Vibration characteristics analysis and suspension parameter optimization of tractor/implement system with front axle suspension under ploughing operation condition.

[Display omitted] • Front axle suspension deteriorate the ride comfort but improve the handing stability obviously. • Farmland road roughness and tillage resistance can reduce the vibration responses of the tractor system significantly. • The largest vertical vibration acceleration exists on the front axle. • The optimum stiffness and damping of the front axle suspension are recommended to be 60 kNm−1 and 8.919 kNsm−1, respectively. To improve the riding comfort and driving safety of the tractor system, it's necessary to build a vibration model of wheeled tractor/implement system to analyze its corresponding vibration characteristics. A discrete element model of plough-soil coupling system was developed in this work to obtain the tillage resistance and its effectiveness is verified through experiment. Then, the vibration model of wheeled tractor/implement system with front axle suspension under ploughing condition was constructed and the corresponding vibration characteristics of the tractor system under road transportation, farmland transportation and plough operation conditions were simulated. It's demonstrated that the simulated vibration responses agree well with the measured data and the validity of the proposed model is proved. The simulation results show that the natural frequency of the tractor system almost remains constant under the three working conditions above and the natural frequencies of vertical vibration for front axle, cabin, driver seat and implement are 2.09 Hz, 2.84 Hz, 2.84 Hz and 2.09 Hz, respectively. The existence of front axle suspension will deteriorate the ride comfort of driver but improve the handing stability obviously. The farmland road roughness and tillage resistance can reduce the vibration responses of the wheeled tractor/implement system with front axle suspension significantly. With the increase of tillage speed or depth, the vibration responses of the tractor system rise tremendously. When the tillage speed or depth is constant, the largest vertical vibration acceleration exists on the front axle. In addition, the multi-objective optimization of stiffness and damping parameters for the front axle suspension is implemented through particle swarm algorithm and the optimal stiffness and damping are recommended to be 60 kNm−1 and 8.919 kNsm−1, respectively. [ABSTRACT FROM AUTHOR]