中文摘要：

双平行四杆型远程运动中心机构作为腕部结构广泛应用于微创手术辅助机器人中，可为手术工具提供一个相对固定的插入点。基于这个特点，通过型综合给出这类远程运动中心机构的10种可能构型。通过杆件的弯折可以合理地安排虚拟转动中心的位置，并为末端执行器和驱动电动机留出安装的空间。根据设计需求，使用6个参数完全确定机构连杆长度尺寸，并说明了这些参数的物理意义。分析受力和结构刚度用来决定杆件断面参数，使设计的机构体积小，重量轻。对整个机构进行驱动力矩估算以便选择合适的电动机，并指出对于一个双平行四杆型远程运动中心机构，可以使用一个配重使其平衡。最后给出应用实例说明了该机构的可行性和有效性。

英文摘要：

The double parallelogram type of remote center of motion （RCM） mechanisms is generally used as wrist module in minimally invasive surgery （MIS） assisted robots, which can provide a fixed entry point during operation process, enhance safety and quality of the surgery, and give facilities for surgeons. With type synthesis, 10 types of double parallelogram RCM mechanisms are enumerated. By making some links crooked, the virtual center can be arranged properly, which also makes the arrangements of end-effector and motor more convenient. In order to design a double parallelogram RCM mechanism, six independent parameters are needed. The forces and structure stiffness of linkage are analyzed to assist in determining sectional sizes of links. The driven moment is estimated to select a right motor. The analysis shows that a double parallelogram RCM mechanism can be balanced by one counterweight. At last, an example is given to illuminate the mechanism＇s feasibility and validity.