采用压电弯曲器实现径向运动的混合R-θ光纤定位机器人
A Hybrid R-Theta Fiber Positioning Robot Using a Piezoelectric Bender for Radial Motion
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中文总结 AI 辅助
针对下一代光谱仪器对紧凑型光纤定位器的需求，提出混合R-θ光纤定位概念，制作原型测试验证直接压电弯曲器驱动的可行性，残余稳定性约2微米均方根。
中文摘要 AI 辅助
未来大规模多目标光谱观测需要焦平面配备越来越密集的机器人光纤定位器阵列。基于两轴θ-φ电动架构的DESI（暗能量光谱仪）光纤定位器在运行中展现出优异的可靠性与性能，为评估新型概念提供了基准。然而，Spec-S5等下一代仪器要求定位器间距远小于DESI的设计，直接缩放现有设计颇具挑战。本文提出一种混合R-θ光纤定位概念：绕中心轴的旋转由类DESI的θ电机提供，径向位移则由耦合轻质碳纤维脊的压电双晶片弯曲器产生。该设计在成熟的中心旋转机制基础上，用紧凑型压电执行器替代了φ臂。本文讨论了电动定位器、压电滑动-倾斜脊、管状压电执行器与直接压电弯曲器驱动之间的权衡。基于DESI定位器制作了原型，采用商用双晶片弯曲器与8英寸碳纤维延伸件进行测试，利用光纤相机反馈的闭环控制，经两次校正后光纤到达目标，残余稳定性约为2微米均方根。这些结果表明，直接压电弯曲器驱动是紧凑型光纤定位的有前景方法，前提是解决闭环运行问题。
英文摘要
Future massively multiplexed spectroscopic surveys require focal planes with increasingly dense arrays of robotic fiber positioners. The DESI (Dark Energy Spectroscopic Instrument) fiber positioners, based on a two-axis Theta-Phi motorized architecture, have demonstrated excellent reliability and performance during operations and provide the benchmark for evaluating new concepts. However, proposed next-generation instruments such as Spec-S5 require a substantially smaller positioner pitch than DESI, making direct scaling of the existing design challenging. Here we describe a hybrid R-Theta fiber positioning concept in which the rotation about the central axis is provided by a DESI-like Theta motor, while the radial displacement is produced by a piezoelectric bimorph bender coupled to a lightweight carbon-fiber spine. This design builds on the heritage of the the proven central rotation mechanism while replacing the Phi arm with a compact piezoelectric actuator. We discuss the trade-offs between motorized positioners, piezoelectric slip-stick tilting spines, tubular piezo actuators, and direct piezo-bender actuation. A prototype based on a DESI positioner was fabricated and tested using a commercial bimorph bender and an 8-inch carbon-fiber extension. With closed-loop control using feedback from a fiber-view camera the fiber was brought on target after two corrections with residual stability of approximately 2 microns RMS. These results indicate that direct piezo-bender actuation is a promising approach for compact fiber positioning, provided that closed-loop operation is addressed.
