一种用于眼内手术的混联机构设计与运动学分析

Design and Kinematics Analysis of a Serial-parallel Hybrid Mechanism Used for Intraocular Surgeries

为利用机器人实现眼内手术操作所需的远程运动中心(Remote center of motion,RCM)运动模式,提出了一种新型六自由度混联机构(RP+PPRRP/PPRR)。首先受U副结构形式的启发,利用两组RPPRP平面五杆机构单元重构出PPRRP/PPRR并联构型。根据螺旋理论计算该机构的自由度,并分析自由度性质,从而确认机构对RCM运动模式的兼容性。利用坐标变换方法建立机构的正运动学模型以及包含RCM参数(算法)的逆运动学模型。然后基于机构构型,设计、构建了物理样机。最后采用主从控制方式进行物理样机运动实验,验证运动学模型(算法)的正确性以及机构对眼内手术的适配性。

To realize RCM(remote center of motion)motion mode required for robot-assisted intraocular surgeries,a novel six-degree-of-freedom series-parallel hybrid mechanism(RP+PPRRP/PPRR)is proposed.Firstly,inspired by the structure of U pair(Universal pair),the parallel configuration(PPRRP/PPRR)is reconstructed by two sets of planar five-bar mechanism(RPPRP)units.After calculating the DOFs(degrees of freedom)and analyzing their characteristics based on screw theory,the capability of RCM motion mode for this mechanism is confirmed.Subsequently,the forward kinematics model and the inverse kinematics model of this mechanism containing RCM parameters are established through coordinate transformation method.Then,according to the configuration of the mechanism,a physical prototype is designed and established.Finally,based on master-slave control method,a motion experiment is performed to verify the correctness of the kinematic model and the adaptability of this mechanism to intraocular surgeries.