Research on considering tracking performance and riding comfort for intelligent tractor based on hierarchical cooperative control

• A adaptive method is proposed to enhance the trajectory tracking performance. • Derive a tractor vertical dynamics model considering the effect of velocity. • A model predictive control is proposed for an active seat suspension. • Longitudinal-lateral-vertical cooperative control method for tractors is proposed. • Tracking performance and riding comfort are simultaneously improved. Tracking accuracy and ride comfort are important performance indicators of tractors. In order to improve the tracking performance and ride comfort of intelligent tractors at the same time, this paper proposes a tractor longitudinal-lateral-vertical hierarchical cooperative control method. Based on the kinematic principle, the longitudinal-lateral kinematic models are constructed. Considering the influence of actual velocity on road excitation, the vertical dynamics model is constructed by combining automobile system dynamics theory. In the longitudinal and lateral aspects, a steady-state transient hybrid operating condition trajectory tracking adaptive control method is proposed to improve the tracking accuracy; in the vertical aspect, an active seat suspension control method integrating velocity factors is proposed by using model predictive control to improve the ride comfort of tractors. Finally, the variable transfer of longitudinal and lateral and vertical control is realized through actual velocity, forming a tractor longitudinal-lateral-vertical hierarchical cooperative control method. In order to verify the superiority of the proposed method, the tractor longitudinal-lateral-vertical hierarchical cooperative control method is simulated and analyzed under random road excitation and S-curve trajectory with the coordinated control method formed by pure tracking control and proportional-integral-derivative control. The results indicate that the proposed control method can simultaneously enhance the tractor trajectory tracking accuracy and riding comfort.