Environmental sensing using a contact force and position sensor incorporating four pairs of quartz resonators

Abstract

Many force sensors used in robots use strain gauges. Because they have an analogue output, these force sensors are readily affected by electrical noise. They also often require amplifiers, low pass filters and AD converters. However, force sensors which use quartz resonators are robust to electrical noise since the output is a frequency which shifts in response to a change in an external force. The output frequency can be converted easily into a digital signal through a frequency counter. This type of force sensor also has quick response, high sensitivity, high resolution and wide bandwidth. Although force sensors with quartz resonators have many advantages, as mentioned above, such sensors have not yet been applied to measuring dynamic force such as in a contact force and position sensor. In this paper, a finger with four pairs of quartz resonators as a contact force and position sensor is proposed. The finger can detect two components of contact force and one-dimensional contact position along the finger. The performance of the finger was examined experimentally. As an application of the finger to sensing an environment, the two-dimensional shape of an environment was reconstructed by tracing the surface with the finger.