A Bio-Inspired Manipulator with Claw Prototype for Winged Aerial Robots: Benchmark for Design and Control

Daniel Feliu-Talegon,Anibal Ollero,Alejandro Suarez,José Ángel Acosta

doi:10.3390/app10186516

Abstract

Nature exhibits many examples of birds, insects and flying mammals with flapping wings and limbs offering some functionalities. Although in robotics, there are some examples of flying robots with wings, it has not been yet a goal to add to them some manipulation-like capabilities, similar to ones that are exhibited on birds. The flying robot (ornithopter) that we propose improves the existent aerial manipulators based on multirotor platforms in terms of longer flight duration of missions and safety in proximity to humans. Moreover, the manipulation capabilities allows them to perch in inaccessible places and perform some tasks with the body perched. This work presents a first prototype of lightweight manipulator to be mounted to an ornithopter and a new control methodology to balance them while they are perched and following a desired path with the end effector imitating their beaks. This allows for several possible applications, such as contact inspection following a path with an ultrasonic sensor mounted in the end effector. The manipulator prototype imitates birds with two-link legs and a body link with an actuated limb, where the links are all active except for the first passive one with a grabbing mechanism in its base, imitating a claw. Unlike standard manipulators, the lightweight requirement limits the frame size and makes it necessary to use micro motors. Successful experimental results with this prototype are reported.

Highlights

Aerial manipulation platforms have been demonstrated to be a very efficient solution for applications, including contact inspection in industrial environments, cooperative free-flying for assembly and contact inspection in sites that are inaccessible by conventional means (e.g., European projects ARCAS FP7 [1] and the AEROARMS H2020 [2])
Electric-powered multirotor platforms have been demonstrated to be very efficient for manipulation, they still suffer some technology deficiencies e.g., the well-known relatively short flight missions of about few minutes and other inherent limitations when interacting within the proximity of people like noise and hazard situations
Two main control objectives have been studied with these kind of systems: (1) the stabilization of the system around an equilibrium point and (2) the swing-up problem. Unlike these standard underactuated manipulators, in this work we demonstrate that the use of a grabbing mechanism at its base imitating a bird’s claw allows us to simplify the controller design by combining the friction exerted by the mechanism and an adequate control of the system posture, and, more importantly, it allows us to follow trajectories with the end effector of the manipulator while balancing the system, which will be necessary for performing manipulation tasks such as the contact inspection following trajectories with an ultrasonic sensor mounted in the end-effector

Summary

Introduction

Aerial manipulation platforms have been demonstrated to be a very efficient solution for applications, including contact inspection in industrial environments, cooperative free-flying for assembly and contact inspection in sites that are inaccessible by conventional means (e.g., European projects ARCAS FP7 [1] and the AEROARMS H2020 [2]). All of these achievements have been possible thanks to the additional manipulation capabilities added to standard UAVs providing them with the ability to interact with the environment.

Objectives

Results

Conclusion