This paper describes a camera position control with aerial manipulator for visual test of bridge inspection. Our developed unmanned aerial vehicle (UAV) has three‐degree‐of‐freedom (3‐DoF) manipulator on its top to execute visual or hammering test of the inspection. This paper focuses on the visual test. A camera was implemented at the end of the manipulator to acquire images of the narrow space of the bridge such as bearings, which the conventional UAV without the camera‐attached manipulators at its top cannot achieve the fine visual test. For the visual test, it is desirable that the camera is above the body with enough distance between the camera and the body. As obvious, the camera position in the inertial coordinate system is effected by the movement of the body. Therefore we implement the camera position control compensating the body movement into the UAV. As a result of an experiment, it is assessed that the proposed control reduces the position error of the camera comparing the one of the body. The mean position error of the camera is 0.039 m that is 51.4% of the one of the body. Our world‐first study enables to acquire the image of the bearing of the bridge by a camera mounted at the end effector of aerial manipulator fixed on UAV.

中文翻译：

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使用三自由度机械手的无人驾驶飞机的稳定摄像机位置控制，用于桥梁检查的视觉测试

本文介绍了一种用于空中检查桥梁检测的带有空中操纵器的摄像机位置控制。我们开发的无人机（UAV）的顶部具有三自由度（3-DoF）机械手，用于执行检查的视觉或锤击测试。本文着重于视觉测试。机械臂末端安装了一个摄像头，以获取桥梁狭窄空间（例如轴承）的图像，而传统的无人机在其顶部没有安装摄像头的传统无人机无法实现良好的视觉测试。对于视觉测试，希望照相机在身体上方，并且照相机和身体之间具有足够的距离。显而易见，相机在惯性坐标系中的位置受人体运动的影响。因此，我们实现了摄像机位置控制，以补偿人体向无人机的运动。作为实验的结果，据估计，与身体中的一个相比，所提出的控件减少了相机的位置误差。摄像机的平均位置误差为0.039 m，占机身之一的51.4％。我们的全球首项研究使通过安装在固定在无人机上的空中机械手的末端执行器上的摄像头能够获取桥梁承重的图像。