Air cooling design for the motor system of electric agricultural robots

To address the challenges of motor system temperature rising and the failure of temperature-sensitive components in electric agricultural robots, this study focuses on the cooling design for the motor system of a specific electric weeding robot using simulation and experiment methods. Optimal cooling fan configuration was proposed, and the safe operational fan airflow volume range at varying working ambient temperatures was determined. First, the thermal properties of the physical model, including component materials, internal heat sources, and fluid conditions, were analyzed. A three-dimensional, full-domain simulation model was then developed, and steady-state fluid-thermal coupling field calculations were performed for three different fan configurations. These simulations identified the optimal fan configuration and highlighted the motor as the primary heat-generating component. Under this configuration, the cooling performance improved by 22.7% and 22.3% compared to the other two configurations. Furthermore, based on the optimal fan setup and the operational temperature characteristics of the electric weeding robot, the relationships between motor temperature, fan airflow, and ambient temperature were analyzed and modeled. Real-time, high-precision steady-state temperature experiments were conducted to validate the airflow-motor temperature relationship, leading to the establishment of a safe operational airflow range based on the maximum allowable motor temperature. The implementation of this safe airflow range reduces the probability of motor system failure by at least 60%. This work provides theoretical and practical insights for enhancing the cooling design of motor systems in electric agricultural robots.