Image Dynamics-Based Visual Servo Control for Unmanned Aerial Manipulatorl With a Virtual Camera

Abstract

This article proposes a visual servo control method based on image dynamics for an unmanned aerial manipulator (UAM) combining an unmanned aerial vehicle (UAV) with a multidegree-of-freedom onboard manipulator. First, taking into account the dynamic characteristics of the coupled UAM, the dynamic model of the coupled system is derived. Then, based on the perspective projection model, the appropriate image features are defined on the virtual image plane to obtain decoupled image feature dynamics. Combining image features dynamics and UAM dynamics, the position and attitude controller of the UAM flying platform with the center of gravity compensation is derived. Furthermore, the image feature motion is further applied to the positioning control of the end-effector of the onboard manipulator. In addition, the UAM motion distribution strategy is designed to coordinate the movement between the UAM flying platform and the onboard manipulator. The simulation results illustrate the performance of the proposed visual servo control based on image dynamics. As a result, the trajectories of the feature points are smooth in the real image plane, which means the UAM movement is stable. Finally, the experimental results in an outdoor environment verify the practicability and effectiveness of the proposed visual servo control method for autonomous operations. The proposed control method manages the UAM from an unknown initial position to the desired position, which can be applied to various types of aerial operations missions such as object transmission.