Cable Crosstalk Suppression in Resistive Sensor Array with 2-Wire S-NSDE-EP Method

Abstract

With long flexible cables connected to the 1-wire setting non-scanned-driving-electrode equipotential (S-NSDE-EP) circuit, the resistive sensor array modules got flexibility in robotic operations but suffered from the crosstalk problem caused by wire resistances and contacted resistances of the cables. Firstly, we designed a new S-NSDE-EP circuit using two wires for every driving-electrode and every sampling-electrode to reduce the crosstalk caused by the connected cables in the 2D networked resistive sensor array. Then, an equivalent resistance expression of the element being tested (EBT) for this circuit was analytically derived. Then, the 1-wire S-NSDE-EP circuit and the 2-wire S-NSDE-EP circuit were evaluated by simulations. The simulation results show that the 2-wire S-NSDE-EP circuit, though it requires a large number of wires, can greatly reduce the crosstalk error caused by wire resistances and contacted resistances of the cables in the 2D networked resistive sensor array.

An Improved Zero Potential Circuit for Readout of a Two-Dimensional Resistive Sensor Array

“…The crosstalk caused by R switch s was partly suppressed by the IIDFC [15] with a simpler structure and the crosstalk caused by R switch s was completely suppressed by the IIDFC with compensation [16], in which two sampling channels were used. The crosstalk for long cables and R switch s was well suppressed by the two-wire circuits, including the two-wire VFC [22], the two-wire S-NSDE-EPC [23], the multi-channel part two-wire ZPC [24], and the multi-channel full two-wire ZPC [25]. However, in these two-wire circuits, more extra components and more sampling channels were necessary.…”

“…Some ZPCs [17,20,21,23], each with one op-amp in negative feedback, were proposed to access all elements in the 2-D resistive sensor array, in which only one element could be selected and measured at the same time. Liu et al [17] classified these basic ZPCs into the setting non-scanned-electrode zero potential circuit (S-NSE-ZPC), the setting non-scanned-sampling-electrode zero potential circuit (S-NSSE-ZPC), and the setting non-scanned-driving-electrode zero potential circuit (S-NSDE-ZPC).…”

“…Thus, the EBT’s row electrode and its column electrode were connected to the inverting input of the Amp1 and the constant voltage source ( V in ) respectively, and all non-scanned electrodes were directly connected to a constant voltage ( V zp ) in the basic circuit. The V zp could be zero potential as shown in Figure 1a for the ZPCs [17,20,21] or another constant voltage for the equipotential circuits [23]. Through the scanning row 2:1 multiplexer ( R sr 1 ), the current ( I L ) on the feedback resistor ( R L ) was injected into the scanning row electrode of the array.…”

“…The effect of the bypass current was also influenced by the multiplexer’s switch-on resistance ( R switch ). Based on the VFC, with extra resistors and extra sampling channels, the improved isolated drive feedback circuit (IIDFC) [15] and the IIDFC with compensation [16] were proposed for suppress the crosstalk caused by R switch s. The two-wire circuits, such as the two-wire VFC [22], the two-wire setting non-scanned-driving-electrode equipotential circuit (S-NSDE-EPC) [23], the multi-channel part two-wire ZPC [24], and the multi-channel full two-wire ZPC [25], were proposed for suppressing the crosstalk for long cables, and good performances were obtained. However, in these two-wire circuits, many extra components, including many wires and many operational amplifiers (op-amps), were necessary.…”

High-Accuracy Readout Electronics for Piezoresistive Tactile Sensors

“…The Zero Potential Method also allows the reading circuit to be constructed using both a single readout circuit [20,21,22,23,24,25] and a series of additional multiplexers to control the row and column wires. However, if the number of sensors in these circuits is high, given that the time required to read all the sensors is M · N · t r , the time needed may be too great to evaluate important characteristics in tactile arrays such as grip or slippage.…”