| Compared with other types of robots,the most remarkable pattern of an MIS robot is that its manipulator is made up of remote center of motion(RCM)mechanisms.This passage focused on the type synthesis of planar and spatial RCM mechanisms and conducted the kinematic analysis of the typical 2UPR-UPRR mechanism.According to the most concerned issues of precision,kinematic performance and integration of work space about RCM mechanism,several indexes were put forward to analyze the topology optimization,dimensional optimization and performance evaluation.Details are as follows.First,according to the screw theory,all planar mechanisms share three common constraint screws,and the type synthesis of planar RCM mechanisms meets the challenges limited kinematic pair types and the hinge connection from the RCM point.With the adoption of the common constraint screws,this passage regarded the closed loop in a plane as a general kinematic pair and found a series of new planar 1R-RCM and 1R1T-RCM mechanisms based on the motion-reproduction method.Second,based on the visual chain method,this passage found a series of novel spatial parallel mechanisms.A new 2UPR-UPRR parallel mechanism can be get based on the method.The kinematic pattern of the mechanism was discussed and a visual prototype was built to verify the motion of the mechanism.Last but not least,according to the special MIS environment,this passage proposed an evaluation system based on the topology,dimension and application levels,and can evaluate the precision,motion&force transmission and work space versus mechanism volume performance.And the previous 2UPR-UPRR mechanism was used in proving this method. |
