Cooperative Multilift Slung Load Transportation Using Haptic Admittance Control Guidance

Abstract

This paper presents the first haptically guided cooperative small unmanned aircraft system payload transport system with experimental validation. A team of five quadrotors is connected with individual tethers to an instrumented payload. A user issues haptic guidance commands by applying force on the slung payload. The system estimates user-applied force and direction from inline tension sensors in real time. This force updates the virtual dynamics of an admittance controller to execute the desired trajectory of the payload in the direction of the applied force. A centralized payload controller commands quadrotor trajectories to track the admittance controller trajectory. Custom open-source autopilot software tracks user commands by translating each quadrotor to pull on the tethers in a manner that collectively moves the payload according to user input force. Simulation and experimental flight-test results in a netted facility validate the system with a user applying force directly on the slung payload to guide it.