Abstract:

One of the weaknesses of multi-rotor unmanned aerial vehicles (UAVs) or vertical take-off and landing aircraft is that they need a flat surface to make a safe landing. In order to reduce the impact of this weakness, it is inevitable to add systems that will give the UAV some additional capabilities related to landing capability. In this study, a four-arm adaptive landing gear is designed and kinematically analyzed for a multi-rotor UAV. The adaptability feature is achieved by positioning the arm ends relative to the uneven ground by automatically changing the angles of the revolute joints so that the vehicle can land safely on uneven ground. The joint angles of the adaptive landing gear, which consists of four robotic arms, each with two joints, are changed by the controller depending on the distance information received from the ultrasonic distance sensor. This distance information is evaluated in the controller according to the determined algorithm and the required angle values of the joints are determined. Within the scope of this study, a scaled adaptive landing gear was designed for an eight-rotor UAV whose mathematical model was also obtained. According to proposed landing gear, which consists of four arms with two limbs, each with a length of 200 mm, the maximum angle of inclination of the uneven ground on which the UAV can land safely is calculated as 44.5°. In addition, the motion trajectory of the end point of the arm, which is the part of the arm that will contact the ground, was obtained with the simulation performed.

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