Modeling, control, and evaluation of aircraft tire-runway interactions
Creators: name: Gong, Yongbin
Publisher: name: No Publisher Supplied
Year: 2024

description: Although landing takes only 1% of the total flight time in commercial air transportation, 31% of fatal accidents happened during the landing stage for worldwide commercial jet fleet during 2013-2022. Aircraft landing tire-runway interactions plays a critical role for safe operation of aircraft, particularly under severe weather conditions, such as rain, snow, slush, etc. Understanding and quantification of tire-runway friction under different environmental conditions are among the most important tasks for aircraft takeoff and landing performance assessment. Research studies underscored the critical role of maintaining adequate tire-runway interaction friction forces, as it directly influenced accidents such as overruns by impacting braking distances. This significance is particularly pronounced when runways are wet, with data from various regions indicating that approximately 20% of fatal accidents occur in such conditions. The goal of this dissertation is to provide a modeling, analysis and control of aircraft tire-runway interactions.After reviewing the modeling and analysis literature, the second chapter of this dissertation presents tire-runway friction estimation under wet pavement conditions and hydrodynamics analysis for aircraft tire-runway interactions. Understanding wet tire-runway interactions is critical for predicting unstable operating conditions such as hydroplaning and for safety operation. We present an analytical method to compute water film pressure and thickness distributions on the viscous hydrodynamic region between the tire and the i ground. The hydrodynamic models and analysis are obtained for the smooth tire surface and tires with transverse tread elements. We present analytical conditions to predict the hydroplaning occurrence. The impact of wet condition on tire-runway friction forces is also discussed through the effective length of the contact patch and a LuGre friction model. Simulation results are presented to demonstrate the modeling development. Comparisons with other existing models illustrate the advantage of the proposed models and analysis. Implementing grooves on aircraft runways has been proven effective in maintaining skid resistance under wet conditions. However, due to the inherent complexities involving hydrodynamics and the interaction between the tire and grooved pavement, the modelling of the friction force in such conditions has been rarely studied. In Chapter 3, we present a method to evaluate tire/runway friction under wet conditions and on grooved pavement sur faces. This evaluation involves examining the interaction force generated between the tire and grooved pavement, and studying of the drainage capacity of the grooves. Comparisons between the model-predicted friction coefficients and results from indoor testbed experiments are provided to demonstrate the feasibility of the proposed model and its potential for incorporation into aircraft braking systems to improve their performance. Embedded sensors inside the tire rubber layer potentially enables attractive features to estimate and obtain the real-time tire-runway interactions information. The fourth chapter of this dissertation presents a new tire-runway force sensing and estimation scheme with embedded flexible sensors. A physics-based tread beam model is developed and integrated with the LuGre friction model to evaluate the rubber deformation as well as the contact pressure distribution. A sensor model is then proposed to build the relationship between the measured longitudinal stress of the tire tread rubber and the external friction force at the tire-runway contact patch. Feature points on measurement curves are analyzed and used to estimate tire runway friction forces. A tire friction testbed is developed for comprehensive experimental validation under conditions such as various slip, surface roughness, etc. Experimental results demonstrate the feasibility of using the force-sensitive sensors ii for predicting tire/road friction characteristics. Compared with passenger vehicles, aircraft tire-runway friction measurements face different characteristics and additional challenges. Because of heavy weight, large size and high speed, it is more challenging and expensive to conduct full-size tire-runway friction tests for commercial aircraft than passenger vehicles. In the fifth chapter, we present a novel scaled testbed for studying aircraft tire-runway interactions during landing and braking stage. The indoor testbed is built on a platform with a rotational arm to support an aircraft landing wheel on a circular, re-configurable runway track. By designing the braking torque, the rotating arm motion, and the pneumatic normal load, the testbed possesses the capability to emulate the dynamic characteristics of aircraft tire-runway interactions and braking maneuvers under various pavement conditions. Besides the mechatronic design of the testbed, we present the modeling and control of the platform subsystems to demonstrate the capability and performance for simulation of various braking maneuvers under different pavement and wet conditions. The dimensionless analysis and design are presented to represent the equivalent simulation of braking process of full-size aircraft. Experimental results demonstrate the efficacy of the testbed design in studying the interactions between the aircraft tire and the runway pavement. In the last chapter of the dissertation, we summarize the concluding remarks of the research progress and also present the ongoing research directions. We mainly focus on the friction modeling and analysis of the aircraft landing tire on different pavement groove patterns under dry and wet conditions. Using the developed scaled testbed, we plan to validate the modeling and analysis experimentally and further develop a real-time control of the tire-runway interactions on different groove patterns and wet conditions.