Biologically inspired legs for UAV perched landing

Abstract

The ability of UAVs to perform a “perch and stare” manoeuvre could significantly enhance their effectiveness during surveillance and reconnaissance missions. Herein, the concept of a biologically inspired leg-based landing system has been presented. The controllers have been tested in simulation and designed to minimize the forces experienced by UAVs during the perched landing manoeuvre, which is significant considering the sensitive payloads carried by them. With accurate position control, velocity matching using a polynomial spline trajectory can be used to minimize impact with the perch. Cushioning the inside of the gripper mechanism with a material that has spring-damper properties can help reduce the impact and prevent slip and bounce on contact with the target. Estimating the kinetic energy of UAVs during the capture provides the controller with sufficient information to vary the amount of force being applied in real-time to decelerate it. By combining an adaptive bell-shaped stiffness controller and velocity matching scheme, a safe and successful perched landing manoeuvre can be accomplished. The required accuracy and high speed of operation required for this manoeuvre are limited by the performance of available actuators and the control bandwidth of the hardware. A video render of the perched landing manoeuvre is included as a part of this submission and can be found at [26].