Feasibility study of an aerial manipulator interacting with a vertical wall
Naval Postgraduate School Monterey United States
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Modeling and control of aerial manipulators are presented in this study. An aerial manipulator is an unmanned aerial vehicle UAV equipped with a robotic arm. Aerial manipulators have potential for many applications, such as rescue operations along tall buildings and high cliffs, maintenance and repairing of power line equipment, and retrieval of items from difficult-to-access locations. Control of aerial manipulators is a challenging problem due to dynamic interactions between aerial vehicles and robotic arms. Additionally, when an aerial manipulator operates near or on a vertical surface such as a wall, there is the near-wall effect, which is the aerodynamic disturbance caused by the proximity of the flying vehicle to a wall. One of the objectives of this dissertation is to study the near-wall effect and develop controllers that are able to mitigate this disturbance when they are flying close to a wall. Another objective is to develop a controller to allow an aerial manipulator to fly in close proximity to a vertical surface and perform manipulation tasks by interacting with the surface to achieve the desired interaction forces and torques. Nonlinear models of generic aerial manipulators, as well as of a prototype aerial manipulator composed of a hexacopter with a three-joint robotic arm, are established. The near-wall effect is characterized by laboratory flight experiments. A free-flight controller incorporating the near-wall effect is proposed to compensate the near-wall disturbance. An equilibrium-based forcetorque controller is developed for executing tasks that require the aerial manipulator to exert forces and torques on a wall. The simulation and experimental results validated the performance of the controllers with successful near-wall flying while applying a specified amount of forces and torques on an object fixed on a wall.
- Pilotless Aircraft