Radial-Axial Ring Rolling (RARR) is an industrial forging process for making strong, seamless metal rings. Conventionally, rings are made circular with constant cross-section. In this work we demonstrate a sensing and control strategy to create rings with variable radial wall thickness and variable curvature using standard RARR hardware. This has a number of potentially useful applications but also provides an understanding of how to control these properties for conventional RARR. The sensing uses a calibrated video camera to take a series of images of the ring top surface. Image processing is employed to measure and track the ring material in-situ. The complete state of the ring is represented by the ring thickness and curvature as a function of its volume fraction, which is computed by combining the measurements from the unoccluded areas with estimates of the ring shape elsewhere. Additionally, we present a marking technique for tracking of material as it rotates through the rolling machine, even after significant deformation of the ring has occurred. We show that rings with a wide range of variation in local thickness and curvature can be formed using conventional RARR hardware and a photogrammetric state measurement technique, combined with open-loop scheduling and feedback control of thickness and curvature. Rings with both variable thickness and non-circular shapes have been produced virtually using numerical simulations and in reality using modelling clay as a material to simulate metals at forging temperatures. We demonstrate that this technique extends the range of shapes achievable with standard RARR hardware.

径向-轴向环轧制（RARR）是一种用于制造坚固无缝金属环的工业锻造工艺。通常，将环制成具有恒定横截面的圆形。在这项工作中，我们演示了使用标准RARR硬件创建具有可变径向壁厚和可变曲率的环的传感和控制策略。这具有许多潜在有用的应用程序，但也使您了解了如何控制常规RARR的这些属性。感应使用已校准的摄像机拍摄环形顶面的一系列图像。图像处理用于现场测量和跟踪环材料。环的完整状态由环的厚度和曲率表示，作为环的体积分数的函数，通过将未遮挡区域的测量值与其他位置的环的估计值相结合来计算环的完整状态。另外，我们提出了一种标记技术，即使在环显着变形后，也可以跟踪材料在轧制机中的旋转情况。我们显示，可以使用常规RARR硬件和摄影测量状态测量技术，结合开环调度和厚度和曲率的反馈控制，来形成局部厚度和曲率变化范围广的环。厚度可变和非圆形的环实际上都是通过数值模拟生产的，实际上是使用模型粘土作为材料来模拟锻造温度下的金属。我们证明了该技术扩展了标准RARR硬件可达到的形状范围。