Morphological Design of Soft Capacitive Force Sensor

This paper describes the design of soft capacitive force sensors. Capacitive force sensors are simple in structure and stable in sensor output. Recently, soft capacitive force sensors, in which electrodes and dielectric are made of soft materials, have been proposed. The output of a soft capacitive force sensor depends not only on the acting force but also on the contact area between the sensor and the environment. We should remove the influence of the contact area to obtain force information alone. In this paper, we propose area-independent soft capacitive force sensor by designing the material properties of the dielectric. First, we demonstrate the dependency of capacitive soft sensor signals on contact area. Next, we build a simple model of a capacitive soft sensor to formulate the dependency. We then apply numerical optimization to minimize the dependency, which directly yields an area-independent soft capacitive force sensor.