Aggressive Flight With Quadrotors for Perching on Inclined Surfaces

Abstract

Micro-aerial vehicles (MAVs) face limited flight times, which adversely impacts their efficacy for scenarios such as first response and disaster recovery, where it might be useful to deploy persistent radio relays and quadrotors for monitoring or sampling. Thus, it is important to enable micro-aerial vehicles to land and perch on different surfaces to save energy by cutting power to motors. We are motivated to use a downward-facing gripper for perching, as opposed to a side-mounted gripper, since it could also be used to carry payloads. In this paper, we predict and verify the performance of a custom gripper designed for perching on smooth surfaces. We also present control and planning algorithms, enabling an underactuated quadrotor with a downward-facing gripper to perch on inclined surfaces while satisfying constraints on actuation and sensing. Experimental results demonstrate the proposed techniques through successful perching on a glass surface at various inclinations, including vertical.

Energetics in robotic flight at small scales

“…Gecko-inspired adhesives have been found successful for perching on smooth inclined and vertical surfaces [70,93,94]. In addition, rotorcraft perching can be achieved via various attachments such as suction-based mechanisms [95], spines [96], and passive [97,98] and active [2,99] grippers.…”

Touchdown to take-off: at the interface of flight and surface locomotion

“…For robots, similar scaling applies. However, by employing systems to distribute adhesive stress evenly, rotorcraft that perch with dry adhesives can exceed 0.5 kg [142]. As animals get larger, they rely increasingly on claws.…”

“…Despite the strict control requirement, pitch-up manoeuvres offer design advantages for surface attachment. In a pitched up configuration, the robot can align its structure more closely to the surface, which minimizes the destabilizing pitch-back moment from the centre of mass with respect to the surface contact points (figure 3b,c) [18,43,51,52,[142][143][144]159].…”

“…As a result, many demonstrations of pitch-up manoeuvres with physical prototypes, both with fixed wings and quadrotors, have relied on motion capture systems for absolute situational awareness. These systems have been used for experiments to empirically generate the required control for trajectory planning (figure 3a) [57,156] and can give continuous position feedback (figure 3c) [142,143,[157][158][159][160][161][162]. The few robots that have not required a motion capture system use sensors to detect a wall and initiate a pitch-up manoeuvre ( figure 3b,c) [18,51,52,163].…”

Attitude, Linear Velocity and Depth Estimation of a Camera Observing a Planar Target Using Continuous Homography and Inertial Data

“…Significant advances have also been obtained in the last few years in the domain of controlling aerial robotic vehicles. We may cite, for instance, quadrotor landing on inclined surfaces [26], quadrotor manoeuvring with a cable-suspended payload [25], inverted pendulum balancing and catching [3]. However, in these examples the local environment is not taken into account.…”