Non-destructive evaluation of residual stress using the collaborative robot

在斯特拉斯克莱德大学超声工程中心（CUE），焊接和线材+电弧增材制造（WAAM）残余应力的无损评估被认为是一个更大项目的一部分，由Javadi博士领导的5年校长奖学金。因此，将在该中心最先进的机器人设施中开发用于过程中残余应力测量的先进机器人系统：传感器自动化，机器人和控制中心（SEARCH）。测量过程将使用(i)相控阵超声波系统和（ii）柔性机器人单元进行。机器人残余应力测量的创新思想有望通过减少人为误差和提高测量系统的定位精度来提高测量的重复性和准确性，同时也节省了测量时间。传统上，大多数残余应力测量方法都是手工进行的，并有一些基本的自动化，整个过程仍然需要高技能的操作员（无损检测和残余应力领域的专家）的监督。在这个项目中，一个类似于库卡KMR iiwa的协作机器人（Cobot）将被用来促进从手动过程（残余应力测量）到自动化过程的过渡，与高技能的操作员（这位博士生）直接合作。这种智能协作机器人可以同时完成(a)成品部件的离线残余应力测量和(B)高温过程残余应力测量。对于离线测量，由于操作者需要到达焊缝的不同部分、热影响锌（HAZ）和部件的母材进行综合残余应力测量，因此有望增加测量的灵活性。这种灵活性还需要处理组件尺寸和几何形状的变化，因为WAAM组件的复杂几何形状在手动残余应力测量过程中很难完全覆盖。此外，在重复的过程中，过程的某些部分是耗时的，协作机器人可以由操作员在其中一个测试部分进行培训，然后相同的过程将自动重复整个测量，以达到更准确的结果并节省时间/精力。对于高温过程中残余应力测量，cobot还可以在热样品上进行初始测试和实验，以方便从手动测量过渡到全自动过程中检测。本项目将考虑所有这些发展，以探索协作机器人残余应力测量系统的要求。

In the Centre for Ultrasonic Engineering (CUE) at the University of Strathclyde, the non-destructive evaluation of residual stress in welding and Wire + Arc Additive Manufacturing (WAAM) is considered as part of a larger programme through a 5-year Chancellor's fellowship led by Dr Javadi. Therefore, an advanced robotic system for the in-process residual stress measurement will be developed within the centre's state of the art robotic facility: Sensor Enabled Automation, Robotics & Control Hub (SEARCH). The measurement process will be carried out using (i) a phased array ultrasonic system and (ii) a flexible robotic cell. The innovative idea of robotic residual stress measurement is anticipated to increase the repeatability and the accuracy of the measurement, through reducing human errors and increasing the positioning accuracy of the measurement system, and also saving the measurement time. Traditionally, the majority of residual stress measurement methods are carried out manually with some basic automation, where the whole process still requires supervision by a highly skilled operator (expert in both areas of NDE and residual stress). In this project, a collaborative robot (Cobot) similar to KUKA KMR iiwa, will be used to facilitate the transition from a manual process (residual stress measurement) to an automated process in direct collaboration with the highly skilled operator (this PhD student). Such a smart collaborative robot can help with the residual stress measurement in both (A) offline measurement on the as-built components and (B) high-temperature in-process residual stress measurement. For the offline measurement, it is expected to increase the flexibility of the measurement as the operator should reach the different sections of weld, Heat Affected Zine (HAZ) and parent material of the component for the comprehensive residual stress measurement. This flexibility is also required to deal with the variations in the size and geometry of the components because the complex geometry of WAAM components is challenging to be fully covered during a manual residual stress measurement process. Furthermore, some parts of the process are time consuming in a repetitive procedure, The cobot can be trained by the operator on one of the testing sections and then the same process will be repeated automatically for the whole measurement reaching a more accurate results and saving time/energy. For the high-temperature in-process residual stress measurement, the cobot can also allow the initial testing and experiments on the hot sample to facilitate the transition from the manual measurement to the fully automated in-process inspection. All of these developments will be considered in this project to explore the requirements of a system of cobot residual stress measurement.