# Visual-Inertial Teach and Repeat for Aerial Inspection

## TL;DR

This paper introduces a system enabling human operators to teach aerial inspection tasks to drones via demonstration, utilizing visual-inertial mapping for robust operation in GPS-denied environments, with real-time multi-robot tracking capabilities.

## Contribution

The novel system allows easy teaching of inspection paths to MAVs using a handheld device and employs a visual-inertial framework for accurate localization without GPS.

## Key findings

- Successful autonomous inspection path following
- Robust operation in GPS-denied environments
- Real-time multi-robot pose tracking

## Abstract

Industrial facilities often require periodic visual inspections of key installations. Examining these points of interest is time consuming, potentially hazardous or require special equipment to reach. MAVs are ideal platforms to automate this expensive and tedious task. In this work we present a novel system that enables a human operator to teach a visual inspection task to an autonomous aerial vehicle by simply demonstrating the task using a handheld device. To enable robust operation in confined, GPS-denied environments, the system employs the Google Tango visual-inertial mapping framework as the only source of pose estimates. In a first step the operator records the desired inspection path and defines the inspection points. The mapping framework then computes a feature-based localization map, which is shared with the robot. After take-off, the robot estimates its pose based on this map and plans a smooth trajectory through the way points defined by the operator. Furthermore, the system is able to track the poses of other robots or the operator, localized in the same map, and follow them in real-time while keeping a safe distance.