Runway Identification Algorithm In The Aircraft Antiskid Braking Application Study

Wheel braking system is one of the key airborne equipments which plays an important role in taking off and landing safely. In addition, aircraft antiskid braking system has a strong real-time, nonlinear and strong unpredictable nature.While affected by dreadful conditions and many critical factors such as runway conditions, airport cross-winds and asymmetric landing. The antiskid braking system must have the capability of runway adaptive in the large aircraft with large tonnage and high speed. Deep researches to the algorithm of antiskid braking system have been carried on by domestic researchers, but most of them lay emphasis more on the best slip rate than runway state identification. Therefore, runway state identification must be involved in the algorithm of antiskid braking system to improve braking efficiency essentially.Based on the theory of the antiskid braking system in the paper, established in domestic large passenger aircraft braking system model, and the dynamic inertia test experiment has been used to verify the accuracy of the model. As the interaction between tyres and runway is so complex, the friction model for tyres and runway should be analyzed deeply. To achieve the best slip rate, a new type of nonlinear state observer which is based on the dynamic distributed LuGre friction model was designed. What's more, braking efficiency could be improved by applying the state observer to the antiskid control algorithm.In the end, with the use of the SIMULINK toolbox in MATLAB software, the antiskid braking control algorithm is simulated on the model to study the antiskid braking performance in different conditions such as wet, icy runway and runway condition mutated. Comparing with the simulation results above to the proposed algorithm, it indicates that the antiskid control algorithm with capability of runaway state identification does well in improving the braking performance.