This thesis investigates the problem of ground handling and pushback of small aircraft in constrained environments through the design and simulation-based evaluation of an omni-wheeled towbarless aircraft tug. Conventional towing solutions remain effective for straightforward longitudinal maneuvers, but their non holonomic nature limits their efficiency when precise repositioning is required inside hangars, maintenance areas, or other restricted operating spaces. In response to this limitation, the present work investigates a compact tug architecture capable of directly handling the aircraft nosewheel and exploiting omnidirectional mobility to improve maneuverability, reduce the operational footprint of the maneuver, and increase positioning accuracy during low-speed ground operations.
The tug structure, wheel layout, and nosewheel handling concept were developed in SolidWorks as a towbarless platform in which the aircraft nosewheel is lifted, captured and supported inside a central bay. On the control side, the study focuses on the kinematic and dynamic behavior of the tug and of the coupled tug-aircraft system. Once the nosewheel is lifted into the tug, the vehicle can no longer be modeled as an isolated omnidirectional platform, since the aircraft main landing gears remain in ground contact and introduce additional rolling constraints. The work therefore develops the corresponding kinematic framework of the complete tug-aircraft assembly and studies the relation between commanded chassis motion, wheel-speed allocation, and the resulting motion of the coupled system.
The simulation environment was developed in MATLAB/Simulink and Simscape Multibody in order to preserve both the mechanical and control aspects of the problem within the same platform. The control architecture includes trajectory generation, inverse kinematics, motor-side actuation, and closed-loop wheel-speed regulation, so that the system is evaluated beyond an idealized geometric model. Representative maneuvers were simulated to assess the feasibility of the proposed concept and to examine the ability of the tug to generate controlled omnidirectional motion while towing the aircraft through the nosewheel interface. The results provide a structured basis for evaluating the relevance of an omni-wheeled towbarless tug for small-aircraft handling and establish a foundation for future refinement toward prototype development and experimental validation.

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