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JianFeng Wu, Lei Wang, "Cable Crosstalk Suppression in Resistive Sensor Array with 2Wire SNSDEEP Method", Journal of Sensors, vol. 2016, Article ID 8051945, 9 pages, 2016. https://doi.org/10.1155/2016/8051945
Cable Crosstalk Suppression in Resistive Sensor Array with 2Wire SNSDEEP Method
Abstract
With long flexible cables connected to the 1wire setting nonscanneddrivingelectrode equipotential (SNSDEEP) 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 SNSDEEP circuit using two wires for every drivingelectrode and every samplingelectrode 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 1wire SNSDEEP circuit and the 2wire SNSDEEP circuit were evaluated by simulations. The simulation results show that the 2wire SNSDEEP 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.
1. Introduction
Resistive sensor arrays were widely used in tactile sensing [1–8], light sensing [9], infrared sensing [10], and so forth. In robotic applications, long flexible cables were preferred for flexibility and limited space of the sensitive areas. With tested cables of lengths from 55 mm to 500 mm (as shown in Table 1), different modules of resistive sensor arrays were connected to the test circuits through the plugs and the sockets. VidalVerdú et al. [1, 3] designed and compared circuits of networked piezoresistive sensor arrays. Speeter [2] designed a flexible sensing system with 16 × 16 resistive taxels. Yang et al. [4] designed a 32 × 32 flexible array within a 160 mm × 160 mm temperature and tactile sensing area. Zhang et al. [5] reported a 3 × 3 thin tactile force sensor array based on conductive rubber. CastellanosRamos et al. [6] reported a 16 × 16 tactile sensor array based on conductive polymers with screenprinting technology. Kim et al. [7] reported a flexible tactile sensor array with high performance in sensing contact force. Lazzarini et al. [8] reported a 16 × 16 tactile sensor array for practical applications in manipulation. But cables had different wire resistances which increased with the increase of their lengths. Between the plugs of the connected cables and the sockets of the test circuits, there existed contacted resistances of tens of milliohms to several ohms varying with the variation of mechanical vibration and time. But new methods are still lacking, which can be used to suppress crosstalk caused by long cables.

For this purpose, we present a novel cable crosstalk suppression circuit based on a 2wire method for the 2D networked resistive sensor arrays in the rowcolumn fashion. This paper begins with an overview of the application fields of the 2D networked resistive sensor arrays. Secondly, a novel cable crosstalk suppression method will be proposed and its equivalent resistance expression of the element being tested (EBT) will be analytically derived. Then simulations will be implemented to evaluate this method with different parameters such as wire resistances and contacted resistances of the cables, the array size, the measurement range of the EBT, and the adjacent elements’ resistances of 2D networked resistive sensor arrays. Finally, the results of experiments will be analyzed and conclusions for the method will be given.
2. Principle Analyses
In the rowcolumn fashion, 2D resistive sensor arrays needed few wires but suffered from crosstalk caused by parasitic parallel paths. For suppressing crosstalk, many methods have been proposed and analyzed in literatures, such as the passive integrators method [3], the inserting diode method [11], the resistive matrix array method [12], the voltage feedback methods [2, 13–17], and the zero potential methods (ZPMs) [1, 3–10, 16–20]. Wu et al. have suppressed the crosstalk caused by the adjacent column elements and the adjacent row elements with the Improved Isolated Drive Feedback Circuit (IIDFC) [13] and the Improved Isolated Drive Feedback Circuit with Compensation (IIDFCC) [14]. Wu et al. have also proposed a general voltage feedback circuit model [15] for fast analyzing the performances of different voltage feedback circuits. D’Alessio has analyzed measurement errors in the scanning circuits of piezoresistive sensors arrays [16]. Saxena et al. [18, 19] have suppressed the crosstalk caused by the adjacent column elements with large number of opamps using the zero potential method. Roohollah et al. [20] have suppressed the crosstalk error caused by the input offset voltage and input bias current of the opamp with a novel doublesampling technique. In these methods, the measurement accuracy of the EBT still suffered from cable crosstalk.
Liu et al. [17] defined the setting nonscannedelectrode zero potential (SNSEZP) method, the setting nonscannedsamplingelectrode zero potential (SNSSEZP) method, and the setting nonscanneddrivingelectrode zero potential (SNSDEZP) method for the zero potential methods, in which bipolar power sources were necessary for opamps and analog digital converters (ADCs). In some circuits [1, 3], the reference voltages were not zero, so opamps and ADCs with unipolar power sources, which were of less cost and were more convenient for use, could be used. So we defined those equipotential methods as the setting nonscannedelectrodeequipotential (SNSEEP) method, the setting nonscannedsamplingelectrodeequipotential (SNSSEEP) method, and the setting nonscanneddrivingelectrodeequipotential (SNSDEEP) method. In this analysis, the SNSDEEP circuit was taken for example. Traditional SNSDEEP circuit of resistive networked sensor array in shared rowcolumn fashion was shown as Circuit A in Figure 1(a). In Circuit A, the row electrodes and the column electrodes were used as the sampling electrodes and the driving electrodes, respectively. In Circuit A, in the resistive array was the element being tested (EBT); only one connected wire was used for every column and row electrode between the sensor array and the circuit; only one equal current : 1 multiplexer was used between the current setting resistor () and the row electrodes of the sensor module. On column electrodes of the circuit, 2 : 1 multiplexers had multiplexer switch resistances (s); column wires had column resistances (s) including column wire resistances and column contacted resistances. On row electrodes of the circuit, the equal current : 1 multiplexers had multiplexer switch resistances (s); row wires had row resistances (s) including row wire resistances and row contacted resistances. Thus Circuit A had one row sampling opamp, one : 1 multiplexer, 2 : 1 multiplexers, and wires.
(a)
(b)
(c)
(d)
Under an ideal condition, all s and all s were omitted. Thus the voltage () on the column electrode of the EBT was equal to the feedback voltage (), and the voltages on the nonscanned column electrodes were equal to the reference voltage (). At the same time, all s and all s were omitted. Thus the voltage () on the inverting input of the row sampling opamp was equal to the voltage () on the row electrode of EBT. Under the effect of the ideal opamp, was equal to and the current () on the EBT was following the change of the current () on . As the voltages on the nonscanned column electrodes were equal to , the currents on the adjacent row elements of EBT were equal to zero. At the same time, the current on the inverting input of the ideal opamp was omitted for its infinite input impedance, the current () on the EBT was equal to the current () on . Thus, and were equal. As and were known, could be measured by ADC, so the equivalent resistance value () of the EBT in Circuit A could be calculated with the following:
But under the real condition as shown in Figure 1(b), was not equal to for and , and was not equal to for and . The ideal feedback condition was destroyed by the row wires and the column wires, so extra measurement errors of the EBT existed.
For suppression cable crosstalk in the 2D networked resistive arrays, we proposed a 2wire equipotential method (Circuit C, as shown in Figure 1(c)). In Circuit C, we used two wires for every row electrode and every column electrode between the sensor module and the test circuit; also we used one column driving opamp for every column electrode and one more equipotential : 1 multiplexer between the row electrodes and the row sampling opamp. Thus Circuit C had one row sampling opamp, column driving opamps, 2 : 1 multiplexers, two : 1 multiplexers, and connected wires.
Every column electrode in the sensor module was connected with the output of its column driving opamp by one driving wire and it was also connected with the inverting input of its column driving opamp by one driving sampling wire. The noninverting input of every column driving opamp was connected with the common port of its column 2 : 1 multiplexer; thus every noninverting input was connected with or . The noninverting input of EBT’s column driving opamp was connected with and the noninverting inputs of other column driving opamps were connected with .
As the input impedance of every column driving opamp was much bigger than , the effect of could be omitted. So the voltage on the noninverting input of every column driving opamp was equal to the input voltage ( or ) of its 2 : 1 multiplexer. If the column driving opamps had sufficient driving ability, the voltage on every column electrode was following the change of the voltage on the noninverting input of its column driving opamp. So was equal to , and the voltages on nonscanned column electrodes were equal to . Thus the crosstalk effect of and was suppressed.
By one equal current wire, every row electrode in the sensor module was connected with one channel of the equal current : 1 multiplexer with its common port connected with . In the equal current : 1 multiplexer, only the row electrode of EBT was gated and all other nonscanned electrodes were suspended. So only the row electrode of the EBT was connected with .
By one equipotential wire, every row electrode in the sensor module was also connected with one channel of the equipotential : 1 multiplexer with its common port connected with the inverting input of the row sampling opamp. In the equipotential : 1 multiplexer, only the row electrode of EBT was gated and all other nonscanned electrodes were suspended. So only the EBT’s row electrode was connected with the inverting input of the row sampling opamp. From the output port of the EBT’s column driving opamp, the test current firstly flowed through the EBT, then it flowed through the row equal current wire, then it flowed through the equal current : 1 multiplexer, and finally it flowed through to ground.
As the input impedance of the row sampling opamp was much bigger than its series resistances such as the switch resistance of the equipotential : 1 multiplexer, the wire resistance of the equipotential wire, and the contacted resistance, the voltage on the inverting input of the row sampling opamp was equal to the voltage () of the EBT’s row electrode.
Under the effect of the row sampling opamp, the current () on the EBT followed the change of the current () on . As the input impedance of the row sampling opamp was much bigger than its parallel resistances such as , , and , the leak current on the inverting input of the voltage feedback opamp could be ommited. And the voltage on every nonscanned column electrode was equal to , which was also equal to . Thus the currents on the EBT’s row adjacent elements were zero. So was equal to . The current with equal value also flowed through and . As was known and was equal to , we could know if the voltage () on and the voltage () on the EBT were known. Thus we could get of the EBT.
But was not equal to for (as shown in Figure 1(d)) which was the crosstalk caused by the row wire. Thus extra measurement error of the EBT was caused by it. From the above discussion, we could know that the currents on , , and had equal values. So we could use (2) to calculate in Circuit C. We found that did not exist in (2). As and were known, and could be measured by ADC, so the equivalent resistance value () of the EBT in Circuit C could be calculated with (2). Thus the crosstalk caused by the row wire was suppressed:
From the above discussion, the 2wire SNSDEEP method can depress the crosstalk caused by the row wires and the column wires such as s, s, s, and s.
3. Simulation Experiments and Discussion
To emulate the performance of our method, OP07 was selected as the macromodel of the opamp (from the datasheet, the offset voltage, the bias current, the gainbandwidth, and the gain are equal to 75 μV, 2.8 nA, 0.60 MHz, and 126 dB, resp.) in the simulations of National Instrument (NI) Multisim 12. In simulations, was set at 0.1 V, was set at 1 kΩ, the positive voltage source of the opamps was set at 9 V, and the negative voltage source of the opamps was set at −6 V.
3.1. Effect Simulation in NI Multisim
Cable resistance (, ) including the wire resistance and the contacted resistance affected the performance of the 2D networked resistive circuits. We investigated the effect of including wire resistance and contacted resistance on the 1wire SNSDEEP circuit and the 2wire SNSDEEP circuit in NI Multisim. In simulations, we fixed some parameters including all elements in the resistive sensor array at 10 kΩ and and at 8, and in sensor arrays varied synchronously with the same resistance value in 0.1 Ω–100 Ω. The simulation results of the two circuits in NI Multisim 12 were shown in Figure 2. In the results, as shown in Figure 2, the deviation effect of caused by the row line and the row multiplexer was also considered.
From Figure 2, with varied from 0.1 Ω to 100 Ω, errors in the 1wire SNSDEEP circuit showed a significant change (from 0.025% to 9.017%) with an obvious positive increase coefficient, while errors in the 2wire SNSDEEP circuit eliminating the deviation effect of showed a tiny change (from −0.000% to −0.003%). But if the deviation effect of was ignored, errors in the 2wire SNSDEEP circuit with would be significant (from −0.002% to −9.083%) as shown in Figure 2. Thus, the 2wire SNSDEEP circuit eliminating the deviation effect of has a better performance than the 1wire SNSDEEP circuit when is varied from 0.1 Ω to 100 Ω; the absolute errors of the 2wire SNSDEEP circuit eliminating the deviation effect of are small enough to be negligible when is less than 100 Ω.
In the data of the simulation results, we also found the offset value of from was varied from 0.19 mV to 9.08 mV with changing from 2 Ω to 100 Ω.
3.2. Array Size Effect Simulation Experiment
Parameters of the array size such as the row number () and the column number () were proved to have effect on the performance of the 2D networked resistive sensor arrays [9–19]. We investigated the effect of and on the 1wire SNSDEEP circuit and the 2wire SNSDEEP circuit in NI Multisim. In simulations, we fixed some parameters including all elements in the resistive sensor array at 10 kΩ, or at 8, and at 2 Ω, and or was one number in (8, 15, 29, 57, 113, and 225). The results of the array size effect on the 1wire SNSDEEP circuit and the 2wire SNSDEEP circuit were simulated in NI Multisim and the results were shown in Figure 3. In the results, as shown in Figure 3, the deviation effect of caused by the row line and the row multiplexer was also considered.
From Figure 3, with the increase of the column number, the errors in the 1wire SNSDEEP circuit had a positive coefficient (from 0.196% to 4.722%) while the errors in the 2wire SNSDEEP circuit eliminating the deviation effect of had a negative coefficient (from −0.000% to −0.044%). But if the deviation effect of was ignored, we found a deviation of errors (from −0.191% to −0.235%) in the 2wire SNSDEEP circuit with in Figure 3. The absolute errors in the 2wire SNSDEEP circuit eliminating the deviation effect of had been reduced significantly comparing with the absolute errors in the 1wire SNSDEEP circuit.
From Figure 3, with the row number changed in the range from 8 to 113, the errors in both circuits changed little (from 0.196% to 0.194% for the 1wire SNSDEEP circuit, about 0.000% for the 2wire SNSDEEP circuit eliminating the deviation effect of , about −0.191% for the 2wire SNSDEEP circuit with ); but when the row number changed in the range from 113 to 225, the errors in both circuits changed clearly (from 0.194% to −0.067% for the 1wire SNSDEEP circuit, from 0.000% to 0.032% for the 2wire SNSDEEP circuit eliminating the deviation effect of , from −0.191% to −0.159% for the 2wire SNSDEEP circuit with ). If every column driving opamp had a sufficient current driving ability, the row number had less influence on the errors in both circuits. In the data of the simulation results, we also found the offset value of from was about 0.19 mV with array size changed.
Thus, in the 2wire SNSDEEP circuit eliminating the deviation effect of , the influence of array size on the error has been decreased greatly.
3.3. The Adjacent Elements Effect Simulation
In literatures [9–19], the adjacent elements played a significant role in affecting the measurement accuracy of the EBT. In simulations, we fixed some parameters including the resistance value of nonadjacent elements and all other adjacent elements at 10 kΩ, and at 8, and at 2 Ω. The resistance value of an adjacent element varied in the range from 0.1 kΩ to 1 MΩ. The adjacent element could be an adjacent row element () or an adjacent column element (). The simulation results of the 1wire SNSDEEP circuit and the 2wire SNSDEEP circuit in NI Multisim were shown in Figures 4–7.
From Figures 4–7, the errors of the EBT of both circuits had negative coefficient when the resistance value of the EBT increased; the errors of the EBT showed irregular variations when the resistances of the EBT was bigger than a certain value (≥30 kΩ for the 1wire SNSDEEP circuit, ≥50 kΩ for the 2wire SNSDEEP circuit). We found that the output voltages of the row sampling opamp in both circuits were saturated for a bigger resistance value of the EBT. Under the same power source voltage, the measurement range of the 2wire SNSDEEP circuit was bigger than that of the 1wire SNSDEEP circuit.
From Figures 4–7, the errors of the EBT with a bigger resistance value were susceptible to interference from by one or one with a smaller resistance value. In both circuits, the changes of the errors for the change of one were bigger than the changes of the errors for the change of one . With one or one varied from 0.1 kΩ to 1 MΩ, the changes of the errors (with at 30 kΩ, from −0.307% to −0.048% for one and from −3.022% to −0.051% for one ) in the 1wire SNSDEEP circuit were significant, while those (with at 50 kΩ, from −0.006% to −0.006% for one and from −0.106% to −0.005% for one ) in 2wire SNSDEEP circuit were small. Thus, in the 2wire SNSDEEP circuit, the influence of the adjacent elements on the error has been decreased greatly.
3.4. The OpAmp’s Offset Voltage Effect Simulation
As many opamps were used in the 2wire SNSDEEP circuit, the offset voltages of the opamps would affect the performance of the proposed circuit. In simulations, we fixed some parameters including the resistance value of all other row elements at 10 kΩ, and at 8, at 2 Ω, and all s at the same resistance value in (100 Ω, 300 Ω, 1 kΩ, and 10 kΩ). The offset voltages of the nonscanned column driving opamps varied synchronously with the same value in (−75 μV–75 μV), and the 2wire SNSDEEP circuit was simulated in NI Multisim and the results were shown in Figure 8.
From Figure 8, we found that the offset voltages of the opamps and the resistances of the row adjacent elements affected the 2wire SNSDEEP circuit. The smaller these resistances were and the larger the offset voltage was, the larger the error in the proposed circuit was.
3.5. The OpAmp’s Driving Capability Effect Simulation
The opamp’s driving capability affected the performance of the 2wire SNSDEEP circuit. The nonscanned elements’ bypass effect on the EBT in the 2D resistive sensor array was obvious when the EBT had large resistance and all nonscanned elements had the small resistances. In the worst case, the EBT had the maximum resistance and all nonscanned elements had the minimum resistances [17]. In the experiments, we were about to simulate the opamp’s driving capability with all nonscanned elements of different fixed small resistances and the EBT of a large resistance. In simulations, we fixed some parameters including and at 8 and at 2 Ω and all nonscanned elements at the same resistance value in (100 Ω, 300 Ω, 500 Ω, 1 kΩ, and 3 kΩ). The resistance value of the EBT varied in the range from 0.1 kΩ to 60 kΩ. The 2wire SNSDEEP circuit with the opamp of OP07 was simulated in NI Multisim and the results were shown in Figure 9 and Table 2. Also the opamps of OP07 ( mA) were replaced by the opamps of AD797 ( mA), and the 2wire SNSDEEP circuit was simulated.

From Figure 9 and Table 2, with the resistances of all nonscanned elements fixed, the 2wire SNSDEEP circuit failed to work normally when the EBT’s resistance exceeded certain values; with the minimum resistances of all nonscanned elements increased, the maximum resistance which could be tested in the 2wire SNSDEEP circuit increased; with a larger opamp’s driving capability, the 2wire SNSDEEP circuit with its opamp of AD797 had a larger measurement range.
3.6. Discussion
From the results in Figure 1, the 1wire SNSDEEP circuit had one voltage feedback opamp, 2 : 1 multiplexers, one : 1 multiplexers, and wires; the 2wire SNSDEEP circuit had one voltage feedback opamp, N column driving opamps, 2 : 1 multiplexers, two : 1 multiplexers, and wires. Thus more components and more wires were used in the 2wire SNSDEEP circuit.
From the results in Figure 2, the 2wire SNSDEEP method was verified to be efficient in depressing the crosstalk caused by the row wires and the column wires such as , , , and . It should be noticed that all conductions were right under the assumption that the column driving opamps had sufficient driving ability and the row sampling opamp had very big input impedance on its inverting input.
From the results in Figures 3, 6, and 7, the 2wire equipotential circuit was failed to work normally with too much big resistance value of the EBT. If the resistance of the adjacent elements in resistive sensor array was too small, the absolute errors of the EBT would increase significantly. At the same time, if the row sampling opamp did not have very big input impedance or the elements in resistive sensor array had very big resistance values for the row sampling opamp’s input impedance, would be not equal to . Thus the ideal work conditions were destroyed for the 2wire SNSDEEP circuit and the error would be significant.
From the results in Figures 2, 3, and 8, in the 2wire SNSDEEP circuit had a significant effect on the error when the resistances such as the wire resistance, the contacted resistance, and the switchon resistance of the equal current : 1 multiplexer were large. Thus the deviation value of , mainly caused by the connected cable and the equal current : 1 multiplexers should be carefully considered in the 2wire SNSDEEP circuit. In the proposed method, the deviation effect of had been eliminated and the 2wire SNSDEEP circuit with good performance was obtained. As the offset value of from was varied from 0.19 mV to 9.08 mV with changing from 2 Ω to 100 Ω, one more opamp was necessary for amplifying the signal of in the case of using an analogdigital converter with limited resolution in the 2wire SNSDEEP circuit.
From the results in Figure 8, the offset voltages of the column driving opamps had an obvious influence on the performance of the 2wire SNSDEEP circuit, and the offset voltage’s effect would be more obvious for the element being tested with its row adjacent elements of smaller resistance values. With the increase of the offset voltage, the error increased. As the column number of the sensor array had accumulation influence on the conductance values of the row adjacent elements, it would enhance the effect of the offset voltage. Obviously, the offset voltage of the row sampling opamp had similar influence on the performance of the 2wire SNSDEEP circuit. Thus in the practical circuit, the opamps with smaller offset voltages were preferred. In the opamp’s offset voltage effect simulation experiments, the offset voltages of all nonscanned driving opamps varied synchronously with the same value and their effect was obvious. But, in a practical circuit, the opamps’ offset voltages would be the uncertain values less than the offset voltage given in their datasheets and their effect would be weaker. In the 2wire SNSDEEP circuit, the doublesampling technique [20] was also useful for eliminating the effect of those nonidealities of the opamps such as the input offset voltage and the input bias current.
From the results in Figure 9 and Table 2, the opamp’s driving capability affected the measurement range of the 2wire SNSDEEP circuit; with the opamp fixed, there was an approximate linear relation between the minimum resistance and the maximum resistance in the 2wire SNSDEEP circuit. But the maximum resistance which could be tested in the 2wire SNSDEEP circuit was also limited by the test current and the power source voltage. Thus the opamps with large driving capability were preferred in the 2wire SNSDEEP circuit. But the opamps with large driving capability always had a large offset voltage. So the contradiction between the driving capability affecting its measurement range and the offset voltage affecting its measurement accuracy should be balanced according to the test requirement.
For good performance of the IIDFC [13] and the IIDFCC [14], special compensated resistors with their resistances equal to their multiplexers’ switchon resistances are necessary. But the multiplexers’ switchon resistances may vary in the practical circuits, and the ideal performances of the IIDFC and the IIDFCC are difficult to realize. In the 2wire SNSDEEP method, two wires for every row electrode and every column electrode between the sensor module and the test circuit, though it requires a large number of wires, are easier to achieve. The 2wire SNSDEEP method’s performance and its limitation have been verified by simulation experiments. Similar methods can also be used in the SNSSEEP circuit and the SNSEEP circuit. But these should be verified in future practical application.
4. Conclusion
Firstly, a 2wire SNSDEEP method of the 2D networked resistive sensor array was proposed. Secondly, the formula was given for the equivalent resistance expression of the element being tested in the networked sensor array by principle analyses. Then, the effects of some parameters on the measurement accuracy of the EBT were simulated with the National Instrument Multisim 12, the parameters including the wire resistances and the contacted resistances of long cables, the array size and the adjacent elements of the 2D resistive sensor array, and the offset voltages of the opamps. The simulation results show that the 2wire equipotential method was verified to be efficient in depressing the crosstalk caused by the row wires and the column wires such as , , , and ; in the 2D networked resistive sensor array with the 2wire SNSDEEP circuit, the influence of the adjacent column elements and the adjacent row elements on the measurement error of the element being tested has been reduced greatly. Finally, the factors which affected the performance of the 2wire SNSDEEP circuit were discussed and the conclusion was given.
Conflict of Interests
The authors declare that there is no conflict of interests regarding the publication of this paper.
Acknowledgment
This study was supported by the Specialized Research Fund Program for the Doctoral Program of Higher Education (no. 20130092110060). This study was also supported by the Scientific Research Fund Project of Nanjing Institute of Technology (no. CKJB201405), the Open Fund of the Key Laboratory of Remote Measurement and Control Technology in Jiangsu Province (nos. YCCK201401 and YCCK201006), the National Major Scientific Equipment R&D Project (Grant no. ZDYZ20102), and NSAF (no. U1230114).
References
 F. VidalVerdú, M. Jose Barquero, J. CastellanosRamos et al., “A large area tactile sensor patch based on commercial force sensors,” Sensors, vol. 11, no. 5, pp. 5489–5507, 2011. View at: Publisher Site  Google Scholar
 T. H. Speeter, “A tactile sensing system for robotic manipulation,” The International Journal of Robotics Research, vol. 9, no. 6, pp. 25–36, 1990. View at: Publisher Site  Google Scholar
 F. VidalVerdú, Ó. OballePeinado, J. A. SánchezDurán, J. CastellanosRamos, and R. NavasGonzález, “Three realizations and comparison of hardware for piezoresistive tactile sensors,” Sensors, vol. 11, no. 3, pp. 3249–3266, 2011. View at: Publisher Site  Google Scholar
 Y.J. Yang, M.Y. Cheng, S.C. Shih et al., “A $32\times 32$ temperature and tactile sensing array using PIcopper films,” The International Journal of Advanced Manufacturing Technology, vol. 46, no. 9, pp. 945–956, 2010. View at: Publisher Site  Google Scholar
 X. Zhang, Y. Zhao, and X. Zhang, “Design and fabrication of a thin and soft tactile force sensor array based on conductive rubber,” Sensor Review, vol. 32, no. 4, pp. 273–279, 2012. View at: Publisher Site  Google Scholar
 J. CastellanosRamos, R. NavasGonzález, H. Macicior, T. Sikora, E. Ochoteco, and F. VidalVerdú, “Tactile sensors based on conductive polymers,” Microsystem Technologies, vol. 16, no. 5, pp. 765–776, 2010. View at: Publisher Site  Google Scholar
 M.S. Kim, H.J. Shin, and Y.K. Park, “Design concept of highperformance flexible tactile sensors with a robust structure,” International Journal of Precision Engineering and Manufacturing, vol. 13, no. 11, pp. 1941–1947, 2012. View at: Publisher Site  Google Scholar
 R. Lazzarini, R. Magni, and P. Dario, “A tactile array sensor layered in an artificial skin,” in Proceedings of the IEEE/RSJ International Conference on Intelligent Robots and Systems, Human Robot Interaction and Cooperative Robots, vol. 3, pp. 114–119, Pittsburgh, Pa, USA, August 1995. View at: Publisher Site  Google Scholar
 R. S. Saxena, R. K. Bhan, and A. Aggrawal, “A new discrete circuit for readout of resistive sensor arrays,” Sensors and Actuators A: Physical, vol. 149, no. 1, pp. 93–99, 2009. View at: Publisher Site  Google Scholar
 R. S. Saxena, R. K. Bhan, C. R. Jalwania, and S. K. Lomash, “A novel test structure for process control monitor for uncooled bolometer area array detector technology,” Journal of Semiconductor Technology and Science, vol. 6, no. 4, pp. 299–312, 2006. View at: Google Scholar
 D. Prutchi and M. Arcan, “Dynamic contact stress analysis using a compliant sensor array,” Measurement, vol. 11, no. 3, pp. 197–210, 1993. View at: Publisher Site  Google Scholar
 L. Shu, X. Tao, and D. D. Feng, “A new approach for readout of resistive sensor arrays for wearable electronic applications,” IEEE Sensors Journal, vol. 15, no. 1, pp. 442–452, 2015. View at: Publisher Site  Google Scholar
 J. F. Wu, L. Wang, and J. Q. Li, “Design and crosstalk error analysis of the circuit for the 2D networked resistive sensor array,” IEEE Sensors Journal, vol. 15, no. 2, pp. 1020–1026, 2015. View at: Publisher Site  Google Scholar
 J. F. Wu, L. Wang, J. Q. Li, and A. G. Song, “A novel crosstalk suppression method of the 2D networked resistive sensor array,” Sensors, vol. 14, no. 7, pp. 12816–12827, 2014. View at: Publisher Site  Google Scholar
 J. F. Wu, L. Wang, and J. Q. Li, “General voltage feedback circuit model in the twodimensional networked resistive sensor array,” Journal of Sensors, vol. 2015, Article ID 913828, 8 pages, 2015. View at: Publisher Site  Google Scholar
 T. D'Alessio, “Measurement errors in the scanning of piezoresistive sensors arrays,” Sensors and Actuators A: Physical, vol. 72, no. 1, pp. 71–76, 1999. View at: Publisher Site  Google Scholar
 H. Liu, Y.F. Zhang, Y.W. Liu, and M.H. Jin, “Measurement errors in the scanning of resistive sensor arrays,” Sensors and Actuators A: Physical, vol. 163, no. 1, pp. 198–204, 2010. View at: Publisher Site  Google Scholar
 R. S. Saxena, R. K. Bhan, N. K. Saini, and R. Muralidharan, “Virtual ground technique for crosstalk suppression in networked resistive sensors,” IEEE Sensors Journal, vol. 11, no. 2, pp. 432–433, 2011. View at: Publisher Site  Google Scholar
 R. S. Saxena, S. K. Semwal, P. S. Rana, and R. K. Bhan, “Crosstalk suppression in networked resistive sensor arrays using virtual ground technique,” International Journal of Electronics, vol. 100, no. 11, pp. 1579–1591, 2013. View at: Publisher Site  Google Scholar
 Y. Roohollah, A. Safarpour, and R. Lotfi, “An improvedaccuracy approach for readout of largearray resistive sensors,” IEEE Sensor Journal, vol. 16, no. 1, pp. 210–215, 2015. View at: Publisher Site  Google Scholar
Copyright
Copyright © 2016 JianFeng Wu and Lei Wang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.