JPH0640036B2 - Pressure sensor output signal preprocessor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention grasps an object, for example, by attaching it to a hand of a robot and measuring the pressure distribution of its gripping portion,
The present invention relates to a pressure sensor output signal preprocessing device for facilitating computer processing of an output signal of a pressure sensor that detects a gripping state such as a release or a slip.

[Prior Art] A pressure detection unit of a pressure sensor to which the present invention is applied includes, for example, three sets of pressure sensors that detect forces in the X-axis, Y-axis, and Z-axis directions of a pressure receiving surface and temperature characteristics of the pressure sensors. One set of temperature sensors for compensation is one unit (hereinafter referred to as a pressure sensor module), and a large number of the pressure sensor modules are arranged in a matrix. Spans hundreds of circuits.

No output signal preprocessing device for this kind of pressure sensor is found at present, but for a device consisting of a very small number of pressure sensor modules, a temperature characteristic compensating circuit as shown in FIG. 6 is connected to each output circuit. You can take the means to do so.

In the figure, the influence of the temperature characteristic of the semiconductor strain gauge on the output of the pressure detecting unit 1 formed of a semiconductor bridge such as a semiconductor strain gauge is removed by the temperature characteristic compensating circuit 2. That is, in this temperature compensation circuit 2,
The signal from the pressure detector 1 is received by the analog integrated circuit 3 and the analog integrated circuit 4, and the span and offset of the signal are adjusted by these integrated circuits and the span adjusting resistor 5 and the offset adjusting resistor 6, and the zero adjusting resistor is also adjusted. 7
And the analog integrated circuit 8 adjust the zero of the signal. Further, after the temperature compensation of the pressure signal is performed by the zero temperature characteristic compensation resistor 9, the analog integrated circuit 8 and the analog integrated circuit 11 of the span temperature characteristic compensation resistor 10, the signal output terminal
An output signal is output from 12. 13 is a power supply terminal, and 14 is an analog ground terminal.

[Problems to be Solved by the Invention] However, when such a conventional technique is applied to a large number of pressure sensor modules as described above, as shown in FIG. Since it will be connected, more than 1,000 analog integrated circuits, resistors, etc. must be mounted, so the miniaturization and weight reduction required for the robot hand pressure sensor cannot be achieved,
It also had the drawback of being extremely uneconomical.

Therefore, an object of the present invention is to provide a pressure sensor output signal preprocessing device which eliminates the above-mentioned drawbacks and can economically measure a pressure distribution.

[Means for Solving the Problems] In order to achieve this object, the present invention provides a plurality of pressure detection module parts having unique addresses, a plurality of pressure detection parts located in the pressure detection module part, and a pressure detection module part. Is located inside the pressure detecting module and the temperature detecting section for detecting the temperature of the pressure detecting section.
The first analog switch that turns on and off the outputs of both temperature detection units, the first analog switch that is located in the pressure detection module unit, and that controls the on and off of the first analog switch at the first address given to the pressure detection module unit. 2 analog switch, analog signal switch that sequentially selects one output from the output group of both pressure detection parts sent via the first analog switch of the pressure detection module at the given second address, pressure The first address of the detection module section and the first address for each output signal of both detection sections of the pressure detection module section.
The address generator that generates the address of 2 and the analog digital that converts the pressure signal and the temperature signal sent from the pressure detector and the temperature detector addressed by the address generator through the analog signal switcher into analog-to-digital A converter, and an information processing unit for performing temperature compensation of the pressure signal by performing a calculation by a predetermined arithmetic expression using the pressure signal and the temperature signal digitized by the analog-digital converter. Characterize.

Further, the present invention is characterized in that the power supply to the pressure detection unit and the temperature detection unit is applied while being floated from another earth in the apparatus.

[Operation] In the present invention, a large number of pressure detection modules three-dimensionally constructed by a plurality of pressure detection units are arranged in a matrix,
This module is selectively swept by the vertical axis address and the horizontal axis address, and the output of each pressure detection unit in the selected module is selectively swept one by one by the signal address, and the offset for each pressure detection unit is selected. The temperature distribution of the span, etc. is compensated by using the output of the temperature detection unit and the microcomputer to measure the pressure distribution in a two-dimensional plane shape or a three-dimensional solid shape.

Further, according to the present invention, since the temperature detecting section is provided for each pressure detecting module including a plurality of bridges and the amplifier of the temperature measuring circuit is shared with the amplifier of the pressure detecting circuit, the configuration is simplified and downsizing can be achieved. To be achieved. further,
According to the present invention, one of the wires from the pressure detector to the analog signal switch is made common by modularizing the pressure detector composed of a plurality of bridge circuits in which the applied power source is floated from another circuit arm. Therefore, further miniaturization is achieved.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a circuit configuration of an embodiment of the present invention. here,
Reference numeral 15 is a pressure detection block that detects pressure sensations such as pressure sensation and tactile sensation together with temperature detection, 16 is an amplifier that amplifies the output of the pressure detection block 15, and 17 is a microcomputer unit that performs temperature correction of the output of the amplifier 16. And the device of this embodiment consists of these circuit elements 15-17.

The pressure detection block 15 is composed of a plurality of pressure detection modules 18 and a single analog signal switch 19. Although not shown in the drawing, a large number of pressure detection modules 18 are arranged in a matrix in the vertical and horizontal directions and given a unique address,
A vertical axis decoder line group 43 and a horizontal axis decoder line group 44, which will be described later, are connected to each pressure detection module 18.

In each pressure detection module 18, a plurality of pressure detection units 1X, 1Y, 1Z provided in consideration of three-dimensional pressure measurement and the like, and one temperature detection unit 20 for detecting the temperature of the pressure detection units are provided. Arrange. The pressure detection units 1X, 1Y, 1Z are made of bridges such as semiconductor strain gauges, and the temperature detection unit 20 is made of a thermistor or the like. 21X, 21Y, 21Z and 21T are pressure detectors 1
X, 1Y, 1Z and the signal switch section as an analog switch for opening and closing the detection output of the temperature detection section 20, 22 is an analog switch for controlling the open / close of the detection output for each module 18 through this signal switch section. This is a module switch, and one set of the above-mentioned switch units 21X, 21Y, 21Z, and 21T perform opening / closing operations by an instruction signal from the switch 22.

Switch 22 for each module is a pressure detection module
It consists of switches SX and SY that open and close in response to instructions from the decode signals on the horizontal and vertical axes indicating the address of 18, and a resistor R that encodes this open / close operation in a potential manner. Switch SX and SX when the associated pressure detection module 18 is selected by selecting the decoder described later for the axis.
Close SY and simultaneously open all signal switch parts 21X, 21Y, 21Z, 21T in the module to which it belongs.

Further, to the common power supply terminal 13 and the analog ground terminal 14, connect one temperature detecting section 20 for each pair of pressure detecting sections 1X, 1Y, 1Z, and connect the output terminals of these detecting sections to the above-mentioned terminals. Of 1
Connect the pair of signal switch units 21X, 21Y, 21Z, 21T.

As shown in FIG. 2, the analog signal switching unit 19 is composed of a plurality of switches, receives signals from each pressure detection module 18, and outputs a set of signals among them as a signal decoder described later.
Selective output based on the output value of 25.

Amplifier section 16 connected to the output terminal of analog signal switching section 19
As shown in FIG. ₃ , it is composed of analog integrated circuits 3, 4 and 11 which operate as an operational amplifier and a plurality of resistors R ₀ to R ₃ . The output _{0 of the} amplification unit 16 has an input of ₁ ,
_{If it is 2} , it is given by the following equation (1).

Since this amplification unit 16 is resistant to conduction noise, it has less common-mode voltage noise, and is common to the bridge of the detection unit 1 and the ground of the amplification unit 16.
(Common connection to the ground line) has an advantage that a floating power supply is unnecessary.

The microcomputer unit 17 is composed of a plurality of components 23 to 24. Here, 23 is a vertical axis decoder that generates a corresponding vertical axis decode signal according to a vertical axis address described below, and 24 is a horizontal axis decoder that generates a corresponding horizontal axis decode signal according to a horizontal axis address described below. , One of the pressure detection modules 18 is selected by both of the decode signals described above. Reference numeral 25 denotes a signal decoder, which generates a corresponding decode signal in accordance with a signal address described later, and outputs the vertical and horizontal axis decoders 23, 24.
1 out of 4 signal groups of pressure detection module 18 selected in
The set is selected via the analog signal switch 19.

Further, reference numeral 26 is an A / D (analog-digital) converter connected to the output terminal of the amplification section 16, and A / D converts the pressure signal and the temperature signal amplified by the amplification section 16. 27 is an A / D converter
For temporary storage that temporarily stores the digital signal output from 26
RAMs (random access memories) 28 and 29 are a processor for multiplication and a processor for division which perform an operation for temperature compensation of the data digitized by the A / D converter 26.

Reference numeral 30 is a ROM (read-on memory) in which arithmetic expressions, constants, control programs, etc. are stored in advance, and 31 is a corrected data storage RA for storing detection data temperature-compensated by calculation.
M and 32 are signal output ports that output the temperature-compensated detection data to the outside, 33 is a CPU (Central Processing Unit) that controls the entire system, and 34 is the pressure detection module address and its signal address from the CPU 33. , Vertical axis decoder 23,
An address output port for outputting to the horizontal axis decoder 24 and the signal decoder 25.

Further, 35 is an internal data bus of the microcomputer unit 17, 36 is an address bus of the microcomputer unit 17,
37 is a data bus for signal output of the microcomputer unit 17. 38 and 39 are digital power supply and ground terminals of the microcomputer unit 17, and 40 and 41 are positive and negative power supply terminals for the operational amplifier (operational amplifier) of the amplification unit 16. 42 goes out from the signal decoder 25 and is an analog signal switch
Connect to 19. Decode line group, 43 is vertical axis decoder 23
Output from the horizontal axis decoder 24, and a vertical axis decode line group connected to the switch SY of each module switch section 22 for each vertical axis, and 44 from the horizontal axis decoder 24, and a switch SX of each module switch section 22 for each horizontal axis. It is a horizontal axis decode line group connected to.

In the above configuration, the CPU 33 determines which of the pressure detection modules of the plurality of pressure detection modules 18 to output to the signal output data bus 37 based on the control program stored in the ROM 30. When determined, the address of the pressure detection module and the address of the pressure detection unit are output to the signal decoder 25, the vertical axis decoder 23, and the horizontal axis decoder 25 via the address output port 34. Here, the addresses given in advance to the pressure detection units 1X, 1Y, 1Z and the temperature detection unit 20 in each pressure detection module 18 are addresses specified for each detection unit, for example, signal address, vertical axis. Indicates the code value when the address and the horizontal axis address are arranged.

Next, each of the decoders 23 to 25 decodes the input address and decodes the signal line, the vertical axis line and the horizontal axis line corresponding to the address, respectively, to the signal decode line group 42, the vertical axis decode line group 43 and the horizontal axis decode. The line group 44 is selected, and only the analog selector 19 and the switches SX and SY connected to these selected lines are turned on (conducting).

That is, as shown in FIG. 2, the vertical axis decoder 23 selectively turns on the switch SX in the column-direction pressure detection module 18 through the vertical axis decode line group 43, and the horizontal axis decoder 24 moves horizontally. The switch SY in the row-direction pressure detection module 18 is selectively turned on through the axis decode line group 44. When both switches SX and SY are turned on, the signal switch 22 is turned on, and the pressure and temperature signals of the pressure detection module 18 to which the switch 22 belongs (specified by the address) are output all at once. Thus, the above-mentioned decoder 2
The signal decoder 25 is an analog switch to select a set of signals from the pressure detection module 18 signals selected in 3,24.
Turn on any of the switches in 19.

As a result, the specific pressure detection unit 1X, 1Y, 1Z having the address designated by the CPU 33 is selected, and the output signal of the selected pressure detection unit is amplified by the amplification unit 16. Similarly, the output of the temperature detecting section 20 is amplified by the amplifying section 16 through the above-described signal selection process only by changing the address by the CPU 33.

Next, the pressure signal and the temperature signal amplified by the amplification unit 16 are A /
A / D conversion is performed by the D converter 26. The A / D-converted digital pressure signal and temperature signal are separately stored in separate areas via the internal data bus 35 in the RAM 27 for temporary storage, and further stored in the CPU 33, the processor 28 for multiplication, and An operation for temperature compensation of the pressure signal is performed by the division processor 29. Here, the multiplication processor 28 and the division processor 29 are used to speed up the above-described compensation calculation.

Such compensation calculation is performed as follows. First, the A / D converter
The analog value V _OP of the pressure signal input to 26 is the offset that occurs when pressure is not applied to the pressure detector 1 (1X, 1Y, and 1Z representative numbers) and the proportional constant that determines the span. Using approximately, The pressure applied to the pressure detector 1 can be expressed as
P can be calculated from the following equation (3).

However, T: the absolute temperature of the pressure detection unit 1, a ₀ , a ₁ , a ₂ , b ₀ , b ₁ , b ₂ : a known constant determined individually for the pressure detection unit 1.

In addition, the analog value V of the temperature signal input to the A / D converter 26
_OT can be approximately expressed as V _OT = C ₀ + C ₁ T _OT when the temperature detection unit 20 is, for example, a thermistor, and thus the temperature T _OT can be obtained from the following equation.

However, C ₀ and C ₁ are known constants that are determined for each temperature detection unit 20, and T ₀ is the absolute temperature of the temperature detection unit 20.

Therefore, the temperature T ₀ of the temperature detector 20 is the temperature of the pressure detector 1.
If the temperature detection unit 20 and the pressure detection unit 1 are installed sufficiently close to each other so as to be considered as T, the temperature T _OT calculated by the above equation (4) is used as T and the above (3 It is possible to calculate an accurate pressure value P by removing the effect of temperature T from the equation. In this way, the calculated digital pressure data P is stored in the post-correction data storage RAM 31 in the same manner as when it is output from the signal output data bus 37 to the outside via the signal output port 32. It can be output when needed.

As described above, the output signal of the specific pressure detection unit 1 is processed by the microcomputer unit 7 and output to the signal output data bus 37. Similarly, other output detectors
The output of 1 is also detected by being sequentially addressed through the vertical axis decoder 23, the horizontal axis decoder 24, and the signal decoder 25, processed by the microcomputer unit 17, and output to the signal output data bus 37. To be done. Pressure detector 1 of multiple pressure detector modules 18 in matrix arrangement
When the sweeping of all of the temperature detecting section 20 is completed in this way, a data file of the pressure distribution is completed in the corrected data storage RAM 31.

In this way, in this example, the pressure detection module constructed with a plurality of pressure detection units
A large number of 18 are arranged in a matrix form, and a vertical axis decoder 23 and a horizontal axis decoder 24 sequentially select and sweep out the signals of one pressure detection module 18, and then select and take out the selected signals as a signal decoder 25. The analog switch 19 is used to further select and sweep, and a set of detection signals is sequentially extracted from the signals, and the pressure and temperature signals are amplified in the same path by sharing the amplifier, and then temperature compensation such as offset and span is performed. Since the same signal is bundled in the pressure detection unit, the number of leads from the pressure detection module 18 is reduced and the number of analog switches is reduced. Therefore, the tactile part (in which the sensor array and the IC such as the multiplexer are integrated) can be miniaturized.

It should be noted that de-modulating the pressure detection unit 1 in units of several units is, for example, to construct a three-component force detection pressure-sensitive module that decomposes the applied pressure into three component forces that are orthogonal to each other and detects them as a single component. Then, it becomes an effective means. In addition, the temperature detection unit 20
Need not be arranged for each pressure detection module 18, but may be arranged, for example, by limiting the number and positions so as not to impair the temperature compensation.

FIG. 4 shows a circuit configuration of another embodiment of the present invention. still,
The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The pressure detection unit 1 (1X, 1Y, 1Z) and the temperature detection unit 20 of this example are
It is composed of a bridge circuit, and the power supply terminal 45 for the bridge and the ground terminal 46 as the power supply for that are connected to other circuit grounds 39, 4
Floating with respect to 1, the detection output is generated between the terminals 47 and 48, and the terminal 48 is used as one of the common lines of the output of each detecting section. That is, in this example, the first point is that one wiring (output line) from the detection units 1 and 20 to the analog signal switch 19 is made common by floating the power supply of the detection unit from the other circuit ground. Different from the embodiment shown.

As described above, since the power supplies of the pressure detection unit 1 and the temperature detection unit 20 are floated, the signal switch unit 21 '(21'X, 21'Y, 21'Z, for extracting the output signal is used.
21'T) and the number of switches in the amplifier 16 '
And the number of analog integrated circuits (eg, operational amplifiers) 11 therein can be minimized.

The amplifying unit 16 'is an amplifier connected to the output terminal of the analog signal switch 19, and as shown in FIG.
It consists of 11 and several resistors R ₁ and R ₂ . The output ₀ of the amplifier 16 'is given by the following equation (5), where _i is the input.

The amplifier 16 'has an analog integrated circuit 11 as an amplifier.
It can consist of one and four resistors. Therefore, the circuit is greatly simplified and the cost is reduced, and the power consumption is also reduced. For example, according to experiments, an analog integrated circuit 11 is PMI OP37 (product number), and the power supply is ±
The power consumption of the amplifying section 16 'when it is set to 15V, ± 8V is 140mW, 42
The power consumption was 420 mW and 125 mW in the case of the amplifying section 16 of FIG. The other structure is almost the same as that of the embodiment shown in FIG. 1 and its detailed description is omitted.

As described above, in this example, the power supply of the detection units 1 and 20 is floated from the other circuit ground, one of the ships from the detection unit to the analog signal switch 19 is shared, and the configuration of the amplification unit 16 'is configured. Since it is simplified to obtain low power consumption,
It is possible to obtain an economical pressure sensor that is extremely small and lightweight.

[Effects of the Invention] As described above, according to the present invention, a large number of pressure detection modules constructed by a plurality of pressure detection units are arranged in a matrix, and the pressure detection modules are provided on a vertical axis assigned to each module. Address and horizontal axis address are sequentially selected, and the output of each pressure detection unit in the selected module is further selected one by one by signal address, and each pressure detection unit is selected for the selected detection signal. Since the offset span and other temperature compensation is performed,
It is no longer necessary to sweep the outputs of multiple pressure detectors and separately provide temperature compensation circuits for each pressure detector, as in the conventional device shown in Fig. 2. Not only can the miniaturization be achieved, but the pressure distribution can be measured inexpensively and economically.

Further, according to the present invention, by floating the power supply of the pressure detection unit from the other circuit ground, the number of constituent parts of the ship allocation, the switch and the amplification unit can be further reduced, and as a result, the size and weight are economical. Pressure sensor can be obtained at a relatively low cost.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a circuit diagram showing the configuration of the analog signal switch of FIG. 1, and FIG. 3 is a circuit showing the configuration of the amplifier section of FIG. FIG. 4, FIG. 4 is a circuit diagram showing the configuration of another embodiment of the present invention, FIG. 5 is a circuit diagram showing the configuration of the amplifier section of FIG. 4, and FIG. 6 is a temperature characteristic compensation circuit for a conventional pressure sensor. FIG. 7 is a block diagram showing a system configuration example in the case of measuring pressure distribution using a conventional pressure sensor and its temperature characteristic compensation circuit. 1 ... Pressure detection unit, 2 ... Temperature characteristic compensation circuit, 3 ... Analog integrated circuit, 4 ... Analog integrated circuit, 5 ... Span adjustment resistor, 6 ... Offset adjustment resistor, 7 ... Zero adjustment resistor, 8 ... Analog integrated circuit, 9 ... Zero temperature characteristic compensation resistance, 10 ... Span temperature characteristic compensation resistance, 11 ... Analog integrated circuit, 12 ... Signal output terminal, 13 ... Power supply terminal, 14 ... Analog Ground terminal, 15 ... Pressure detection block, 16 ... Amplification section, 17 ... Microcomputer section, 18 ... Pressure detection module, 19 ... Analog signal selector, 20 ... Temperature detection section, 21 ... Signal Switch section, 22 …… Module switch, 23 …… Vertical axis decoder, 24 …… Horizontal axis decoder, 25 …… Signal decoder, 26 …… A / D converter, 27 …… Temporary storage RAM, 28 …… Multiplying processor, 29 ... Dividing processor , 30 …… ROM, 31 …… RAM for storing corrected data, 32 …… Signal output port, 33 …… CPU, 34 …… Address output port, 35 …… Internal data bus, 36 …… Address bus, 37 …… Signal output data bus, 38 …… Digital power supply terminal, 39 …… Digital ground terminal, 40 …… Positive power supply terminal for operational amplifier, 41 …… Negative power supply terminal for operational amplifier, 42 …… Signal decoding line group , 43 …… Vertical axis decode line group, 44 …… Horizontal axis decode line group, 45 …… Bridge power supply terminal, 46 …… Bridge ground terminal, 47,48 …… Pressure detector output terminal.

Claims (1)

[Claims] 1. A plurality of pressure detection module parts each having a unique address, a plurality of pressure detection parts located in the pressure detection module part, and a temperature which is located in the pressure detection module part and detects the temperature of the pressure detection part A detection unit, a first analog switch located in the pressure detection module unit, which turns on and off outputs of both the pressure detection unit and the temperature detection unit, and a pressure detection module located in the pressure detection module unit. A second analog switch for controlling on / off of the first analog switch with a first address given to the pressure detecting module; An analog signal switching device for sequentially selecting one output from a group of outputs at a given second address; An address generating section for generating a first address and the second address for each output signal of both detecting sections of the pressure detecting module section, the pressure detecting section addressed by the address generating section, and the address detecting section. An analog-digital converter that performs analog-digital conversion between a pressure signal and a temperature signal sent from a temperature detection unit via the analog signal switch, and the pressure signal and the temperature signal digitized by the analog-digital converter And an information processing unit that performs temperature compensation of the pressure signal by performing a calculation with a predetermined arithmetic expression using the pressure detecting unit and the temperature detecting unit. A pressure sensor output signal pre-processing device, which is applied by being floated from the ground.