Random, Quasi-Periodic and Chaotic Vibrations of Farm Tractors

Abstract

The nonlinear dynamics of a larger size tractor was investigated experimentally using a frequency response test over a wide range of forward speed chosen as the controlled parameter. The analysis was carried out in the time domain and the qualitative changes of the dynamics of the tractor were analyzed using the phase portrait and Poincaré section that identified the quasi-periodic vibrations in the middle speed range of 1.51-3.08m/s. Quantitative analysis using the correlation dimension analysis identified the random vibration in the low speed range of 0.63-1.42m/s and deterministic chaotic vibration with the largest Lyapunov exponents occurred in the high-speed range of 3.32-4.50 m/s.