What happens when you drive your car over a curb? Usually nothing. The steering linkages and suspension parts do not break, and this is a good thing. That these parts survive the shocks and stresses of everyday driving is the result of a comprehensive test program designed to determine the forces that are applied to critical parts of a vehicle’s suspension and steering.

Measurement of the forces acting on the suspension parts requires that strain gages be placed at critical points on each piece. Strain gages require excitation, bridge completion and high amplification in order to produce a signal useful for data acquisition.

String pot displacement sensors are used to measure the position of the suspension parts. Signal conditioning for the string pots and strain gages must be compact and operate from vehicle power in order to be useful for vehicle testing.

The Validyne MC170-X operates from vehicle power, and is a rugged signal conditioning system measuring just 3.5” x 6” x10”. The SG297A strain gage amplifiers provide precision excitation and amplification. The SG297A also provides for lead-wire compensation to reduce errors and bridge completion for single-active gage measurements.

The PC202 potentiometer conditioner provides excitation for the string pots and scaling for the output signal.

The MC170 system provides a +/-10 Vdc output signal for each strain gage or potentiometer signal that is suitable for input to a high speed data acquisition system. The dynamic relationship between the stress on a part and its position can be studied as the vehicle is driven over an obstacle course.