The growing market demand for highly automated and autonomous vehicles and the need to equip vehi... more The growing market demand for highly automated and autonomous vehicles and the need to equip vehicles with ever higher standards of comfort, safety and performance requires knowledge of physical quantities that are often difficult or expensive to measure directly. The absence of direct sensors, the difficulty of implementation, and their cost have led researchers to identify alternative solutions that allow estimating the physical quantity of interest by aggregating other available information. The interaction forces between tire and road are among the most significant. Given that the dynamics of a vehicle are strongly linked to the forces exchanged between the tire and the road, their knowledge is fundamental in the development of control systems aimed at improving performance in terms of handling, road holding or comfort. This paper presents a new technique for the estimation of tire-road interaction forces based on the integration of models and measures. A Central Difference Kalm...
The employment of intelligent tires to test the vehicle performances is ever-increasing in the la... more The employment of intelligent tires to test the vehicle performances is ever-increasing in the last years. Many research activities have been made to correlate measurements provided by sensors to the tire dynamics. In this paper, a novel tire-road forces estimation technique is presented. The developed estimator is based on an approximation of the well-known Flexible Ring Tire Model (FRTM) and therefore, it is suitable for real-time normal and tangential forces identification. Only the tread band strain measurements are employed in the developed algorithm which can estimate the tire-road forces at every wheel revolution. The tool is validated through both numerical and experimental tests. The results indicate that the developed estimation algorithm, obtained by a mathematical inversion of the FRTM, can be employed as a monitoring tool for tires and vehicles.
Abstract The lack of validated physical models concerning the degradation of the coefficient of f... more Abstract The lack of validated physical models concerning the degradation of the coefficient of friction of sliding isolators induced from the heating of the sliding surfaces during the seismic motion hampers the interpretation of experimental data and the formulation of accurate numerical models. An estimator based on a Constrained Unscented Kalman Filter (CUKF), suitable for real-time monitoring, combined with a Random Walk Model approach (RWM) which identifies the friction degradation function without the a priori knowledge of a physical model and ensuing analytical law has been developed in the study. Both numerical analyses and experimental tests of a 2 DOF shear-type physical model are employed to demonstrate the validity of the technique. The proposed estimator is able to provide an accurate estimation of the state of the system, by predicting the structural displacement histories, and to identify the hysteretic degradation function in different friction conditions, from low to high friction.
In railway vehicles, the secondary anti-yaw suspension system is subjected to degradation so that... more In railway vehicles, the secondary anti-yaw suspension system is subjected to degradation so that it must undergo maintenance. In order to optimize the maintenance costs and to improve the safety, model-based real-time monitoring techniques are used. This paper presents a constrained nonlinear estimation procedure to monitor the anti-yaw damping through a railway vehicle model with a wheel-rail contact model characterized by a random walk approach. The application of state constraints allows to reduce the parameter variation sensitiveness. This technique considers the constraints applied to the estimated states and is advantageous in terms of unsensitiveness linked to the phenomenon of wheel-rail contact and a no prior knowledge of the track irregularities is required.
The performance of the vehicle's active safety systems depends on accurate knowledge of the v... more The performance of the vehicle's active safety systems depends on accurate knowledge of the vehicle state, and the frictional forces resulting from tyre contact and the road surface. This paper aims to estimate the vehicle states and tyre-road coefficient of friction through and Extended Kalman Filter (EKF), integrated with the Double-Track model and the Pacejka Magic Formula that allows knowledge of the lateral force of the tyre. Besides, this approach can estimate the overall coefficient of lateral friction on each side of the vehicle, left and right respectively. Simulations based on a reference vehicle model are performed on different road surfaces and driving manoeuvres to verify the effectiveness of the proposed estimation method, in order to obtain good performance from different vehicle control systems.
The growing market demand for highly automated and autonomous vehicles and the need to equip vehi... more The growing market demand for highly automated and autonomous vehicles and the need to equip vehicles with ever higher standards of comfort, safety and performance requires knowledge of physical quantities that are often difficult or expensive to measure directly. The absence of direct sensors, the difficulty of implementation, and their cost have led researchers to identify alternative solutions that allow estimating the physical quantity of interest by aggregating other available information. The interaction forces between tire and road are among the most significant. Given that the dynamics of a vehicle are strongly linked to the forces exchanged between the tire and the road, their knowledge is fundamental in the development of control systems aimed at improving performance in terms of handling, road holding or comfort. This paper presents a new technique for the estimation of tire-road interaction forces based on the integration of models and measures. A Central Difference Kalm...
The employment of intelligent tires to test the vehicle performances is ever-increasing in the la... more The employment of intelligent tires to test the vehicle performances is ever-increasing in the last years. Many research activities have been made to correlate measurements provided by sensors to the tire dynamics. In this paper, a novel tire-road forces estimation technique is presented. The developed estimator is based on an approximation of the well-known Flexible Ring Tire Model (FRTM) and therefore, it is suitable for real-time normal and tangential forces identification. Only the tread band strain measurements are employed in the developed algorithm which can estimate the tire-road forces at every wheel revolution. The tool is validated through both numerical and experimental tests. The results indicate that the developed estimation algorithm, obtained by a mathematical inversion of the FRTM, can be employed as a monitoring tool for tires and vehicles.
Abstract The lack of validated physical models concerning the degradation of the coefficient of f... more Abstract The lack of validated physical models concerning the degradation of the coefficient of friction of sliding isolators induced from the heating of the sliding surfaces during the seismic motion hampers the interpretation of experimental data and the formulation of accurate numerical models. An estimator based on a Constrained Unscented Kalman Filter (CUKF), suitable for real-time monitoring, combined with a Random Walk Model approach (RWM) which identifies the friction degradation function without the a priori knowledge of a physical model and ensuing analytical law has been developed in the study. Both numerical analyses and experimental tests of a 2 DOF shear-type physical model are employed to demonstrate the validity of the technique. The proposed estimator is able to provide an accurate estimation of the state of the system, by predicting the structural displacement histories, and to identify the hysteretic degradation function in different friction conditions, from low to high friction.
In railway vehicles, the secondary anti-yaw suspension system is subjected to degradation so that... more In railway vehicles, the secondary anti-yaw suspension system is subjected to degradation so that it must undergo maintenance. In order to optimize the maintenance costs and to improve the safety, model-based real-time monitoring techniques are used. This paper presents a constrained nonlinear estimation procedure to monitor the anti-yaw damping through a railway vehicle model with a wheel-rail contact model characterized by a random walk approach. The application of state constraints allows to reduce the parameter variation sensitiveness. This technique considers the constraints applied to the estimated states and is advantageous in terms of unsensitiveness linked to the phenomenon of wheel-rail contact and a no prior knowledge of the track irregularities is required.
The performance of the vehicle's active safety systems depends on accurate knowledge of the v... more The performance of the vehicle's active safety systems depends on accurate knowledge of the vehicle state, and the frictional forces resulting from tyre contact and the road surface. This paper aims to estimate the vehicle states and tyre-road coefficient of friction through and Extended Kalman Filter (EKF), integrated with the Double-Track model and the Pacejka Magic Formula that allows knowledge of the lateral force of the tyre. Besides, this approach can estimate the overall coefficient of lateral friction on each side of the vehicle, left and right respectively. Simulations based on a reference vehicle model are performed on different road surfaces and driving manoeuvres to verify the effectiveness of the proposed estimation method, in order to obtain good performance from different vehicle control systems.
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