Research On Attitude Control And Performance Evaluation Of High-speed Aircraft Based On Stochastic Robust Optimization

The research of hypersonic vehicle has been a hotspot.With the rapid development of relevant technologies and complex flight environments,the control requirements for hypersonic vehicles are bemanding.In view of the characteristics of hypersonic vehicle,such as highly nonlinearity,complex flight environment and uncertain parameters,a control method based on stochastic robust optimization is proposed in this paper.In addition,this paper designed the performance evaluation of the aircraft attitude control system to ensure the correctness and reliability of the flight control system.Aiming at the attitude control of hypersonic vehicles,the linear quadratic regulator(LQR)control method based on stochastic robust optimization is proposed.Firstly,the generation of uncertainty and its range are analyzed.Then the parameters of LQR controller are optimized by stochastic robust method.The robust optimization method utilizes the distribution characteristics of uncertainty,evaluates the stochastic robustness by Monte Carlo simulation statistical instability of the attitude system and the probability of violating the design requirements,and then uses intelligent optimization to optimize the parameters of the controller.The simulation result shows that the hypersonic vehicle meets the design requirements with high probability.Secondly,for the Monte Carlo simulation,when the sampling times are small,the sampling points cannot be spread over the whole sampling interval and the sampling points may gather together.The Latin hypercube sampling method is used to optimize the random sampling process.The Latin hypercube sampling method uses a stratified sampling method with uniform and random characteristics.The controller is designed with the control structure of the inner and outer loops,and the controller parameters are optimized by the stochastic robust optimization method based on Latin hypercube sampling.Then,a six-degree-of-freedom simulation verification is carried out for a high-speed aircraft.The results show that the attitude control system with random robust optimization using Latin hypercube sampling method has better control performance and robustness.Thirdly,according to flight control performance evaluation,first of all,the theory of analytic hierarchy process(AHP)is adopted to establish the evaluation system,through the orthogonal experiment method which design the appropriate experimental scheme,second,based on the analytic hierarchy process(AHP)in the combination of subjective and objective index combined with the empowerment of indicators,third,the system scores,guarantee the accuracy of the evaluation result is reliable.Finally,the comprehensive performances of the two controllers are evaluated by using the above evaluation method.