AN ENDOSCOPIC GRASPER WITH CORRUGATED PLATE-SHAPED TACTILE SENSORS

One of the major weaknesses in current endoscopic surgery is the lack of tactile feedback. This paper reports on the design, finite element modeling, and experimental testing of a corrugated tactile sensor. The sensor, a miniaturized and modified form of our previously developed tactile sensor, consists of a 75 mu m plate-shaped silicon layer and a 25 mu m polyvinylidene fluoride (PVDF) film, patterned on both sides using photolithographic techniques to form three independent sensing elements. The sensor is 15 mm long, 7.5 mm wide, and approximately 3 mm thick, which could make it versatile enough for integration with current endoscopic and medical robotics manipulators. The silicon layer is micromachined in such a way that a U-channel is formed. When a force is applied on the tactile sensor, output voltages from the patterned PVDF-sensing elements are combined to obtain tactile information. Results show that the sensor exhibits high sensitivity and can measure small dynamic loads, comparable to a human pulse, as well as large grasping forces. In addition to measuring the magnitude and position of the applied load, the sensor can determine the modulus of elasticity of the grasped object.