A joint control method considering travel speed and slip for reducing energy consumption of rear wheel independent drive electric tractor in ploughing

Improving tractor traction efficiency is greatly important in increasing energy efficiency and reducing fossil fuel consumption. However, the wheeled tractors have problems with low traction energy efficiency and severe energy consumption due to excessive wheel slip in ploughing. This paper proposed a joint control method considering the travel speed and slip based on the active torque distribution, which is applied to the independent drive electric tractors. Considering the influence factors of time-varying resistance and terrain elevation in ploughing, a time-varying dynamical model for the tractor-implement combination was established to reveal the load transfer rules. Then the optimal slip values of the driving wheels were solved in real-time, and a sliding mode algorithm was used to control the motor torque for efficient tractor operation. Moreover, a hardware-inthe-loop platform was built, and ploughing tests were performed. The results indicated that the tractor slip, traction energy efficiency and motor energy consumption of the tractor were optimal in the torque active distribution mode. Compared to the torque average distribution mode, the proposed method reduced the tractor slip by 14.1%, the motor energy consumption by 6.8% and increased the traction energy efficiency by 6.8%. This study provided technical support for reducing energy dissipation in ploughing.