GCRIS

With the development of the technology, robots are started to be used in many medical application including minimally invasive surgery to overcome disadvantages of conventional open surgery procedures. This thesis is a part of the research project called “Robot-assisted endoscope control that can be controlled by the surgical tools (NeuRobo- Scope)” for the minimally invasive endoscopic pituitary gland tumor surgery side. During the procedure, endoscope is handled by a robot which moves the endoscope in the human nasal cavity and the movement of the endoscope is constrained by soft tissues. Another operation scenario is the positioning of the endoscope by the surgeon backdriving the endoscope holder robot. In the scope of this thesis, two research problems are addressed which are controlling the interaction between (1) surgeon - robot and (2) robot - soft tissue. First, the interaction of the surgeon and the robot is studied. Effects of the compliant controller parameters are experimentally tested by using a single degree of freedom non-backdrivable experimental set-up. A task is defined to quantitatively compare the effect of the controller parameters on the performance in terms of the energy efficiency and the accuracy. The second research problem involves human nasal tissue modeling in order to design an accurate controller. To acquire data from the human cadaver, a new hand-held measurement device is designed. The external forces and moments and the soft tissue models are obtained in an ex-vivo experiment. After the soft tissue models are identified, a modified interaction control is proposed for the teleoperated endoscope holder robot. The defined surgery procedure is tested with the proposed interaction controller via single degree-of-freedom experimental set-up. Experiments of the proposed controllers were successful for the defined operation scenario and the results show that it is possible to realize the motion control of the surgical robots in a constrained environment.

SUMMARY In this study, a bilateral teleoperation control algorithm is developed in which the model-mediation method is integrated with an impedance controller. The model-mediation method is also extended to three-degrees-of-freedom teleoperation. The aim of this controller is to compensate for instability issues and excessive forcing applied to the slave environment stemming from time delays in communication. The proposed control method is experimentally tested with two haptic desktop devices. Test results indicate that stability and passivity of the bilateral teleoperation system is preserved under variable time delays in communication. It is also observed that safer interactions of the slave system with its environment can be achieved by utilizing an extended version of the model-mediation method with an impedance controller.

Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection

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