Core Concepts
This work presents a novel aerial vehicle tailored for handling heavy tools on non-horizontal surfaces. The platform can shift its center-of-mass towards the work surface to enhance horizontal force generation and reduce the moment arm between the end-effector and the center-of-mass.
Abstract
The content describes the design, modeling, and control of a novel aerial vehicle for handling heavy tools on non-horizontal surfaces.
Key highlights:
- The aerial vehicle has a coaxial octocopter configuration with fixed front rotors and tiltable back rotors. This allows decoupling of horizontal force generation and gravity compensation.
- The system's center-of-mass can be shifted along the body axis by moving a shifting-mass plate. This enables the center-of-mass to reach the maximum displacement towards the work surface.
- A self-positioning approach is proposed to automatically determine the optimal shifting-mass position to achieve the maximum center-of-mass displacement.
- The control design includes a low-level geometric attitude controller and a high-level selective impedance controller, with a control allocation module to map the desired wrenches to the rotor inputs.
- Simulation results validate the proposed concepts and demonstrate the platform's capabilities in free flight and physical interactions with a vertical surface.
Stats
The aerial vehicle has a total mass of m, with the shifting-mass having a mass of mS.
The moments of inertia along the body axes are given by:
Iyy(l) = 0.49l^2 + 0.0538 (kgm^2)
Izz(l) = 0.52l^2 + 0.0795 (kgm^2)
Quotes
"Carrying heavy tools at the EE tip of the manipulator with an extended moment arm can lead to system instability and potential damage to the servo actuators used in the manipulator."
"The CoM shifting is accomplished by the linear motion of a movable plate equipped with major heavy components, including the manipulator for heavy-tool handling, referred to as the shifting-mass."
"Ideally, it is desired to have the system's CoM shifted to the maximum displacement d = L during interactions, where the shifting-mass is positioned outside the rotor-defined area towards the work surface."