Abstract The remote centre-of-motion (RCM) mechanism plays an important role in minimally invasive surgery robotics to cause minimal pain and damage to a patient. It ensures that the end-effector operates through a small incision. In this study, motivated by a one-degree-of-freedom (1-DOF) parallelogram RCM mechanism, a novel two-DOF (2-DOF) parallel mechanism is designed based on a 3-UU parallel mechanism. The important advantage of the proposed novel mechanism is that the position of its RCM point is independent of the basement of the parallel mechanism, which suggests a variable RCM. Because of the unique structure of the proposed novel mechanism, consisting of a multi-loop closure and an abnormal end-effector, its mobility and RCM characteristic are demonstrated through a four-step screw theory analysis. To describe the kinematics of the novel mechanism completely, a revised combined Jacobian is proposed. Two main actuation arrangements are analysed by the Jacobian to obtain singular configurations and instantaneous singularities in the workspace. Finally, simulations are performed for verifying the analyses, and several deformed configurations are proposed to expand the application of the proposed novel mechanism.

中文翻译：

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一种新型双自由度远程运动中心机构的设计与分析

摘要 远程运动中心 (RCM) 机制在微创手术机器人技术中起着重要作用，可将患者的疼痛和伤害降至最低。它确保末端执行器通过小切口进行操作。在这项研究中，受单自由度 (1-DOF) 平行四边形 RCM 机构的启发，基于 3-UU 并联机构设计了一种新型的双自由度 (2-DOF) 并联机构。所提出的新型机构的重要优点是其 RCM 点的位置与并联机构的基底无关，这表明可变 RCM。由于所提出的新型机制的独特结构，由多环闭合和异常末端执行器组成，通过四步螺旋理论分析证明了其移动性和 RCM 特性。为了完整地描述新机构的运动学，提出了一种改进的组合雅可比行列式。Jacobian 分析了两种主要的驱动装置，以获得工作空间中的奇异配置和瞬时奇异性。最后，进行模拟以验证分析，并提出了几种变形配置，以扩展所提出的新型机制的应用。