Faculty Publications

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Publications by NITK Faculty

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Author: search.filters.author.Kumar, H.Subject: search.filters.subject.Degrees of freedom (mechanics)

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    Study the dynamic behaviour of seven DOF of full car model with semi-active suspension system
    (Inderscience Publishers, 2021) Hemanth, H.; Shamanth, S.; Devaraj, D.; Kumar, H.; Gangadharan, K.V.
    This paper presents an investigation on the ride comfort and road-holding performance of a vehicle equipped with the semi-active suspension system. The full car semi-active suspension model with 7 degrees of freedom (7 DOF) system is adopted for the study and a fuzzy-logic control strategy is considered for minimising the effect of road disturbance on vehicle performance. The responses of a vehicle have been analysed under the Indian average random road profile (ISO8608) against the conventional passive suspension system. The performance of the semi-active suspension system is evaluated by heave, roll and pitch acceleration of the vehicle body around its centre of gravity. The performance of a vehicle with the semi-active suspension system has been compared with the response conventional passive suspension system. The result specifies that, the semi-active suspension system with a fuzzy-logic controller reduces around 43% of vibration amplitude at the resonance frequency of vehicle than the passive suspension system. © © 2021 Inderscience Enterprises Ltd.
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    Design and development of MR damper for two wheeler application and Kwok model parameters tuning for designed damper
    (SAGE Publications Ltd, 2022) Devikiran, P.; Puneet, N.P.; Hegale, A.; Kumar, H.
    Magnetorheological dampers have been the interest of many researchers for a few decades for the reason of being an effective and rapidly progressing technology in the field of semi-active controlled suspension. The dynamic behaviour of these devices with nonlinear hysteresis is quite a complicated phenomenon. Hence, this paper aims at the design, modelling and simulation of a custom-made MR damper for a two-wheeler vehicle. The Kwok model has been chosen to mathematically model the MR damper. The model parameters have been optimised by minimizing the error difference between experimental and model-generated force results. A PID control is designed to control the damper effectively depending on the deflection of the damper. The two-wheeler vehicle modelled with four degrees of freedom is coupled with a mathematical model of MR damper in front and rear suspension. Further, the dynamic analysis has been performed in MATLAB/Simulink considering random road input for different velocities and current input conditions. The improved performance of MR damper was observed in suppressing road irregularities using a PID controller. As an implementation part of the work, the developed damper has been implemented in a two wheeler vehicle for performance evaluation at on-road testing conditions. The results showed significant improvement in damper performance with increment of constant current controlling MR dampers. © IMechE 2021.
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    Experimental and Analytical Evaluation of an Acceleration-Based Semiactive Control Strategy for Automotive Suspension Systems with Magneto-Rheological Damper
    (SAE International, 2023) Jamadar, M.E.H.; Devikiran, P.; Kumar, H.; Joladarshi, S.
    Most of the control strategies presented to date are based on either the velocities or displacement of the vehicle body and the wheel which are derived by filtering and converting the data from the accelerometer. This increases the computational load and therefore directly affects the performance of the semiactive suspension system. This study presents a control strategy purely based on the acceleration for semiactive control of vehicle suspension with a magneto-rheological MR damper. The effectiveness of the acceleration-based skyhook (ASH) control strategy is compared with the existing velocity-based skyhook (VSH) control strategy based on the vibration response of a single-degree-of-freedom (SDOF) system. The effectiveness of ASH is evaluated experimentally, and the reaction time is evaluated analytically. The experimental results revealed that the ASH reduces the peak displacement and peak acceleration of the mass under the free vibration test and also improves the settling time as compared to VSH. The amplitude of the displacement and acceleration was also found to be reduced under the forced vibration test with maximum improvement observed during high-frequency excitation. The reaction time of ASH was also found to be considerably lower than VSH. Therefore, it was learned that the proposed ASH performed better under high-frequency excitation than under lower-frequency excitation. Moreover, the lower reaction time of the ASH could improve the overall performance of the semiactive suspension system. © 2023 SAE International.