面向微创手术器械臂的可变刚度机理综述

微创手术以体表小切口或人体腔道为入路，造成的组织创伤更小，代表着外科手术的最前沿。对于位置深远的病灶，需采用细长柔性器械来适应复杂的体腔环境。具有变刚度特性的手术器械臂，可实现柔性器械的刚柔并济，是保障术中人机交互安全、兼顾操作精度和力输出的关键。聚焦于微创手术器械臂领域，对变刚度机理进行综述，将其分类为：阻塞法、热响应材料法、形状锁合法、力对抗法、梁特征重构法以及混合法。根据对器械臂的性能要求，首先讨论、比较了各变刚度机理在刚化能力、响应时间、空间占用等方面上的性能。然后，综述了潜在的器械臂变刚度设计方法并分析其前景与挑战。最后，总结展望了该研究领域，指出发掘新型变刚度材料及基于仿生理念开展结构/功能一体化设计是本领域寻求突破的重点。

Review of Variable Stiffness Mechanisms in Minimally Invasive Surgical Manipulators

Taking one or several small cuts on skin or a body orifice as the path, minimally invasive surgery can significantly reduce the tissue damage, thus representing the future trend of the surgery. To reach a lesion far away from the path, slender and flexible device should be adopted for its adaptability to the complicated body-cavity condition. A surgical manipulator with variable stiffness can fulfill stiffening-softening function of the flexible device, and it thus becomes the key to ensure a safe human-machine interaction, a good precision, and an enough force output of manipulation during the surgery. Focused on the field of minimally invasive surgical manipulator, the current variable stiffness mechanisms are reviewed and classified as those based on jamming, thermally responsive material, shape-locking, antagonistic actuation force, reconfigurable cantilever, and combinations of them. Under the consideration of the application requirements, performances of manipulators in stiffening capability, response time, and space consumption, are firstly compared and discussed under different variable stiffness mechanisms. Next, potential variable stiffness mechanisms that could be applied in manipulators are reviewed, and the prospects and challenges are also analyzed. Finally, the field is summarized and forecasted. It is pointed out that developing new variable-stiffness material and carrying out integrated design of structures and functions based on biomimetic concepts are the main future directions.