فهرست نشریات علمی دسترسی آزاد ایران

The rail vehicle dynamics are greatly impacted by the different forces present at the ‎contact region of wheel and rail. Since the wheel and rail adhesion force is the key ‎element in maintaining high braking and acceleration performance of rail vehicles, ‎continuous monitoring of this factor is very important. Damage to the infrastructures ‎and lack of transportation convenience are the most obvious consequences of ‎improper levels of adhesion force. Adhesion modeling is a time consuming task. In ‎addition, due to the difficulties exist in directly measuring the adhesion force, the use ‎of alternative methods in which state observers are adopted has attracted much ‎attention. The selection of the primary model of the studied system and the ability of ‎the selected estimator have a significant effect on the success of the proposed ‎approach in estimating the variables. ‎In this paper, the dynamics of the wheelset is simulated in the presence of ‎irregularities that can be encountered in the railroad. Estimation of wheel-rail adhesion ‎force is done indirectly by nonlinear filters as estimators and their accuracies in the ‎estimation are compared to identify the better one. Meanwhile, inertial sensors ‎‎(accelerometer and gyroscope) outputs are used as measuring matrix and employed to ‎simulate actual situation and evaluate the estimators performances. To check the ‎accuracy and ability of the estimators in estimating states and variables, the proposed ‎approache implemented in Matlab.‎This study introduces an advantageous approach that uses the longitudinal, lateral and ‎torsional dynamics to estimate wheel-rail adhesion force in variable conditions. ‎Experimental results showed high precision, fast convergence, and low error values in ‎variable estimation. ‎Real time knowledge of the contact condition results in proper traction and braking ‎performances. The results of proposed method can lead to decreasing wheel ‎deterioration and operational costs, minimizing high creep levels, maximizing the use ‎of already-existing adhesion, and mproving the frequency of service. It is worth‏ ‏noting ‎that the proposed method is beneficial for both conventional railway transport and ‎automated driverless trains.‎