JP4850805B2 - Optical communication type 3D sensing stone with built-in triaxial acceleration sensor and PIC microcomputer - Google Patents

Description

  The present invention relates to an optical communication type three-dimensional sensing stone incorporating a triaxial acceleration sensor and a PIC (Programmable Interrupt Controller: one-chip microcomputer with built-in AD converter), and in particular, the tertiary of a ballast crushed stone when a railway vehicle is loaded. The present invention relates to a measurement sensor that precisely measures original motion (translational motion and rotational motion), converts it into a digital signal inside a crushed stone, and then transfers data as clean digital information without noise using an optical cable.

  In order to grasp the progress of fracture of a structure composed of discontinuous aggregates such as crushed stones and to elucidate the mechanism, it is impossible to actually measure the behavior of individual members constituting the discontinuous aggregate structure. In particular, when the crushed stones are densely packed like the road bed, the local and three-dimensional translational and rotational behavior of each crushed stone is assumed to trigger the bed bed destruction. However, the individual members of the discontinuous assembly are inside the discontinuous assembly and are not visible from the outside. Moreover, the behavior is a translational motion in the triaxial direction of the x, y, and z axes, and further, there is a rotational motion with respect to the three axes of the x, y, and z axes, so that the behavior cannot be measured conventionally. It was.

  For example, the track structure during train running has been conventionally measured, but both relate to rails and sleeper surfaces, and there are few examples of directly measuring the crushed stone behavior inside the road bed, which is difficult to measure. Although there are measurement examples in which an acceleration sensor is embedded in crushed stone, the data obtained are only measured values for a specific uniaxial direction, and it is not possible to know which axis the crushed stone itself is pointing to. I couldn't figure out the movement.

  In addition, in order to measure the movement of a falling rock, there is one in which an acceleration sensor is attached to the inside of the falling rock (see Non-Patent Document 1 below).

  However, this measurement method uses a uniaxial sensor and cannot detect a change in the direction of movement when the falling rock rotates. In addition, since it is not a wired connection, it is difficult to obtain measurement data.

The inventor of the present application has previously proposed a three-dimensional sensing stone using a three-axis acceleration sensor as Patent Document 1 (unpublished: Japanese Patent Application No. 2006-260726).
Japanese Patent Application No. 2006-260726 “Study on rock movement mechanism, Part 2-Measurement method of rock fall movement”, Takeshi Ujo, Shoji Shinohara, Kazumi Ieishi, Symposium on Geo-disaster and Geo-environment in Shikoku, Geotechnical Society Shikoku Branch, September 2004

  In order to develop a ballast trajectory degradation model, it is essential to measure the three-dimensional movement of crushed stone under actual load environment. As described above, the inventor of the present application manufactured a sensing stone using a triaxial acceleration sensor, conducted an on-site measurement experiment on a railroad sales line, and was able to measure crushed stone from low frequency to high frequency that could not be measured by conventional measuring means. We succeeded in measuring the translational behavior and the rotational behavior at the same time.

  However, since this sensing stone performs multi-axis measurement, the number of output cables is large, and many thick cables must be routed during measurement. Furthermore, in order to record the output signals, it is necessary to carry in and install large-scale measuring equipment such as A / D converters, data loggers, and generators at the site. Is extremely difficult. Therefore, in order to measure the behavior of a large number of crushed stones in the field measurement, it is necessary to improve the connection method of the triaxial acceleration sensor and the data logger and the data processing method.

  In addition, since a high voltage of 20,000 volts acts on the railway business line, an induced current is generated from the traveling vehicle in the output cable extended from the sensing stone to the outside, and noise is included in the measurement data. Therefore, it is necessary to develop a noise reduction method.

  As described above, in order to put the sensing stone into practical use, two points are important: (1) digital processing of measurement information inside the sensing stone, and (2) examination of noise reduction countermeasures related to the interface.

  In view of the above situation, the present invention provides an optical communication type three-dimensional sensing stone that incorporates a digital processing of measurement information inside the sensing stone and a three-axis acceleration sensor and a PIC microcomputer that take measures for noise reduction related to the interface. The purpose is to do.

In order to achieve the above object, the present invention provides
[1] In an optical communication type three-dimensional sensing stone incorporating a triaxial acceleration sensor and a PIC microcomputer, a one-chip microchip with a built-in AD converter that processes the triaxial acceleration sensor and an output signal from the triaxial acceleration sensor A PIC microcomputer, which is a computer, is incorporated in the crushed stone, and the multi-channel analog data of the three-axis acceleration sensor is automatically converted and output as digital data by the ROM program inside the PIC microcomputer, and the three-axis acceleration By constructing a multi-channel transfer protocol dedicated to the sensor and transferring the output data from the PIC microcomputer to the outside using an optical cable that is not affected by electrical noise, Reduce noise And wherein the door.

  [2] In an optical communication type three-dimensional sensing stone incorporating the triaxial acceleration sensor according to [1] above and a PIC microcomputer, the triaxial acceleration sensor and an output signal from the triaxial acceleration sensor are processed. An electrostatic shield is provided to cover a PIC microcomputer, which is a one-chip microcomputer with a built-in AD converter.

  [3] In the optical communication type three-dimensional sensing stone incorporating the three-axis acceleration sensor and the PIC microcomputer as described in [1] above, a power source unit disposed inside the crushed stone is provided with a filter for removing noise from the power source. It is characterized by that.

  According to the present invention, in the measurement of the three-dimensional movement of crushed stone, it is possible to digitalize the measurement information inside the three-dimensional sensing stone and to take noise reduction measures for the interface.

  An optical communication type three-dimensional sensing stone incorporating a triaxial acceleration sensor and a PIC microcomputer according to the present invention is a three-chip acceleration sensor and an AD converter built-in type one-chip microprocessor that processes an output signal from the triaxial acceleration sensor. A PIC microcomputer, which is a computer, is incorporated in the crushed stone, and the multi-channel analog data of the three-axis acceleration sensor is automatically converted and output as digital data by the ROM program inside the PIC microcomputer, and the three-axis acceleration By constructing a multi-channel transfer protocol dedicated to the sensor and transferring the output data from the PIC microcomputer to the outside using an optical cable that is not affected by electrical noise, Reduce noise.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is an overall block diagram of an optical communication type three-dimensional sensing stone system incorporating a triaxial acceleration sensor and a PIC microcomputer according to an embodiment of the present invention.

  In this figure, 1 is a triaxial acceleration sensor, 2 is a PIC microcomputer that reads an analog signal from the triaxial acceleration sensor 1, 3 is an output interface, 4 is a power supply unit, 5 is a triaxial acceleration sensor 1 and a PIC microcomputer. The electrostatic shield surrounding 2, 6 is an optical fiber for sending output serial data from the PIC microcomputer 2, 7 is a microcomputer (H8) for receiving output serial data sent via the optical fiber 6, and 8 is a microcomputer (H8) 7. RS-232C line 9 for sending output data from, and 9 is an external computer for receiving the output data sent via RS-232C line 8.

  Here, as shown in FIG. 2, the communication protocol between the PIC microcomputer 2 and the microcomputer (H8) 7 includes a port number 3 bits and measurement data 10 bits, data 13 bits, a header “1” of 14 bits, and an end “ Three bits of “010” are provided.

  FIG. 3 shows the appearance of the piezoresistive triaxial acceleration sensor chip (H48D) 10. A block diagram of the piezoresistive triaxial acceleration sensor chip 10 is shown in FIG. The piezoresistive triaxial acceleration sensor chip 10 includes an X sensor 11, a Y sensor 12, a Z sensor 13, a temperature sensor 14, an amplifier (AMP) 15, a control unit 16, and a reference power supply 17.

  Next, the arrangement of piezoresistive elements for detecting acceleration will be described.

  5 shows the structure of the piezoresistive element. FIG. 5 (a) is a plan view of the piezoresistive element, and FIG. 5 (b) is a cross-sectional view taken along line AA of FIG. 5 (a). FIG. 6 is a diagram showing a piezoresistive element and its circuit.

  In these figures, 21 is a piezoresistive triaxial acceleration sensor chip, and 22 is a semiconductor piezo element.

  Next, the structure of a three-dimensional sensing stone using a piezoresistive triaxial acceleration sensor chip and its operating principle will be described.

  FIG. 7 is an operation principle diagram of the three-dimensional sensing stone.

In FIG. 7, two piezoresistive triaxial acceleration sensor chips are arranged at the vertices on the diagonal line of the rectangular parallelepiped whose side lengths are L _x , L _y , and L _z , respectively. They are referred to as “A sensor” 31 and “B sensor” 32, respectively. The linear distance L between the two sensors is L = √ (L _x ² + L _y ² + L _Z ² ) from the sum of three squares. Further, if the direction cosine formed by the straight line L connecting the two sensors and the three axes of the x, y, and z axes is represented by θ _x , θ _y , and θ _z , respectively, cos θ _x = L _x / L, cos θ _y = The relationship L _y / L, cos θ _Z = L _z / L is established. Further, when the inter-axis distances T _x , T _y , T _z of the A sensor 31 and the B sensor 32 are obtained in consideration of the plane orthogonal to the x, y, z axes, the x ₁ , x ₂ inter-axis distances T _x , y _{The 1} and y ₂ interaxial distances T _y , z ₁ and z ₂ interaxial distances T _z are obtained by the following equations, respectively.

T _x = L sin θ _x = √ (L ² −L _x ² ) = √ (L _y ² + L _Z ² ), T _y = L sin θ _y = √ (L ² −L _y ² ) = √ (L _Z ² + L _x ² ), T _Z = L sin θ _z = √ (L ² −L _Z ² ) = √ (L _x ² + L _y ² )
It is assumed that translational motion and rotational motion are simultaneously generated in the rectangular parallelepiped, and accelerations of different magnitudes are generated in both the A and B sensors 31 and 32 attached to the vertex of the rectangular parallelepiped. The acceleration measurement values for the x, y, and z axes of the A sensor 31 are x ₁ , y ₁ , and z ₁ , respectively, and the acceleration measurement values for the x, y, and z axes of the B sensor 32 are x ₂ , y ₂ , and z, respectively. ₂ and the acceleration evaluation point related to the movement of the rectangular parallelepiped is the midpoint of the A sensor 31 and the B sensor 32. The average values α _x , α _y , and α _z for the two sensors for the x, y, and z axes are as follows.

α _x = (x ₁ + x ₂ ) / 2, α _y = (y ₁ + y ₂ ) / 2, α _z = (z ₁ + z ₂ ) / 2 (m / s ² )
Further, regarding the A sensor 31, deviations β _x , β _y , β _z from the average value are obtained for each axis as follows.

β _x = x ₁ −α _x = x ₁ − (x ₁ + x ₂ ) / 2 = (x ₁ −x ₂ ) / 2
β _y = y ₁ −α _y = y ₁ − (y ₁ + y ₂ ) / 2 = (y ₁ −y ₂ ) / 2
β _z = z ₁ −α _z = z ₁ − (z ₁ + z ₂ ) / 2 = (z ₁ −z ₂ ) / 2 (m / s ² )
That is, the average values α _x , α _y , and α _z represent the acceleration related to the translational motion at the acceleration evaluation point at the center of the rectangular parallelepiped, while the deviation amounts β _x , β _y , β _z represent the rotation at the acceleration evaluation point at the center of the rectangular parallelepiped. Represents acceleration related to movement.

Here, the acceleration relating to the rotational motion is related to the length of the axis between the acceleration evaluation point and the measurement point. Therefore, the rotation components β _x , β _y , β _z of acceleration are normalized by dividing by the distance (T _x / 2, T _y / 2, T _z / 2) between the acceleration evaluation point and both sensors. Acceleration components γ _x , γ _y , and γ _z .

γ _x = β _x / (T _x / 2) = {(x ₁ −x ₂ ) / 2} / (T _x / 2) = (x ₁ −x ₂ ) / T _x = (x ₁ −x ₂ ) / √ (L _y ² + L _z ² ),
γ _y = β _y / (T _y / 2) = {(y ₁ −y ₂ ) / 2} / (T _y / 2) = (y ₁ −y ₂ ) / T _y = (y ₁ −y ₂ ) / √ (L _z ² + L _x ² ),
γ _z = β _z / (T _z / 2) = {(z ₁ −z ₂ ) / 2} / (T _z / 2) = (z ₁ −z ₂ ) / T _z = (z ₁ −z ₂ ) / √ (L _x ² + L _y ² )
As described above, by taking the average and difference between the measured values of each axis of the two sensors, the three-dimensional translational behavior and rotational behavior of the crushed stone can be measured very easily and simultaneously. If the unit of acceleration measurement is m / s ² , the units of translational acceleration components α _x , α _y , α _z are m / s ² which is the same as the measured value. On the other hand, the acceleration components γ _x , γ _y , γ _z in the rotational direction are divided by the radius orthogonal to the axis, so that the axial acceleration (m / s ² ) ÷ the inter-axis radius (m), the unit is rad / s ²

  FIG. 8 is a diagram showing the structure of a three-dimensional sensing stone.

  As shown in this figure, the A sensor and the B sensor shown in FIG. 7 are arranged in the three-dimensional sensing stone 41 to perform the above-described three-dimensional sensing.

  FIG. 9 is a diagram showing the installation status of the three-dimensional sensing stone.

  In this figure, 41 is a three-dimensional sensing stone, 42 is a roadbed, 43 is a ballast, 44 is a sleeper, 45 is a rail, and the three-dimensional sensing stone 41 is arranged in the ballast 43.

  FIG. 10 is a circuit diagram of a three-dimensional sensing stone.

  As shown in this figure, the three-dimensional sensing stone 50 includes three-axis acceleration sensors 51 and 52, a PIC microcomputer 53, an output interface 54, and a power supply unit 55. The power supply unit 55 is supplied with power from outside. Supplied. The power supply unit 55 is provided with filters 55A and 55B for removing noise.

  An optical fiber 56 that is not affected by electrical noise is connected from the output interface 54 to the receiving side.

  FIG. 11 is a diagram showing the pin arrangement of the PIC microcomputer (PIC16F88), and FIG. 12 is a diagram showing the H8 microcomputer.

  Information processing can be performed by one PIC microcomputer shown in FIG.

  Further, the H8 microcomputer shown in FIG. 12 can capture output data from the optical fiber and connect it to an external computer.

  In the present invention, for practical use of the three-dimensional sensing stone, (1) circuit design related to digital processing of output information and (2) noise reduction countermeasures related to the interface were studied and improved.

  For the former, a one-chip microcomputer (PIC) with built-in AD converter is built into the crushed stone, and the multi-channel analog data of the triaxial acceleration sensor is automatically converted and output as digital data by the ROM program inside the PIC. I made it.

  For the latter, a new multi-channel transfer protocol dedicated to this sensor will be constructed, and the output data from the PIC microcomputer will be transferred to the outside using an optical cable that is not affected by electrical noise. As a result, noise during measurement could be reduced.

  Noise reduction measures for 3D sensing stones and simplification with optical cables have made it possible to measure the vibration of the roadbed more accurately and easily.

  In addition, this invention is not limited to the said Example, Based on the meaning of this invention, a various deformation | transformation is possible and these are not excluded from the scope of the present invention.

  The optical communication type three-dimensional sensing stone incorporating the three-axis acceleration sensor and the PIC microcomputer of the present invention can accurately grasp the three-dimensional movement of the crushed stone.

1 is an overall block diagram of an optical communication type three-dimensional sensing stone system incorporating a triaxial acceleration sensor and a PIC microcomputer according to an embodiment of the present invention. It is a figure which shows the communication protocol between the PIC microcomputer and H8 microcomputer which show the Example of this invention. It is a figure which shows the external appearance of the piezoresistive type triaxial acceleration sensor chip which shows the Example of this invention. FIG. 4 is a block diagram of the piezoresistive triaxial acceleration sensor chip shown in FIG. 3. It is a figure which shows the structure of the piezoresistive element which shows the Example of this invention. It is a figure which shows the piezoresistive element which shows the Example of this invention, and its circuit. It is an operation | movement principle figure of a three-dimensional sensing stone. It is a figure which shows the structure of a three-dimensional sensing stone. It is a figure which shows the installation condition of a three-dimensional sensing stone. It is a circuit diagram of a three-dimensional sensing stone. It is a figure which shows pin arrangement of a PIC microcomputer (PIC16F88). It is a figure which shows a H8 microcomputer.

Explanation of symbols

1, 51, 52 Triaxial acceleration sensor 2, 53 PIC microcomputer 3, 54 Output interface 4, 55 Power supply unit 5 Electrostatic shield 6 Optical fiber 7 Microcomputer (H8)
8 RS-232C line 9 External computer 10, 21 Piezoresistive triaxial acceleration sensor chip 11 X sensor 12 Y sensor 13 Z sensor 14 Temperature sensor 15 Amplifier (AMP)
16 control unit 17 reference power source 22 semiconductor piezo element 31 A sensor 32 B sensor 41, 50 three-dimensional sensing stone 42 roadbed 43 ballast 44 sleeper 45 rail 55A, 55B filter (power source unit)

Claims (3)

  A triaxial acceleration sensor and a PIC microcomputer, which is a one-chip microcomputer with a built-in AD converter, for processing an output signal from the triaxial acceleration sensor are incorporated in a crushed stone, and by a ROM program in the PIC microcomputer, Multi-channel analog data of the three-axis acceleration sensor is automatically converted and output as digital data, and a multi-channel compatible transfer protocol dedicated to the three-axis acceleration sensor is constructed to output data from the PIC microcomputer. An optical communication system incorporating a triaxial acceleration sensor and a PIC microcomputer, which reduces noise during triaxial acceleration measurement by transferring to the outside using an optical cable that is not affected by electrical noise Three-dimensional sensing stone.   2. An optical communication type three-dimensional sensing stone having a built-in triaxial acceleration sensor and a PIC microcomputer according to claim 1, wherein the triaxial acceleration sensor and the AD converter built-in type process an output signal from the triaxial acceleration sensor. An optical communication type three-dimensional sensing stone incorporating a three-axis acceleration sensor and a PIC microcomputer, comprising an electrostatic shield that covers a PIC microcomputer that is a one-chip microcomputer.   The optical communication type three-dimensional sensing stone incorporating the three-axis acceleration sensor and the PIC microcomputer according to claim 1, further comprising a filter for removing noise from a power source in a power source portion arranged inside the crushed stone. Optical communication type 3D sensing stone with built-in triaxial acceleration sensor and PIC microcomputer.