  Wearable sensors are gaining in popularity because they enable outdoor
experimental monitoring. This paper presents a cost-effective sensorised insole
based on a mesh of tactile capacitive sensors. Each sensor's spatial resolution
is about 4 taxels/cm^2 in order to have an accurate reconstruction of the
contact pressure distribution. As a consequence, the insole provides
information such as contact forces, moments, and center of pressure. To
retrieve this information, a calibration technique that fuses measurements from
a vacuum chamber and shoes equipped with force/torque sensors is proposed. The
validation analysis shows that the best performance achieved a root mean square
error (RMSE) of about 7 N for the contact forces and 2 N m for the contact
moments when using the force/torque shoe data as ground truth. Thus, the insole
may be an alternative to force/torque sensors for certain applications, with a
considerably more cost-effective and less invasive hardware.
