Design and Control of an Implement Leveling System for Crawler Tractors

Crawler tractors are essential equipment for modern agricultural mechanization. Most existing mounted implement leveling systems rely on single-cylinder or dual-cylinder structures. These system can only make small-angle leveling and struggle under complex conditions such as large roll angles and asymmetric obstacle crossing. To address this, a modular auxiliary-frame leveling system (MALS) for agricultural implements is proposed. A 3D model of the leveling mechanism is designed, and a fuzzy adaptive PID control algorithm is implemented. The electric cylinder actuator is modeled via a transfer function linking input voltage to mechanical displacement, This provides a theoretical basis for controller design and dynamic performance evaluation. Subsequently, a crawler tractor asymmetric obstacle-crossing simulation model is constructed in Adams and integrated with Simulink to form a co-simulation platform, analyzing system performance under a 220 mm single-side obstacle condition. Simulation results indicate that the MALS achieves an extreme adjustment range of ±25°. Further validation on the integrated prototype confirms the effectiveness of the simulation model and control strategy. This demonstrated that the system can be adapted for use in complex terrain operations.