robust control theory,design the adaptive robust controller of the electro-hydraulic load simulator.The control strategy not only gives the system transient tracking performance,but also guarantees the system steady precision.And when only existing parameter uncertainties,the asymptotic stability is also obtained.In order to make the system adaptive parameters have a good convergence,the indirect adaptive robust controller is also designed.4.To achieve the high-precision tracking of the electro-hydraulic load simulator,the paper also designs a robust adaptive controller,which has a good treatment to the parameter uncertainties and shows a certain restrain ability to the unmodeled dynamics and external disturbances.On this basis,combined the robust adaptive control with the extended state observer by the feedforward elimination method,design a robust adaptive control strategy based on the extended state observer.