Design Of Hardware-In-The-Loop Simulation Platform For Aircraft Braking System Based On LabVIEW

ABSTRACT:For aircraft, anti-skid braking control system is important airborne equipment, and it plays very important role in the overall performance and safety of the aircraft. Aircraft landing brake process complex work environment, short duration, while also including a variety of internal and external uncertainties interference, so the requirements of aircraft braking system is safe, reliable, fast performance.The main research object of the thesis is an experiment platform of hardware-in-the-loop simulation for the aircraft braking system. The platform can simulate actual working condition of the aircraft braking system, and realize real time simulation by software of some factors. The factors include aircraft wheel and brake device movement process, track status. Through the analysis of the structure and working principle of the aircraft braking system and needs analysis to determine the simulation platform, based on the principle of the semi-physical simulation technology, the overall design of the simulation platform is designed in this thesis. The mathematical models of aircraft wheel movement mechanics, wheel movement, brakes, brake disk, tire, runway, runway coefficient and electro-hydraulic servo valve are built in Matlab/Simulink and introduced in the simulation loop. The mathematical models and real accessories of brake such as braking control box, electro-hydraulic servo valve, wheel speed sensor and brake command sensor make up of the hardware-in-the-loop simulation platform of braking system. Then, Lab VIEW and SIT toolkit were used to achieve real-time interaction of the data between the mathematical models and the physical models. On the basis of simulation research, the software and hardware design for the hardware-in-the-loop simulation platform are accomplished. In the matter of hardware design, embedde PXI systems of NI company and ADLINK company are implied in the thesis, equipped with relative data acquisition card and fault injection card and so on. In the matter of software design, LabVIEW is used to achieve the development of the man-machine interface of the hardware-in-the-loop simulation platform. Though the man-machine interface, the operating instructions are issued and data is transmitted, displayed and stored. To solve the real-time and interaction of the semi-physical simulaiton, the Windows real-time expansion tool(RTX) were introduced.The thesis does in-depth analysis on the most widely used "PID+PBM" braking control algorithm, and explores the underlying cause of its low speed sliding, and skid inefficient in a low associative law coefficient runway and low speed sliding. On this basis, this paper design the "BP+PBM" control algorithm. The deceleration rate of the reference speed by BP neural network self-tuning, and finally the braking effect of the two algorithms were compared and analyzed through semi-physical simulation. The simulation results show that the "BP+PBM" braking control algorithm can effectively enhance the braking effect and the platform of the hardware-in-the-loop simulation system reflects real environment, it can provide an actual experimentation platform for designing and improve the aircraft braking system.Figures(57), tables(3), references(72).