Design And Implementation Of An Obstacle Avoidance System For UAV Assisted By Machine Vision In Low-altitude Environment

With the rapid development of the UAV(unmanned aerial vehicle),the technology of it has been playing an inseparable role in many areas and has gradually become a research hot spot.Among the technologies of the UAV,autonomous obstacle avoidance technology stands out as an important one.It not only guarantees the completion of flight missions,but also represents the security and intelligence of the UAV to some extent.Among a variety of obstacle avoidance methods,the research focus is the visual obstacle avoidance method,which has a broad application prospect and meets the requirement of the UAV in low altitude environment.Therefore,this paper aims to design a UAV obstacle avoidance system based on stereo vision,and the main tasks are listed as follows.Firstly,it focuses on the overall design of both the software and hardware of the UAV visual obstacle avoidance system.The system is divided into the aerial part and ground part,which mainly includes visual information detection system,wireless data link communication system,flight control system,ground return control system and other subsystems.By dividing it,each part of the system becomes independent,which grants the system with advantages such as flexible combination,easy debugging and transplantation etc.,while also reserves the scalability of increasing new features.Secondly,it introduces the theoretical framework of the binocular vision detection system as well as the application of the software and hardware systems,specifically including the use of the OpenCV for image collection and process and the MATLAB for camera calibration.In the meantime,it obtains the disparity results through eliminate distortion,correcting and matching so as to detect the obstacles and collect the obstacle distance information.Finally,it designs wireless serial communication software aimed at the threatening targets,which can immediately send the obstacle-avoiding decision made by the ground system based on the visual information to the air control system so as to complete the task of controlling the flight attitude and avoiding obstacles.At the end of this paper,it conducts the test of the obstacle avoidance system and analyzes the results to verify the feasibility and effectiveness of the system.