To obtain the necessary information on fuel debris and water leakages during the decommissioning task of the Fukushima Daiichi Nuclear Power Plant, an ultrasonic-based method was proposed for future internal investigation of the primary containment vessel (PCV). In this article, we describe the rotatable winch mechanism and visual localization method, which were used to aid the investigation. We used the rotatable winch mechanism to adjust the height and orientation of the ultrasonic sensor and localized the robot with cameras to localize the sensor, to provide assisting information for data combination. We studied the feasibility of the conventional visual odometry method for application to the situation and performed localizing accuracy evaluation experiments with a mobile robotic platform prototype. The results showed that the visual odometry method could generate intuitive bird’s-eye-view maps, and provided an average error rate of 35 mm/1500 mm, which met the required maximum error rate of 100 mm/1500 mm for the grating movement. Experiments were also conducted with adjustable parameter ranges that could provide the required accuracy.

中文翻译：

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用于检测漏水和燃油碎片的机器人系统的研究-视觉里程表提供直观鸟瞰的系统建议和可行性研究-

为了在福岛第一核电站退役期间获得有关燃料碎片和漏水的必要信息，提出了一种基于超声波的方法，用于将来对主安全壳（PCV）进行内部调查。在本文中，我们描述了可旋转的绞盘机制和视觉定位方法，它们被用于辅助调查。我们使用可旋转的绞盘机制来调整超声传感器的高度和方向，并使用摄像头对机器人进行定位以对传感器进行定位，从而为数据组合提供辅助信息。我们研究了常规视觉里程计方法应用于这种情况的可行性，并使用移动机器人平台原型进行了定位精度评估实验。结果表明，视觉测距法可以生成直观的鸟瞰图，并提供35 mm / 1500 mm的平均误差率，满足光栅移动所需的100 mm / 1500 mm的最大误差率。还使用可提供所需精度的可调参数范围进行了实验。