Enhanced Accuracy in Magnetic Actuation: Closed-Loop Control of a Magnetic Agent With Low-Error Numerical Magnetic Model Estimation
Enhanced Accuracy in Magnetic Actuation: Closed-Loop Control of a Magnetic Agent With Low-Error Numerical Magnetic Model Estimation
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DOI：
10.1109/lra.2022.3191047
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发表时间：
2022-10-01
影响因子：
5.2
通讯作者：
Diaz-Mercado，Yancy
中科院分区：
文献类型：
--
作者：
Erin，Onder;Raval，Suraj;Diaz-Mercado，Yancy
磁驱动有望无线控制小型磁性手术工具，并可能实现下一代超微创手术机器人系统。安全的外科手术和准确的状态控制需要精确的扭矩和施力。偶极子场估计模型在远离电磁体的地方表现良好，但在靠近线圈的地方会产生很大的误差。因此，线圈附近的操作会遭受严重的 (10x) 场建模误差。我们通过使用高度错误的偶极子模型和更精确的数值磁模型来实验量化闭环磁体控制性能，以估计任何给定机器人姿态的二维磁力和扭矩。我们将偶极子模型和基于有限元分析 (FEA) 的线圈附近场模型的实验测量值与估计误差进行比较。通过为本研究设计的五种不同路径，我们证明，与偶极子模型相比，基于 FEA 的磁场建模将定位均方根 (RMS) 误差降低了 48% 至 79%。模型显示出磁场方向估计的紧密一致性，显示出类似的方向控制精度。这种改进的磁建模对于需要对定位代理的磁力进行可靠估计的系统至关重要，特别是在外科手术等力敏感环境中。
Magnetic actuation holds promise for wirelessly controlling small, magnetic surgical tools and may enable the next generation of ultra minimally invasive surgical robotic systems. Precise torque and force exertion are required for safe surgical operations and accurate state control. Dipole field estimation models perform well far from electromagnets but yield large errors near coils. Thus, manipulations near coils suffer from severe (10x) field modeling errors. We experimentally quantify closed-loop magnetic agent control performance by using both a highly erroneous dipole model and a more accurate numerical magnetic model to estimate magnetic forces and torques for any given robot pose in 2D. We compare experimental measurements with estimation errors for the dipole model and our finite element analysis (FEA) based model of fields near coils. With five different paths designed for this study, we demonstrate that FEA-based magnetic field modeling reduces positioning root-mean-square (RMS) errors by 48% to 79% as compared with dipole models. Models demonstrate close agreement for magnetic field direction estimation, showing similar accuracy for orientation control. Such improved magnetic modelling is crucial for systems requiring robust estimates of magnetic forces for positioning agents, particularly in force-sensitive environments like surgical manipulation.