受寄生蜂产卵器启发,实现无导线结肠镜自推进。
OSCAR: An Ovipositor-Inspired Self-Propelling Capsule Robot for Colonoscopy
- 模仿寄生蜂产卵器运动,用弹簧凸轮驱动滑块产生方向性摩擦力。
- 实测平均牵引力0.85N,速度达3.08mm/s,可匹配传统结肠镜进镜时间。
- 摩擦各向异性可控,适合在黏滑肠道环境中稳定前行,适用于医疗机器人研发者。
自推进式机器人胶囊可消除传统结肠镜的导管缠绕问题,减轻患者不适。然而,在黏滑、粘弹性肠道环境中的可靠移动仍是重大挑战。本文提出OSCAR,一种受寄生蜂产卵器启发的自推进胶囊机器人,将寄生蜂的运输策略转化为结肠镜推进机制。通过弹簧凸轮系统驱动十二个环向滑块,以协调的相位差序列运动,优化回缩相相对于前进步的时长比例,从而在界面形成可控的摩擦各向异性,产生净向前推力。我们建立了一个包含Kelvin-Voigt模型的解析模型,描述滑块与组织间的粘弹性粘滞-滑移相互作用,揭示了前进与回缩相位不对称性与平均推力的关系,以及滑块反向同步性与推力稳定性之间的联系。体外猪结肠实验显示,平均稳态牵引力为0.85N,与模型预测高度一致。进一步验证表明,推力与速度无关,且随相位不对称性线性增长,符合理论预期,凸显其可预测性与可扩展性。在运动性能测试中,OSCAR实现平均速度3.08 mm/s,足以匹配传统结肠镜到达盲肠的时间。通过相位编码摩擦各向异性和预测模型,OSCAR在低法向载荷下实现可控推力,为机器人胶囊结肠镜提供更安全、更稳健的自推进方案。
原文摘要 · Abstract (English)
Self-propelling robotic capsules eliminate shaft looping of conventional colonoscopy, reducing patient discomfort. However, reliably moving within the slippery, viscoelastic environment of the colon remains a significant challenge. We present OSCAR, an ovipositor-inspired self-propelling capsule robot that translates the transport strategy of parasitic wasps into a propulsion mechanism for colonoscopy. OSCAR mechanically encodes the ovipositor-inspired motion pattern through a spring-loaded cam system that drives twelve circumferential sliders in a coordinated, phase-shifted sequence. By tuning the motion profile to maximize the retract phase relative to the advance phase, the capsule creates a controlled friction anisotropy at the interface that generates net forward thrust. We developed an analytical model incorporating a Kelvin-Voigt formulation to capture the viscoelastic stick--slip interactions between the sliders and the tissue, linking the asymmetry between advance and retract phase durations to mean thrust, and slider-reversal synchronization to thrust stability. Comprehensive force characterization experiments in ex-vivo porcine colon revealed a mean steady-state traction force of 0.85 N, closely matching the model. Furthermore, experiments confirmed that thrust generation is speed-independent and scales linearly with the phase asymmetry, in agreement with theoretical predictions, underscoring the capsule's predictable performance and scalability. In locomotion validation experiments, OSCAR demonstrated robust performance, achieving an average speed of 3.08 mm/s, a velocity sufficient to match the cecal intubation times of conventional colonoscopy. By coupling phase-encoded friction anisotropy with a predictive model, OSCAR delivers controllable thrust generation at low normal loads, enabling safer and more robust self-propelling locomotion for robotic capsule colonoscopy.
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