A micromachined piezoelectric teeth-like laparoscopic tactile sensor: theory, fabrication and experiments

Currently available laparoscopic graspers have a teeth-like surface without any sensors built on them. Thus the surgeon loses the tactile feedback required to manipulate tissues safely. The paper reports on the design, fabrication and testing of a micromachined piezoelectric tactile sensor which can measure the combined magnitude and position of the applied force on the sensor without changing the design of the the present day laparoscopic grasper. It consists of a teeth-like upper silicon layer, a patterned polyvinylidene fluoride (PVDF) film and an elastic substrate. The sensor exhibits good linearity, wide bandwidth, high force sensitivity and negligible noise to signal ratio. The theoretical analyses of various applied loads on the sensor are made and compared with experimental values. The advantages and limitations of the sensor are also discussed. It is shown that the sensor is integrated into a prototype laparoscopic grasper