Aiming at the demand of great dexterity in minimally invasive operation, one minimally invasive surgical robot was designed with hybrid structure. The configuration of the robot was optimized based on results of dexterous workspace. To layout an incision and plan the operation path reasonably, the dexterous workspace was analyzed according to the service sphere and service areas of the end tool. So the flexibility ratio of any point in the workspace was obtained by numerical approach. The dexterity distribution of workspace horizontal section was also mapped out. The results provided operational data for incision layout and operation path planning. The number of points in the workspace horizontal section, whose dexterity degree was greater than 0.85, was taken as the appraise criterion. Therefore, the influence on the dexterity, coming from the wrist joint rotation range and the length of the operation tool,was analyzed quantitatively.It provided computation basis for structure optimization of the minimally invasive surgical hybrid robot. Both the results of simulation and actual motion of model proved that the hybrid robot could satisfy the dexterous requirement of minimally invasive surgical.
