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Investigation of Transmissibility of an all-terrain vehicle with spring and damper tuning.
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on November 21, 2019 by SAE International in United States
Event: NuGen Summit
The application in ride and handling development has been mostly subjective or intuitive. Suspension settings are based on the opinions of experts. The product of this research will enable to quantify the performance of a suspension in terms of its ability to minimize the transmission of road irregularities to the chassis and achieve good mechanical grip with the road surface. This work presents a dynamical analysis of the transmissibility of an off-road vehicle suspension, developed in VIT Vellore for Baja SAE India competition. A baseline spring rates curve for ride is developed to provide a solid foundation to tune from. The shock absorbers used for testing are Fox Float Evol R air shock absorbers with progressive damping. A thorough data acquisition of the force curves for shocks from a test rig is done. A detailed characteristic of the air shocks is obtained at various loading conditions. The basic damping curve is modified towards the desired ideal nature with the data obtained. The speculated optimum setting is validated on the ATV vehicle with ultrasonic sensors and accelerometers. This is done for varying vehicle speed and varying bump heights to evaluate the transmissibility of the suspension with an aim to reduce it below 1.5, and other important dynamic characteristics. Finally the data acquired from the vehicle setup and testing is developed to study the behavior of the suspension and the influence of the main parameters in the transmissibility. A high damping ratio at low damper velocity and a low damping ratio at high velocity tend towards optimal damping characteristics. An estimate for an optimal suspension adjustment is obtained with the methodology and can be used as an effective tool for design and improvement of vehicle.