| In the past few years,UAV-related technologies have a great development,so that the UAVs have been widely used in many fields such as rescue,electric power,agriculture,and exploration.In addition,kinds of drones are being used more and more widely in the military field,and the battlefield is gradually evolving towards unmanned and intelligent.In response to this trend,this article uses a quadrotor UAV as an application platform and uses visual sensors to design an UAV system with tracking and attacking capabilities.Since it is convenient to carry and take off,it can be widely used in soldier squads to expand the combat range.The main research contents are as follows:Firstly,according to the requirements of the system mission,the system is divided into two parts: the four-rotor UAV platform and the ground station,and then the design is completed from the two aspects of hardware and software.Among them,the software design of the UAV platform is emphasized,which is divided into four levels: visual layer,application layer,middle layer and bottom driving layer according to functional requirements,and realizes the modular design of functions in each layer.Secondly,in order to accurately describe the image information and movement state information of the UAV,multiple Coordinate Systems in the system are established,and the mutual conversion relationship between the Coordinate Systems is also constructed.In addition,based on the camera model and image information,the formula for calculating the relative position of the drone and the target is derived when there is only a pitch angle.Then,the focus is on the target tracking algorithm.Through the analysis of the principle of the KCF target tracking algorithm,we obtained the reason why it cannot adapt to the change of the target scale.Then,in response to this defect,an improved KCF algorithm which could handle the variable target scale problem is designed;According to the actual problems faced by the system,the tracking method is selected as the guidance law of the system to guide the UAV attacking the target;Using image information as system feedback,a double closed-loop control scheme with the inner loop as the attitude loop and the outer loop as the image servo controller is designed.Image servo controllers are designed for the two processes of target tracking and target attack.Finally,the feasibility of the system algorithm was verified on the quad-rotor UAV platform.The experiments of target tracking and target attack were carried out respectively,and the specific performance of the system was analyzed through the actual performance and flight log of the quad-rotor UAV. |
