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Keywords: roller rig, contact, multibody simulation.

Summary

In railway applications, the increasing speed, capacity and safety levels are leading to the introduction of complex mechatronic systems that monitor and control several aspects of train running. These complex subsystems have to be properly tested and in particular their interactions have to be carefully evaluated, especially in particularly critical situations.

The authors in some previous work described the features of a locomotive full scale roller rig for the simulation of degraded adhesion conditions between the wheel and the simulated rail. The design of the rig control system was based on the hypotheses that the contact between the roller and the wheel may be considered as a pure rotating constraint, while the loss of adhesion is simulated by modulating the torque applied to the roller motor in order to reproduce the same speed profiles that the wheel would have in reality.

The control law performance of both the full scale and the scaled roller rig is substantially based on the hypothesis that no sliding occurs between the wheel and the roller, but the pure rotating constraint between the wheel and the roller is only approximately guaranteed and highly depends on the force distribution in the wheel-roller contact area: a sliding between the rolling surfaces may arise if the applied torque increases or in the presence of dynamic effects (high accelerations), that could be present when degraded adhesion conditions are simulated, due to the intervention of anti-slip and wheel slide protection systems. Furthermore the rig control system may be affected by the dynamics of the roller in the lateral direction. So further analyses were performed in order to understand if the previously neglected phenomena can play a significant role on the roller rig control system. This is the motivation of the development of a detailed multibody model of the scaled roller rig and scaled bogie, in which particular attention was devoted to the model of the wheel-roller contact, since we need to evaluate the effect of local sliding and of the position of the wheel-rail contact point on the dynamics of the whole system.

The paper presents the main details of the simulation model developed, with a particular attention to the wheel-roller contact model, then the results of some preliminary numerical tests are presented, the test results will be used in future develompents to discuss the effectiveness of the proposed control laws.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 93 PROCEEDINGS OF THE TENTH INTERNATIONAL CONFERENCE ON COMPUTATIONAL STRUCTURES TECHNOLOGY Edited by: Paper 7 Simulation of Degraded Wheel-Rail Adhesion Conditions on a Scaled Roller Rig for Railway Bogies: The Effect of Wheel-Roller Contact on Control Performance M. Malvezzi¹, E. Meli² and L. Pugi² ¹Department of Information Engineering, University of Siena, Italy ²Department of Energetics, University of Florence, Italy doi:10.4203/ccp.93.7 purchase the full-text of this paper Full Bibliographic Reference for this paper M. Malvezzi, E. Meli, L. Pugi, "Simulation of Degraded Wheel-Rail Adhesion Conditions on a Scaled Roller Rig for Railway Bogies: The Effect of Wheel-Roller Contact on Control Performance", in , (Editors), "Proceedings of the Tenth International Conference on Computational Structures Technology", Civil-Comp Press, Stirlingshire, UK, Paper 7, 2010. doi:10.4203/ccp.93.7 Keywords: roller rig, contact, multibody simulation. Summary In railway applications, the increasing speed, capacity and safety levels are leading to the introduction of complex mechatronic systems that monitor and control several aspects of train running. These complex subsystems have to be properly tested and in particular their interactions have to be carefully evaluated, especially in particularly critical situations. The authors in some previous work described the features of a locomotive full scale roller rig for the simulation of degraded adhesion conditions between the wheel and the simulated rail. The design of the rig control system was based on the hypotheses that the contact between the roller and the wheel may be considered as a pure rotating constraint, while the loss of adhesion is simulated by modulating the torque applied to the roller motor in order to reproduce the same speed profiles that the wheel would have in reality. The control law performance of both the full scale and the scaled roller rig is substantially based on the hypothesis that no sliding occurs between the wheel and the roller, but the pure rotating constraint between the wheel and the roller is only approximately guaranteed and highly depends on the force distribution in the wheel-roller contact area: a sliding between the rolling surfaces may arise if the applied torque increases or in the presence of dynamic effects (high accelerations), that could be present when degraded adhesion conditions are simulated, due to the intervention of anti-slip and wheel slide protection systems. Furthermore the rig control system may be affected by the dynamics of the roller in the lateral direction. So further analyses were performed in order to understand if the previously neglected phenomena can play a significant role on the roller rig control system. This is the motivation of the development of a detailed multibody model of the scaled roller rig and scaled bogie, in which particular attention was devoted to the model of the wheel-roller contact, since we need to evaluate the effect of local sliding and of the position of the wheel-rail contact point on the dynamics of the whole system. The paper presents the main details of the simulation model developed, with a particular attention to the wheel-roller contact model, then the results of some preliminary numerical tests are presented, the test results will be used in future develompents to discuss the effectiveness of the proposed control laws. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £145 +P&P)
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