| The multi-objective control of aero-engines is considered to be the focus of research in aviation control.In order to ensure both rapidity and small overshoot during the acceleration process,the research of speed adjusting switching control system has been carried out based on linear models of aero-engines.In order to ensure rapidity and security of aero-engines at the same time,the regulation/protection control system is designed that provides a possible switching strategy to solve the problem of security protection of aero-engines.Firstly,to get the augmented linearization model,the control variable is introduced into the linearization model of turbofan engines as the augmented state.According to the above model,two sub-controllers are designed for speed control.The first sub-controller is the augmented LQR state feedback controller which is designed with LQR control theory to meet the requirement of rapidity in the acceleration process.The other sub-controller is also the state feedback controller which is designed by using the method of regional pole placement to meet the requirement of small overshoot during the acceleration process.Then,three types of switching rules are designed.By making some simulations,three types of switching rules are compared.The first one is an event-based switching rule.This method is simple and easy to achieve.However,the anti-interference ability is weak and the stability of the system may not be satisfactory.The second one is the soft switching rule.This method has a transition process which can reduce the jump of control output during switching,but the performance of the system may deteriorate and the design may be complex.The last one is an event-based switching rule that satisfies the average dwell time which combines average dwell time with event-based switching rule.By using this mothed,the stability of switching systems can be ensured and the anti-interference ability of systems is greatly improved.Finally,in order to solve the conflict between rapidity and safety of the aero-engines,the regulation/protection control system is designed.In this system,not only the speed control loop is designed to ensure the rapidity,but two safety protection controllers are designed to make sure the security,including surge protection control loop and temperature protection control loop.Then the corresponding satefy protection switching rules are designed,including switching rule for speed loop and temperature protection loop and switching rule for speed loop and surge protection loop.Simulation results verify the correctness and effectiveness of the above switching principles.Considering the extreme conditions that the false overtemperature and false surge happen at the same time,the reasonable switching principle is given. |
