Direct yaw moment control and realization mode of handling stability for high-clearance sprayer

To solve the problem of poor handling and stability control effect of self-propelled high-clearance sprayer under low-speed operating conditions, a direct yaw moment control scheme of handling stability was proposed. The 7-degree-of-freedom vehicle model including Dugoff nonlinear tire model was established, and a vehicle torque controller was designed with longitudinal control and lateral control. The longitudinal control was used to drive the wheels according to the error between actual vehicle speed and expected vehicle speed, and the force was controlled by PID closed-loop control. The lateral control was mainly composed of sliding mode controller and torque distributor, which was used to make up for the lack of longitudinal control on the driving force control. Five wheel control schemes were designed to achieve direct yaw moment for the realization of lateral control torque. The quadratic rotation orthogonal combination test was designed by the direct yaw moment realization scheme with vehicle speed and load quality as factors. By the response surface method, Design Expert software was used to explore the relationship between three factors and optimization index of handling and stability of working vehicle after introducing the direct yaw moment. The simulation test results show that the vehicle torque controller can effectively improve the steering stability of vehicle, and by changing the control scheme of inner wheel, the optimization index reaches as high as 55.2% under the combination of working speed of 1.25 m·s ^-1 and load of 1 000 kg.