Lightweight and Compliant Long Reach Aerial Manipulator for Inspection Operations

Abstract

The proximity between the multirotor blades and the environmental obstacles restricts the application of aerial manipulators in inspection tasks due to the risk of impacts, the limitation in the reach of the arm, and the physical interactions. This paper presents a long reach aerial manipulator consisting of a hexarotor platform equipped with a 2-DOF compliant joint arm attached at the tip of a one-meter-length link in passive pendulum configuration. The arm integrates magnetic encoders for force/torque estimation-control based on joint deflection, a range sensor in the forearm link for measuring the distance to the contact point, and a camera for visual inspection. A 2-DOF wearable exoskeleton interface has been developed, allowing the teleoperation of the arm with visual feedback in a more intuitive way. The paper also covers the kinematics and dynamics of the aerial manipulator, including the dynamics of the flexible long reach link. The developed system has been evaluated in testbench and in outdoor flight tests.

Nonlinear Model Predictive Control for the Stabilization of a Wheeled Unmanned Aerial Vehicle on a Pipe

“…The problem of carrying out large forces in contact with the environment with an underactuated drone is instead investigated in [3] through the use of LQRoptimized state feedback on the roll and yaw angle. In case the inspections measurements are performed in a crowded and narrow environment, and the drone is too bulky to stay close to the surface to be inspected, a long reach aerial manipulator can be employed [4].…”

Online Detection and Tracking of Pipes During UAV Flight in Industrial Environments

“…Recent research has explored the use of Unmanned Aerial Vehicles (UAVs) in industrial environments in order to endow robots with the necessary capabilities to navigate and interact with pipes. In a recent work, [9] developed a long reach aerial manipulator for pipe inspection. Assuming the location of the pipe structure was known and relying on contact force sensing, the authors presented a 2-DOF compliant arm attached at the tip of a pendulum bar to contact the non-accessible sides of the pipes.…”

Development of SAM: cable-Suspended Aerial Manipulator

“…To resolve these issues, several prototypes with long reach manipulators have recently been developed [20], [21]. Long reach means that the robotic manipulator is attached to the UAV using a long flexible link instead of being mounted directly.…”