Agricultural Tractor Chassis Suspension System for Improved Ride Comfort

An exploratory concept for a chassis suspension system for improving the operator ride comfort of an agricultural tractor is presented in this paper. The first section of the paper describes the criteria and concepts that have been incorporated into the design of a hybrid leading and trailing arm chassis suspension system. The second section of the paper discusses the evaluation of this suspension system and its parameters by simulating nine (9) different tractor and nine (9) different tractor-plow models, derived from the various combination of suspension configurations and operator cab locations. A generalized mechanical system simulation program is utilized to predict the dynamic linear transfer function behavior of each vehicle model. With frequency domain analysis techniques and the Fast Fourier Transform (FFT) algorithm, the dynamic vehicle response to the ISO 5007 Smooth Track excitation is computed. Finally, ISO 2631 and SAE J1013 Standards are utilized to compute comparative ride numbers and it is shown that, in theory, a suspended chassis would provide improved ride comfort. Additional design factors, which must be considered prior to a hardware development, are then summarized for future consideration.