Abstract: In the last years a large number of new surgical devices have been developed so as to improve the operation outcomes and reduce the patientís trauma. Nevertheless the dexterity and accuracy required in positioning the surgical devices are often unreachable if the surgeons are not assisted by a suitable system. From a kinematic point of view, the robot must reach any target position in the patientís body being less invasive as possible with respect to the surgeonís workspace. In order to meet such requirements a suitable design of the robot kinematics is needed. This paper presents the kinematic design of a special robot for neurosurgical operations, named NEUMESY (NEUrosurgical MEchatronic SYstem).
NEUMESY is a six joints serial manipulator whose kinematic structure lets the robot to adapt to different patientís positions while minimizing the overall dimensions. Owing to the usual symmetry of a surgical tool, the kinematic dimension of the neurosurgical task is five, being given by one point and one direction on the space. Therefore the NEUMESY is kinematically redundant, leaving an extra DOF to the surgeon to choose a suitable robot configuration which minimally limits his movements during the surgical operations. The link lengths have been optimized in order to maximize the robot workspace with respect to the surgical task, while minimizing the links static deformations.