An integrated force-position tactile sensor for improving diagnostic and therapeutic endoscopic surgery

This paper reports on the design, fabrication, testing, and modeling of a novel semiconductor microstrain gauge endoscopic tactile sensor. The designed assembly consists of two semiconductor microstrain gauge sensors, which are positioned at the back-face of a prototype endoscopic grasper. The sensor can measure, with reasonable accuracy, the magnitude and the position of an applied load on the grasper. The in-house electrical amplification system for the microstrain gauges is also designed, fabricated, and tested. The intensity of the magnitude of the applied force to the endoscopic grasper can be visually seen on a light emitting diode (LED) device. In total, 20 different force magnitudes, from 0.5 to 10 N with an increment of 0.5 N, for 7 different locations of the endoscopic grasper were tested experimentally. The sensor exhibits high force sensitivity, large dynamic range, and good linearity. It is insulated and can operate safely in wet environments. A 3-dimensional finite element modeling (FEM) is used to predict the behavior of the designed system under various loading conditions. There is a good correlation between the theoretical predictions of the force magnitudes and their points of application, which are computed by FEM, and experimentally obtained results. Potentially, the miniaturized electronic device could be integrated with an endoscope and the complete system could be used in operating rooms.