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Steering and suspension system has to be designed properly to achieve improved handling characteristics. Improper design of steering systems will result in steering errors such as bump steer and roll steer. These steering errors results in reduced steering performance. During the design of steering system the tie rod length has to be properly selected to reduce these steering errors. The purpose of the work is to analyze the effects of tie rod length variation on bump steer. Multi body dynamic model of the selected vehicle was created using MSC ADAMS Car software. Ideal design of steering system to achieve zero bump steer was created. The tie rod length was later varied up to 10% to study the effect of varying length on bump steer. Parallel wheel travel analysis was conducted to study the tie rod length variation on bump steer. Acceleration test was conducted on a flat road having bump to analyze the effect of changing tie rod length on steering performance of the vehicle.

Exposure to high level of vibrations encountered in driver’s cabin of heavy duty truck over extended time causes driver fatigue and leads to serious health disorders. In most of the current heavy duty trucks in India, absence of proper vibration isolation system for driver’s seat results in transmission of high levels of vibration to the driver. A proper seat isolation system, combined with proper cushioning of seat can considerably reduce vibration transmissibility to the driver. The work presented here addresses the problem of vibration levels in a heavy duty truck and proposes solution for reducing vibration transmissibility to driver seat by using isolation and cushioning system. Vibration levels on floor, driver’s seat and seat back of an existing truck were measured using tri-axial accelerometer and 9 channel spectrum analyzer. Measured vibration levels in the vertical direction were found to be exceeding comfortable level.

Vehicle dynamics is the study of response of the vehicle to driver’s input. Various parameters like location of center of gravity (CG), suspension spring stiffness, wheel alignment parameters, etc. determine the handling behavior of the vehicle. This is a study to investigate the effects of aforesaid parameters on handling characteristics of an intercity bus using MSC ADAMS software tool. Handling performance is determined by evaluating various parameters such as understeer gradient, roll gradient, etc. Understeer gradient is influenced by various parameters like location of CG, tire cornering stiffness, etc. Roll gradient of a vehicle depend on various parameters like vertical stiffness of tires, anti-roll bars (ARB) diameter, location of CG, etc. As a part of this study, four different configurations of MBD models were built to investigate the effect of location of ARB on handling behavior of bus. Several vehicle dynamic tests are virtually conducted on the MBD model of the bus.

Expanding and improving road network in India has been a catalyst for increased use of road transport in both passenger and goods sector. With improved road quality, bigger commercials vehicles have entered the market. These provide a larger cabin area and better amenities in the truck driver cabin. One of the most welcome features is berths for lying down and sleeping. In most designs though, only the functionality of the berth has been taken into consideration. Safety of the occupants of the berths in the event of panic braking or collision of the vehicle, has not been given adequate consideration. In this work, design of such berths from occupant safety point of view has been assessed. Kinematics of occupants, sleeping in different typical postures, during frontal impact, has been simulated and resulting critical injury levels have been estimated. Based on this information, different arrangements of belts in “screen” type configuration were developed.