Data Acquisition Equipment

Abstract

To suppress decrease of sampling frequency and mitigate processing load of a control part.SOLUTION: A data acquisition device 1 includes a sensor 7 for detecting physical amount as analog data, a digital storage circuit 14 for storing physical amount of digital data, difference circuits (16, 17) for calculating differences (ΔV1, ΔV2) between a previous value Vn-1 of the physical amount stored in the digital storage circuit 14 and a current value Vn of the physical amount detected as analog data, comparators (18, 19) for comparing the differences to predetermined threshold values (Vt1, Vt2), and a control part 13. The control part 13 causes a value calculated by adding or subtracting predetermined change amounts (Vc1, Vc2) and / from the previous value Vn-1 of the physical amount to be stored in the digital storage circuit 14 as a current value Vn when the differences exceed or fall below the threshold values. Decrease of sampling frequency is suppressed since the physical amount is updated without performing A / D conversion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to data acquisition devices, and more particularly to data acquisition devices that acquire digital data from analog data. [Background technology]

[0002] An engine control circuit for controlling engine operation is known that includes an A / D converter that performs analog-to-digital conversion of a sensor's output voltage (see Patent Document 1). This engine control circuit reads a current A / D-converted value output from the A / D converter at predetermined time intervals and calculates the difference between the absolute value of the difference between the previous A / D-converted value and the current A / D-converted value and the absolute value of the difference between the A / D-converted value two years before last and the previous A / D-converted value. If this difference is equal to or less than a threshold, the engine control circuit determines that the current A / D-converted value is not noise and updates the input value with the current A / D-converted value. If this difference is greater than the threshold, the engine control circuit determines that the current A / D-converted value may be noise, does not update the input value, and maintains the previous input value as is. This engine control circuit also includes a multiplexer that selects sensor signals from multiple sensors and reads them via the A / D converter.

[0003] Furthermore, an A / D conversion circuit device capable of suppressing defects caused by sudden changes in analog signals is known that includes a comparison unit that compares a temperature detection signal (analog signal) from a temperature sensor with a D / A conversion voltage from a D / A converter, and a processing unit (control unit) that performs a judgment process based on the comparison result of the comparison unit and determines the A / D conversion result based on the judgment process so that the change in the current A / D conversion result relative to the previous A / D conversion result is equal to or less than a predetermined value (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 1999-62689 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-103660 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional A / D conversion circuit devices convert all analog signals into digital signals to obtain the A / D conversion results (i.e., digital data). Therefore, if the time required for A / D conversion is long, the sampling frequency decreases. As a result, when the digital data from the A / D conversion circuit device is used to control a robot, the robot's responsiveness deteriorates. Furthermore, if a judgment process or a process to determine the final result data is performed on all digital data to calculate the digital data, the processing load on the control unit increases. As a result, power consumption increases and the control unit becomes hot.

[0006] In particular, when analog data is input from a huge number of sensors, the time required for A / D conversion increases in proportion to the amount of data, and the sampling period of each sensor becomes longer. While the sampling period can be shortened by reducing the number of sensors, this results in a sparser sensor distribution density and a deterioration in spatial resolution. In other words, there is a trade-off between shortening the sampling period and improving spatial resolution, and it has been difficult to achieve both.

[0007] In view of this background, the present invention , regulation It is an object of the present invention to provide a data acquisition device that can reduce the processing load on the control unit. [Means for solving the problem]

[0008] In order to solve such a problem, one embodiment of the present invention is a data acquisition device (1) including at least one sensor (7) that detects a predetermined physical quantity (e.g., pressure) as analog data (voltage). a sensor device (2) for outputting the physical quantity detected by the sensor (7) at predetermined sampling intervals. and the sensor Device The physical quantity of analog data output from Writean analog storage circuit (15) for storing the initial value or updated value of the physical quantity of digital data; a digital storage circuit (14) for storing the initial value or updated value of the physical quantity of digital data; Device The physical quantity of the analog data output from the current value V n The physical quantity stored in the analog memory circuit (15) is set to the previous value V n-1 The current value V of the physical quantity of analog data n The previous value V n-1 The first difference ΔV1, which is the difference with respect to V n -V n-1 and a first difference circuit (16) that calculates the physical quantity of the analog data stored in the analog storage circuit (15) based on the previous value V n-1 and the sensor Device The physical quantity of the analog data output from the current value V n and the previous value V of the physical quantity of the analog data n-1 The current value V n The second difference ΔV2, which is the difference with respect to V n-1 -V n (=-ΔV1), comparison circuits (18, 19) that compare the first difference ΔV1 with a predetermined first threshold Vt1 and the second difference ΔV2 with a predetermined second threshold Vt2, and a control unit (13) that controls the storage of the digital storage circuit (14) and the storage of the analog storage circuit (15), and when the comparison result of the comparison circuit indicates that the first difference ΔV1 exceeds the first threshold Vt1 (ST12: Yes), the control unit (13) controls the storage of the analog storage circuit (15) to store the previous value V of the physical quantity stored in the digital storage circuit (14). n-1 (ST13), and the calculated value is used as the current value V of the physical quantity. n When the comparison result of the comparison circuit indicates that the second difference ΔV2 exceeds the second threshold value Vt2 (ST14: Yes), a second change amount Vc2 set in advance is subtracted from the physical quantity stored in the digital storage circuit (14) (ST15), and the calculated value is used as the current value V of the physical quantity. nand stores the physical quantities stored in the digital storage circuit (14) as (ST6), and when the comparison result of the comparison circuit indicates that the first difference ΔV1 is equal to or smaller than the first threshold value Vt1 (ST12: No) and that the second difference ΔV2 is equal to or smaller than the second threshold value Vt2 (ST14: No), The physical quantity stored in the analog storage circuit (15) is retained as it is in the analog storage circuit (15). (ST16)

[0009] According to this configuration, the physical quantity is the previous value V n-1 When the change from Vt1 to Vt2 exceeds the first threshold Vt1 to the positive side or Vt2 to the negative side, the control unit (13) n-1 The value obtained by adding the first change amount Vc1 to or subtracting the second change amount Vc2 from the physical quantity V n In other words, the physical quantity can be updated without A / D conversion by the A / D converter (12). do. Furthermore, the data difference calculation and data comparison that were conventionally performed by the control unit (13) are now performed by the first difference circuit (16), the second difference circuit (17) and the comparison circuits (18, 19), which are analog circuits, respectively, and the control unit (13) does not need to perform these processes. This reduces the processing load on the control unit (13). Furthermore, there is no need to perform processes that require a long processing time, such as D / A conversion, for comparison processes performed by analog circuits. stomach.

[0010] In the above configuration, the sensor Device The control unit (13) further includes an A / D converter (12) that converts the physical quantity of analog data output from the sensor into digital data, and upon startup (ST4: Yes), the control unit (13) causes the A / D converter (12) to perform A / D conversion (ST6), and Device The physical quantity of analog data output from the digital memory circuit (14) is converted into digital data, and the converted value is stored in the digital memory circuit (14) as an initial value of the physical quantity (ST7).

[0011] According to this configuration, the A / D converter (12) performs A / D conversion at the time of startup, thereby accurately acquiring the initial value of the physical quantity as digital data and storing it in the digital storage circuit (14).

[0012] In the above configuration, the control unit (13) causes the A / D converter (12) to perform A / D conversion (ST6) at a predetermined timing after startup (ST11: Yes), and Device The physical quantity of the analog data output from the digital memory circuit (14) is converted into digital data, and the converted value is stored as the physical quantity in the digital memory circuit (14) (ST7).

[0013] According to this configuration, even if the value of the physical quantity calculated by adding the first change amount Vc1 or subtracting the second change amount Vc2 deviates from the actual value, the physical quantity is corrected to an accurate value by the A / D converter (12) performing A / D conversion at a predetermined timing.

[0014] Instead of the control unit (13) causing the A / D converter (12) to perform A / D conversion at startup, the digital storage circuit (14) may store a predetermined initial value of the physical quantity.

[0015] According to this configuration, the control unit (13) can acquire the initial values ​​of the physical quantities stored in the digital storage circuit (14) from the digital storage circuit (14) without performing A / D conversion at startup. Therefore, the control unit (13) can acquire the initial values ​​in a short time. This configuration is suitable when the physical quantities at startup of the control unit (13) are fixed.

[0016] In the above configuration, the first change amount Vc1 may be the same value as the first threshold value Vt1 (Vc1=Vt1), and the second change amount Vc2 may be the same value (Vt2) as the second threshold value Vt2 (Vc2=Vt2).

[0017] According to this configuration, the physical quantity of the digital data is not changed by a larger amount than the actual change in the physical quantity.

[0018] In a configuration in which the first change amount Vc1 is equal to the first threshold value Vt1 and the second change amount Vc2 is equal to the second threshold value Vt2, the control unit (13) may be configured to update (ST8) the physical quantity stored in the analog memory circuit (15) with the physical quantity calculated to be stored in the digital memory circuit (14).

[0019] With this configuration, the previous value V n-1 The physical quantity of the analog data used as the analog input signal coincides with the value of the physical quantity stored in the digital storage circuit 14. Therefore, even if the physical quantity of the digital data is calculated by adding the first change amount Vc1 or subtracting the second change amount Vc2, the calculated value of the physical quantity is prevented from deviating significantly from the actual value.

[0020] In the above configuration, the first threshold value Vt1 and the second threshold value Vt2 are the same value (Vt1=Vt2=Vt), and the first difference circuit and the second difference circuit are Device and an absolute value circuit (26) that calculates the absolute value (|ΔV|) of the difference between the physical quantity of the analog data output from the analog storage circuit (15) and the physical quantity stored in the analog storage circuit (15).

[0021] According to this configuration, the rate of change of the physical quantity of the digital data (the amount of change per sampling period) cannot be made different when the physical quantity increases and decreases, but the number of processes can be reduced. Reduction of processing load on the control unit (13) This can be achieved with a simple circuit configuration.

[0022] In the above configuration, the control unit (13) may be configured to change at least one of the first threshold value Vt1 and the second threshold value Vt2 (ST10) in accordance with a predetermined condition (ST9: Yes).

[0023] According to this configuration, when more accurate physical quantities of digital data are required or when the requirements can be met with coarser physical quantities of digital data, the physical quantities of digital data can be obtained with the desired accuracy by setting the conditions.

[0024] In the above configuration, at least one of the sensors (7) constitutes a sensor unit (6) including a plurality of the sensors (7) connected to the analog storage circuit (15) via a multiplexer (9), the analog storage circuit (15) stores the physical quantity for each of the sensors (7), and the control unit (13) switches the multiplexer (9) in synchronization with switching of the physical quantities supplied to the first difference circuit (16) and the second difference circuit (17) (ST2).

[0025] According to this configuration, the sensor unit (6) including the plurality of sensors (7) can realize high spatial resolution while reducing the processing load on the control unit (13). [Effects of the Invention]

[0026] Thus, according to the present invention , regulation It is possible to provide a data acquisition device that can reduce the processing load on the control unit. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a data acquisition device according to a first embodiment. [Figure 2] Flow diagram of data acquisition processing executed by the control unit [Figure 3] FIG. 10 is a block diagram showing a schematic configuration of a data acquisition device according to a second embodiment. [Figure 4] A circuit diagram showing the detailed configuration of the differential circuit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0029] First Embodiment A first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a block diagram showing a schematic configuration of a data acquisition device 1 according to the first embodiment. The data acquisition device 1 acquires a predetermined physical quantity as analog data at a predetermined sampling period. output The sensor device 2 includes: a controller 3 that acquires the physical quantity of the digital data based on the physical quantity of the analog data output from the sensor device 2; and a determination circuit 4.

[0030] The sensor device 2 includes a sensor unit 6 connected to a power source 5. The sensor unit 6 includes at least one sensor 7 (sensor portion). In this embodiment, the sensor unit 6 has a matrix structure with four channels in the Y direction and eight channels in the X direction, and includes a total of 32 sensors 7 arranged on a plane. Each sensor 7 detects a predetermined physical quantity as analog data. The predetermined physical quantity may be, for example, pressure, load, strain, temperature, etc., and outputs an analog electrical signal corresponding to these physical quantities. The sensor 7 of this embodiment is supplied with a predetermined applied voltage (e.g., 5 V) from the power source 5 and outputs a detection voltage corresponding to the pressure. The sensor unit 6 includes multiple sensors 7, thereby achieving high spatial resolution.

[0031] The sensor device 2 further includes a demultiplexer 8 provided on a signal line connecting the power supply 5 and the sensor unit 6, a multiplexer 9 provided on a signal line connecting the sensor unit 6 and the controller 3, a low-pass filter 10, and an amplifier 11. The demultiplexer 8 switches between the four channels in sequence as the channel to which the applied voltage is to be supplied from the power supply 5 in accordance with a command from the controller 3. The multiplexer 9 switches between the eight channels in sequence as the channel to which the detected voltage is to be output from the sensor unit 6 in accordance with a command from the controller 3. The demultiplexer 8 and the multiplexer 9 are switched by the controller 3, so that the sensor device 2 outputs the detected voltages of the 32 sensors 7 in sequence at predetermined sampling intervals.

[0032] The controller 3 is an electronic processing device composed of a CPU, ROM, RAM, etc. The controller 3 includes an A / D converter 12, a control unit 13, and a digital storage circuit 14. The A / D converter 12 converts analog electrical signals into digital electrical signals. The control unit 13 controls the execution of A / D conversion by the A / D converter 12. The digital storage circuit 14 stores the physical quantities of the digital data detected by the sensor device 2 and converted by the A / D converter 12. The controller 3 may be configured as a single piece of hardware, or may be configured as a unit composed of multiple pieces of hardware.

[0033] The digital storage circuit 14 is configured with a ROM, a RAM, etc., and stores the physical quantity of digital data (in this embodiment, the detected voltage according to the pressure). The digital storage circuit 14 stores the detected voltage for each sensor 7. The detected voltage stored in the digital storage circuit 14 is erased when the data acquisition device 1 is stopped. Therefore, when the data acquisition device 1 is started, the digital storage circuit 14 stores the previous value V of the detected voltage for each sensor 7. n-1 The digital storage circuit 14 stores a predetermined initial value of the detection voltage, and the initial value may be reset to the detection voltage when the data acquisition device 1 is started. The initial value is set according to the expected usage environment of the data acquisition device 1 and is stored in the digital storage circuit 14.

[0034] In addition to the detected voltage, the digital storage circuit 14 also stores a first threshold value Vt1 and a second threshold value Vt2, which will be described later. The digital storage circuit 14 may store the first threshold value Vt1 and the second threshold value Vt2 for each sensor 7, or may store the first threshold value Vt1 and the second threshold value Vt2 as common values ​​for all sensors 7. In this embodiment, the first threshold value Vt1 and the second threshold value Vt2 are common values ​​for all sensors 7. On the other hand, the first threshold value Vt1 and the second threshold value Vt2 are stored in association with conditions as values ​​that change depending on the conditions. In other embodiments, the first threshold value Vt1 and the second threshold value Vt2 may be constant values. In this embodiment, the first threshold value Vt1 and the second threshold value Vt2 are the same value.

[0035] The A / D converter 12 performs a comparison process multiple times, for example, using a method similar to a successive approximation type, and converts the analog data into digital data represented by a multi-bit (e.g., 10-bit) A / D conversion result. The A / D converter 12 performs A / D conversion at a predetermined timing in accordance with a command from the control unit 13. The detected voltage converted into digital data is stored in the digital storage circuit 14 in association with the sensor 7. The A / D converter 12 of this embodiment performs A / D conversion at a timing corresponding to a sampling period only when it receives an execution command from the control unit 13, as will be described later, and does not perform A / D conversion at any other timing.

[0036] The control unit 13 is configured by a CPU, and executes various controls by reading a program stored in a ROM or the like and executing arithmetic processing in accordance with the program. For example, the control unit 13 outputs a switching command to the demultiplexer 8 and the multiplexer 9 at a timing synchronized with the sampling period, thereby causing the detection voltages of the analog data detected by the 32 sensors 7 to be output in order to the sensor device 2. The detection voltages of the analog data output from the sensor device 2 (current value V of the detection voltage of each sensor 7) are calculated as follows: n ) is supplied to the A / D converter 12 and the decision circuit 4 of the controller 3.

[0037] The control unit 13 also supplies the voltage of the digital data corresponding to the physical quantity, and the predetermined first threshold value Vt1 and second threshold value Vt2 of the digital data stored in the digital storage circuit 14, to the determination circuit 4. The control unit 13 calculates the previous value V of the voltage corresponding to the physical quantity of the digital data of the corresponding sensor 7 at each sampling period. n-1 The control unit 13 also supplies the first threshold value Vt1 and the second threshold value Vt2 to the determination circuit 4 every time they are changed in accordance with the conditions.

[0038] Furthermore, the control unit 13 calculates the current value V of the detected voltage of the analog data of each sensor 7 outputted in sequence from the sensor device 2. nThe control unit 11 determines the analog data that should be A / D converted by the A / D converter 12 and controls the A / D conversion by the A / D converter 12.

[0039] The decision circuit 4 includes an analog storage circuit 15, a first difference circuit 16, a second difference circuit 17, a first comparison circuit 18, a second comparison circuit 19, a first threshold circuit 20, and a second threshold circuit 21.

[0040] The analog storage circuit 15 may be, for example, a sample and hold circuit including an operational amplifier and a switch. The analog storage circuit 15 samples the detected voltage of the analog data input from the sensor device 2, and stores the sampled detected voltage as a previous value V n-1 In this embodiment, the analog storage circuit 15 updates the stored detected voltage with the value of the detected voltage in digital data supplied from the control unit 13. The analog storage circuits 15 are provided according to the number of sensors 7. The detected voltage stored in the analog storage circuit 15 is updated to the previous value V in the subsequent sampling period of the corresponding sensor 7. n-1 In another embodiment, the analog storage circuit 15 does not update the value supplied from the control unit 13, but uses the detected voltage input from the sensor device 2 as the previous value V n-1 may continue to be held as

[0041] The first difference circuit 16 and the second difference circuit 17 output the difference between the two analog data. Specifically, the first difference circuit 16 calculates the current value V of the detected voltage input from the sensor device 2. n , the previous value V of the detected voltage input from the analog memory circuit 15 n-1 Subtract the first difference ΔV1 (=V n -V n-1 The second difference circuit 17 calculates the previous value V of the detected voltage input from the analog storage circuit 15. n-1 The current value V of the detected voltage input from the sensor device 2 n Subtract the second difference ΔV2 (=V n-1 -V nThe second difference ΔV2 is a value obtained by inverting the polarity of the first difference ΔV1 (ΔV2=−ΔV1).

[0042] The first comparison circuit 18 and the second comparison circuit 19 compare the two analog data and output the comparison result. Specifically, the first comparison circuit 18 compares the first difference ΔV1 with a first threshold Vt1 supplied from a first threshold circuit 20. The first threshold Vt1 is a positive value. If the first difference ΔV1 exceeds the first threshold Vt1 (ΔV1>Vt1), the first comparison circuit 18 outputs a positive event signal indicating an increase in the detected voltage due to an increase in pressure acting on the sensor 7. The second comparison circuit 19 compares the second difference ΔV2 with a second threshold Vt2 supplied from a second threshold circuit 21. The second threshold Vt2 is a positive value. If the second difference ΔV2 exceeds the second threshold Vt2 (ΔV2>Vt2), the second comparison circuit 19 outputs a negative event signal indicating a decrease in the detected voltage due to a decrease in pressure acting on the sensor 7. The positive event signal and the negative event signal are input to the control unit 13.

[0043] The determination circuit 4 executes these processes for each sensor 7 at timings corresponding to the switching of the demultiplexer 8 and the multiplexer 9.

[0044] The control unit 13 changes the first threshold Vt1 of the first threshold circuit 20 and the second threshold Vt2 of the second threshold circuit 21 when a predetermined condition such as input of a positive event signal or input of a negative event signal is satisfied. The predetermined condition is the current value Vt1 of the detected voltage of the digital data. nThis includes the case where the first threshold Vt1 and the second threshold Vt2 are different from their initial values. When a predetermined condition is satisfied, the control unit 13 changes the first threshold Vt1 and the second threshold Vt2 to values ​​with smaller absolute values. When the predetermined condition is no longer satisfied, the control unit 13 changes the first threshold Vt1 and the second threshold Vt2 to values ​​with larger absolute values. The control unit 13 may change the first threshold Vt1 and the second threshold Vt2 in stages or all at once. The first threshold circuit 20 and the second threshold circuit 21 may be memory circuits that store the voltages of the first threshold Vt1 and the second threshold Vt2 as analog data, or may be D / A converters. When a memory circuit that stores analog data is used, the control unit 13 can quickly change the first threshold Vt1 and the second threshold Vt2 using a GPIO (general purpose input / output). The control unit 13 also controls updating the detection voltage stored in the analog memory circuit 15 with the detection voltage value of digital data stored in the digital memory circuit 14 using the GPIO. Therefore, the detected voltage of the analog data is updated at high speed, and a decrease in the sampling frequency is suppressed.

[0045] When a positive event signal is input, the control unit 13 adds a predetermined first change amount Vc1 to the detected voltage of the corresponding sensor 7 stored in the digital storage circuit 14, and updates the detected voltage of the corresponding sensor 7 with the calculated value. That is, the control unit 13 updates the detected voltage (previous value V n-1 The value obtained by adding the first change amount Vc1 to the value treated as n (latest value) in the digital storage circuit 14. The first change amount Vc1 is set to the same value as the first threshold value Vt1 (Vc1=Vt1). When the control unit 13 changes the first threshold value Vt1, the control unit 13 changes the first change amount Vc1 to be added to the detected voltage so that it matches the first threshold value Vt1.

[0046] When a negative event signal is input, the control unit 13 updates the detected voltage of the corresponding sensor 7 with a value obtained by subtracting a predetermined second change amount Vc2 from the detected voltage of the corresponding sensor 7 stored in the digital storage circuit 14. That is, the control unit 13 updates the detected voltage (previous value V n-1 The value obtained by subtracting the second change amount Vc2 from the value treated as the current value V of the detected voltage n (latest value) in the digital storage circuit 14. The second change amount Vc2 is set to the same value as the second threshold value Vt2 (Vc2=Vt2=Vt1=Vc1). When the second threshold value Vt2 is changed, the control unit 13 changes the second change amount Vc2 to be subtracted from the detected voltage so that it matches the second threshold value Vt2.

[0047] As described above, the first threshold Vt1 and the second threshold Vt2 are the same value, and therefore the first change amount Vc1 and the second change amount Vc2 are also the same value.

[0048] If neither a positive event signal nor a negative event signal is input, the control unit 13 does nothing. That is, the previous value V of the detected voltage of the corresponding sensor 7 stored in the digital memory circuit 14 is n-1 This time the value is V n are stored in the digital storage circuit 14 as

[0049] In this way, the detected voltage corresponding to the pressure is the previous value V n-1 When the voltage Vt1 exceeds the first threshold Vt1 to the positive side or when the voltage Vt2 exceeds the second threshold Vt2 to the negative side, the control unit 13 updates the detected voltage in the digital storage circuit 14. Specifically, the control unit 13 updates the previous value Vt1 of the detected voltage. n-1 The value obtained by adding the first change amount Vc1 to or subtracting the second change amount Vc2 from this is the current value V of the detected voltage. n In other words, the detected voltage is updated without A / D conversion by the A / D converter 12.

[0050] The control unit 13 calculates the current value V of the detected voltage to be stored in the digital storage circuit 14. nThus, the current value V of the detected voltage of the corresponding sensor 7 stored in the analog memory circuit 15 n This is because the current value of the detected voltage of the analog data, V n Even if the detected voltage V changes significantly, the current value V of the detected voltage stored in the digital storage circuit 14 n is updated by the first change amount Vc1 or the second change amount Vc2. As a result, the detected voltage of the digital data may deviate from the actual detected voltage of the analog data. To prevent this, the control unit 13 updates the detected voltage of the analog data so that it matches the detected voltage of the digital data.

[0051] The data acquisition device 1 can be used, for example, as a contact sensor in which the sensor unit 6 is attached to the skin of a robot's hand and detects contact with a substance. The data acquisition device 1 outputs the acquired digital data from each sensor 7 to a host computer. When each sensor 7 does not detect contact (when the first difference ΔV1 does not exceed the first threshold Vt1 and the second difference ΔV2 does not exceed the second threshold Vt2), the processing load on the control unit 13 is small even if there are a large number of sensors 7. Therefore, the responsiveness of the robot does not deteriorate due to a longer data acquisition time (sampling period). Furthermore, the amount of data processed by the control unit 13 does not become so large that it places a strain on communication.

[0052] If the contact pressure does not change even when each sensor 7 detects contact, the first difference ΔV1 does not exceed the first threshold value Vt1 and the second difference ΔV2 does not exceed the second threshold value Vt2 in the next sampling period. Therefore, the control unit 13 does not perform A / D conversion by the A / D converter 12 and keeps the previous value V n-1 This time the value V n This also reduces the processing load on the control unit 13.

[0053] Next, the data acquisition process executed by the control unit 13 will be described with reference to Fig. 2. Fig. 2 is a flow diagram of the data acquisition process executed by the control unit 13. As shown in Fig. 2, when the control unit 13 is started, it executes the following routine at every predetermined sampling period.

[0054] First, the control unit 13 sets the channel of the demultiplexer 8 (step ST1). In this embodiment, the control unit 13 switches between the four channels of the demultiplexer 8 in sequence every eight routines. Next, the control unit 13 sets the channel of the multiplexer 9 (step ST2). In this embodiment, the control unit 13 switches between the eight channels of the multiplexer 9 in sequence every routine. In this way, the 32 sensors 7 are switched in sequence every routine. Either step ST1 or step ST2 may be performed first.

[0055] Next, the control unit 13 calculates the previous value V of the detected voltage of the sensor 7 to be determined selected in steps ST1 and ST2. n-1 Specifically, the control unit 13 receives the previous value V of the detected voltage from the analog memory circuit 15 corresponding to the sensor 7 to be determined via the GPIO. n-1 is selected to be supplied.

[0056] The control unit 13 determines whether this routine is the first time for the sensor 7 to be determined, i.e., whether this is the first sampling after the data acquisition device 1 is started (step ST4). If this routine is the first time (step ST4: Yes), the control unit 13 sets the threshold value Vt for the sensor 7 to be determined (step ST4). Specifically, the control unit 13 obtains the first threshold value Vt1 and the second threshold value Vt2 set for the sensor 7 to be determined from the digital storage circuit 14, and sets these values ​​in the first threshold value circuit 20 and the second threshold value circuit 21.

[0057] Thereafter, the control unit 13 determines the current value V of the detected voltage of the sensor 7 to be determined. n is converted into a digital signal by the A / D converter 12, and the current value V n Next, the control unit 13 acquires the current value V of the detected voltage of the digital data (step ST6). n The current value V of the detected voltage of the sensor 7 to be judged nThe control unit 13 stores the current value V of the detected voltage of the digital data in the digital storage circuit 14 (step ST7). n The current value V of the detected voltage of the sensor 7 to be judged n and stores it in the analog storage circuit 15 (step ST8), and the above procedure is repeated.

[0058] In step ST4, if this routine is not the first time, the control unit 13 determines whether or not there is a change in the determination result of the predetermined condition (step ST9). n This includes the case where the predetermined condition changes from an unsatisfied state to an satisfied state, or the case where the predetermined condition changes from a satisfied state to an unsatisfied state, the determination in step ST9 is Yes. If the determination in step ST9 is Yes, the control unit 13 changes the first threshold Vt1 and the second threshold Vt2 (step ST10). Specifically, if the determination in step ST9 is Yes for the former reason, the control unit 13 changes the first threshold Vt1 and the second threshold Vt2 so that their absolute values ​​become smaller. If the determination in step ST9 is Yes for the latter reason, the control unit 13 changes the first threshold Vt1 and the second threshold Vt2 so that their absolute values ​​become larger.

[0059] Next, the control unit 13 determines whether a predetermined time has elapsed since the A / D conversion in step ST6 (step ST11). If the predetermined time has elapsed (step ST11: Yes), the control unit 13 proceeds to the A / D conversion in step ST6.

[0060] If the predetermined time has not elapsed (step ST11: No), the control unit 13 determines whether the first difference ΔV1 exceeds the first threshold value Vt1 (step ST12). If the first difference ΔV1 exceeds the first threshold value Vt1 (step ST12: Yes), the control unit 13 adds the first change amount Vc1 to the detected voltage of the digital data stored in the digital storage circuit 14, and calculates the current value V of the detected voltage. n(Step ST13). If the first difference ΔV1 does not exceed the first threshold value Vt1 (No) in Step ST12, the control unit 13 determines whether the second difference ΔV2 exceeds the second threshold value Vt2 (Step ST14). If the second difference ΔV2 exceeds the second threshold value Vt2 (Step ST14: Yes), the control unit 13 subtracts the second change amount Vc2 from the detected voltage of the digital data stored in the digital storage circuit 14, and calculates the current value V of the detected voltage. n (step ST15).

[0061] After the processes of steps ST13 and ST15, the control unit 13 advances the process to step ST7. Specifically, the control unit 13 calculates the current value V n The value of the digital memory circuit 14 is now V n (Step ST7), and the calculated current value of the detected voltage V n The value of the analog memory circuit 15 is now V n (step ST8), and then repeats the above process.

[0062] If the second difference ΔV2 does not exceed the second threshold value Vt2 in step ST14 (No), the control unit 13 does not perform any processing, that is, stores the values ​​of the digital storage circuit 14 and the analog storage circuit 15 as the current value V n (step ST16), and the above process is repeated.

[0063] In this way, the control unit 13 detects whether the detected voltage corresponding to the pressure is the previous value V n-1 When the voltage changes from Vt1 to Vt2, the previous value of the detected voltage Vt1 is n-1 The value obtained by adding the first change amount Vc1 to or subtracting the second change amount Vc2 from this is the current value V of the detected voltage. nThe pressure-corresponding detection voltage is stored in the digital storage circuit 14 as a signal. In other words, the detection voltage corresponding to the pressure can be updated without A / D conversion by the A / D converter 12, thereby suppressing a decrease in the sampling frequency. Furthermore, the data difference calculation and data comparison that were conventionally performed by the control unit 13 are now performed by the first difference circuit 16, the second difference circuit 17, the first comparison circuit 18, and the second comparison circuit 19, which are analog circuits, respectively, and these processes do not need to be performed by the control unit 13. This reduces the processing load on the control unit 13. Furthermore, since the comparison process is performed by analog circuits, there is no need to perform processes that require a long processing time, such as D / A conversion, which also suppresses a decrease in the sampling frequency.

[0064] In this embodiment, the data acquisition device 1 includes an A / D converter 12. At the time of startup (ST4: Yes), the control unit 13 causes the A / D converter 12 to perform A / D conversion (ST6), and obtains the current value V of the detected voltage as analog data. n Then, the control unit 13 converts the converted value into digital data. n As a result, the A / D converter 12 performs A / D conversion at the time of startup, and the current value V of the detected voltage is stored in the digital storage circuit 14 (ST7). n That is, the initial value can be accurately obtained as digital data and stored in the digital storage circuit 14.

[0065] In this embodiment, at a predetermined timing after startup (ST11: Yes), the control unit 13 causes the A / D converter 12 to perform A / D conversion (ST6), and converts the current value V of the detected voltage detected as analog data. n Then, the control unit 13 converts the converted value into digital data. n In other words, the value stored in the digital storage circuit 14 is corrected. As a result, even if the value of the detected voltage calculated by adding the first change amount Vc1 or subtracting the second change amount Vc2 deviates from the actual value, the A / D converter 12 performs A / D conversion at a predetermined timing, and the current value V of the detected voltage is corrected. nis corrected to the correct value.

[0066] In this embodiment, the first change amount Vc1 is the same value as the first threshold value Vt1, and the second change amount Vc2 is the same value (Vt2) as the second threshold value Vt2. As a result, when the first difference ΔV1 exceeds the first threshold value Vt1, that is, when the current value V of the detected voltage of the analog data n is the previous value V n-1 When the second difference ΔV2 exceeds the second threshold Vt2, that is, when the current value V of the detected voltage of the analog data is n is the previous value V n-1 When the voltage detected by the digital data falls below the second threshold Vt2, the voltage detected by the digital data is decreased by the second threshold Vt2. Therefore, the voltage detected by the digital data is not changed by a larger amount than the amount of change in the actual detected voltage.

[0067] In this embodiment, the control unit 13 calculates the current value V of the detected voltage to be stored in the digital storage circuit 14. n Thus, the current value V of the detected voltage stored in the analog memory circuit 15 is n (ST8). This updates the previous value V n-1 The detected voltage of the analog data used as the analog voltage is equal to the value of the detected voltage stored in the digital storage circuit 14. Therefore, even if the detected voltage of the digital data is calculated by adding the first change amount Vc1 or subtracting the second change amount Vc2, the calculated detected voltage value is prevented from deviating significantly from the actual value.

[0068] The control unit 13 changes at least one of the first threshold value Vt1 and the second threshold value Vt2 in accordance with a predetermined condition (ST9: Yes) (ST10). As a result, when a more accurate physical quantity of digital data is required or when a coarser physical quantity of digital data satisfies the requirement, the physical quantity of digital data can be acquired with the desired accuracy by setting the condition.

[0069] In this embodiment, the data acquisition device 1 includes a sensor unit 6 having a plurality of sensors 7 connected to an analog storage circuit 15 via a multiplexer 9, and the analog storage circuit 15 stores the detected voltage for each sensor 7. This achieves high spatial resolution. Furthermore, the control unit 13 switches the multiplexer 9 in synchronization with the switching of the detected voltages set in step ST2 and supplied to the first difference circuit 16 and the second difference circuit 17. This makes it possible to achieve both high spatial resolution and a reduced processing load on the control unit 13.

[0070] Note that instead of the control unit 13 causing the A / D converter 12 to perform A / D conversion (ST6) at startup (ST4: Yes), the digital storage circuit 14 may store a predetermined initial value of the detection voltage. This allows the control unit 13 to acquire the initial value of the detection voltage stored in the digital storage circuit 14 from the digital storage circuit 14 without performing A / D conversion at startup. This allows the control unit 13 to acquire the initial value in a short time. This configuration is suitable when the physical quantity at startup of the control unit 13 is fixed.

[0071] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Figures 3 and 4. Elements that are the same as or similar to those in the first embodiment are given the same reference numerals, and duplicated descriptions will be omitted.

[0072] Fig. 3 is a block diagram showing a schematic configuration of a data acquisition device 1 according to the second embodiment. As shown in Fig. 3, in this embodiment, the configuration of the determination circuit 4 is different from that of the first embodiment. The determination circuit 4 includes an analog storage circuit 15, an absolute difference circuit 26, a comparison circuit 27, and a threshold circuit 28. The analog storage circuit 15 is the same as in the first embodiment.

[0073] The absolute difference circuit 26 outputs the absolute value of the difference between the two analog data. Specifically, the absolute difference circuit 26 calculates the current value V of the detected voltage input from the sensor device 2. n and the previous value V of the detected voltage input from the analog memory circuit 15. n-1The absolute value of the differential voltage ΔV |ΔV| (|ΔV|=|V n -V n―1 |) is calculated.

[0074] Fig. 4 is a circuit diagram showing the detailed configuration of the absolute difference circuit 26 shown in Fig. 3. As shown in Fig. 2, the absolute difference circuit 26 has a first subtractor 29, a second subtractor 30, and an adder 31. The first subtractor 29 receives the current value V of the detected voltage. n is input as an additional value, and the previous value of the detected voltage V n-1 is input as a subtraction value. The second subtractor 30 receives the previous value V of the detected voltage. n-1 is input as an additional value, and the current value of the detected voltage V n is input as a subtraction value. The output of the first subtractor 29 and the output of the second subtractor 30 are input to the adder 31. The first subtractor 29 subtracts the current value V of the detected voltage n is the previous value V n-1 When it is larger than (V n >V n-1 ), this time value V n to the previous value V n-1 The value obtained by subtracting (V n -V n-1 The second subtractor 30 outputs the current value V n is the previous value V n-1 When V is smaller than n <V n-1 ), previous value V n-1 From this value V n The value obtained by subtracting (V n-1 -V n The adder 31 adds the output of the first subtractor 29 and the output of the second subtractor 30, and outputs the absolute value |ΔV| of the differential voltage ΔV.

[0075] Returning to FIG. 3, the comparison circuit 27 compares the two analog data and outputs the comparison result. Specifically, the comparison circuit 27 compares the absolute value |ΔV| of the differential voltage ΔV with a threshold value Vt supplied from the threshold circuit 28. The threshold value Vt is a positive value. If the absolute value |ΔV| of the differential voltage ΔV exceeds the threshold value Vt (|ΔV|>Vt), the comparison circuit 27 outputs "1," indicating an increase in the detected voltage as the pressure acting on the sensor 7 increases. If the absolute value |ΔV| of the differential voltage ΔV does not exceed the threshold value Vt (|ΔV|≦Vt), the comparison circuit 27 outputs "0," indicating that the pressure acting on the sensor 7 has not changed.

[0076] When the control unit 13 receives "1" from the determination circuit 4, the control unit 13 adds a predetermined change amount Vc to the detected voltage of the corresponding sensor 7 stored in the digital storage circuit 14, and updates the detected voltage of the corresponding sensor 7 with the calculated value. When the control unit 13 receives "0" from the determination circuit 4, it does not perform any processing. In other words, the control unit 13 updates the previous value V of the detected voltage of the corresponding sensor 7 stored in the digital storage circuit 14. n-1 This time the value is V n are stored in the digital storage circuit 14 as

[0077] When "1" is input from the judgment circuit 4, the control unit 13 changes the threshold value Vt of the threshold circuit 28. For example, the control unit 13 may change the threshold value Vt to a smaller value. The control unit 13 changes the first threshold value Vt1 and the second threshold value Vt2 to values ​​with smaller absolute values. This makes it possible to obtain the physical quantities of the digital data with the desired accuracy when more accurate physical quantities of the digital data are required.

[0078] In this manner, in this embodiment, the data acquisition device 1 acquires the current value V of the detected voltage detected as analog data. n and the previous value V of the detected voltage stored in the analog memory circuit 15. n-1The circuit is provided with an absolute difference circuit 26 that calculates the absolute value |ΔV| of the difference between the detected voltage of the digital data and the detected voltage. As a result, although it is not possible to make the rate of change of the detected voltage (the amount of change per sampling period) different when the detected voltage is increasing and when it is decreasing, it is possible to shorten the sampling period by reducing the number of processes with a simple circuit configuration.

[0079] Although the description of the specific embodiment has been completed above, the present invention is not limited to the above embodiment and can be widely modified and implemented. For example, in the above embodiment, the data acquisition device 1 has been described as being used as a contact sensor for a robot, but the data acquisition device 1 can be widely applied to devices other than robots. Furthermore, the specific configuration, arrangement, quantity, and predetermined procedure of each component and part can be changed as appropriate within the scope of the present invention. Meanwhile, not all of the components shown in the above embodiment are necessarily required and can be selected as appropriate. [Explanation of symbols]

[0080] 1: Data acquisition device 2: Sensor device 3: Controller 6: Sensor unit 7: Sensor 8: Demultiplexer 9: Multiplexer 12: A / D converter 13: Control section 14: Digital memory circuit 15: Analog memory circuit 16: 1st differential circuit 17:Second differential circuit 18: 1st comparison circuit 19:Second comparison circuit 20: First threshold circuit 21: Second threshold circuit 26: Absolute difference circuit 27: Comparison circuit 28: Threshold circuit 29: First subtractor 30: Second subtractor 31: Adder Vc: Amount of change Vc1: First change amount Vc2: Second change amount V n : Current value of detected voltage V n-1 : Previous value of detected voltage Vt: threshold Vt1: First threshold Vt2: Second threshold ΔV1: First differential voltage ΔV2: Second differential voltage ΔV: differential voltage

Claims

1. A data acquisition device (1), a sensor device (2) including at least one sensor (7) that detects a predetermined physical quantity as analog data, and that outputs the physical quantity detected by the sensor (7) at a predetermined sampling period; an analog storage circuit (15) for storing the physical quantity of analog data output from the sensor device (2); a digital storage circuit (14) for storing an initial value or an updated value of the physical quantity of digital data; The physical quantity of the analog data output from the sensor device (2) is the current value V ｎ and the physical quantity of the analog data stored in the analog storage circuit (15) is set to the previous value V ｎ－１ The current value V of the physical quantity of the analog data ｎ The previous value V ｎ－１ The first difference ΔV1, which is the difference with respect to V ｎ -V ｎ－１ a first difference circuit (16) that calculates the difference; The physical quantity of the analog data stored in the analog storage circuit (15) is the previous value V ｎ－１ The physical quantity of the analog data output from the sensor device (2) is set as the current value V ｎ and the previous value V of the physical quantity of the analog data ｎ－１ The current value V ｎ The second difference ΔV2, which is the difference with respect to V ｎ－１ -V ｎ A second difference circuit (17) that calculates (=-ΔV1), a comparison circuit (18, 19) that compares the first difference ΔV1 with a predetermined first threshold Vt1 and compares the second difference ΔV2 with a predetermined second threshold Vt2; a control unit (13) that controls the storage of the digital storage circuit (14) and the storage of the analog storage circuit (15); The control unit (13) When the comparison result of the comparator circuit indicates that the first difference ΔV1 exceeds the first threshold value Vt1 (ST12: Yes), a preset first change amount Vc1 is added to the physical quantity stored in the digital storage circuit (14) (ST13), the physical quantity stored in the digital storage circuit (14) is updated with the calculated value (ST7), and the physical quantity of the analog data stored in the analog storage circuit (15) is updated with the calculated value (ST8). When the comparison result of the comparator circuit indicates that the second difference ΔV2 exceeds the second threshold value Vt2 (ST14: Yes), a preset second change amount Vc2 is subtracted from the physical quantity stored in the digital storage circuit (14) (ST15), the physical quantity stored in the digital storage circuit (14) is updated with the calculated value (ST7), and the physical quantity of the analog data stored in the analog storage circuit (15) is updated with the calculated value (ST8). When the comparison result of the comparison circuit indicates that the first difference ΔV1 is equal to or less than the first threshold value Vt1 (ST12: No) and that the second difference ΔV2 is equal to or less than the second threshold value Vt2 (ST14: No), the data acquisition device (1) is configured to hold the physical quantity stored in the digital memory circuit (14) as is in the digital memory circuit (14) and hold the physical quantity stored in the analog memory circuit (15) as is in the analog memory circuit (15) (ST16).

2. The sensor device (2) further includes an A / D converter (12) that converts the physical quantity of the analog data output from the sensor device (2) into digital data, The data acquisition device (1) according to claim 1, wherein the control unit (13) is configured to, upon startup (ST4: Yes), cause the A / D converter (12) to perform A / D conversion (ST6), convert the physical quantity of the analog data output from the sensor device (2) into digital data, store the converted value in the digital memory circuit (14) as an initial value of the physical quantity (ST7), and store the converted value in the analog memory circuit (15) as the initial value of the physical quantity of the analog data (ST8).

3. The data acquisition device (1) according to claim 2, wherein the control unit (13) is configured to, at a predetermined timing (ST11: Yes) after startup, cause the A / D converter (12) to perform A / D conversion, convert the physical quantity of the analog data output from the sensor device (2) into digital data, update the physical quantity stored in the digital memory circuit (14) with the converted value (ST7), and update the physical quantity of the analog data stored in the analog memory circuit (15) with the converted value (ST8).

4. The data acquisition device (1) according to any one of claims 1 to 3, wherein the first change amount Vc1 is the same value as the first threshold value Vt1 (Vc1 = Vt1), and the second change amount Vc2 is the same value as the second threshold value Vt2 (Vc2 = Vt2).

5. The data acquisition device (1) according to any one of claims 1 to 4, wherein the control unit (13) is configured to change at least one of the first threshold value Vt1 and the second threshold value Vt2 (ST10).

6. The sensor device (2) includes a plurality of the sensors (7), and the plurality of sensors (7) form a sensor unit (6) connected to the analog memory circuit (15) via a multiplexer (9), The analog storage circuit (15) stores the physical quantity for each of the sensors (7), The digital memory circuit (14) stores the physical quantity for each of the sensors (7), The data acquisition device (1) according to any one of claims 1 to 5, wherein the control unit (13) switches the multiplexer (9) in synchronization with switching of the previous value Vn-1 of the physical quantity of the analog data supplied from the analog memory circuit (15) to the first difference circuit (16) and the second difference circuit (17).

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