As a key piece of agricultural mechanization equipment, harvesters play a crucial role in improving agricultural productivity and operational quality. With the increasing complexity of operating environments, especially under hilly and mountainous terrain and on wet, slippery soils, harvester slip has become an increasingly prominent problem. Excessive slip seriously impairs traction efficiency, energy consumption, operational stability, and working quality, making slip-ratio control a core technology for addressing this challenge. This paper reviews slip control methods for harvesters under complex terrain conditions, including slip-ratio observation and estimation, slip prediction, and control strategies. Different categories of slip control methods and their current applications are discussed in detail. Existing limitations are analyzed, and future research directions are proposed to provide new technical support for improving the efficiency and stability of harvesters in complex operating environments.

Electric tractors driven by dual motors have become a critical research topic in the field of pure electric tractor research. As a key component of the transmission system, the optimization of the internal parameters of the power-coupled transmission gearbox has a crucial impact on the power transmission of the whole machine. This work combines the characteristics of low speed and high torque during tractor operation, and adopts the transmission form of double motor input and double planetary group coupling output to design the transmission structure of the gearbox. Then, this paper proposes a dynamic optimization method of the transmission system based on the Improved Deep Deterministic Policy Gradient (IDDPG) algorithm, which realizes the optimization of the gear ratio of the transmission system by constructing a virtual prototype and hardware-in-the-loop simulation environment. In transport mode, the optimized gear ratios shorten the acceleration time of the tractor from 0-20 km/h by 13.6% and increase the motor efficiency by 10%; in rotary mode, the acceleration performance is improved by 28.5% and the motor efficiency is increased by 5%. The study shows that the proposed method is significantly better than the traditional static design and provides a new technical path for the intelligent optimization of the electric tractor drive train, while promoting the efficient and sustainable development of agricultural machinery.