A computer based mathematical method for predicting the directional response of trucks and tractor-trailers, phase II: motor truck braking and handling performance study

Abstract

THE PURPOSE OF THE STUDY WAS TO ESTABLISH A DIGITAL COM- PUTER BASED MATHEMATICAL METHOD FOR PREDICTING THE BRAKING PERFORMANCE OF TRUCKS AND TRACTOR-TRAILERS. TWO SIMULATION PROGRAMS WERE DEVELOPED, EACH BASED ON A TWO-DIMENSIONAL (VERTICAL PLANE) MATHEMATICAL MODEL, ONE OF WHICH CAN REPRESENT A TWO- OR THREE-AXLE TRUCK, THE OTHER A THREE-, FOUR-, OR FIVE-AXLE TRACTOR-TRAILER COMBINATION. IN EACH CASE THE USER MAY SPECIFY THE VEHICLE GEOMETRY, BRAKES, SUSPENSION, TIRE AND TIRE-ROAD INTERFACE CHARACTERISTICS, WEIGHT, AND PAYLOAD DISTRIBUTION. THE USER CAN ALSO INTRODUCE ROAD ROUGHNESS INTO THE PROGRAM IN ORDER TO STUDY ITS EFFECT ON BRAKING PERFORMANCE. DETAILED DESCRIPTIONS OF THE MATHEMATICAL MODELS OF THE VEHICLES, SUSPENSION SYSTEMS, TIRES, BRAKES, AND BRAKE SYSTEMS ARE GIVEN IN SECTION 2. IN SEC. 3, THE DIGITAL COMPUTER PROGRAMS FOR SIMULATING VEHICLE BRAKING PERFORMANCE ARE DESCRIBED. SEC. 4 TREATS VEHICLE PARAMETERS AND THEIR MEASUREMENT. THE DYNAMIC TESTS ON THE FULL SCALE VEHICLES ARE REPORTED IN SEC. 5. COMPARISON OF THE RESULTS FROM VEHICLE SIMULATION AND VEHICLE TESTS ARE MADE IN SEC. 6, ALONG WITH A DISCUSSION OF THESE RESULTS. /AUTHOR/