Pergamon PII: S0957-4158(97)00030-5 Mechatronics Vol. 7, No. 8, pp. 701 710, 1997 © 1997 Elsevier Science Ltd. All rights reserved. Printed in Great Britain. 09574158/97 $17.00+0.00 AN OPTICAL FIBRE SENSOR FOR USE IN A TISSUE CUTTING TOOL C. DURING,* T. KOMEDA, M. MATSUTO and H. FUNAKUBO Shibaura Institute of Technology, Center of Education and Research, 307 Tameihara, Fukasaku, Omiya-city, Saitama 330, Japan (Received 11 September 1996; accepted 30 June 1997) Abstract--This pre-study investigates a fibre optic alternative to more conventional sensors for measuring force indirectly as bending or deflection in a medical robotic application. The paper discusses problems regarding the integration of fibre optics into a cutting tool for the removal of prostate gland tissue. The aim is to integrate the sensor in a tube rod with an inner diameter of 0.6 mm and use it as a force feed- back sensor for the control system of the robot. The paper proposes and evaluates an inexpensive opto-mechatronic device for launching light into and detecting light received from an optical fibre. A simple sensor prototype is constructed to show the feasibility to use a fibre optic sensor for the prostate gland cutting tool. © 1997 Elsevier Science Ltd 1. INTRODUCTION This paper investigates, in a pilot-study, if a fibre optic method can be used for measuring the force as bending motion of the cutting tool during Transurethral Resection of the Prostate gland (TURP). The work is a part of a larger project concerning robot assisted TURP operations. Figure I illustrates schematically the outline of the system. The concept is aiming at higher precision and control of the motions of the surgical instrument and thereby enhance the safety of the patient. Furthermore, the surgeon is separated from the patient, which reduces the contamination risk for the physician and provides him with a less tiresome working situ- ation. The new strategy implies that the surgeons always shall be in charge and have full control of the operation. This eliminates the use of a fully automatic surgical system in contradiction * Royal Institute of Technology, Department of Machine Design, DAMEK S-100 44 Stockholm, Sweden. 701