微创柔性穿刺针的光纤式位姿感知及反馈控制研究

柔性针导航定位及位姿操控是靶向穿刺成功与否的关键，但受软组织变形、针弯扭形变以及自感知缺乏等因素影响，难以实现精确、实时的针位姿操控，加之现有成像设备存在速度慢、放射性、精度低等不足。项目提出将刻有FBG的光纤植入柔性针内部进行针体形态重构，融合光纤-超声多模态影像及针位姿反馈的滑模控制的方案。首先，有限元模拟针体弯曲、扭转应变分布，建立光纤传感模型，探明针体变形对FBG的应变传递规律并优化FBG布置；其次，开展FBG特征信号提取、滤波、弯曲与扭转信息的分离与提取、光纤柔性针三维重构与可视化研究；然后，开展光纤-超声多模态影像融合研究，增强软组织及柔性针边界特征，提高影像可靠性及容错性；最后，完成针尖位姿反馈的滑模控制，搭建闭环反馈的穿刺仿真控制平台并验证控制效果。本课题研究对于提高柔性针导航定位、靶向穿刺、穿刺控制鲁棒性及适应性等都具有重要的研究意义及实用价值。

Flexible needle navigation and needle posture control are the keys to the success of target puncture diagnosis and treatment. However, it is difficult to achieve the precise and real-time posture control, because of the deformation of soft tissue, flexible needle bending and self-perception lacking. In view of the drawbacks of the existing medical imaging devices, such as low speed, low precision and radioactive. The project proposes a scheme for the shape reconstruction of needle body and optical fiber-ultrasonic image fusion with embedding optical fiber in the flexible needle, and realize the sliding mode control of flexible needle position feedback. First, the strain distribution characteristics of needle body is analyzed with Finite Element Simulation. The model of optical fiber sensing is established to explore the transmit rule of needle body deformation on FBG. Secondly, the FBG perceptual information extraction, filtering, bending and torsion information separating, dynamic reconstruction and visualization are studied. Then, the method of fiber optic-ultrasonic multi-modal influence fusion, registration and error compensation are studied to enhance the soft tissue-flexible needle boundary characteristics and improve image reliability and fault tolerance. Finally, the sliding mode control strategy with needle tip position feedback and chattering suppression are studied. The puncture simulation control plat-form of closed loop feedback control system are built, and the control effect is verified. The research is of great significance and practical application value for improving the needle body positioning, target puncture and the robustness and adaptability of the puncture control.