VEHICLE DYNAMICS LABORATORY
FIG. VIBRATION SIMULATOR
The vibration simulator consists of a platform of 2 m × 2 m size and incorporates a table and two chairs with rigid wooden seats securely fixed, which allows participation of two subjects simultaneously. Three electro-dynamic vibration shakers with vibration controllers are used to provide sinusoidal or random vibration stimuli to the platform in three axes; fore-and-aft (X-axis), lateral (Y-axis) and vertical (Z-axis). Mainly used to study the effect of whole body vibrations on sedentary activities and vibration transmissibility. Additionally facilities are available for measurement of physiological parameters like Pulse Rate, Respiration Rate, Galvanic Skin Response, Skin Temperature, Heart Rate, and Heart Rate Variability (HRV) values on BIOPAC MP 150 WSW system.
FIG. SETUP FOR MEASURING ROLLING DYNAMIC STIFFNESS OF SMALL SIZE TYRES
The dynamically balanced drum, driven by a variable speed motor and a gearbox is capable of achieving speeds up to 300 rpm. A swing arm attachment is provided along the side of the drum. The tyre is mounted on the free end side of the swing arm and is loaded by clamping dead weights on the arm. The rolling drum excites the tyre by means of a cleat of 5 mm height mounted on the drum. The vibrations of the swing arm are recorded through the accelerometer pick-up mounted on it.
FIG. SETUP FOR MEASURING STATIC STIFFNESS OF SMALL SIZE TYRES
The set-up consists of a hub attached to a column, which slides in the guides, moving in the vertical direction. The test tyre is mounted on the hub and load is applied through pneumatic pressure, to press the tyre against the base plate. The loads are applied through two pneumatic cylinders, which could be mounted in different locations to apply lateral, longitudinal and twist moments, as required. Three dial gauges measure the tyre deflections in vertical, and horizontal directions. Measurements of the contact patch are obtained from the print of the contact patch on paper placed between the horizontal base plate and the tyre.
FIG. SETUP FOR MASS AND C.G. LOCATION
Mass and c.g. location of steering system
The center of mass of vehicle bodies or of the complete vehicle is located by using two different types of laboratory facilities, viz. the suspension rig and the inertia platform. Due to working convenience and better measurement accuracy, the suspension rig is suitable for light vehicle bodies, while the inertia platform is more appropriate for heavy vehicle bodies. Two strain gauge type load cells are mounted on the horizontal beam and can move horizontally on dovetail guides fixed to the beam. The reactions on the load cells are measured and the distance of plane of the center of mass from load cells is found out.
FIG. SETUP FOR MOMENT OF INERTIA MEASUREMENT OF VEHICLE
For measurement of mass and location of c.g. of heavier objects like the vehicle body, an inertia platform is used. It is a rigid rectangular frame structure, which is hinged on rolling element bearings on one end while the free end is supported on a load cell (proving ring) or a spring as required.