Contact Inertial Odometry: Collisions are your Friends

TL;DR

This paper introduces a contact-based inertial odometry (CIO) method enabling drones to navigate cluttered environments solely with an IMU by exploiting collisions as a source of information, bypassing the need for exteroceptive sensors.

Contribution

It presents a novel collision-based odometry algorithm and a hybrid vehicle model that together allow autonomous flight without external sensors, validated through hardware experiments.

Findings

Quadrotor successfully navigates cluttered environments using only IMU data.

Collision exploitation improves robustness in perceptually degraded conditions.

The framework enables drones to recover from visual odometry failures.

Abstract

Autonomous exploration of unknown environments with aerial vehicles remains a challenge, especially in perceptually degraded conditions. Dust, fog, or a lack of visual or LiDAR-based features results in severe difficulties for state estimation algorithms, which failure can be catastrophic. In this work, we show that it is indeed possible to navigate in such conditions without any exteroceptive sensing by exploiting collisions instead of treating them as constraints. To this end, we present a novel contact-based inertial odometry (CIO) algorithm: it uses estimated external forces with the environment to detect collisions and generate pseudo-measurements of the robot velocity, enabling autonomous flight. To fully exploit this method, we first perform modeling of a hybrid ground and aerial vehicle which can withstand collisions at moderate speeds, for which we develop an external wrench estimation algorithm. Then, we present our CIO algorithm and develop a reactive planner and control law which encourage exploration by bouncing off obstacles. All components of this framework are validated in hardware experiments and we demonstrate that a quadrotor can traverse a cluttered environment using an IMU only. This work can be used on drones to recover from visual inertial odometry failure or on micro-drones that do not have the payload capacity to carry cameras, LiDARs or powerful computers.