Drone Arrestment System

Sammanfattning

Autonomous fixed wing drones have the potential to significantly improve maritimesearch and rescue operations by providing early situational awareness before rescuevessels depart. A central challenge for such systems is the reliable and autonomousretrieval of the drone after a completed mission. This thesis addresses that challengeby investigating and developing a mechanical drone arrestment system intended asa test platform for the Swedish Sea Rescue Society’s autonomous drone program.The work focuses on conceptual design, mechanical feasibility, and preliminary dimensioningof an arrestment system inspired by existing mid air recovery solutions.A capture concept based on a fixed hook mounted on the drone and a ground basedstring mechanism was selected and developed through iterative prototyping. Specialattention was given to compensating for the roll motion typical of flying wingaircraft, as well as to handling the high mechanical loads generated during the arrestmentevent.A kinematic model based on a cylindrical coordinate system was developed to describethe position of the capture string relative to the approaching drone. Thismodel was used to guide the mechanical layout of the system and to support aproof of concept control approach. Several energy absorption concepts were evaluated,and a constant force band spring was selected as a compact and mechanicallysimple solution for controlled deceleration. Physical prototypes and preliminarystructural analyses were used to assess geometric feasibility and to identify criticaldesign constraints.The outcome of the project is a mechanically viable arrestment system conceptsupported by analytical reasoning, CAD models, and prototype testing. Althoughfull scale validation and closed loop control were outside the scope of the work,the results demonstrate that the proposed approach is feasible and provide a clearfoundation for future experimental testing and system integration.