CN113483923B - Conditioning circuit and method for solving signal crosstalk and multipoint detection of flexible array piezoresistive sensor - Google Patents
Conditioning circuit and method for solving signal crosstalk and multipoint detection of flexible array piezoresistive sensor Download PDFInfo
- Publication number
- CN113483923B CN113483923B CN202110762479.2A CN202110762479A CN113483923B CN 113483923 B CN113483923 B CN 113483923B CN 202110762479 A CN202110762479 A CN 202110762479A CN 113483923 B CN113483923 B CN 113483923B
- Authority
- CN
- China
- Prior art keywords
- row
- channel
- column
- analog switch
- signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L1/00—Measuring force or stress, in general
- G01L1/18—Measuring force or stress, in general using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/04—Programme control other than numerical control, i.e. in sequence controllers or logic controllers
- G05B19/042—Programme control other than numerical control, i.e. in sequence controllers or logic controllers using digital processors
- G05B19/0423—Input/output
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/20—Pc systems
- G05B2219/25—Pc structure of the system
- G05B2219/25257—Microcontroller
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Electronic Switches (AREA)
Abstract
The invention discloses a conditioning circuit for solving signal crosstalk and multipoint detection of a flexible array piezoresistive sensor, which comprises a row strobe signal line interface P1, a column strobe signal line interface P2, a group of row control lines, a group of column control lines, a multi-channel analog switch U1, a multi-channel analog switch U2, a multi-channel single-pole single-throw analog switch U3, a multi-channel single-pole single-throw analog switch U4, a decoder U5, a decoder U6, a multi-channel general operational amplifier U7, a multi-channel general operational amplifier U8, a precise operational amplifier U9, a multi-input OR gate U10, a triode Q1, a filter circuit and a main control chip MCU. For the flexible array piezoresistive transducer, the flexible array piezoresistive transducer does not need to be changed, and only row and column leads need to be led out and some peripheral circuits need to be led out, so that the flexible array piezoresistive transducer not only solves the problem of signal crosstalk, but also can improve the detection speed, thereby better realizing the multipoint detection function without losing the advantages of softness, easy stretching and bending, light weight, simplicity and the like.
Description
Technical Field
The invention relates to the technical field of pressure detection, in particular to a conditioning circuit and a conditioning method for solving signal crosstalk and multipoint detection of a flexible array piezoresistive sensor.
Background
A flexible array piezoresistive sensor is a piezoresistive sensor composed of a composite material. The device has the advantages of flexibility, easy stretching and bending, portability, simplicity, capability of realizing multipoint pressure detection and the like. Therefore, the pressure sensor is often used as a pressure detection module in a robot tactile sensor. Each piezoresistive unit in the flexible array piezoresistive sensor can be used as an independent pressure detection unit, and the resistance value of each piezoresistive unit can be changed along with the change of the pressure, so that the magnitude of the applied force can be known by detecting the resistance value of each piezoresistive unit. After the piezoresistive units are arrayed, the multipoint detection of pressure can be completed in a row-column scanning mode, so that the function of the robot touch sensor is realized.
The piezoresistive units in the traditional flexible array piezoresistive sensor have a complex series-parallel relationship, and if the gated piezoresistive units are detected by using a conventional row-column scanning method, crosstalk is generated on the gated piezoresistive units by other non-gated piezoresistive units, and the crosstalk is increased sharply along with the increase of the number of array rows and columns, so that the final detection result is greatly influenced. For the suppression crosstalk, utility model patent 2017210143960 provides a multipoint network array type pressure acquisition circuit, this circuit needs to dispose a set of operational amplifier circuit for each way input signal, for bigger array for example 16 x 16 way array has 256 input signals altogether, if adopt this method will need 256 sets of operational amplifier circuit, the circuit scale will be very huge, the cost also can be very high, and 256 leads need to draw forth, to flexible array piezoresistive sensor, so many external leads are not advisable in actual operation design, can make flexible array piezoresistive sensor lose advantages such as soft easy tensile bending, light, succinct. The utility model patent 201921952994.1 provides a method of connecting a diode in series with each piezoresistive unit to block the loop of crosstalk current, thereby isolating crosstalk signals. This approach is equally unsuitable for flexible array piezoresistive sensors with a large number of rows and columns. Taking a 16 by 16 array as an example, 256 diodes would be required in this way, and mounting 256 diodes on a flexible array piezoresistive sensor would be cumbersome and would also cause it to lose the advantages of being flexible, easily stretchable, flexible, lightweight, compact, etc., and would not be suitable for use in pressure sensing in a robotic tactile sensor.
The traditional multipoint detection method is to detect the state of each piezoresistive unit by row-column scanning polling, so as to achieve the purpose of multipoint detection. The speed of the line and row scan is particularly critical. This method of multi-spot detection is not suitable for flexible array piezoresistive sensors with large number of rows and columns, such as a 16 x 16 array with 256 piezoresistive units, and assuming that the detection time of each piezoresistive unit is 10us, the time for completing one array scan is 2.56ms, and if multiple pressures occur within 2ms, the multi-spot detection function cannot be realized, so it would be necessary to reduce the time for one array scan.
Disclosure of Invention
The invention aims to provide a conditioning circuit and a conditioning method for solving the problems of signal crosstalk and multi-point detection of a flexible array piezoresistive sensor, so as to solve the defects of the prior art.
The invention adopts the following technical scheme:
a conditioning circuit for solving signal crosstalk and multipoint detection of a flexible array piezoresistive sensor comprises a row strobe signal line interface P1, a column strobe signal line interface P2, a group of row control lines, a group of column control lines, a multi-channel analog switch U1, a multi-channel analog switch U2, a multi-channel single-pole single-throw analog switch U3, a multi-channel single-pole single-throw analog switch U4, a decoder U5, a decoder U6, a multi-channel general operational amplifier U7, a multi-channel general operational amplifier U8, a precision operational amplifier U9, a multi-input OR gate U10, a triode Q1, a filter circuit and a main control chip MCU;
the row strobe signal line interface P1 is used for accessing a row lead of the flexible array piezoresistive sensor to be tested;
the column gating signal line interface P2 is used for connecting a column lead of the flexible array piezoresistive sensor to be tested, and the column gating signal line interface P2 is connected with the ground reference resistor Ref;
the row control line is controlled by a group of GPIO1 ports of the MCU, the other end of the row control line is connected with the multi-channel analog switch U1 and the decoder U5 and is respectively used for controlling the multi-channel analog switch U1 to carry out a row gating function, namely, one row of the gated flexible array piezoresistive sensor is gated and is used for controlling the output of the decoder U5, the output of the decoder U5 controls the multi-channel single-pole single-throw analog switch U3 to achieve the purpose of gating other rows where the gating is not carried out, so that specific voltage is fed back to all unselected rows except the gated rows to achieve the purpose of row equipotential;
the column control line is controlled by a group of GPIO2 ports of the MCU, the other end of the column control line is connected with the multi-path analog switch U2 and the decoder U6 and is respectively used for controlling the multi-path analog switch U2 to carry out column gating, namely, the column gating is carried out after the row gating, so that a specific piezoresistance unit is selected and used for controlling the output of the decoder U6, the output of the decoder U6 controls the multi-path single-pole single-throw analog switch U4 to achieve the purpose of gating other non-gated columns, so that specific voltage is fed back to all the non-gated columns except the gated columns, and the purpose of row equal potential is achieved;
the multi-path analog switch U1 has one input and multiple outputs, is connected with a specific level, and selects one output channel from a plurality of output channels of the multi-path analog switch U1 through a row control line to output the input voltage of the multi-path analog switch U1 so as to gate a certain row;
the multi-path analog switch U2 is input and output, when the row is gated, voltage signals on all columns of a certain row signal line of the flexible array piezoresistive sensor are transmitted to the multi-path analog switch U2, at the moment, one channel is selected from the multiple channels through a column control line and is used as a final sampling signal to be transmitted to a subsequent conditioning circuit, and any one piezoresistive unit in the flexible array piezoresistive sensor can be selected through a row and column scanning method;
the multi-channel single-pole single-throw analog switch U3 is used for providing specific voltage for the un-gated row signal wire so as to meet the requirement of row equipotential;
the multi-channel single-pole single-throw analog switch U4 is used for providing specific voltage for the un-gated column signal wire so as to meet the requirement of column equipotential;
the decoder U5 controls the multi-channel single-pole single-throw analog switch U3, and the effective level output by the decoder U5 needs to enable the multi-channel single-pole single-throw analog switch U3 to be in a state that only one switch is closed and the other switches are opened so as to achieve the purpose of equal potential;
the decoder U6 controls the multi-channel single-pole single-throw analog switch U4, and the effective level output by the decoder U6 needs to enable the multi-channel single-pole single-throw analog switch U4 to be in a state that only one switch is closed and the other switches are opened so as to achieve the purpose of row equipotential;
the output of the multi-path analog switch U1 is connected with the input in-phase end of the multi-path general operational amplifier U7, the output is fed back to the inverting end to be a follower, and the output of the multi-path general operational amplifier U7 is connected to the row strobe signal line interface P1 to play a role of buffering and isolation;
the output of the multi-path analog switch U2 is connected with the input in-phase end of the multi-path general operational amplifier U8, the output is fed back to the inverting end to be a follower, and the output of the multi-path general operational amplifier U8 is connected to a column gating signal line interface P2 to play a role in buffering and isolation;
the precision operational amplifier U9 amplifies the acquired signal by proper times through an amplifying circuit, then filters the signal through a filter circuit, and then inputs the signal into an ADC port of the MCU to convert the acquired analog voltage signal into a digital signal, thereby acquiring the pressure condition of the flexible piezoresistive sensor;
the triode Q1 determines whether power is supplied to a multi-path general operational amplifier U8 in the column equipotential circuit or not in a conducting state, so that whether the column equipotential circuit works or not is controlled;
the multi-input or gate U10 is used for taking each column of signal wires as the input of the multi-input or gate U10, the output level of the multi-input or gate U10 is a level signal of GPIO4 of the MCU, under the condition that the column equipotential circuits are closed, the level signal of the GPIO4 of the MCU is monitored at all times, rapid line detection is carried out, if the GPIO4 is low level, no pressure resistance unit in the selected line is stressed, the next line is changed to continue to detect the selected line, and if the GPIO4 is high level, the pressure resistance unit in the selected line is stressed; when the gated row piezoresistive unit is detected to be stressed, the fast row detection circuit needs to be closed, the column equipotential circuit needs to be opened to eliminate signal crosstalk, and then the required sampling signal is acquired.
Further, the multi-channel analog switch U1, an input multi-output, uses the output of the conventional multi-channel analog switch as an input, and is connected to a specific level.
Furthermore, a control signal of the multi-channel single-pole single-throw analog switch U3 needs to be matched with an effective output level of the decoder U5, if a control pin of the multi-channel single-pole single-throw analog switch U3 is high level effective, the output level of the decoder U5 needs to be low level effective, and when a certain line can be gated, the decoder U5 outputs a corresponding level signal with a low level or a high level, so that the multi-channel single-pole single-throw analog switch U3 always only has an analog switch of one channel closed, and analog switches of the other channels are opened, and a specific voltage signal is fed back to a line signal line to meet the requirement of row equipotential;
the control signal of the multi-channel single-pole single-throw analog switch U4 needs to be matched with the effective output level of the decoder U6, if the control pin of the multi-channel single-pole single-throw analog switch U4 is high level effective, the output level of the decoder U6 needs to be low level effective, and when a certain column can be gated, the decoder U6 outputs a corresponding level signal with a low level or a high level, so that the multi-channel single-pole single-throw analog switch U4 always only has the analog switch of one channel closed, the analog switches of the other channels are opened, and a specific voltage signal is fed back to the column signal wire to meet the requirement of the column equipotential.
Furthermore, a high level is output by controlling the GPIO3 of the MCU, so that the triode Q1 is conducted, and the power supply Von voltage of the multi-path general operational amplifier U8 is close to 0V, thereby achieving the purpose of closing the column equipotential circuit; the low level is output by controlling the GPIO3 of the MCU, so that the triode Q1 is cut off, the power supply Von voltage of the multi-path general operational amplifier U8 is close to the power supply voltage VCC, and the column equipotential circuit works normally at the moment.
Furthermore, the precision operational amplifier U9 can change the amplification factor by changing the ground resistance Rd of the feedback resistance Rf connected to the inverting terminal, and amplify the acquired signal by a suitable factor through the amplifying circuit.
Further, the filter circuit is a first-order low-pass filter circuit.
The conditioning method for solving the problems of signal crosstalk and multi-point detection of the flexible array piezoresistive sensor by using the conditioning circuit comprises the following steps:
1) Respectively connecting a row lead and a column lead of the flexible array piezoresistive sensor to be detected into a row gating signal line interface P1 and a column gating signal line interface P2;
2) And array row gating: the row control line led out by a group of GPIO1 ports of the MCU controls the multi-channel analog switch U1 to send the row selection voltage Vnow to a certain row signal line so as to achieve the purpose of row selection, meanwhile, the row control line also controls the decoder U5, the output level signal of the decoder U5 can gate all channels of the multi-channel single-pole single-throw analog switch U3 except the channel selected by the multi-channel analog switch U1, and finally the sampled voltage signal Vadc is fed back to the row lead wire of the flexible array piezoresistive sensor through the multi-channel general operational amplifier U7 which plays a role of buffering and isolation, so that the purpose of row equipotential is achieved;
3) And (3) fast line detection: the control triode Q1 does not supply power to the multi-path general operational amplifier U8 to close the column equipotential circuit, and under the condition that the column equipotential circuit is closed, the level signal of GPIO4 of the MCU is constantly monitored, the level signal of the GPIO4 is the output level of the multi-input OR gate U10, the input of the multi-input OR gate U10 is a column lead in the flexible array piezoresistive sensor, therefore, if the GPIO4 is low level, no piezoresistive unit is stressed in the selected channel at the moment, the next row is changed to continue to detect the selected channel, and if the GPIO4 is high level, the piezoresistive unit is stressed in the selected channel at the moment;
when the gated row piezoresistive unit is detected to be stressed, the fast row detection circuit needs to be closed, the power is supplied to the multi-path general operational amplifier U8 through the control triode Q1, and the row equipotential circuit is started to eliminate signal crosstalk;
4) Array column gating: the column control line led out through a group of GPIO2 ports of the MCU controls the channel enable of the multi-channel analog switch U2, only one channel is gated each time, the voltage on a ground reference resistor Ref connected with the channel is taken as the input voltage of the channel and is output to the non-inverting input end of a precise operational amplifier U9 through the multi-channel analog switch U2, so that the purpose of column gating is achieved, meanwhile, the column control line also controls a decoder U6, the output level signal of the decoder U6 gates all channels of the multi-channel single-pole single-throw analog switch U4 except the channel selected by the multi-channel analog switch U2, and the row gating power supply voltage Vrow is fed back to a column lead wire of the flexible array piezoresistive sensor through a multi-channel general operational amplifier U8 which plays a role in buffering and isolation, so that the purpose of column equipotential is achieved;
5) After row-column gating, a certain piezoresistive unit of the flexible array piezoresistive sensor can be selected and connected with a ground reference resistor Ref in series, the ground voltage generated by the ground reference resistor Ref is input into a precise operational amplifier U9 to be amplified in a certain proportion through a series resistor voltage division principle, useless interference noise signals are filtered out through a filter circuit, a final smooth analog sampling voltage signal Vadc is obtained, the Vadc is input into a built-in ADC module of the MCU, and therefore the resistance value of the piezoresistive unit to be detected can be measured.
Further, in the step 3), a high level is output by controlling the GPIO3 of the MCU, so that the triode Q1 is conducted, and the power supply Von voltage of the multi-path general operational amplifier U8 is close to 0V, thereby achieving the purpose of closing the column equipotential circuit; the low level is output by controlling the GPIO3 of the MCU, so that the triode Q1 is cut off, the power supply Von voltage of the multi-path general operational amplifier U8 is close to the power supply voltage VCC, and the column equipotential circuit works normally at the moment.
Further, in the step 5), the precision operational amplifier U9 can change the amplification factor by changing the ground resistance Rd of the feedback resistance Rf connected to the inverting terminal, and amplify the acquired signal by a suitable factor through the amplifying circuit.
Further, step 5) filters useless interference noise signals through a first-order low-pass filter circuit.
The invention has the beneficial effects that:
the flexible array piezoresistive sensor does not need to change the flexible array piezoresistive sensor, and only row and column leads and peripheral circuits need to be led out, so that a signal line is prevented from being led out for each piezoresistive unit of the flexible array piezoresistive sensor, and a diode does not need to be connected in series with each piezoresistive unit, so that the advantages of flexibility, easiness in stretching, bending, portability, simplicity and the like of the flexible array piezoresistive sensor are not lost.
On the premise of not losing the advantages of flexibility, easy stretching and bending, portability, simplicity and the like of the flexible array piezoresistive sensor, the invention solves the problem of signal crosstalk commonly existing among all piezoresistive units of the flexible array piezoresistive sensor by only adding a plurality of peripheral circuits to form a row-column equipotential circuit, thereby greatly improving the detection precision and the detection range of signals; the multi-input OR gate is skillfully utilized to form the rapid row detection circuit, and whether all the piezoresistive units on the gated row are stressed can be rapidly judged only through the output level of the logic gate, so that the piezoresistive units on the gated row do not need to be detected one by one, and the detection speed of the flexible array piezoresistive sensor is greatly improved; therefore, the aim of more effectively and accurately completing multi-point detection by a row-column scanning method is fulfilled.
Drawings
Fig. 1 is a 16-by-16 array pressure sensing schematic.
FIG. 2 is a schematic diagram of a flexible array piezoresistive sensor conditioning circuit for eliminating crosstalk and realizing rapid line detection by using a row-column equipotential method.
Fig. 3 is a schematic diagram of crosstalk elimination by 3 × 3 array row-column equipotential method.
Fig. 4 is a schematic diagram of series-parallel resistance equivalence.
FIG. 5 is a schematic diagram of a fast line detection method.
Detailed Description
The invention is further explained below with reference to examples and figures. The following examples are provided only for illustrating the present invention and are not intended to limit the scope of the present invention.
The invention provides a conditioning circuit and a conditioning method for solving signal crosstalk and multipoint detection of a flexible array piezoresistive sensor. And then a row-column equipotential method is provided to eliminate the problem of signal crosstalk among the array piezoresistive units. The rapid line detection method can rapidly detect whether the piezoresistive units on the selected traffic are stressed or not without detecting all the piezoresistive units one by one, thereby greatly shortening the line and row scanning time and improving the speed of multi-point detection. The row-column equipotential method eliminates the signal crosstalk problem commonly existing between the gated piezoresistive unit to be detected and other non-gated piezoresistive units in the flexible array piezoresistive sensor due to the series-parallel connection relationship of the gated piezoresistive units, and improves the accuracy and precision of pressure detection.
The fast row detection method refers to that when a voltage is applied to a row, i.e., the row is gated, and no pressure is applied to the piezoresistive units on the row, the resistance values of the piezoresistive units can be regarded as infinite, and due to the existence of the ground reference resistor, the voltage signals on different columns of the row approach the ground voltage (at this time, the column equipotential circuit is turned off first), so that the logic levels of the columns can be considered as low levels, and if a pressure is applied to the piezoresistive units on a column of the row, the output voltage of the column can be made greater than a set threshold value once the piezoresistive units on the row detect the pressure within a pressure detection range by setting an appropriate reference resistor, so that the output level of the column is made as a logic high level. Thus, by connecting all column signals as inputs to a multiple input or gate and detecting the output, it is possible to determine whether a force is acting on the row. If the or gate outputs a logic low level indicating that no pressure is applied to all the piezoresistive cells in the row, the next row may be sensed, and if the or gate outputs a logic high level indicating that pressure is applied to one of the piezoresistive cells in the row, the piezoresistive cells of the row may be sensed one by one to determine which piezoresistive cell is acted upon by the force.
The row-column equipotential method comprises a row equipotential method and a column equipotential method.
Specifically, the row equipotential method refers to that when a certain piezoresistive unit is selected by gating a row and column line, the voltage of a measured signal, which is the voltage on a column signal line in the piezoresistive unit, is fed back to other un-gated row signal lines through a feedback circuit, so that the voltages on all un-gated row signal lines except the selected row are the same and are equal to the voltage of the selected column line, which is the voltage of the measured signal, and the voltages at two ends of other un-gated resistors on the column except the gated piezoresistive unit in the gated column are the same, so that no current flows through the un-gated resistors, thereby eliminating the problem of signal crosstalk caused by the series-parallel relationship between the gated piezoresistive unit and other column piezoresistive units.
Specifically, the column equipotential method refers to that when a certain piezoresistive unit is selected by gating a row line and a column line, the voltage on the row signal line in the piezoresistive unit, namely the row voltage which is required to be provided when the certain piezoresistive unit is gated, is fed back to other un-gated column signal lines through a feedback circuit, so that the voltages on all un-gated column lead wires except for the selected column are the same and are equal to the voltage on the selected row line, namely the gating voltage, and the voltages on two ends of the other un-gated resistors except for the gated piezoresistive unit are the same, so that no current flows through the resistors, and the problem of signal crosstalk caused by the series-parallel relationship between the gated piezoresistive unit and the other row piezoresistive units is solved.
A conditioning circuit for solving signal crosstalk and multipoint detection of a flexible array piezoresistive sensor comprises a row strobe signal line interface P1, a column strobe signal line interface P2, a group of row control lines, a group of column control lines, a multi-channel analog switch U1, a multi-channel analog switch U2, a multi-channel single-pole single-throw analog switch U3, a multi-channel single-pole single-throw analog switch U4, a decoder U5, a decoder U6, a multi-channel general operational amplifier U7, a multi-channel general operational amplifier U8, a precise operational amplifier U9, a multi-input OR gate U10, a triode Q1, a filter circuit and a main control chip MCU.
And the row strobe signal line interface P1 is used for connecting in a row lead of the flexible array piezoresistive sensor to be tested.
And the column gating signal line interface P2 is used for connecting a column lead of the flexible array piezoresistive sensor to be tested, and the column gating signal line interface P2 is connected with the ground reference resistor Ref.
The row control line is controlled by a group of GPIO1 ports of the MCU, the other end of the row control line is connected with the multi-path analog switch U1 and the decoder U5 and is respectively used for controlling the multi-path analog switch U1 to carry out the row gating function, namely, one row of the gated flexible array piezoresistive sensor is gated and is used for controlling the output of the decoder U5, the output of the decoder U5 controls the multi-channel single-pole single-throw analog switch U3 to achieve the purpose of gating other rows where the non-gating exists, so that specific voltage is fed back to all the non-gated rows except the gated rows, and the purpose of row equipotential is achieved.
The column control line is controlled by a group of GPIO2 ports of the MCU, the other end of the column control line is connected with the multi-path analog switch U2 and the decoder U6 and is respectively used for controlling the multi-path analog switch U2 to carry out column gating, namely, the column gating is carried out after the row gating, so that a specific piezoresistance unit is selected and used for controlling the output of the decoder U6, the output of the decoder U6 controls the multi-path single-pole single-throw analog switch U4 to achieve the purpose of gating other non-gated columns, so that specific voltage is fed back to all the non-gated columns except the gated columns, and the purpose of column equipotential is achieved.
The multi-path analog switch U1 is an input multi-output switch, the output end of the traditional multi-path analog switch is used as input, a specific level is connected, one output channel is selected from a plurality of output channels of the multi-path analog switch U1 through a row control line, and the input voltage of the multi-path analog switch U1 is output so as to gate a certain row.
The multi-path analog switch U2 is provided with multiple inputs and one output, when the row is gated, voltage signals on all columns of a certain row signal line of the flexible array piezoresistive sensor are transmitted to the multi-path analog switch U2, at the moment, one channel is selected from the multiple channels through a column control line and is used as a final sampling signal to be transmitted to a subsequent conditioning circuit, and any one piezoresistive unit in the flexible array piezoresistive sensor can be selected through a row and column scanning method.
The multi-channel single-pole single-throw analog switch U3 is used for providing specific voltage for the un-gated row signal wire so as to meet the requirement of row equipotential; the control signal of the multi-channel single-pole single-throw analog switch U3 needs to be matched with the effective output level of the decoder U5, for example, if the control pin of the multi-channel single-pole single-throw analog switch U3 is high level effective, the output level of the decoder U5 needs to be low level effective, and when a certain line can be gated, the decoder U5 outputs a corresponding level signal with a low level or a high level, so that only the analog switch of one channel of the multi-channel single-pole single-throw analog switch U3 is closed, the analog switches of the other channels are opened, and a specific voltage signal is fed back to the line signal wire to meet the requirement of the line equipotential.
The multi-channel single-pole single-throw analog switch U4 is used for providing specific voltage for the un-gated column signal line so as to meet the requirement of column equipotential; for example, if the control pin of the multi-channel single-pole single-throw analog switch U4 is high-level active, the output level of the decoder U6 must be low-level active to gate a certain column, and the decoder U6 outputs a corresponding level signal of one low level or more, so that only the analog switch of one channel of the multi-channel single-pole single-throw analog switch U4 is turned off, and the analog switches of the other channels are turned on, and a specific voltage signal is fed back to the column signal line to meet the requirement of the column equipotential.
The decoder U5 controls the multi-channel single-pole single-throw analog switch U3, and the effective level output by the decoder U5 needs to enable the multi-channel single-pole single-throw analog switch U3 to be in a state that only one switch is closed and the rest switches are opened, so that the purpose of equal potential is achieved.
The decoder U6 controls the multi-channel single-pole single-throw analog switch U4, and the effective level output by the decoder U6 needs to enable the multi-channel single-pole single-throw analog switch U4 to be in a state that only one switch is closed and the rest switches are opened, so that the purpose of row equipotential is achieved.
The output of the multi-path analog switch U1 is connected with the input in-phase end of the multi-path general operational amplifier U7, the output is fed back to the inverting end to be a follower, and the output of the multi-path general operational amplifier U7 is connected to the row strobe signal line interface P1 to play a role in buffering and isolation, so that interference is reduced, and measurement accuracy is improved.
The output of the multi-path general operational amplifier U8 and the output of the multi-path analog switch U2 are connected with the input in-phase end of the multi-path general operational amplifier U8, the output is fed back to the inverting end to be made into a follower, and the output of the multi-path general operational amplifier U8 is connected to the column gating signal line interface P2 to play a role in buffering and isolation, so that interference is reduced, and the measurement precision is improved.
The precision operational amplifier U9 can change the amplification factor by changing the ground resistance Rd of the feedback resistance Rf connected with the inverting terminal, amplifies the acquired signal by a proper factor through the amplification circuit, then filters the signal through the first-order low-pass filter circuit, and then inputs the analog voltage signal into the ADC port of the MCU to convert the acquired analog voltage signal into a digital signal, thereby knowing the pressure condition of the flexible piezoresistive sensor.
The triode Q1 determines whether power is supplied to a multi-path general operational amplifier U8 in the column equipotential circuit or not in a conducting state, so that whether the column equipotential circuit works or not is controlled; specifically, a triode Q1 is conducted by controlling GPIO3 of the MCU to output high level, and the power supply Von voltage of a multi-path general operational amplifier U8 is close to 0V, so that the aim of closing the column equipotential circuit is fulfilled; the low level is output by controlling the GPIO3 of the MCU, so that the triode Q1 is cut off, the power supply Von voltage of the multi-path general operational amplifier U8 is close to the power supply voltage VCC, and the column equipotential circuit works normally at the moment.
The multi-input or gate U10 is used for taking each column of signal wires as the input of the multi-input or gate U10, the output level of the multi-input or gate U10 is a level signal of GPIO4 of the MCU, under the condition that the column equipotential circuits are closed, the level signal of the GPIO4 of the MCU is monitored at all times, rapid line detection is carried out, if the GPIO4 is low level, no pressure resistance unit in the selected line is stressed, the next line is changed to continue to detect the selected line, and if the GPIO4 is high level, the pressure resistance unit in the selected line is stressed; when the gated row piezoresistive units are detected to be stressed, the fast row detection circuit needs to be closed, the column equipotential circuit needs to be opened to eliminate signal crosstalk, and then the required sampling signals are collected.
The conditioning method for solving the signal crosstalk and multi-point detection of the flexible array piezoresistive sensor by using the conditioning circuit comprises the following steps:
1) And respectively connecting a row lead and a column lead of the flexible array piezoresistive sensor to be detected into a row gating signal line interface P1 and a column gating signal line interface P2.
2) And array row gating: the row control line led out by a group of GPIO1 ports of the MCU controls the multi-channel analog switch U1 to send the row selection voltage Vnow to a certain row signal line so as to achieve the purpose of row selection, meanwhile, the row control line also controls the decoder U5, the output level signal of the decoder U5 can gate all channels of the multi-channel single-pole single-throw analog switch U3 except the channel selected by the multi-channel analog switch U1, and finally the sampled voltage signal Vadc is fed back to the row lead wire of the flexible array piezoresistive sensor through the multi-channel general operational amplifier U7 which plays a role of buffering and isolation, thereby achieving the purpose of row equipotential.
3) And (3) fast line detection: since the fast row detection method needs to work normally under the condition of no column equipotential, introducing column equipotential will affect the result of the fast row detection. Therefore, in the actual circuit, the row equipotential circuit is closed first, and the selected row is detected by using the fast row detection method. If the row of the piezoresistive units is detected to be under the action of pressure, the row equipotential circuit is started again to sample and output the output signals of the piezoresistive units, and if the pressure is not detected, the row equipotential circuit does not need to be started, and the next row can be continuously detected.
Specifically, the transistor Q1 is conducted by controlling the GPIO3 of the MCU to output high level, the power supply Von voltage of the multi-path general operational amplifier U8 is close to 0V, and at the moment, the column equipotential circuit does not work, namely, the row power supply voltage cannot be fed back to each column line voltage. At this time, when a certain row is selected, feedback voltage existing due to a column equipotential circuit does not exist in an ungated column in the row, at this time, a rapid row detection method can be used for judging whether a voltage-resistance unit of the row is stressed or not, a column lead in the flexible array piezoresistive sensor is used as input of the multi-input or gate U10, a level signal of GPIO4 of the MCU is monitored at all times, the level signal of the GPIO4 is the output level of the multi-input or gate U10, if the GPIO4 is low level, it means that no voltage-resistance unit in the selected row is stressed at this time, the next row is used for continuously detecting the selected row, and if the GPIO4 is high level, it means that a voltage-resistance unit in the selected row is stressed at this time. If the column equipotential circuit is not turned off, even if the piezoresistive unit is not under pressure, the output of the multi-input or gate U10 is at a high level due to the existence of the feedback voltage, and at this time, it is impossible to determine whether the piezoresistive unit in a certain row is under pressure according to the output level of the multi-input or gate U10.
When the gated row piezoresistive unit is detected to be stressed, the fast row detection circuit needs to be closed, the GPIO3 of the MCU is controlled to output a low level, the triode Q1 is cut off, the power supply Von voltage of the multi-path general operational amplifier U8 is close to the power supply voltage VCC, the column equipotential circuit works normally at the moment, and the column equipotential circuit is started to eliminate signal crosstalk.
4) Array column gating: the column control line led out by a group of GPIO2 ports of the MCU controls the channel enable of the multi-channel analog switch U2, only one channel is gated each time, the voltage on a ground reference resistor Ref connected with the channel is taken as the input voltage of the channel and is output to the non-inverting input end of the precision operational amplifier U9 through the multi-channel analog switch U2, so that the purpose of column gating is achieved, meanwhile, the column control line also controls the decoder U6, the output level signal of the decoder U6 can gate all channels of the multi-channel single-pole single-throw analog switch U4 except the channel selected by the multi-channel analog switch U2, and the output level signal of the multi-channel single-pole single-throw analog switch U4 is fed back to the column lead wire of the flexible array piezoresistive sensor through the multi-channel general operational amplifier U8 which plays a role in buffering and isolation, so that the purpose of column equipotential is achieved.
5) After row-column gating, a certain piezoresistive unit of the flexible array piezoresistive sensor can be selected and connected with a ground reference resistor Ref in series, the ground voltage generated by the ground reference resistor Ref is input to a precise operational amplifier U9 through the principle of voltage division of the series resistors, the amplification factor can be changed by changing the ground resistor Rd connected with the inverting terminal through a feedback resistor Rf, the acquired signals are amplified in a certain proportion through an amplifying circuit, then useless interference noise signals are filtered through a first-order low-pass filter circuit, and finally, smoother analog sampling voltage signals Vadc are obtained and input to a built-in ADC module of the MCU, so that the resistance value of the piezoresistive unit to be measured can be measured.
To further illustrate the present invention, the following description will specifically refer to the 16 × 16 array as the array to be tested.
As shown in fig. 1, it is only necessary to lead out row and column leads, and there is no need to separately lead out leads for each piezoresistive unit in the flexible array piezoresistive sensor. The row lead wire led out from the array to be tested in fig. 1 is connected to the row strobe signal interface P1 in fig. 2, and the column lead wire led out is connected to the column strobe signal interface P2 in fig. 2.
After row and column leads of the piezoresistive unit array to be tested are respectively connected to a row strobe signal interface P1 and a column strobe signal interface P2 in the figure 2, array row strobe is firstly carried out, namely row strobe voltage Vrow is sent to a certain row signal wire by controlling a multi-channel analog switch U1 through a row control line led out from a first group of GPIO1 ports of an MCU (micro control unit), so that the purpose of row strobe is achieved. Meanwhile, the row control line can also control the decoder U5, an output level signal of the decoder U5 can gate all channels of the multi-channel single-pole single-throw analog switch U3 except for a channel selected by the multi-channel analog switch U1, and finally, a sampled voltage signal Vadc is fed back to a row lead wire of the array piezoresistive sensor through a multi-channel general operational amplifier U7 with the buffering and isolating functions, so that the aim of row equipotential is fulfilled.
And then performing quick line detection. The aim of closing the column equipotential circuit is achieved by controlling the GPIO3 of the MCU to output high level to enable the triode Q1 to be conducted, the voltage of the power supply Von of the multi-path general operational amplifier U8 is close to 0V, and then the level signal of the GPIO4 of the MCU is monitored at any time, because the level signal of the GPIO4 is the output level of the multi-input OR gate U10, and the input of the multi-input OR gate U10 is a column lead wire in the flexible array piezoresistive sensor, if the GPIO4 is low level, no piezoresistive unit is stressed in the selected channel at the moment, the next row is changed to continue to detect the selected channel, and if the GPIO4 is high level, the piezoresistive unit is stressed in the selected channel at the moment. When the gated row piezoresistive unit is detected to be stressed, the fast row detection circuit needs to be closed, the column equipotential circuit needs to be opened to eliminate signal crosstalk, and then the required sampling signal is acquired. Specifically, the GPIO3 of the MCU is controlled to output low level, so that the triode Q1 is cut off, and the power supply Von voltage of the multi-path general operational amplifier U8 is close to the power supply voltage VCC.
Array column gating is performed. The column control line led out through a group of GPIO2 ports of the MCU controls the channel enable of the multi-channel analog switch U2, only one channel is gated each time, the voltage on the ground reference resistor Ref connected with the channel is taken as the input voltage of the channel and is output to the non-inverting input end of the precision operational amplifier U9 through the multi-channel analog switch U2, and therefore the purpose of column gating is achieved. Meanwhile, the row control line can also control the decoder U6, an output level signal of the decoder U6 can gate all channels of the multi-channel single-pole single-throw analog switch U4 except a channel selected by the multi-channel analog switch U2, and a row gate power supply voltage Vrow is fed back to a row lead wire of the flexible array piezoresistive sensor through a multi-channel general operational amplifier U8 which plays a role in buffering and isolation, so that the aim of row equipotential is fulfilled.
After row-column gating, a certain piezoresistive unit of the flexible array piezoresistive sensor can be selected and connected with a ground reference resistor Ref in series, the ground voltage generated by the ground reference resistor Ref is input into a precise operational amplifier U9 to be amplified in a certain proportion through a series resistor voltage division principle, then useless interference noise signals are filtered out through a first-order low-pass filter circuit, and finally a smoother analog sampling voltage signal Vadc is obtained and input into a built-in ADC module of the MUC, so that the resistance value of the piezoresistive unit to be measured can be measured.
To further illustrate the principle of eliminating signal crosstalk by the row-column equipotential method, fig. 3 and 4 are illustrated by a simpler 3 × 3 small-array piezoresistive sensor, and the principle of eliminating signal crosstalk of a large-array piezoresistive sensor is the same.
In fig. 3, the piezoresistive unit R5 is selected by the row and column control signals, and if no row and column equipotential circuit is added, the actual measured resistance value of the selected piezoresistive unit R5 is not the resistance value of R5, but the resistance value of R5 after being connected in series and in parallel with other piezoresistive units, as shown in the left circuit diagram of fig. 4.
The principle of the line equipotential method is as follows:
when selecting the resistor unit R5 in fig. 3, a row selection voltage Vrow (V +) needs to be provided on the row lead x2, and at this time, the column lead y2 has a certain voltage Vadc due to the serial voltage division of the resistors R5 and Ref 2. In order to prevent the current from flowing back to the x3 or x1 row through R8 or R2 after flowing through R5, the voltage Vadc on the y2 column can be fed back to the x3 and x1 rows, and the voltages at the two ends of R8 and R2 are equal, so that no current flows through R8 and R2, and the problem of column signal crosstalk is eliminated.
The principle of the column isoelectric method is as follows:
when the resistance unit R5 is selected in fig. 3, a row selection voltage Vrow (V +) needs to be provided on the row lead x2, and a voltage Vadc is provided on the column lead y 2. In order to prevent the current from flowing through R5 and a part of the current flowing through R4 or R6, which may cause the crosstalk problem, the voltage Vrow on x2 row may be fed back to y3 and y1 columns, and the voltages at both ends of R4 and R6 are equal, so that no current flows through R4 and R6, which may achieve the requirement of equal potential of the columns to eliminate the row signal crosstalk.
The resistance value of the measured resistance unit is shown in the right circuit of fig. 4 after the row-column equipotential method is used, so that the problem of signal crosstalk of the flexible array piezoresistive sensor is solved.
The principle of the rapid assay is as follows:
when the rapid row detection method is used, a column equipotential method cannot be used, and because the column equipotential method can influence the result of the rapid row detection method, the rapid row detection method is used firstly in actual detection, when the pressure of a resistance unit on the row is detected, the column equipotential method is used for eliminating signal crosstalk, otherwise, the next row is continuously detected. Therefore, firstly, the transistor Q1 needs to be controlled to be in a conducting state by a GPIO3 high-level signal through the MCU, so that the supply voltage Von of the multi-path general operational amplifier U8 used by the column equipotential circuit is close to the ground voltage 0V, and at this time, the multi-path general operational amplifier U8 is in a non-operating state, which cuts off the voltage feedback loop of the column equipotential circuit, and at this time, the column equipotential method is invalid, which will not affect the result of the fast row detection method. As shown in the left diagram of fig. 5, when the piezoresistive cell R5 is selected, a row selection voltage Vrow (V +) needs to be provided on a row lead x2, and at this time, if no piezoresistive cell is under pressure on the row, the resistance values of the row piezoresistive cells R4, R5, R6 can be regarded as infinite, because the ground reference resistors Ref1, ref2, ref3 exist, the voltages Vref1, vref2, vref3 on the columns y1, y2, y3 are all approximately 0V, corresponding to a logic level low level of 0, and each column signal is input as an input signal to the multi-input or gate U10, the output level of the multi-input or gate U10 is low, which means that no pressure is detected by the piezoresistive cell on the selected row, and at this time, the next row detection can be directly performed without scanning and detecting each column of the row again, for example, 16 times need to detect each piezoresistive cell in the 16 × 16 array one by one, and only n times of the row detection needs to detect n (16 × n) times of the row without increasing the row detection speed one by one, and the row detection is not detected by one by n (16 × 16). As shown in the right side of fig. 5, when the piezoresistive unit R5 is selected, a row selection voltage Vrow (V +) needs to be provided on a row lead x2, at this time, the piezoresistive unit R5 on the row is under pressure, resistance values of the row piezoresistive units R4 and R6 can be regarded as infinite, due to the existence of ground reference resistors Ref1 and Ref3, voltages Vref1 and Vref3 on columns y1 and y3 are both approximately 0V, corresponding to a logic level 0, and since the resistance value of the piezoresistive unit R5 is no longer infinite, but has a relatively fixed resistance value, at this time, an appropriate reference resistor Ref2 is selected, voltage division principle is used according to a series resistor, so that the voltage Vref2 on the column y2 is greater than an input high level threshold of a multi-input or gate U10, so that a logic level represented by Vref2 is a high level, at this time, an output level of the multi-input or gate U10 is a high level representing the row detection pressure, a GPIO3 low level signal controls a triode potential Q1 to be in a cut-off state, so that a multi-path voltage applied to a VCC equal-path power supply circuit approaches a multi-path voltage sampling operational point U8, and a multi-path crosstalk detection operational amplifier is acquired.
Claims (10)
1. A conditioning circuit for solving signal crosstalk and multipoint detection of a flexible array piezoresistive sensor is characterized by comprising a row strobe signal line interface P1, a column strobe signal line interface P2, a group of row control lines, a group of column control lines, a multi-channel analog switch U1, a multi-channel analog switch U2, a multi-channel single-pole single-throw analog switch U3, a multi-channel single-pole single-throw analog switch U4, a decoder U5, a decoder U6, a multi-channel general operational amplifier U7, a multi-channel general operational amplifier U8, a precise operational amplifier U9, a multi-input OR gate U10, a triode Q1, a filter circuit and a main control chip MCU;
the row strobe signal line interface P1 is used for connecting a row lead of the flexible array piezoresistive sensor to be tested;
the column gating signal line interface P2 is used for connecting a column lead of the flexible array piezoresistive sensor to be detected, and the column gating signal line interface P2 is connected with a ground reference resistor Ref;
the row control line is controlled by a group of GPIO1 ports of the MCU, the other end of the row control line is connected with the multi-path analog switch U1 and the decoder U5 and is respectively used for controlling the multi-path analog switch U1 to carry out the row gating function, namely, one row of the gated flexible array piezoresistive sensor is gated and is used for controlling the output of the decoder U5, the output of the decoder U5 controls the multi-channel single-pole single-throw analog switch U3 to achieve the purpose of gating other rows where the non-gating exists, so that specific voltage is fed back to all the non-gated rows except the gated rows to achieve the purpose of row equipotential;
the column control line is controlled by a group of GPIO2 ports of the MCU, the other end of the column control line is connected with the multi-path analog switch U2 and the decoder U6 and is respectively used for controlling the multi-path analog switch U2 to carry out column gating, namely, the column gating is carried out after the row gating, so that a specific piezoresistance unit is selected and used for controlling the output of the decoder U6, the output of the decoder U6 controls the multi-path single-pole single-throw analog switch U4 to achieve the purpose of gating other non-gated columns, so that specific voltage is fed back to all the non-gated columns except the gated columns, and the purpose of row equal potential is achieved;
the multi-path analog switch U1 has one input and multiple outputs, is connected with a specific level, and selects one output channel from a plurality of output channels of the multi-path analog switch U1 through a row control line to output the input voltage of the multi-path analog switch U1 so as to gate a certain row;
the multi-channel analog switch U2 is input and output, when the row is gated, voltage signals on each row of a certain row signal line of the flexible array piezoresistive sensor are transmitted to the multi-channel analog switch U2, at the moment, one channel is selected from the multiple channels through a row control line and is used as a final sampling signal to be transmitted to a rear-stage conditioning circuit, and any one piezoresistive unit in the flexible array piezoresistive sensor can be selected through a row and column scanning method;
the multi-channel single-pole single-throw analog switch U3 is used for providing specific voltage for the un-gated row signal line so as to meet the requirement of row equipotential;
the multi-channel single-pole single-throw analog switch U4 is used for providing specific voltage for the un-gated column signal wire so as to meet the requirement of column equipotential;
the decoder U5 controls the multi-channel single-pole single-throw analog switch U3, and the effective level output by the decoder U5 needs to enable the multi-channel single-pole single-throw analog switch U3 to be in a state that only one switch is closed and the other switches are opened so as to achieve the purpose of equal potential;
the decoder U6 controls the multi-channel single-pole single-throw analog switch U4, and the effective level output by the decoder U6 needs to enable the multi-channel single-pole single-throw analog switch U4 to be in a state that only one switch is closed and the other switches are opened so as to achieve the purpose of row equipotential;
the output of the multi-path analog switch U1 is connected with the input in-phase end of the multi-path general operational amplifier U7, the output is fed back to the inverting end to be a follower, and the output of the multi-path general operational amplifier U7 is connected to the row strobe signal line interface P1 to play a role in buffering and isolation;
the output of the multi-path analog switch U2 is connected with the input in-phase end of the multi-path general operational amplifier U8, the output is fed back to the inverting end to be a follower, and the output of the multi-path general operational amplifier U8 is connected to a column gating signal line interface P2 to play a role in buffering and isolation;
the precise operational amplifier U9 amplifies the acquired signal by proper times through the amplifying circuit, filters the signal through the filter circuit, and inputs the signal into an ADC port of the MCU to convert the acquired analog voltage signal into a digital signal, so that the pressure condition of the flexible piezoresistive sensor is known;
the triode Q1 determines whether power is supplied to a multi-path general operational amplifier U8 in the column equipotential circuit or not in a conducting state, so that whether the column equipotential circuit works or not is controlled;
the multi-input or gate U10 is used for taking each row of signal wires as the input of the multi-input or gate U10, the output level of the multi-input or gate U10 is a level signal of GPIO4 of the MCU, under the condition that the row equipotential circuit is closed, the level signal of the GPIO4 of the MCU is monitored constantly to carry out rapid line detection, if the GPIO4 is low level, no pressure resistance unit in the selected line is stressed, the next line is used for continuously detecting the selected line, and if the GPIO4 is high level, the pressure resistance unit in the selected line is stressed; when the gated row piezoresistive unit is detected to be stressed, the fast row detection circuit needs to be closed, the column equipotential circuit needs to be opened to eliminate signal crosstalk, and then the required sampling signal is acquired.
2. The conditioning circuit for solving the problems of signal crosstalk and multi-point detection of the flexible array piezoresistive transducer according to claim 1, wherein the multi-way analog switch U1 is an input multi-output switch, and the output end of the traditional multi-way analog switch is used as an input to be connected to a specific level.
3. The conditioning circuit for solving the problems of crosstalk and multi-point detection of signals of the flexible array piezoresistive transducer according to claim 1, wherein the control signal of the multi-channel single-pole single-throw analog switch U3 needs to be matched with the effective output level of the decoder U5, if the control pin of the multi-channel single-pole single-throw analog switch U3 is high-level effective, the output level of the decoder U5 needs to be low-level effective, and when a certain row is gated, the decoder U5 outputs a corresponding level signal of low or high level, so that the multi-channel single-pole single-throw analog switch U3 always has only one analog switch of the channel closed, and the analog switches of the other channels open, and feeds a specific voltage signal back to the row signal line to meet the requirement of row equipotential;
the control signal of the multi-channel single-pole single-throw analog switch U4 needs to be matched with the effective output level of the decoder U6, if the control pin of the multi-channel single-pole single-throw analog switch U4 is high level effective, the output level of the decoder U6 needs to be low level effective, and when a certain column can be gated, the decoder U6 outputs a corresponding level signal with a low level or a high level, so that the multi-channel single-pole single-throw analog switch U4 always only has the analog switch of one channel closed, the analog switches of the other channels are opened, and a specific voltage signal is fed back to the column signal wire to meet the requirement of the column equipotential.
4. The conditioning circuit for solving the problems of signal crosstalk and multipoint detection of the flexible array piezoresistive sensor according to claim 1, wherein a triode Q1 is conducted by controlling a GPIO3 of an MCU to output a high level, and the Von voltage of a power supply of a multi-path general operational amplifier U8 is close to 0V, so that the aim of closing a column equipotential circuit is fulfilled; the low level is output by controlling the GPIO3 of the MCU, so that the triode Q1 is cut off, the power supply Von voltage of the multi-path general operational amplifier U8 is close to the power supply voltage VCC, and the column equipotential circuit works normally at the moment.
5. The conditioning circuit for solving the problems of signal crosstalk and multipoint detection of the flexible array piezoresistive sensor according to claim 1, wherein the precision operational amplifier U9 can change the amplification factor by changing the ground resistance Rd of the feedback resistance Rf connected to the inverting terminal, and the collected signals are amplified by the proper factor through the amplification circuit.
6. The conditioning circuit for solving the problems of signal crosstalk and multi-point detection in a flexible array piezoresistive sensor according to claim 1, wherein the filter circuit is a first-order low-pass filter circuit.
7. The conditioning method for solving the problems of signal crosstalk and multi-point detection of the flexible array piezoresistive sensor by using the conditioning circuit as claimed in claim 1, comprising the following steps:
1) Respectively connecting a row lead and a column lead of the flexible array piezoresistive sensor to be detected into a row strobe signal line interface P1 and a column strobe signal line interface P2;
2) And array row gating: the row control line led out by a group of GPIO1 ports of the MCU controls the multi-channel analog switch U1 to send the row selection voltage Vnow to a certain row signal line so as to achieve the purpose of row selection, meanwhile, the row control line also controls the decoder U5, the output level signal of the decoder U5 can gate all channels of the multi-channel single-pole single-throw analog switch U3 except the channel selected by the multi-channel analog switch U1, and finally the sampled voltage signal Vadc is fed back to the row lead wire of the flexible array piezoresistive sensor through the multi-channel general operational amplifier U7 which plays a role of buffering and isolation, so that the purpose of row equipotential is achieved;
3) And (3) fast line detection: the control triode Q1 does not supply power to the multi-path general operational amplifier U8 to close the column equipotential circuit, and under the condition that the column equipotential circuit is closed, the level signal of GPIO4 of the MCU is constantly monitored, the level signal of the GPIO4 is the output level of the multi-input OR gate U10, the input of the multi-input OR gate U10 is a column lead in the flexible array piezoresistive sensor, therefore, if the GPIO4 is low level, no piezoresistive unit is stressed in the selected channel at the moment, the next row is changed to continue to detect the selected channel, and if the GPIO4 is high level, the piezoresistive unit is stressed in the selected channel at the moment;
when the gated row piezoresistive unit is detected to be stressed, the fast row detection circuit needs to be closed, the power is supplied to the multi-path general operational amplifier U8 through the control triode Q1, and the row equipotential circuit is started to eliminate signal crosstalk;
4) Array column gating: the column control line led out by a group of GPIO2 ports of the MCU controls the channel enable of the multi-channel analog switch U2, only one channel is gated each time, the voltage on a ground reference resistor Ref connected with the channel is taken as the input voltage of the channel and is output to the non-inverting input end of a precise operational amplifier U9 through the multi-channel analog switch U2, so that the purpose of column gating is achieved, meanwhile, the column control line also controls a decoder U6, the output level signal of the decoder U6 can gate all channels of the multi-channel single-pole single-throw analog switch U4 except the channel selected by the multi-channel analog switch U2, and the output level signal of the multi-channel single-pole single-throw analog switch U4 is fed back to a column lead wire of the flexible array piezoresistive sensor through the multi-channel general operational amplifier U8 which plays a role in buffering and isolation, so that the purpose of column equipotential is achieved;
5) After row-column gating, a certain piezoresistive unit of the flexible array piezoresistive sensor can be selected and connected with a ground reference resistor Ref in series, the ground reference resistor Ref generates ground voltage and is input to a precise operational amplifier U9 for amplification in a certain proportion through the principle of series resistor voltage division, then useless interference noise signals are filtered out through a filter circuit, a final smooth analog sampling voltage signal Vadc is obtained, the Vadc is input to a built-in ADC module of the MCU, and therefore the resistance value of the piezoresistive unit to be measured can be measured.
8. The conditioning method for solving the problems of signal crosstalk and multi-point detection of the piezoresistive flexible array sensor according to claim 7, wherein in step 3), the GPIO3 of the MCU is controlled to output a high level, so that the transistor Q1 is turned on, and the Von voltage supplied by the multi-path general operational amplifier U8 approaches 0V, thereby achieving the purpose of turning off the column equipotential circuit; the low level is output by controlling the GPIO3 of the MCU, so that the triode Q1 is cut off, the power supply Von voltage of the multi-path general operational amplifier U8 is close to the power supply voltage VCC, and the column equipotential circuit works normally at the moment.
9. The conditioning method for solving the problems of signal crosstalk and multipoint detection of the piezoresistive flexible array sensor according to claim 7, wherein in step 5), the precision operational amplifier U9 can change the amplification factor by changing the ground resistance Rd of the feedback resistor Rf connected to the inverting terminal, and the acquired signal is amplified by a suitable factor through the amplification circuit.
10. The conditioning method for solving the problems of signal crosstalk and multipoint detection of the piezoresistive flexible array sensor according to claim 7, wherein step 5) is to filter out useless interference noise signals through a first-order low-pass filter circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110762479.2A CN113483923B (en) | 2021-07-06 | 2021-07-06 | Conditioning circuit and method for solving signal crosstalk and multipoint detection of flexible array piezoresistive sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110762479.2A CN113483923B (en) | 2021-07-06 | 2021-07-06 | Conditioning circuit and method for solving signal crosstalk and multipoint detection of flexible array piezoresistive sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113483923A CN113483923A (en) | 2021-10-08 |
| CN113483923B true CN113483923B (en) | 2023-01-13 |
Family
ID=77941249
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110762479.2A Active CN113483923B (en) | 2021-07-06 | 2021-07-06 | Conditioning circuit and method for solving signal crosstalk and multipoint detection of flexible array piezoresistive sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113483923B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115267340B (en) * | 2022-07-29 | 2023-06-16 | 北京津发科技股份有限公司 | Detection circuit and device based on equipotential shielding |
| CN115628761B (en) * | 2022-09-30 | 2023-10-13 | 华南理工大学 | Low-power-consumption anti-disturbance resistance type sensor and wearable equipment |
| CN115615586B (en) * | 2022-10-22 | 2024-04-26 | 福州大学 | High-precision crosstalk suppression acquisition circuit of resistor type flexible array sensor |
| CN116858405B (en) * | 2023-07-19 | 2024-04-02 | 杭州创乐电子科技有限公司 | Pressure measuring method of piezoresistor matrix |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2820474Y (en) * | 2005-09-02 | 2006-09-27 | 杭州电子科技大学 | Array type robot tactile sensor |
| WO2009120270A2 (en) * | 2008-03-15 | 2009-10-01 | Taylor Geoffrey L | Adaptive cushion method and apparatus for minimizing force concentrations on a human body |
| CN101695001A (en) * | 2009-10-27 | 2010-04-14 | 哈尔滨工业大学 | Array piezoresistive tactile sensor adopting voltage array feedback method to weaken return circuit interference of scanning circuits |
| CN107631818A (en) * | 2016-07-19 | 2018-01-26 | 中国科学院沈阳自动化研究所 | Flexible array pressure measurement sensor and its measuring method based on piezoresistive effect |
| CN110631609A (en) * | 2018-06-21 | 2019-12-31 | 久耀电子科技（江苏）有限公司 | Resistive sensor array rapid reading circuit based on two-wire system equipotential method |
| WO2020051639A1 (en) * | 2018-09-12 | 2020-03-19 | Lenexa Medical Pty Ltd | Addressing circuit for conductor arrays |
| CN211452677U (en) * | 2019-11-07 | 2020-09-08 | 浙江理工大学 | Array type piezoresistor sensor capable of preventing crosstalk |
| CN211452676U (en) * | 2019-09-30 | 2020-09-08 | 浙江理工大学 | Array type voltage dependent resistor network driving circuit capable of preventing crosstalk |
| CN113030573A (en) * | 2021-03-09 | 2021-06-25 | 江南大学 | Adaptive detection method and system based on resistance type sensor array |
-
2021
- 2021-07-06 CN CN202110762479.2A patent/CN113483923B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2820474Y (en) * | 2005-09-02 | 2006-09-27 | 杭州电子科技大学 | Array type robot tactile sensor |
| WO2009120270A2 (en) * | 2008-03-15 | 2009-10-01 | Taylor Geoffrey L | Adaptive cushion method and apparatus for minimizing force concentrations on a human body |
| CN101695001A (en) * | 2009-10-27 | 2010-04-14 | 哈尔滨工业大学 | Array piezoresistive tactile sensor adopting voltage array feedback method to weaken return circuit interference of scanning circuits |
| CN107631818A (en) * | 2016-07-19 | 2018-01-26 | 中国科学院沈阳自动化研究所 | Flexible array pressure measurement sensor and its measuring method based on piezoresistive effect |
| CN110631609A (en) * | 2018-06-21 | 2019-12-31 | 久耀电子科技（江苏）有限公司 | Resistive sensor array rapid reading circuit based on two-wire system equipotential method |
| WO2020051639A1 (en) * | 2018-09-12 | 2020-03-19 | Lenexa Medical Pty Ltd | Addressing circuit for conductor arrays |
| CN211452676U (en) * | 2019-09-30 | 2020-09-08 | 浙江理工大学 | Array type voltage dependent resistor network driving circuit capable of preventing crosstalk |
| CN211452677U (en) * | 2019-11-07 | 2020-09-08 | 浙江理工大学 | Array type piezoresistor sensor capable of preventing crosstalk |
| CN113030573A (en) * | 2021-03-09 | 2021-06-25 | 江南大学 | Adaptive detection method and system based on resistance type sensor array |
Non-Patent Citations (1)
| Title |
|---|
| 集成现场标定功能的MEMS加速度传感器;吴迪东 等;《杭州电子科技大学学报（自然科学版）》;20170930;第37卷(第5期);12-16 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113483923A (en) | 2021-10-08 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN113483923B (en) | Conditioning circuit and method for solving signal crosstalk and multipoint detection of flexible array piezoresistive sensor | |
| CN204903688U (en) | Multicore cable comprehensive tester | |
| CN102393484A (en) | Device for detecting stability of current | |
| CN103001636B (en) | Single event effect detection method of folding interpolating-type analog-digital conversion device | |
| CA2903981C (en) | System and method for multiplexed and buffered miniaturized sensor arrays | |
| CN201133916Y (en) | Multimeter provided with alarming function data collection card | |
| CN104122814B (en) | Switch acquisition transition detection circuitry and detection method thereof | |
| CN111289157B (en) | Circuit and method for measuring pressure distribution through piezoresistive sensing array | |
| CN100384551C (en) | Optical coupling screening device | |
| CN101695001B (en) | Array piezoresistive tactile sensor adopting voltage array feedback method to weaken return circuit interference of scanning circuits | |
| CN105356880A (en) | Circuit for collecting dual-path sensor data by utilizing one-path AD acquisition channel | |
| CN110763983A (en) | Open short circuit detection circuitry based on special interface chip | |
| CN117147968A (en) | Relay matrix switch with internal resistance self-checking function | |
| CN111190047B (en) | Current acquisition diagnosis circuit and failure diagnosis method thereof | |
| CN201045624Y (en) | Resistor detection circuit for automobile instrument | |
| CN111796208A (en) | Keyboard open-short circuit detection device and method | |
| CN105824000A (en) | Method for calibrating output board card | |
| CN209821627U (en) | Multichannel strain signal synchronous acquisition system | |
| CN115615586B (en) | High-precision crosstalk suppression acquisition circuit of resistor type flexible array sensor | |
| CN117906646A (en) | Multipoint detection system and method for inhibiting crosstalk of resistive sensor array signals | |
| CN105823938A (en) | Method for detecting state of output board card | |
| CN217820547U (en) | Isolated multi-path voltage type analog sampling circuit | |
| CN220188889U (en) | Multichannel data measuring device of automatic control system | |
| CN214750888U (en) | Temperature channel of low-power consumption automatic meteorological station signal simulator | |
| CN209514023U (en) | The normal instruction system of multiple power supplies output |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |