Percutaneous needle-based intervention is a technique used in minimally invasive surgical procedures such as brachytherapy, thermal ablation, and biopsy. Targeting accuracy in these procedures is a defining factor for success. Active needle steering introduces the potential to increase the targeting accuracy in such procedures to improve the clinical outcome. In this work, a novel 3D steerable active flexible needle with shape memory alloy actuators was developed. Active needle actuation response to a variety of actuation scenarios was analyzed to develop a kinematic model. Shape memory alloy actuators were characterized in terms of their actuation strain, electrical resistance, and required electrical power to design a self-sensing electrical resistance feedback control system for position tracking control of the active needle. The control system performance was initially tested in position tracking control of a single shape memory alloy actuator and then was implemented on multiple interacting shape memory alloy actuators to manipulate the 3D steerable active needle along a reference path. The electrical resistance feedback control of the multiple interacting shape memory alloy actuators enabled the active needle to reach target points in a planar workspace of about 20 mm. Results demonstrated shape memory alloys as promising alternatives for traditional actuators used in surgical instruments with enhanced design, characterization, and control capabilities.

中文翻译：

---

3D 可控主动针中多个相互作用形状记忆合金执行器的自感反馈控制

经皮针刺介入是一种用于微创外科手术的技术，例如近距离放射治疗、热消融和活检。在这些程序中瞄准准确性是成功的决定性因素。主动针头转向有可能提高此类手术中的瞄准精度，从而改善临床结果。在这项工作中，开发了一种具有形状记忆合金致动器的新型 3D 可转向主动柔性针。分析了对各种致动场景的主动针致动响应以开发运动学模型。形状记忆合金致动器的特征在于它们的致动应变、电阻和所需的电力，以设计用于主动针位置跟踪控制的自感应电阻反馈控制系统。控制系统性能最初在单个形状记忆合金致动器的位置跟踪控制中进行测试，然后在多个相互作用的形状记忆合金致动器上实施，以沿参考路径操纵 3D 可转向主动针。多个相互作用的形状记忆合金致动器的电阻反馈控制使主动针能够在约 20 毫米的平面工作空间内到达目标点。结果表明，形状记忆合金是手术器械中使用的传统致动器的有前途的替代品，具有增强的设计、表征和控制能力。