Reachability-Based Collision Recovery Strategy of a Quadrotor

Collisions with surrounding objects pose huge threat to flying quadrotors, especially in unknown environments. Unfortunately, quadrotors equipped with sensors (cameras, radars, etc.) cannot effectively detect small objects such as wires and branches. In this paper, a global stability control strategy is proposed for collision recovery based on the reachability theory. Reachability analysis is used to divide the collision recovery process into three modes:1)collision, 2)idling, 3)recovery. Safe switching conditions between different modes are generated by using solution of the Hamilton - Jacobi equation. A safe control law is presented based on the quaternion, which is proven to be globally stable and can quickly recovered from any attitude. Feasibility and performance of the proposed method are verified by experiments with collision maneuvers. Copyright (C) 2020 The Authors.