A tactile proximity sensor

Abstract

This paper introduces a novel tactile sensor with the ability to detect objects in the sensor's near proximity. For both tasks, the same capacitive sensing principle is used. The tactile part of the sensor provides a tactile sensor array enabling the sensor to gather pressure profiles of the mechanical contact area. Several tactile sensors have been developed in the past. These sensors lack the capability of detecting objects in their near proximity before a mechanical contact occurs. Therefore, we developed a tactile proximity sensor, which is able to measure the current flowing out of or even into the sensor. Measuring these currents and the exciting voltage makes a calculation of the capacitance coupled to the sensor's surface and, using more sensors of this type, the change of capacitance between the sensors possible. The sensor's mechanical design, the analog/digital signal processing and the hardware efficient demodulator structure, implemented on a FPGA, will be discussed in detail.

Methods for safe human-robot-interaction using capacitive tactile proximity sensors

“…principle was developed in a previous work [1]. Sensor identification for the tactile mode and further sensor designs where presented in [2].…”

Tactile proximity sensors for robotic applications

“…In this approach, acceleration sensors, optical proximity sensors and temperature sensors have been used. In [12] we have already introduced a prototype tactile proximity sensor, so only the necessary basics of this sensor will be explained here. Further details can be obtained in this publication.…”

“…MODELLING THE TACTILE PARTAs explained in[12], the behaviour of the tactile sensor is mainly based on the electrical behaviour of a capacitor and the mechanical behaviour of the used polymer foam between the capacitor plates. Applying a load CJp on this tactile Capacitance of a polymer foam filled taxel sensor leads to a compression of the foam which changes the geometry of the air filled capacitor.…”

Compliant Ultrasound Proximity Sensor for the Safe Operation of Human Friendly Robots Integrated with Tactile Sensing Capability

“…In recent years, integrated sensors functioning as both proximity and tactile sensors have been explored as an effort to save cost and space [13][14][15][16]. Göger et al reported a capacitive tactile sensor module that is capable of sensing proximity in combination with another module in the different operational mode [13,14].…”

“…Göger et al reported a capacitive tactile sensor module that is capable of sensing proximity in combination with another module in the different operational mode [13,14]. They employed a polymer foam between electrode layers as a deformable dielectric to sense the tactile pressure.…”