A Real-Time Maximum Tire-Road Friction Tracking Control Method for Aircraft Braking System With Disturbance Compensation

This article proposes a real-time maximum tire–road friction tracking control method with disturbance compensation for aircraft antiskid braking system (ABS). Conventional aircraft ABS cannot accurately set the optimal slip ratio in real time for runways with different friction characteristics, resulting in the maximum tire–road friction not being completely utilized in real time. To address this problem, first, a runway identification method is developed to determine the optimal slip ratio of the initial runway. Then, an optimal slip ratio update algorithm based on the Burckhardt model is proposed to update the optimal slip ratio according to the tire–road friction characteristics. Adaptive forgetting factor recursive least squares is employed to handle the most important parametric uncertainty in aircraft ABS, i.e., the brake torque conversion factor. The residual uncertainties and external disturbances are observed by constructing an extended state observer (ESO). In addition, by effectively integrating modified super-twisting algorithm with ESO, a continuous and chattering-free slip ratio tracking algorithm with disturbance compensation is developed. The proposed method can eliminate the adverse effects of major parametric uncertainties and greatly reduce the burden on ESO, so it achieves accurate tracking while greatly reducing the feedback gain. Finally, the effectiveness of the proposed method is verified by comparative simulation and experimental results.