发表机构
The University of Alabama（阿拉巴马大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对机器人超声中图像反馈延迟导致力扰动的问题，提出基于模型的朝向变化率限制，在双速率控制器中实现，实验表明可降低力误差，主要价值在于速率设计规则。
AI 中文摘要
机器人超声将高采样率的接触力回路与较慢且存在延迟的图像反馈耦合，因此图像引导的超声探头旋转可能在观察到相应图像响应之前扰动接触力。我们推导出一个闭式朝向变化率限制，该限制在有限预测时域内界定了由模型预测的旋转引起的估计力偏移，同时考虑了快速力回路的干扰抑制。该限制取决于局部接触刚度、力回路增益、保守的旋转-力增益界限、偏移预算和预测时域。我们在一个双速率控制器中实现了该模型，该控制器采用基于时间戳的延迟重建和基于关节力矩的力估计，并在弯曲的明胶体模上通过配对控制器比较和组件消融进行了评估。相对于无约束的图像引导，所提出的限速率控制器将第一秒的估计力均方根（RMS）误差降低了0.40 N，同时将提示收敛时间增加了0.94秒。接近分析预测上限的固定速率上限在力误差方面没有产生可分辨的差异，并且收敛速度快了0.32秒，这表明该模型的主要实际价值在于速率设计规则而非在线预测。延迟重建在测试的延迟下没有产生可分辨的影响。单受试者腘窝扫描证明了可行性，尽管在异质组织上图像提示受噪声限制。
英文摘要
Robotic ultrasound couples a high-rate contact-force loop with slower, delayed image feedback, so image-guided ultrasound probe rotation can perturb contact force before the resulting image response is observed. We derive a closed-form orientation-rate limit that bounds the modeled rotation-induced estimated-force excursion over a finite horizon while accounting for disturbance rejection by the fast force loop. The limit depends on local contact stiffness, force-loop gains, a conservative rotation-to-force gain bound, the excursion budget, and the prediction horizon. We implement this model in a dual-rate controller with timestamp-based delay reconstruction and joint-torque-based force estimation, and evaluate it on a curved gelatin phantom using paired controller comparisons and component ablations. Relative to unconstrained image guidance, the proposed rate-limited controller reduced first-second root-mean-square (RMS) estimated-force error by 0.40 N while increasing cue-convergence time by 0.94 s. A fixed rate cap near the analytically predicted ceiling produced no resolvable difference in force error and converged 0.32 s faster, indicating that the principal practical value of the model is the rate-design rule rather than online prediction. Delay reconstruction had no resolvable effect at the tested latency. A single-subject popliteal scan demonstrated feasibility, although the image cue was noise-limited on heterogeneous tissue.
Comments8 pages, 4 gigures, conference
