Research Of Aircraft Auxiliary Power Unit Control

In this paper, with a certain type of aircraft APU, some design of mathematical model，controllaw and the controller is completed. For the mathematical models of APU, its nonlinear modelstructures is completed with the reference to the combination of the current model of aero-enginecomponents and its unique components. Considering the together working conditions of the APUvarious components, the network structure of APU is given. This helps to complete the control lawdesign of APU in simulation software. After the completion of the nonlinear model of APU, a smalldeviation simplified model is built from fuel supply to the APU rotation speed. Finally, thesecond-order transfer function from fuel supply to the APU rotation speed is got.With the application of AIC criteria on APU, we completed the structure identification, and withthe use of stepwise parameter identification algorithm based on ARMAX system model proposed inthis paper, we finished the parameter identification of the APU mathematical model. So we can get acomplete mathematical model.In this paper, in order to give full play of acceleration performance of APU acceleration fuelcontrol, we proposed a algorithm of the optimal APU acceleration fuel control based on improvednonlinear APU simplified feasible sequential quadratic programming (FSQP). The simulation resultsdemonstrate that this proposed algorithm can get the optimal APU acceleration control. And thisalgorithm can give full play to the acceleration features of APU. Because intake and exhaust device ofAPU is actually just servo drive mechanism, therefore, the control of intake and exhaust device isproposed specially in the paper. Firstly, a mathematical model of the intake and exhaust valves is built.Then, a simple three-ring servo control law is designed. At last, a PID adaptive control law based onfuzzy RBF neural network is proposed for the electric servo system similar to intake and exhaustvalves.The upgrades and maintaining of hardware and software will be easy to do with a modulardesign concept. At the same time, the critical signal conditioning and servo drive circuit design arecompleted.