Research on optimization of tractor brake pedal comfort considering environmental factors

Environmental factors are one of the main factors affecting the braking comfort of tractors. This study proposes a tractor “Hydraulic-Electric” dual-acting brake pedal feel simulator based on pedal force compensation to solve the braking impact problem caused by road unevenness input to the driver. The paper establishes a tractor vehicle dynamics model and an impact force transmission model under the influence of road environment; designs a pedal characteristic curve that meets comfort requirements based on the human foot movement law; proposes a pedal force compensation algorithm based on the Wiener-HammerStein nonlinear model, compares and verifies it with PID and ADRC control methods. The WH model outperforms the two comparative methods in four indicators: impact suppression rate, compensation delay rate, local root mean square error, and linearity of the impact area. Bench test results show that the linearity of both the initial and later stage of the brake pedal characteristic curve reached 0.99. Compared to existing tractors, the linearity of the initial stage improved by a maximum of 20.73%, and the linearity of the later stage improved by a maximum of 33.78%. In the two sets of impact tests, the WH model achieved impact force suppression rates of 91.81% and 97.18%, respectively, with a compensation delay rate of 0. The local root mean square error was reduced by 54.20% and 70.60%. Furthermore, the local linearity of both sets of tests exceeded 0.95, demonstrating good resistance to road disturbances. The dual-action pedal feel simulator provides the driver with stable and linear brake pedal force, effectively improving brake pedal comfort and enhancing driver confidence in the braking system.