Novel optical instrumentation for robotic manufacturing

这项提议的目的是开展新型光学仪器的研究，以支持未来更敏捷和灵活的制造系统的制造目标，以及提高传统的基于机器人的制造操作的精度。将结合两种互补的光学测量技术--距离分辨干涉测量和激光散斑相关--开发新的光学仪器。这些传感器将能够远程、高质量和高带宽地测量安装在机器人末端执行器上的传感器和工件之间的相对运动和方向，并累积在一个组合的多参数传感器中。这些传感器的应用在许多制造领域都很常见，可分为三个主要领域：i)末端执行器相对于工件的稳定和控制。ii)运动跟踪，将机器人锁定在移动的装配线上。iii)相对定位操作。在这些应用领域中，需要新的有效、低成本的仪器来提供关于其相对运动和方向的实时反馈，本提案将尝试解决这一问题。在第一个应用领域中，需要在存在末端执行器和/或工件振动的情况下稳定和控制工具的运动、定位和方向。例如，由于典型工业机器人的机械刚度相对较低，因此抛光、钻孔和铆接等接触任务往往是具有挑战性的任务。这可能会导致刀尖过度偏转、振动，从而导致成品零件质量变差。其他监控运动的方法受到限制；视觉系统的更新率有限，而激光扫描/跟踪系统昂贵且不灵活，因为扫描系统需要安装在机器人的外部并保持视线。机器人跟随移动的装配线进行运动跟踪是许多制造操作中的重要应用。目前的视觉系统可以提供一种灵活的传感器，能够以较高的精度确定物体的相对位置和方向，但其更新速度慢和延迟大，不适合用于实时运动控制的许多反馈回路。此外，这些视觉系统有时需要视觉标记或信标来操作，除非摄像机直接安装在末端执行器上，否则在操纵操作结束时，有时视场可能会变得模糊，在控制最关键的点。最后，在相对定位方面，许多应用要求相对于参考的高精度，这使得采用标准机器人变得困难。例如，在机身制造中，钻孔、装填和部件定位操作需要相对于几米外的本地基准的0.2 mm到0.02 mm的高精度，而在远程激光切割中，需要在扫描之间定位切割光束的高精度，任何不对准都会导致多个凹槽和无法切割工件。在这里，激光散斑相关可以提供一种解决方案，所提出的传感器能够在终端执行器和工件之间精确地相对定位(可能精确到1微米(毫米)和50微米(米))，同时依赖于其他手段，例如机器人编码器或视觉系统，来参考绝对位置。

The aim of this proposal is to undertake research into novel optical instrumentation to support future manufacturing aims for more agile and flexible manufacturing systems as well as to improve precision of traditional robot-based manufacturing operations. New optical instrumentation will be developed combining two complimentary optical measurements techniques, range-resolved interferometry and laser speckle pattern correlation. These will be capable of remote, high quality and high-bandwidth measurements of the relative motion and orientation between a robotic end-effector mounted sensor and the workpiece, cumulating in a combined multi-parameter sensor.The applications of these sensors are common to many areas of manufacturing and can be grouped into three main areas:i) The stabilisation and control of the end-effector relative to the workpiece.ii) Motion tracking to lock the robot to a moving assembly line.iii) Relative positioning operations. In these application areas there is a need for new effective, low cost instrumentation to provide real-time feedback about their relative motion and orientations, which this proposal will attempt to address.In the first application area, the stabilisation and control of a tool's motion, positioning and orientation is required in the presence of end-effector and/or workpiece vibrations. For example contact tasks such as polishing, drilling, and riveting are often challenging tasks due to the comparatively low mechanical stiffness of typical industrial robots. This can result in excessive tool-tip deflection, vibration, and resulting poor quality of the finished part. Other methods of monitoring the motion suffer from limitations; vision systems can have limited update rates, whilst laser scanning/tracking systems are expensive and inflexible in that the scanning system needs to be mounted externally to the robot and maintain a line-of-sight.The motion tracking of robotic manipulators to follow moving assembly lines is an important application in many manufacturing operations. Currently vision-systems can provide a flexible sensor capable of determining the relative position and orientation of objects to good precision, but their slow update rate and latency make them unsuitable for many feedback loops for real-time motion control. In addition, these visual systems sometimes require visual markers or beacons for operation and unless the cameras are mounted directly on the end-effector, the field-of-view can sometimes be obscured towards the end of the manoeuvring operation, at the point where control is most critical.Finally, in the area of relative positioning many applications require high accuracy relative to a reference and this makes the adoption of standard robots difficult. For example, in airframe manufacturing the high accuracies of between 0.2 mm and 0.02 mm relative to a local reference a few meters away are required for drilling, fettling and component location operations and in remote laser cutting there is a requirement for high precision in the positioning of the cutting beam between scans, with any misalignment leading to multiple grooves and failure to cut the workpiece. Here laser speckle correlation may offer a solution with the proposed sensors capable of precise relative positioning between the end-effector and workpiece (potentially down to <1 micron in mm's and <50 micron in m's) while relying on other means, such as the robot encoders or vision systems, to reference to an absolute position.