Articles written in Sadhana
Volume 30 Issue 5 October 2005 pp 649-659
We design and investigate the performance of fuzzy logic-controlled (FLC) active suspensions on a nonlinear vehicle model with four degrees of freedom, without causing any degeneration in suspension working limits. Force actuators were mounted parallel to the suspensions. In this new approach, linear combinations of the vertical velocities of the suspension ends and accelerations of the points of connection of the suspension to the body have been used as input variables. The study clearly demonstrates the effectiveness of the fuzzy logic controller for active suspension systems. Suspension working space degeneration is the most important problem in various applications. Decreasing the amplitudes of vehicle body vibrations improves ride comfort. Body bounce and pitch motion of the vehicle are presented both in time domain when travelling over a ramp-step road profile and in frequency domain. The results are compared with those of uncontrolled systems. At the end of this study, the performance and the advantage of the suggested approach and the improvement in ride comfort are discussed.
Volume 33 Issue 1 February 2008 pp 15-25
In this paper, the active suspension control of a vehicle model that has ﬁve degrees of freedom with a passenger seat using a fuzzy logic controller is studied. Three cases are taken into account as different control applications. In the ﬁrst case, the vehicle model having passive suspensions with an active passenger seat is controlled. In the second case, active suspensions with passive passenger seat combination are controlled. In the third case, both the passenger seat and suspensions have active controllers. Vibrations of the passenger seat in the three cases due to road bump input are simulated. At the end of the study, the results are compared in order to select the combination that supplies the best ride comfort.
Volume 38 Issue 2 April 2013 pp 265-280
In this paper, in order to obtain the dynamic forces on the passenger coach axle, a full rail vehicle model with 19-dof (degrees of freedom) has been considered. For a speciﬁc example, the variations of these dynamic forces with velocity of the passenger coach, suspension characteristics and way conditions have been examined. Dynamic forces found in the resonance regions at the range of 2–5 m/s (7.2–18 km/h) has been discussed. Theoretical results obtained for the dynamic forces have been successfully compared with the experimental results of German Railways (Deutsche Bahn-DB).