无人机跟踪系统仿真平台的设计与实现

Design and implementation of simulation platform for UAV tracking system

摘要:

为解决无人机(Unmanned Aerial Vehicle, UAV)在进行地面目标跟踪实验时,存在验证难度大,成本高等问题,设计和实现了基于视景仿真软件和MATLAB/Simulink的仿真平台.首先,选择汽车作为地面目标,在视景仿真软件中导入UAV和汽车的三维模型,并设置虚拟云台和摄像机.其次,利用UAV、汽车与云台之间的相对运动模拟UAV跟踪过程中场景的变化,基于运动补偿的云台控制算法保证了虚拟摄像机始终指向目标.然后,虚拟摄像机采集目标所在区域的图片,图像跟踪算法跟踪图片中的目标,并利用目标图像模型解算目标在世界坐标系下的位置.最后,根据目标位置,使用参考点制导法生成期望的滚转角指令,引导UAV围绕目标盘旋飞行.视景仿真软件、图像跟踪算法和MATLAB/Simulink之间通过共享内存与UDP进行闭环通信.此外,提出一种实用可靠的标定方法,完成了视景仿真软件中虚拟摄像机内参矩阵的标定.仿真结果表明:该仿真平台能较好地模拟UAV对不同运动状态汽车的跟踪,得到的仿真结果具有较高的工程参考价值.本文的研究成果为目标跟踪实验提供了良好的仿真环境,有效减少实验成本.

Abstract:

Ground target tracking experiments using unmanned aerial vehicle (UAV) are difficult to verify and the cost is high. To solve the problem, a simulation platform based on visual simulation software and MATLAB/Simulink was designed and implemented. First, vehicle was selected as ground target. The 3D models of UAV and vehicle were imported into the visual simulation software, and virtual gimbal and camera were set up. Next, the relative motions of the UAV, vehicle, and gimbal were used to simulate scene changes during the tracking process, and the gimbal control algorithm based on motion compensation ensured that the virtual camera always points at the target. Then, the virtual camera was used to capture the image of the target. The image tracking algorithm could track the target in the image and use the target image model to calculate the target position in the world coordinate system. Finally, according to the target position, the reference point guidance method was used to generate the desired roll angle command to guide the UAV to circle around the target. Closed-loop communication between visual simulation software, image tracking algorithm, and MATLAB/Simulink was carried out with UDP and shared memory. In addition, a practical and reliable calibration method was proposed to calibrate the internal matrix of the virtual camera in the visual simulation software. Simulation results demonstrate that the platform can simulate the tracking of ground target by using UAV, and the results have high reference value for engineering. The research in this paper provides a good simulation environment for target tracking experiments and can reduce the cost of experiment effectively.