Optical fibre force sensor for minimal-invasive-surgery grasping instruments

Together with the development of surgical procedures, new instruments are being developed. The grasping instruments used nowadays in minimal invasive surgery have very poor force reflection, which reduces the surgeons sensitivity during the operation. Improvement can be accomplished by using telemanipulation techniques, including force feedback. For this a new force-sensor will be needed, satisfying some requirements related to the application. In this paper a force-sensor is proposed, which is based on optical fibres. The advantage of this is the lack of electrical signals inside the human body and less influence of temperature changes. The sensor measures the intensity of light, reflected by a mirror attached to a diaphragm. The influence of bending of the fibre causes loss of light intensity in the fibre, and thus loss of accuracy of the measurement. Adding an extra reference fibre to the measurement fibre will reduce the bending influences, which makes the system suitable for measuring forces with acceptable accuracy