A Nuclear Decommissioning Manipulator with Novel Variable Impedance Actuator

随着英国塞拉菲尔德（Sellafield）核电站等核设施的老化，以及日本福岛第一核电站（Fukushima Daiichi）最近发生的灾难，核退役是21世纪需要解决的一个重大挑战。创新的退役技术可以帮助最大限度地降低风险和成本，以应对这些复杂的挑战。更具体地说，机器人解决方案已经显示出其潜力，通过几个探索任务，监测福岛的情况和绘制塞拉菲尔德核电站辐射源的地图。然而，只有少数专用的机器人机械手被开发出来，以帮助完成退役任务。由于辐射和环境的不确定性，工业应用中使用的标准机器人机械手不适合退役场景。在这个项目中，我们提出了一个机器人解决方案，以帮助清理福岛的主安全壳，以及塞拉菲尔德的拆除和退役工作。我们将开发一种基于新型可变阻抗执行器（VIA）的机器人操纵器，并利用人工智能技术在核环境中进行有效的勘探和退役。针对现有的基于无级变速器（CVT）的变阻抗致动器需要在交互区域设置传感器并使用反馈控制策略来改变机器人的阻抗的问题，本文提出了一种基于无级变速器（CVT）的变阻抗致动器，该致动器具有固有的碰撞安全特性，能够适应不确定环境，无需额外的交互传感器。为了充分利用机械手改变其阻抗的能力，将开发新的导航和控制策略来执行远程处理任务，并将设计专用的阻抗控制器来根据情况调整机器人的动态交互行为。VIA、操纵器和相关控制策略将最终在Sellafield和福岛挑战的实际用例中得到验证。这种机器人解决方案将有助于解决由于辐射危害而导致传感器可用性有限的挑战，并使我们能够在敏感环境中安全地执行任务，因为VIA提供了安全的固有碰撞。该解决方案还提供了在通信和传感器故障事件或远程操作协议误操作期间的弹性，进一步降低了机器人操作在福岛和塞拉菲尔德的清理和退役任务中的风险。

With the ageing of nuclear facilities such as those in the Sellafield nuclear site in the UK, or the relatively recent disaster that occurred in the Fukushima Daiichi power plant in Japan, nuclear decommissioning is a major challenge that needs to be addressed in the 21st century. Innovative decommissioning technologies can assist in minimizing the risks and costs in tackling these complex challenges. More particularly, robotics solutions have already shown their potential, through several exploration missions, to monitor the conditions in Fukushima and mapping radiation sources in the Sellafield nuclear site. However, only a few dedicated robotic manipulators have been developed to contribute to the decommissioning tasks. Due to the radiation and the environmental uncertainties, standard robotic manipulators used in industrial applications are unsuitable for decommissioning scenarios. In this project, we propose a robotic solution to aid in the clean-up of the primary containment vessel in Fukushima, and dismantling and decommissioning operations in Sellafield. We will develop a robotic manipulator based on a novel Variable Impedance Actuator (VIA) and employ artificial intelligence techniques for efficient exploration and decommissioning in nuclear environments. In contrast to existing VIAs which require sensors in the region of interaction and use feedback control strategies to modify the robot's impedance, we propose a novel Continuously Variable Transmissions(CVT) based Variable Impedance Actuator for an inherently collision-safe manipulator that can adapt to uncertain environments without additional interaction sensors. To fully capitalize on the manipulator's ability to change its impedance, new navigation and control strategies will be developed to perform remote handling tasks and a dedicated impedance controller will be designed to adapt the dynamic interaction behaviour of the robot according to the situation. The VIA, the manipulator and associated control strategies will finally be validated in realistic use-case scenarios representative of the Sellafield and Fukushima challenges.This robotic solution will help to address the challenges associated with limited sensor availability due to radiation hazards and will allow us to safely conduct tasks in sensitive environments owing to the inherent collision safely offered by the VIA. This solution also offers resilience in events of communication and sensor failure or during mis-operation in teleoperation protocols, further de-risking robotic manipulation in the clean-up and decommissioning tasks in Fukushima and Sellafield respectively.