Abstract: The frame of the towing vehicle, as the core load-bearing structure of the aireraft towbarless towing vehicle, di-rectly determines the safety of the aircraft towing and taxiing system through its strength and stiffness. This paperdesigns a frame structure for the towing vehicle tailored to the towing requirements of small aircraft and developsa corresponding dynamic simulation model to thoroughly investigate the effects of towing speed and road obstaclebump height on frame loading. Finite element simulation, structural optimization design, and experimental vali-dation reveal that when the rear wheels of the towing vehicle encounter an obstacle bump, symmetric and equalmaximum forces are generated on the left and right side beams of the frame, and these forces increase significant-y with increasing towing speed. Under the condition of a towing speed of 30 km/h and an obstacle bump height of30 mm, the frame loading and stress level reach their peaks, causing local stress values to exceed the material'sallowable stress limit. After structural optimization, the frame's load-carrying capacity is improved by 86.31%without exceeding the allowable stress, and the accuracy of the optimized model is validated by experimental da-a. This paper can provide important theoretical basis and practical reference for the subsequent design and opti-mization of towing vehicle frames.

Key words: aircraft towing and taxiing, towbarless towing vehicle, Adams simulation, finite element model, vehicle dynamics