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
m plate-shaped
silicon layer and a 25
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.