Dual-Mode Capacitive Proximity Sensor for Robot Application: Implementation of Tactile and Proximity Sensing Capability on a Single Polymer Platform Using Shared Electrodes

Abstract

In this paper, we report a flexible dual-mode capacitive sensor for robot applications which has two sensing capabilities in a single platform; tactile and proximity sensing capability. The sensor consists of a mechanical structure based on PDMS (Polydimethylsiloxane) and a mesh of multiple copper electrode strips. The mesh is composed of 16 top and 16 bottom copper strips crossed each other to form a 16 16 capacitor array. The proposed sensor is able to switch its function from tactile sensing to proximity sensing or vice versa by reconfiguring the connection of electrodes. The tactile sensing capability has been demonstrated already and reported in our previous paper (Lee et al., 2006); therefore, in this paper, we will demonstrate the feasibility of the proximity sensing capability and the dual-mode operation of the proposed sensor in detail. The capacitance change caused by an approaching object has been estimated through simulation of multiple two-dimensional models as an initial study. The measured data have shown similar trends with the simulation results. We tested various materials from conducting metals to a human hand for proximity measurement. The fabricated sensor could detect a human hand at a distance up to 17 cm away from the sensor. We also have successfully demonstrated the feasibility of dual-mode operation of the proposed sensor in real-time exploiting a custom designed PCB, a data acquisition pad, and Labview software.Index Terms-Capacitive sensor, flexible polymer, proximity sensor, tactile sensor.

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

“…The performance of our previous sensor does not meet the requirements for the safety sensor [16]. Therefore, we proposed a compliant safety sensor design to meet those requirements in this work.…”

“…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].…”

“…Our group also has reported an integrated sensor that is small and thin enough to be installed on a robot finger [16]. A 16 by 16 capacitive tactile sensor array with 1 mm special resolution was realized in a 1 mm thick polydimethylsiloxane (PDMS) sheet.…”

A Mechatronic Perspective on Robotic Arms and End-Effectors

“…For instance, a capacitive sensor with top electrodes in a comb-like structure can detect the proximity of an object to the fingers (exteroceptive), as well as the collision of the object with the fingers (haptic). This is achieved by monitoring the fringe capacitance of two adjacent electrodes as a function of the changes in the dielectric constant influenced by the proximity of the object to the electrodes (Lee et al, 2009). The principle of operation is shown in Figure 2.…”

Dispenser printed proximity sensor on fabric for creative smart fabric applications

“…This object can be either a conductor or non-conductor depending on the sensing mechanism of the proximity sensor. Mechanisms that can be used to detect the presence of an object are: inductive [1], optical [2], ultrasonic [3] and capacitive [4]. The inductive mechanism uses an LCR oscillator in which the inductance is altered by an approaching metallic object.…”