实验技术与管理

为解决传统导丝机器人结构复杂、无法主动导航、容易对血管造成损伤等问题，该文利用磁性液体作为机器人驱动介质，使导丝机器人具有柔软性、多自由度和磁驱动性。利用Euler-Bernoulli方程推导出机器人弯曲变形的影响因素包括：驱动磁场的磁感应强度和梯度、机器人结构、外壳材料等，通过实验探究了各变量对驱动性能的影响，并确定机器人长度为50 mm、直径为3 mm。该文采用Halbach排布的驱动永磁体实现定向聚磁与自屏蔽，使距离永磁体表面25 mm时工作面磁场提升151%；通过平面弯曲和空间驱动实验论证了机器人具有大角度偏转驱动和在重力影响下的三维驱动能力；进行模拟血管驱动-定位实验，证明了机器人在受限的模拟血管环境中能完成介入治疗任务，并通过定位装置反演机器人导丝位置。

[Objective] A common treatment for peripheral artery disease is percutaneous endovascular intervention. Minimally invasive procedures typically involve inserting a flexible catheter through an arterial access site. Under image guidance, the guidewire catheter is advanced to the lesion site, and blood flow is restored through balloon dilation or stent placement. To reduce the trauma to patients and to minimize occupational risks for physicians during minimally invasive surgery, and to allow the robot to access complex vascular regions, the robot should exhibit drivability, flexibility, high degrees of freedom, and safety. Current research on soft guidewire robots uses concentric tubes, tendons/cords, multibackbone structures, and shape-memory alloys as driving mechanisms, which often face issues such as complex structures, poor flexibility, and thermal damage. Magnetic control guidewire robots demonstrate immense potential due to their high degrees of freedom; however, the rigid tip made of permanent magnets poses a risk of vascular damage. Additionally, the magnetic field generator for coil-type guidewire robots is bulky and occupies valuable space needed by the physician. [Methods] To address the limitations of magnetic control guidewire robots, such as structural complexity, lack of active navigation, and risk of vascular damage, this study employs a magnetic fluid as the driving medium for the robot. The magnetic fluid soft robot consists of a guidewire, a hollow soft silicone shell, magnetic fluid, and a ring-shaped positioning permanent magnet. The silicone shell is a tube with a wall thickness of 0.25 mm, filled with water-based magnetic fluid, which provides good biocompatibility and leak safety. This design gives the guidewire robot flexibility, multiple degrees of freedom, and magnetic driving capabilities. The magnetic fluid, also known as ferrofluid, consists of a carrier liquid, surfactants, and magnetic nanoparticles. It has wide applications in damping, vibration reduction, sensing technologies, and magnetic hyperthermia. The superparamagnetism of the magnetic fluid ensures a rapid magnetic response, enabling the robot to achieve three-dimensional active steering under the influence of an external magnetic field gradient. Its fluidic properties help maintain the robot's flexibility and degrees of freedom, thereby reducing vascular damage during contact. Using the Euler–Bernoulli equation, the factors influencing the robot's bending deformation are derived, including the magnetic induction strength and direction of the driving magnetic field, the robot's structure, and the casing material. Experiments determined that the optimal robot length is 50 mm, with a diameter of 3 mm. The study uses a Halbach array for the drive system, achieving directional magnetization and self-shielding, which enhances the magnetic field strength on the working surface by 151%. [Results] A series of experiments demonstrated that the robot can achieve ±60° in-plane bending and three-dimensional motion with a vertical displacement of 20 mm. In a constrained simulated vascular environment measuring 20 cm × 20 cm, the robot successfully completed interventional tasks. During its movement, the robot did not encounter substantial friction with the vessel wall that would prevent further advancement. Additionally, the robot's position can be tracked and reversed using a positioning device. [Conclusions] The combination of the robot's terminal permanent magnet positioning and the gradient magnetic field control of the driving permanent magnet enables three-dimensional active navigation and manipulation. This enables the robot to support physicians during procedures without altering the traditional guidewire structure, offering a novel approach for the design of soft guidewire robots.