A common limitation of autonomous tissue manipulation in robotic minimally invasive surgery (MIS) is the absence of force sensing and control at the tool level. Recently, our team has developed haptics-enabled forceps that can simultaneously measure the grasping and pulling forces during tissue manipulation. Based on this design, here we further present a method to automate tissue traction with controlled grasping and pulling forces. Specifically, the grasping stage relies on a controlled grasping force, while the pulling stage is under the guidance of a controlled pulling force. Notably, during the pulling process, the simultaneous control of both grasping and pulling forces is also enabled for more precise tissue traction, achieved through force decoupling. The force controller is built upon a static model of tissue manipulation, considering the interaction between the haptics-enabled forceps and soft tissue. The efficacy of this force control approach is validated through a series of experiments comparing targeted, estimated, and actual reference forces. To verify the feasibility of the proposed method in surgical applications, various tissue resections are conducted on ex vivo tissues employing a dual-arm robotic setup. Finally, we discuss the benefits of multi-force control in tissue traction, evidenced through comparative analyses of various ex vivo tissue resections. The results affirm the feasibility of implementing automatic tissue traction using micro-sized forceps with multi-force control, suggesting its potential to promote autonomous MIS. A video demonstrating the experiments can be found at https://youtu.be/8fe8o8IFrjE.

翻译：自主组织操控在机器人微创手术中的一个常见限制是缺乏工具端的力传感与控制能力。近期，本团队研发了触觉力反馈钳，可同步测量组织操控过程中的夹持力与牵引力。基于该设计，本文进一步提出了一种通过可控夹持力与牵引力实现自动化组织牵引的方法。具体而言，夹持阶段依赖受控的夹持力，而牵引阶段则由受控的牵引力引导。值得注意的是，在牵引过程中，通过力解耦技术可同步控制夹持力与牵引力，以实现更精确的组织牵引。力控制器基于组织操控的静态模型构建，考虑了触觉力反馈钳与软组织间的相互作用。通过一系列对比目标力、估计力与实际参考力的实验，验证了该力控制方法的有效性。为验证该方法在手术应用中的可行性，采用双臂机器人平台对离体组织进行了多种组织切除实验。最后，通过多种离体组织切除的对比分析，讨论了多力控制在组织牵引中的优势。结果证实了采用微尺寸钳实现多力控制自动组织牵引的可行性，表明该方法具有推动自主微创手术发展的潜力。实验演示视频见https://youtu.be/8fe8o8IFrjE。