DYNAMIC SIMULATION OF WHEEL-TRACTOR USING A POWERED SCALE MODEL (VALIDATION OF HIGHWAY-VEHICLE-OBJECT SIMULATION MODEL PROGRAM FOR TRACTOR DYNAMICS)

Study of tractor dynamics has been of interest to many researchers and designers. Studies vary from a simplified two or three degree of freedom model for obtaining specific dynamic responses to a complicated ten degree of freedom model for obtaining generalized tractor dynamic responses. The sophistication and scope of the investigations have advanced from the study of passive responses to small amplitude disturbances to the interactive responses of powered tractor and various terrain conditions.;A powered scale model tractor was used in performing the experimental tests. The physical parameters of the model tractor were measured and discussed. Video-tape techniques were used to film the responses of the scale model tractor. Verification of the mathematical model was assumed to be achieved by a favorable comparison between the films and the perspective drawings from the printed output of the simulation runs.;The mathematical model and simulation programs allow prediction of various tractor motions. The simulation results have helped in analyzing the relative sensitivities of various parameters that affect the tractor motion. The results could be applied to tractor accident reconstruction, improved tractor design, and accident prevention.;The object of this investigation is to develop or to adapt a computer simulation model to predict the dynamic responses of a wheel-tractor under various terrain conditions. The mathematical model of the tractor consists of eleven degrees of freedom--six for the tractor body, one for each wheel and one for the steering. The digital computer program was used to implement the mathematical model and simulate two experimental test situations.