Faculty of Engineering Science
Dynamic Registration and High Speed Visual Servoing in Robot-Assisted Surgery (Dynamische registratie en visuele servoregeling bij hoge snelheid in robot ondersteunde chirurgie)
Doctorandus/a PhD student
  Name: Andrea Blankenstein
Promotie / Defence
  When: 11.06.2008, 17h00
  Language: English
  Where: aula Arenbergkasteel, 01.07, Kasteelpark Arenberg 1, 3001 Heverlee
Promotor / Supervisor
  Prof. dr. ir. Jozef Vander Sloten (promotor)
  Prof. dr. ir. Joris De Schutter (co-promotor)
Samenvatting van het onderzoek / Summary of Research

Robot-assisted surgery provides the surgeon with advanced tools with the objective to increase the quality of medical interventions. In the presented research existing robot assisted surgery systems are enhanced by skills. These are additional qualities of the robot device to react autonomously to changes in the environment. Sensor feedback provides the robot with the necessary information to adapt planned paths to the varying conditions. As framework a three layer architecture of procedure, skill and task is introduced.The possibility to include vision sensors into the robot control architecture is demonstrated with the elaboration of two skills. This control of the robot end-effector by vision, called visual servoing, is implemented for two applications of motion compensation in robot-assisted surgery.The first considered skill, dynamic registration in orthopaedic surgery, realises motion compensation for unexpected motions of the anatomical object. The existing semi-active system, which is moved by human power, is enhanced by an additional vision feedback. The position changes of the anatomical object are measured by the vision sensor and this information is fed back to the robot controller. In a proof of concept three different set-ups are tested with respect to their suitability for orthopaedic surgery. A milling experiment shows that it is possible to clamp non-invasively the anatomical object in such a way that no high frequency vibrations occur.The second skill, high speed visual servoing with ultrasonic motors, brings an enhancement for the control of a master-slave system. This compensates for physiological motion due to heart beat and respiration duringheart surgery. The focus lies on the integration of the dynamic model of the vision sensor into the high speed visual servoing loop to obtain an optimal performance and ensure a stable system. An averaging filter isproposed as possible dynamic model. The suitability to represent the behaviour of a vision system in this way is tested by means of experiments. With the help of this model high speed controllers are developed whichcontrol two kinds of ultrasonic motors. Experiments validate that it isessential to include the model of the vision sensor in a high speed visual servoing loop. 

Volledige tekst van het doctoraat / full text

Examencommissie / Board of examiners
  Prof. dr. ir. Jozef Vander Sloten (promotor)
  Prof. dr. ir. Joris De Schutter (co-promotor)
  Prof. dr. ir. Paul Van Houtte (voorzitter/chairman)
  Prof. dr. ir. Herman Bruyninckx (secretaris/secretary)
  Prof. dr. ir. Georges Van der Perre
  Prof. dr. Paul Herijgers
  Prof. dr. Jacques Gangloff , Ecole Nationale Supérieure de Physique de Strasbourg, Parc d'innovation