JP5679731B2 - Center of gravity height measuring device - Google Patents

Description

  The present invention relates to a center-of-gravity height measuring device that measures the center-of-gravity height of a cargo truck, for example.

  In recent years, major accidents have frequently occurred due to the rollover of cargo trucks. If the position of the center of gravity of the cargo truck increases due to the load, etc., the possibility of rollover on the curved road increases even at low speeds. Measurement of the height of the center of gravity of the cargo truck is important in preventing the cargo truck from overturning.

  As a technique that contributes to the measurement of the height of the center of gravity of a cargo truck, there is a technique proposed in Patent Document 1, for example. In the technology according to Patent Document 1, the height of the center of gravity of the loading platform including the load is obtained based on signals from a load sensor, an acceleration sensor, an inclination sensor, and the like attached to the loading platform of the cargo truck.

JP 2001-97072 A

  By the way, in the technique according to Patent Document 1, signals from an acceleration sensor, an inclination sensor, and the like that are necessary for obtaining the height of the center of gravity of the loading platform are obtained by a cargo truck traveling on a curved or inclined road. It has become.

  For this reason, in the technique according to Patent Document 1, the height of the center of gravity cannot be measured unless the cargo truck travels on a curved road or an inclined road. Therefore, a curved road traveling with the center of gravity height unknown is performed, which is not preferable from the viewpoint of safety.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a center-of-gravity height measuring device that can measure the center-of-gravity height of a measurement object at a fixed position. .

In order to achieve the above object, the center-of-gravity height measuring apparatus according to the present invention comprises:
And the loading table placing the object to be measured of the center of gravity height,
A vibration composed of a horizontal force applying mechanism for applying a horizontal force to the above-mentioned table on which the measurement object is placed and a restoring force generating mechanism for generating a restoring force with respect to the displacement of the above-mentioned table by the horizontal force applying mechanism. Generating means;
While detecting the load while supporting the table, a load cell that bears a part of the restoring force generation mechanism,
Vibration state quantity detecting means for detecting either or both of the displacement and acceleration of the table in the free vibration state;
And a calculation means for calculating the height of the center of gravity of the measurement object based on the detection signal from the load cell and the detection signal from the vibration state quantity detection means.

In the present invention, the horizontal force applying mechanism may be an actuator that applies a horizontal force to the table (the second invention).

In the present invention, the object to be measured is a vehicle carrying a load, and the horizontal force applying mechanism uses the force received from the vehicle when the vehicle that has entered the table stops stops. On the other hand , it may be a link that gives free vibration in a specific direction (third invention).

In the center-of-gravity height measuring apparatus of the present invention, the measurement object is placed on a stage supported by a load cell. The mounting table on which the measurement object is placed is brought into a free vibration state in the horizontal direction by vibration generating means including a horizontal force applying mechanism and a restoring force generating mechanism . Either or both of the displacement and acceleration of the platform in the free vibration state are detected by the vibration state amount detection means. Calculation based on the detection signal from the load cell and the detection signal from the vibration state quantity detection means is executed by the calculation means, and the height of the center of gravity of the measurement object is obtained.
According to the center-of-gravity height measuring apparatus of the present invention, any of the displacement and acceleration of the platform required for obtaining the center-of-gravity height is obtained by freely vibrating the platform on which the measurement object is placed in the horizontal direction. Since one or both of them is obtained, the height of the center of gravity of the measurement object can be measured at a fixed position.

The top view of the gravity center height measuring apparatus which concerns on the 1st Embodiment of this invention (a) and the AA arrow directional view (b) of (a). BB line view of Fig.1 (a) Explanatory drawing of the support structure of the platform Theoretical illustration of the generation of restoring force Schematic system configuration diagram of the control system of the center of gravity height measuring device Functional block diagram of control device Theoretical illustration of how to find the height of the center of gravity (1) Theoretical illustration of how to find the center of gravity height (2) The flowchart explaining the processing content of the gravity center height measurement program performed with the gravity center height measurement apparatus of 1st Embodiment. Time chart of measurement operation of center of gravity height measuring apparatus of first embodiment The principal part structure explanatory drawing (a) of the gravity center height measuring apparatus which concerns on the 2nd Embodiment of this invention, and the theoretical explanatory drawing of the displacement restraint of a mounting base (b) Functional block diagram of control device The flowchart explaining the processing content of the gravity center height measurement program performed with the gravity center height measurement apparatus of 2nd Embodiment. Time chart of measurement operation of center of gravity height measurement apparatus of second embodiment In explanatory drawing (1) of the other example of a mounting support structure, CC sectional view (b) of front view (a) and (a), and the D section enlarged view (c) of (a) It is explanatory drawing (2) of the other example of a mounting support structure, Front view (a), EE sectional view (b) of (a), and F part enlarged view (c) of (a) It is explanatory drawing (3) of the other example of a mounting base support structure, GG sectional drawing (b) of front view (a), (a). FIG. 15A shows a mechanical model related to load detection when the mounting support structure shown in FIG. 15 is adopted, and FIG. 16B shows a mechanical model related to load detection when the mounting support structure shown in FIG. 16 is adopted. (B)

  Next, specific embodiments of the center-of-gravity height measuring device according to the present invention will be described with reference to the drawings.

[First Embodiment]
<Description of schematic configuration of center of gravity height measuring device>
As shown in FIGS. 1 and 2, the center-of-gravity height measuring device 1 includes a weighing platform 3 assembled on an installation base 2. The weighing table 3 includes a platform 5 made of a rectangular plate-like member on which a measurement object 4 (in this example, a cargo truck) that is a target for measuring the height of the center of gravity, and four corners of the platform 5. It consists of four load cells 11, 12, 13, 14 supported from below.
The center-of-gravity height measuring device 1 serves both as a device for measuring the weight of the cargo truck (measurement object 4) (truck scale) and a device for measuring the height of the center of gravity of the cargo truck (measurement object 4). .
Examples of the installation base 2 include pits formed by digging down the ground surface and floor members laid on the ground surface. In addition to the cargo truck loaded with luggage such as container cargo, the measurement object 4 may be only luggage such as container cargo alone.

<Description of basic structure of load cell>
As shown in FIG. 3, the load cells 11 to 14 are double convex loading column type load cells, and include an elastic body 15 and a sealed casing 16.
The elastic body 15 is made of, for example, a metal such as an aluminum alloy or stainless steel and is formed in a substantially cylindrical shape, and is arranged upright with its axis line directed in the vertical direction.
The elastic body 15 has a strain generating portion 17 formed at the central portion in the axial direction, an upper convex surface 18 formed at the upper end, and a lower convex surface 19 formed at the lower end. Both the upper convex surface 18 and the lower convex surface 19 are formed in a partial spherical shape having a predetermined radius of curvature R.
The elastic body 15 is incorporated in the sealed casing 16 in a state in which the strain generating portion 17 is hermetically housed in the sealed casing 16 and the upper end portion and the lower end portion are exposed from the sealed casing 16, respectively.

<Description of Load Cell Upper Receiving Member and Lower Receiving Member>
An upper receiving member 20 is interposed between the upper end portion of the elastic body 15 and the mounting table 5. The upper receiving member 20 has a horizontal seating surface 21, and is fixed to the mounting table 5 with the horizontal seating surface 21 being in contact with the upper convex surface 18 of the elastic body 15.
A lower receiving member 22 is interposed between the lower end of the elastic body 15 and the installation base 2. The lower receiving member 22 has a horizontal seating surface 23 and is fixed to the installation base 2 in a state where the horizontal seating surface 23 is in contact with the lower convex surface 19 of the elastic body 15.

<Description of basic configuration of restoring force generation mechanism>
The restoring force generating mechanism includes an upper convex surface 18 of the elastic body 15 and a horizontal seating surface 21 of the upper receiving member 20, and a lower convex surface 19 of the elastic body 15 and a horizontal seating surface 23 of the lower receiving member 22. . The restoring force generating mechanism generates a restoring force F with respect to the horizontal displacement y ₀ of the mounting table 5. This restoring force F will be described below with reference to FIG.

<Theoretical explanation of the generation of restoring force>
FIG. 4 shows a state in which the elastic body 15 of the load cells 11 to 14 moves from the vertical state by y _{0 in the} horizontal direction and tilts by θ along with the horizontal displacement y ₀ of the mounting table 5. Symbols in the figure are defined as follows.
y ₀ : Amount of movement of the upper part of the elastic body 15 S: Length of contact point between the upper and lower parts of the elastic body 15 H: Height of the elastic body 15 (height of the load cells 11 to 14)
A: radius of curvature of upper convex surface 18 (= R)
B: radius of curvature of lower convex surface 19 (= R)
N: vertical load acting on the elastic body 15 θ: inclination angle of the elastic body 15

In FIG. 4, if the value of the inclination angle θ of the elastic body 15 is very small, the following equation (1) is established.

tan θ≈y ₀ / H (1)

Further, the contact point length S between the upper and lower portions of the elastic body 15 can be expressed by the following equation (2).

S≈A · tan θ + (B−H) tan θ
= (A + B−H) · y ₀ / H (2)

The ratio K between the vertical load N and the restoring force F can be expressed by the following equation (3).

K = F / N≈S / H = (A + B−H) · y ₀ / H ² (3)

From the above equation (3), the restoring force F can be expressed by the following equation (4).

F = N · (A + B−H) · y ₀ / H ² (4)

<Description of actuator giving initial conditions for free vibration>
As shown in FIG. 2, a hydraulic cylinder 24 is arranged in the vicinity of the stage 5 on the side where the load cells 13 and 14 are installed. The hydraulic cylinder 24 may apply a horizontal displacement and speed to the mounting table 5 by applying a horizontal force to the mounting table 5 by pushing the side surface of the mounting table 5 with the piston rod 25 during the extension operation. It has become. The hydraulic cylinder 24 functions as an actuator that gives an initial condition of free vibration to the mounting table 5. Instead of the hydraulic cylinder 24, for example, a pneumatic cylinder or a magnetic fluid cylinder can be used.
Here, the “initial condition” is a concept including “initial displacement” and “initial velocity”, and is a collective term for these.

<Description of hydraulic circuit of hydraulic cylinder>
The hydraulic cylinder 24 is connected to a hydraulic pump 27 via an electromagnetic valve 26. When the hydraulic pump 27 is driven by the operation of the electric motor 28, the pressure oil from the hydraulic pump 27 is supplied to the head side oil chamber or the bottom side oil chamber of the hydraulic cylinder 24 according to the switching operation of the electromagnetic valve 26. It has become.

<Description of hydraulic cylinder operation>
When a valve switching signal indicating an extension command of the hydraulic cylinder 24 is transmitted from the control device 40 described later to the electromagnetic valve 26, the electromagnetic valve 26 performs the following oil path switching operation in accordance with the valve switching signal. That is, the solenoid valve 26 supplies the pressure oil from the hydraulic pump 27 to the bottom side oil chamber of the hydraulic cylinder 24 and at the same time returns the oil inside the head side oil chamber of the hydraulic cylinder 24 to the tank 29. Switch. As a result, the hydraulic cylinder 24 is extended, the side surface of the mounting table 5 is pushed by the piston rod 25, and a horizontal displacement and speed are given to the mounting table 5.
On the other hand, when a valve switching signal indicating a contraction command for the hydraulic cylinder 24 is transmitted from the control device 40 described later to the electromagnetic valve 26, the electromagnetic valve 26 performs the following oil path switching operation in accordance with the valve switching signal. Execute. That is, the solenoid valve 26 supplies the pressure oil from the hydraulic pump 27 to the head side oil chamber of the hydraulic cylinder 24 and at the same time returns the oil in the bottom side oil chamber of the hydraulic cylinder 24 to the tank 29. Switch. As a result, the hydraulic cylinder 24 is contracted and the contact between the mount 5 and the piston rod 25 is released.

<Description of free vibration of the platform>
In order to freely oscillate the mounting table 5 in the horizontal direction (y direction), first, initial conditions (initial displacement and initial speed) are given to the mounting table 5 by the expansion / contraction operation of the hydraulic cylinder 24. A restoring force F from a restoring force generating mechanism for horizontal displacement is applied to the mounting table 5. Thus, by applying the restoring force F to the horizontal displacement of the mounting table 5, the mounting table 5 can be freely vibrated in the horizontal direction.

<Description of displacement sensor>
A displacement sensor 30 is arranged in the vicinity of the side on which the load cells 11 and 12 are installed in the mounting table 5 so as to face the hydraulic cylinder 24. The displacement sensor 30 functions as a displacement detection means for detecting the displacement of the mounting table 5 in the free vibration state. Note that various types of displacement sensors 30 can be employed, and examples thereof include an optical displacement sensor, an eddy current displacement sensor, and a differential transformation displacement sensor.

<Description of acceleration sensor>
An acceleration sensor 31 is disposed in the vicinity of the side on which the load cells 11 and 12 are installed in the mounting table 5 so as to face the hydraulic cylinder 24. The acceleration sensor 31 functions as an acceleration detection unit that detects the acceleration of the mounting base 5 in a free vibration state. Various types of acceleration sensors 31 can be employed, such as a capacitance type acceleration sensor, a metal strain gauge type acceleration sensor, a semiconductor strain gauge type acceleration sensor, and a piezoelectric acceleration sensor. It is done.

<Description of system configuration of control system of center of gravity height measuring device>
As shown in FIG. 5, the center-of-gravity height measuring device 1 includes a control device 40, an operation device 41, and a display device 42.

<Overview of control device>
The control device 40 is mainly composed of an amplifier 43, a low-pass filter 44, a multiplexer 45, an A / D converter 46, an I / O circuit 47, a memory 48, and a microprocessor (MPU) 49. Yes.
The amplifier 43 has a function of amplifying a signal to be sent to a size that can be A / D converted and sending it out.
The low-pass filter 44 has a function of passing only a low frequency as a signal.
The multiplexer 45 has a function of selectively sending out a plurality of signals to be sent based on a command of the selection control signal.
The A / D converter 46 has a function of converting an analog signal from the multiplexer 45 into a digital signal.
The I / O circuit 47 has a function of exchanging various signals and data among the A / D converter 46, the operation device 41, the display device 42, the memory 48, and the MPU 49.
The memory 48 includes a PROM, a RAM, and the like, and has a function of storing a predetermined program, basic data, and the like for a long period of time, and temporarily storing various data, numerical values for calculation, and the like.
The MPU 49 receives a necessary signal through the I / O circuit 47 and receives necessary data from the memory 48 in accordance with an instruction of a predetermined program stored in the memory 48, and performs an operation based on the received signal and data. Has the function to execute.

<Overview of operating device>
The operation device 41 includes operation switches and numerical keys, and is used in various operations such as measurement start / end operations, zero point adjustment operations, use mode switching operations, and numerical value setting operations.

<Overview of display device>
The display device 42 is composed of a liquid crystal display, for example, and displays measurement results and various data input / output screens.

<Outline of processing operation of control system of center of gravity height measuring device>
In the control system of the center-of-gravity height measuring device 1, the signals of the load cells 11 to 14, the displacement sensor 30 and the acceleration sensor 31 are supplied to the amplifier 43, the low-pass filter 44, the multiplexer 45, the A / D converter 46 and the I / D converter 46, respectively. It is sent to the MPU 49 via the O circuit 47. The MPU 49 takes in a signal from the I / O circuit 47 according to a predetermined program stored in the memory 48, reads various data stored in the memory 48, and based on these signals and data, the measurement object 4 plane center-of-gravity coordinates and center-of-gravity height are calculated. The calculation result is displayed on the display device 42.

<Functional explanation of MPU>
In the MPU 49, by executing a predetermined program, the functions of the planar barycentric coordinate calculation unit 50 and the barycentric height calculation unit 51 shown in FIG. 6 are realized.

<Theoretical explanation of how to obtain the plane coordinates (x _G , y _G ) of the center of gravity G>
Next, using FIG. 7 and FIG. 8, when the planar center-of-gravity coordinates of the measuring object 4, that is, the center of gravity G of the measuring object 4 placed on the platform 5 is projected onto the horizontal plane (o-xy plane). A method for obtaining the coordinates (x _G , y _G ) of the center of gravity G on the surface will be described.
In order to simplify the explanation of the theory, the stage 5 is assumed to be a rectangular parallelepiped having a constant density. The origin of the coordinate system o-xyz is set at the center of the platform 5. Assume that the outputs of the load cells 11 to 14 are adjusted to zero when there is no load. The meanings of symbols in FIGS. 7 and 8 and symbols used in the theoretical formula are defined as follows.
G: Center of gravity of the measuring object 4 G ₀ : Center of gravity of the platform 5 a: Distance between the load cell 11 (13) and the load cell 12 (14) b: Between the load cell 11 (12) and the load cell 13 (14) C: Height of the platform 5 H: Height of the load cells 11 to 14 (height of the elastic body 15)
W _i : Static load acting on each of the load cells 11 to 14 (i = 1, 2, 3, 4)
W: Weight of the measuring object 4 (= W ₁ + W ₂ + W ₃ + W ₄ )
W ₁₂ : W ₁ + W ₂
W ₂₄ : W ₂ + W ₄
Of the above symbols, a, b, c, H, and R are known values, and these values are stored in the memory 48 in advance.

<Theoretical explanation of how to obtain the plane coordinates (x _G , y _G ) of the center of gravity G>
The following equations (5) and (6) hold as the balance condition of moment.

W ₂₄ a−W · (a / 2 + x _G ) = 0 (5)
W ₁₂ b−W · (b / 2 + y _G ) = 0 (6)

From the above equations (5) and (6), the following equations (7) and (8) are obtained.

x _G = a · (W ₂₄ / W−1 / 2) (7)
y _G = b · (W ₁₂ / W−1 / 2) (8)

Therefore, the plane coordinates (x _G , y _G ) of the center of gravity G can be obtained by substituting the calculated values of W ₂₄ , W ₁₂ and W into the above formulas (7) and (8) and calculating.

<Theoretical explanation of how to determine the center of gravity height h of the measurement object>
Next, how to obtain the center of gravity height h of the measurement object 4 will be described below mainly using FIG. In the following theoretical explanation, it is assumed that the stage 5 on which the measurement object 4 is placed is in a free vibration state. An initial condition of free vibration is given by the hydraulic cylinder 24 and a restoring force F from the restoring force generating mechanism is applied to cause the platform 5 on which the measurement object 4 is placed to freely vibrate in the horizontal direction (y direction). Let In FIG. 8, the y coordinate y _G of the center of gravity G of the measurement object 4 at rest is represented by d. The o-yz coordinate system is a coordinate system fixed in space.

なお、上記記号のうち、ｍ_０，ｅは既知の値であり、これらの値は予めメモリ４８に記憶される。 Here, a new symbol used in the following description is defined.
(Sentence 1)

Of the above symbols, m ₀ and e are known values, and these values are stored in the memory 48 in advance.

上記式（９），（１０）は、測定対象物４が剛体であるか否かとは関係なく成立する。
また、転倒モーメントのつりあい条件として次式（１１）を得る。 If the measured object 4 is rigid, the relative displacement in the Z-direction between the center of gravity G ₀ of the center of gravity G and the platform 5 of the measuring object 4 is zero. When the measurement object 4 is a non-rigid body, the relative displacement is not zero, but the amount is very small. Therefore, the amount of the relative displacement is ignored in the following equation of motion. That is, Z ₀ (t) = Z _G (t) is set. At this time, the equation of motion of the system is expressed by the following equations (9) and (10).

The above formulas (9) and (10) hold regardless of whether or not the measurement object 4 is a rigid body.
Further, the following equation (11) is obtained as a balance condition of the overturning moment.

ここに、δは、重心Ｇの重心Ｇ_０に対するｙ方向の相対変位である。δは（ｂ／２−ｄ）に比較して微小であるから以下の式変形においては無視する。

Here, [delta] is the relative displacement in the y direction relative to the center of gravity G ₀ of the center of gravity G. Since δ is very small compared to (b / 2−d), it is ignored in the following equation modification.

(Sentence 2)

上記式（１２）より、測定対象物４の重心高さｈを求める次式（１３）が得られる。

From the above equation (12), the following equation (13) for obtaining the center of gravity height h of the measurement object 4 is obtained.

  In the equation (4) for obtaining the restoring force F described above, the vertical load N acting on the elastic body 15 is Mg (g: gravitational acceleration), and the radii of curvature A and B of the upper convex surface 18 and the lower convex surface 19 of the elastic body 15 are Since both have the predetermined radius R, the restoring force F of the mounting table 5 supported by the load cells 11 to 14 can be expressed by the following equation (14).

上記式（１４）を上記式（１３）に代入してｈを書き直すと次式（１５）となる。

When h is rewritten by substituting the above equation (14) into the above equation (13), the following equation (15) is obtained.

ただし、ｋは次式（１６）で表わされるものである。

（文３）

However, k is represented by following Formula (16).

(Sentence 3)

ここで、「剛体」とは、外力による変形が全く生じない「完全剛体」と、外力による変形が若干生じてもその変形による重心高さ測定上の影響が極めて少なくて完全剛体と見なしても何ら支障がない「見なし剛体」とを包含するものである。また、「非剛体」とは、外力による変形が生じてその変形の影響が重心高さ測定上無視できない物体を総称して表現したものである。 (Sentence 4)

Here, “rigid body” means “perfect rigid body” in which deformation due to external force does not occur at all, and even if slight deformation due to external force occurs, the influence on the measurement of the center of gravity height due to the deformation is extremely small, and it can be regarded as a complete rigid body. It includes “deemed rigid bodies” that have no problem. The “non-rigid body” is a generic expression of objects that are deformed by an external force and whose influence cannot be ignored in measuring the height of the center of gravity.

（文５）

(Sentence 5)

<Description of correction of load signal detected by load cell>
By the way, with the free vibration of the mounting base 5 in the horizontal direction, the load cells 11 to 14 become rotational vibration. As a result, the load acting in the axial direction of the load cells 11 to 14 is a function of the rotation angle θ. Now, it is assumed that the load W _i ′ (t) detected by the load cells 11 to 14 is the above-described axial load.

ただし、Ｆｉ（ｔ）およびθはそれぞれ次式（１９）および式（２０）で表わされる。

ここに、Ｆ_ｉ（ｔ）は、各ロードセル１１〜１４に生じる復元力Ｆの符号を逆にしたものである。
上記式（１８）により次式（２１）が得られる。

式（２１）によりＷ_ｉ（ｔ）がＷ_ｉ´（ｔ）とｙ_０（ｔ）から求まることがわかる。
なお、傾斜補正の成されたデジタルロードセルを用いる場合は、その出力はＷ_ｉ（ｔ）であるから、上述の補正は不要となる。 At this time, W _i ′ (t) can be expressed by the following equation (18).

However, Fi (t) and θ are represented by the following equations (19) and (20), respectively.

Here, F _i (t) is obtained by reversing the sign of the restoring force F generated in each of the load cells 11 to 14.
The following equation (21) is obtained from the above equation (18).

It can be seen from Equation (21) that W _i (t) is obtained from W _i ′ (t) and y ₀ (t).
When a digital load cell with tilt correction is used, the output is W _i (t), and thus the above correction is not necessary.

<Explanation of measuring operation of center of gravity height measuring device>
The measurement operation of the center-of-gravity height measuring apparatus 1 configured as described above will be described below mainly using the functional block diagram of FIG. 6, the flowchart of FIG. 9, and the time chart of FIG. In FIG. 9, the symbol “S” represents a step.
The following description of the measurement operation is an example in the case where the measurement object 4 is a vehicle (cargo truck) carrying a load.

ｘ_Ｇ＝ａ・（Ｗ_２４／Ｗ−１／２） ・・・（７）
ｙ_Ｇ＝ｂ・（Ｗ_１２／Ｗ−１／２） ・・・（８）
<Description of processing contents of steps S1 to S4>
Wait until the cargo truck that has entered the platform 5 stops (S1).
After the time (t ₁ + Δt) after a minute time Δt has elapsed from the time t ₁ at which the cargo truck stopped, the planar gravity center calculator 50 receives the static load signals W _i (i = 1, 2, 1, 2) from the load cells 11-14. 3,4) with read, seek read mass static load signal _{W i} measured from the object 4 (by weight) (S2).
In addition, the planar center-of-gravity calculation unit 50 calculates k based on the following equation (16) (S3), and the plane coordinates (G) of the center of gravity G of the measurement object 4 based on the following equations (7) and (8). x _G , y _G ) is calculated (S4).

x _G = a · (W ₂₄ / W−1 / 2) (7)
y _G = b · (W ₁₂ / W−1 / 2) (8)

<Description of processing contents of step S5>
At time t ₂ , the control device 40 (I / O circuit 47) transmits a valve switching signal indicating the extension operation of the hydraulic cylinder 24 to the electromagnetic valve 26. As a result, the hydraulic cylinder 24 is extended, the side surface of the mounting table 5 is pushed by the piston rod 25, and a horizontal displacement and speed are given to the mounting table 5. Thereafter, at a predetermined displacement, the control device 40 transmits a valve switching signal indicating a contraction operation of the hydraulic cylinder 24 to the electromagnetic valve 26. As a result, the hydraulic cylinder 24 is contracted, the contact between the mount 5 and the piston rod 25 is released, and an initial condition of free vibration is given to the mount 5. And since the restoring force F from the restoring force generation mechanism with respect to the displacement in the horizontal direction acts on the mounting table 5, the mounting table 5 vibrates freely in the horizontal direction (y direction).

<Description of processing contents of steps S6 and S7>
(Sentence 6)

<Description of Processing Contents of Step S8>
In a period from the platform 5 is time t ₄ after the still time t _5, the height of the center of gravity calculating section 51, a static load signal obtained in step S2 W _i and the dynamic load signal and Shutoku in step S6 W _{i (t)} Based on the above, ΔW (t) and ΔW ₃₄ (t) are respectively calculated.

<Description of Processing Contents of Step S9>
In a period from after time t ₅ at time t _6, the height of the center of gravity calculating section 51 calculates the center of gravity height h of the center of gravity G of the measured object 4 based on the following equation (15). Note that the measured value of h is the average value of h calculated by Equation (15) at each sampling time within a predetermined time interval.

<Description of Processing Contents of Step S10>
And the control apparatus 40 (I / O circuit 47) transmits the display signal which displays the value of the gravity center height h obtained as a result of the calculation of step S9 to the display apparatus 42. Thereby, the value of the center-of-gravity height h obtained by the calculation in step S9 is displayed on the display device 42.

<Description of Effects of Center of Gravity Height Measurement Device of First Embodiment>
According to the center-of-gravity height measuring apparatus 1 of the first embodiment, the center of gravity of the cargo truck is obtained by freely vibrating the platform 5 on which the cargo truck (measurement object 4) is placed in the horizontal direction. Since the horizontal displacement and acceleration of the platform 5 required in the above can be obtained, the height of the center of gravity of the cargo truck can be measured at a fixed position.

[Second Embodiment]
Next, a center-of-gravity height measuring apparatus according to a second embodiment of the present invention will be described with reference to FIGS. In the center-of-gravity height measuring apparatus 1A of the second embodiment, the same or similar parts as those of the center-of-gravity height measuring apparatus 1 of the first embodiment are designated by the same reference numerals, and detailed descriptions thereof are given. In the following, the description will focus on the differences from the center-of-gravity height measurement apparatus 1 of the first embodiment.

<Outline Explanation of Differences from the Center of Gravity Height Measurement Apparatus of the First Embodiment>
In the center of gravity height measuring apparatus 1A of the second embodiment, as shown in FIG. 11A, instead of the hydraulic cylinder 24 provided in the center of gravity height measuring apparatus 1 of the first embodiment, A required link 55 that connects the mounting table 5 and the installation base 2 is provided.

<Explanation of link arrangement and restraint of displacement of platform due to the link>
As shown in FIG. 11B, the link 55 is disposed with an inclination of θ with respect to the x coordinate axis. By this link 55, the displacements x ₀ and y _{0 in} the x direction and the y direction of the mounting table 5 are constrained by the relationship represented by the following equation (22).

y ₀ = αx ₀ , α = 1 / tan θ (known) (22)

<Description of free vibration of the platform>
The link 55 uses the force received from the cargo truck when the cargo truck (measurement object 4) traveling in the positive direction of the x-axis enters the stage 5 and stops shortly before it stops. The direction of the free vibration is constrained to a horizontal direction (specific direction u) perpendicular to the link 55 (see FIG. 11B). A restoring force F from a restoring force generating mechanism with respect to the u-direction displacement acts on the mounting table 5. Thus, by applying the restoring force F to the horizontal displacement (u direction) of the mounting table 5, the mounting table 5 can be freely vibrated in the horizontal direction (u direction).

上記式（２３）において、ΔＷ_ｙ（ｔ），ΔＷ_３４ｙ（ｔ）は、ロードセル１１〜１４に生じた荷重変化であるが、自由振動はｘ方向へも生じているから、ロードセル１１〜１４で検出される変化量ΔＷ（ｔ），ΔＷ_３４（ｔ）とは異なる。
以下では、ΔＷ_ｙ（ｔ）およびΔＷ_３４ｙ（ｔ）がそれぞれΔＷ（ｔ）およびΔＷ_３４（ｔ）によって求めることができることを示す。なお、添字ｘを付す記号はｘ方向の振動成分によりロードセル１１〜１４に作用する力を表わすものとする。 <Theoretical explanation of how to determine the center of gravity height h of the measurement object>
When the free vibration of the pedestal 5 is constrained in the horizontal direction (u direction), the force acting on the load cells 11 to 14 due to the vibration component in the y direction is given by the suffix y and ΔW _y (t) (= ΔW _1y (t) +... + ΔW _4y (t)), ΔW _34y (t) (= ΔW _3y (t) + ΔW _4y (t)). At this time, the theoretical formula of the center of gravity height h is expressed by the following formula (23).

In the above equation (23), ΔW _y (t) and ΔW _34y (t) are load changes generated in the load cells 11 to 14, but free vibration also occurs in the x direction. This is different from the detected variations ΔW (t) and ΔW ₃₄ (t).
In the following, it is shown that ΔW _y (t) and ΔW _34y (t) can be obtained by ΔW (t) and ΔW ₃₄ (t), respectively. Note that the symbol with the suffix x represents the force acting on the load cells 11 to 14 due to the vibration component in the x direction.

であり、
ΔＷ（ｔ）＝ΔＷ_ｘ（ｔ）＋ΔＷ_ｙ（ｔ）＝（１＋１／α^２）・ΔＷ_ｙ（ｔ）
であるから、ΔＷ_ｙ（ｔ）は次式（２４）で表わすことができる。
ΔＷ_ｙ（ｔ）＝α^２・ΔＷ（ｔ）／（１＋α^２） ・・・（２４）
また、ΔＷ_ｘ（ｔ）は次式（２５）で表わすことができる。
ΔＷ_ｘ（ｔ）＝ΔＷ（ｔ）／（１＋α^２） ・・・（２５） <Theoretical explanation of how to obtain ΔW _y (t)>
ΔW _y (t) can be expressed using ΔW (t) (= ΣΔW _i (t)).
That is,

And
ΔW (t) = ΔW _x (t) + ΔW _y (t) = (1 + 1 / α ² ) · ΔW _y (t)
Therefore, ΔW _y (t) can be expressed by the following equation (24).
ΔW _y (t) = α ² · ΔW (t) / (1 + α ² ) (24)
ΔW _x (t) can be expressed by the following equation (25).
ΔW _x (t) = ΔW (t) / (1 + α ² ) (25)

<Theoretical explanation of how to obtain ΔW _34y (t)>
ΔW _34y (t) can be expressed using ΔW ₃₄ (t) and ΔW (t).
That is,
_{ΔW 34 (t) = ΔW 34x} (t) + ΔW 34y (t)
_Therefore , ΔW _34y (t) can be expressed by the following equation (26).
_{ΔW 34y (t) = ΔW 34} (t) -ΔW 34x (t)
≈ΔW ₃₄ (t) −ΔW _x (t) / 2 (∵b / 2 >> d)
= ΔW ₃₄ (t) −ΔW (t) / 2 (1 + α ² ) (26)

<Explanation of measuring operation of center of gravity height measuring device>
Next, the measurement operation of the center of gravity height measuring apparatus 1A of the second embodiment will be described below mainly using the functional block diagram of FIG. 12, the flowchart of FIG. 13, and the time chart of FIG. In FIG. 13, the symbol “T” represents a step.
In the following description of the measurement operation, the object to be measured 4 is a vehicle (cargo truck) carrying a load, and the cargo truck traveling in the positive direction of the x-axis enters and stops the platform 5 when the cargo truck moves. It is an example in the case of measuring the height of the center of gravity.

<Description of processing contents of step T1>
Wait until the cargo truck that has entered the platform 5 stops (T1).
At this time, the link 55 applies free vibration to the platform 5 in a specific direction (u direction) using the force received from the cargo truck when the cargo truck enters and stops the platform 5. And since the restoring force F from the restoring force generation mechanism with respect to the displacement in the u direction acts on the mounting table 5, the mounting table 5 freely vibrates in the u direction.

<Description of processing contents of steps T2 and T3>
(Sentence 7)

ｘ_Ｇ＝ａ・（Ｗ_２４／Ｗ−１／２） ・・・（７）
ｙ_Ｇ＝ｂ・（Ｗ_１２／Ｗ−１／２） ・・・（８）
<Description of processing contents of steps T4 to T6>
At time t ₄ from the platform 5 the time t ₃ after the transition to stationary state from the free vibration state, planar gravity calculation section 50 reads in a static load signal W _i from the load cell 11 to 14, a static load of read determining the mass of the measured object 4 from the signal _{W i} (wt) (T4).
In addition, the planar center-of-gravity calculation unit 50 calculates k based on the following equation (16) (T5) and the plane coordinates (G) of the center of gravity G of the measurement object 4 based on the following equations (7) and (8). x _G , y _G ) is calculated (T6).

x _G = a · (W ₂₄ / W−1 / 2) (7)
y _G = b · (W ₁₂ / W−1 / 2) (8)

<Description of Processing Contents of Step T7>
Between time t ₄ and time t ₅ , the center-of-gravity height calculation unit 51 is based on the static load signal W _i acquired in step T 4 and the dynamic load signal W _i (t) stored in the memory 48. ΔW (t) and ΔW ₃₄ (t) are respectively calculated.

ΔＷ_ｙ（ｔ）＝α^２・ΔＷ（ｔ）／（１＋α^２） ・・・（２４）
ΔＷ_３４ｙ（ｔ）＝ΔＷ_３４（ｔ）−ΔＷ（ｔ）／２（１＋α^２） ・・・（２６）
<Description of Processing Contents of Step T8>
In a period from the time _{t 5} the time _{t 6,} the height of the center of gravity calculating section 51, the following equation (23), (24), calculates the center-of-gravity height h of the center of gravity G of the measured object 4 based on (26) .

ΔW _y (t) = α ² · ΔW (t) / (1 + α ² ) (24)
ΔW _34y (t) = ΔW ₃₄ (t) −ΔW (t) / 2 (1 + α ² ) (26)

<Description of Processing Contents of Step T9>
And the control apparatus 40 transmits the display signal which displays the value of the gravity center height h obtained as a result of the calculation of step T8 to the display apparatus 42. Thereby, the value of the center-of-gravity height h obtained by the calculation in step T8 is displayed on the display device 42.

<Description of Effects of Center of Gravity Height Measurement Device of Second Embodiment>
Needless to say, according to the center-of-gravity height measurement apparatus 1A of the second embodiment, the same operational effects as those of the center-of-gravity height measurement apparatus 1 of the first embodiment can be obtained. Furthermore, according to the center-of-gravity height measuring apparatus 1A of the second embodiment, the platform 5 is linked to the link 55 using the force received by the platform 5 from the cargo truck when the cargo truck enters and stops on the platform 5. The hydraulic cylinder 24, the electromagnetic valve 26, the hydraulic pump 27, and the hydraulic piping connecting them are required in the center-of-gravity height measuring device 1 of the first embodiment. The electric motor 28 and the like can be omitted, and the apparatus configuration can be simplified.

  As described above, the center-of-gravity height measurement device of the present invention has been described based on a plurality of embodiments. However, the present invention is not limited to the configurations described in the above embodiments, and the configurations described in the respective embodiments are appropriately described. The configuration can be changed as appropriate within a range not departing from the gist, such as a combination.

<Overview of configuration change example>
In each of the above-described embodiments, as shown in FIG. 3, the platform 5 is supported by the double convex loading column type load cells 11 to 14 and the upper and lower receiving members 20 and 22 of the load cells 11 to 14. However, the present invention is not limited to this, and a mounting support structure as shown in FIG. 15 may be adopted.

<Description of another example (1) of the platform support structure>
The mounting support structure shown in FIG. 15 is erected on the installation base 2 so as to be positioned between the pair of leg members 61 and 61 suspended from the mounting 5 and the pair of leg members 61 and 61. A pair of support members 62, 62, an axial load cell 63 connecting the upper ends of the pair of support members 62, 62, a lower pin 64 connecting the lower ends of the pair of leg members 61, 61, and an axial load cell. 63 and a suspension ring member 65 that spans between the lower pin 64 and the lower pin 64.
The axial load cell 63 has a recessed portion 66 that is recessed with a predetermined radius of curvature over the entire circumference at the center in the axial direction. The upper portion of the suspension ring member 65 is hooked on the hollow portion 66. Similarly, the lower pin 64 has a recessed portion 67 that is recessed with a predetermined radius of curvature over the entire circumference in the center in the axial direction. The lower portion of the hanging ring member 65 is hooked on the hollow portion 67.
In this mounting table support structure, a restoring force acts on the displacement of the mounting table 5 in the front-rear direction (horizontal direction orthogonal to the axis of the axial load cell 63) by the action of the pendulum around the axis of the axial load cell 63. Further, since the upper portion of the suspension ring member 65 is hooked on the recess portion 66 of the axial load cell 63, when the suspension ring member 65 moves in the axial direction of the axial load cell 63, the suspension ring member 65 is moved to the recess portion. A rocking force to return to the lowest part of 66 acts. Due to the action of the swing back force, a restoring force against the displacement of the mounting base 5 in the left-right direction (the axial direction of the axial load cell 63) acts.

<Description of another example (2) of the platform support structure>
Moreover, it can replace with the mounting base support structure shown by FIG. 15, and the mounting base support structure shown by FIG. 16 is also employable.
In the mounting table support structure shown in FIG. 16, a pair of leg members 61, 61 suspended from the mounting table 5, and standing on the installation base 2 so as to be positioned between the pair of leg members 61, 61. A pair of support members 62, 62, an upper pin 68 connecting the upper ends of the pair of support members 62, 62, a lower pin 64 connecting the lower ends of the pair of leg members 61, 61, and an upper pin 68. And a suspension ring member 69 that spans the lower pin 64.
The upper pin 68 has a recessed portion 70 that is recessed with a predetermined radius of curvature over the entire circumference at the center in the axial direction. The upper part of the suspension ring member 69 is hooked on the hollow part 70.
A tension load cell 71 is interposed in the center of the hanging ring member 69 in the vertical direction.
In this mounting table support structure, a restoring force against the displacement of the mounting table 5 in the front-rear direction (horizontal direction orthogonal to the axis of the upper pin 68) acts by the action of the pendulum around the axis of the upper pin 68. Further, since the upper portion of the suspension ring member 69 is hooked on the recess portion 70 of the upper pin 68, when the suspension ring member 69 moves in the axial direction of the upper pin 68, the suspension ring member 69 is moved to the recess portion 70. A rocking force to return to the lowest part acts. Due to the action of the swing-back force, a restoring force against the displacement of the mounting base 5 in the left-right direction (the axial direction of the upper pin 68) acts.

<Description of another example (3) of the platform support structure>
Moreover, it can replace with the mounting base support structure shown in FIG. 15, and the mounting base support structure shown in FIG. 17 is also employable.
In the mounting support structure shown in FIG. 17, the upper receiving member 81 fixed to the lower surface of the mounting 5, the lower receiving member 82 fixed on the installation base 2, and the lower receiving member 82 are installed. And a steel ball 84 disposed between the load cell 83 and the upper receiving member 81.
The upper receiving member 81 is formed with an upper receiving seat 85 interposed between the steel balls 84. The upper receiving seat 85 has a concave seat surface 86 that comes into contact with the spherical surface 84 a of the steel ball 84.
The load cell 83 is formed with a lower receiving seat 87 interposed between the steel ball 84. The lower receiving seat 87 has a concave seat surface 88 that comes into contact with the spherical surface 84 a of the steel ball 84.
The radius of curvature of the recessed seat surfaces 86 and 88 is set to be larger than the radius of curvature of the spherical surface 84 a of the steel ball 84.
The restoring force generating mechanism includes a spherical surface 84 a of the steel ball 84 and a concave seat surface 86 of the upper receiving seat 85, and a spherical surface 84 a of the steel ball 84 and a concave seat surface 88 of the lower receiving seat 87. A restoring force is generated for horizontal displacement.

<Explanation of terms>
The hydraulic cylinder 24 corresponds to an “actuator” constituting the “horizontal force applying mechanism” of the present invention.
The configuration including the displacement sensor 30 and the acceleration sensor 31 corresponds to the “vibration state quantity detecting means” of the present invention.
The configuration including the planar barycentric coordinate calculation unit 50 and the barycentric height calculation unit 51 corresponds to the “calculation unit” of the present invention.
The configuration including the upper convex surface 18 of the elastic body 15 and the horizontal seating surface 21 of the upper receiving member 20, and the lower convex surface 19 of the elastic body 15 and the horizontal seating surface 23 of the lower receiving member 22 is the “restoring force generation” of the present invention. Corresponds to "mechanism".
The configuration including the leg member 61, the support member 62, the shaft load cell 63, the lower pin 64, and the suspension ring member 65 corresponds to the “restoring force generating mechanism” of the present invention.
The configuration including the leg member 61, the support member 62, the upper pin 68, the lower pin 64, and the suspension ring member 69 corresponds to the “restoring force generating mechanism” of the present invention.
The configuration including the spherical surface 84a of the steel ball 84 and the concave seating surface 86 of the upper receiving seat 85 and the spherical surface 84a of the steel ball 84 and the concave seating surface 88 of the lower receiving seat 87 is the “restoring force generating mechanism” of the present invention. Equivalent to.

<Description of another example of acceleration detecting means>
In the above-described embodiment, the example in which the acceleration sensor 31 is used as the acceleration detection unit that detects the acceleration of the mounting base 5 in the free vibration state has been described. However, the present invention is not limited to this. For example, the center-of-gravity height calculation unit 51 can obtain the acceleration of the mounting base 5 by executing the differential calculation twice based on the detection signal of the displacement sensor 30. In this case, the acceleration sensor 31 is not necessary. There may be a mode in which the differential calculation is not performed by the center-of-gravity height calculation unit 51, but an acceleration calculation unit is provided separately and the acceleration calculation unit executes the differential calculation.

<Description of another example of measurement of dynamic load fluctuation ΔW (t)>
(Sentence 8)

このＦを式（１３）に代入するにあたり、式（１６）と同じようにｋとして表わすと、次式（２９）で示されるようになる。

このｋを式（１６）に代えて式（１５）に用いればよい。なお、軸形ロードセル６３は鉛直方向の力を検出するものであるとする。
また、測定対象物４が剛体の場合は、式（１７）´のｋを式（１６）に代えて式（２９）を用いればよい。 <Explanation when a load cell other than the double convex loading method is used>
FIG. 18 (a) shows a dynamic model related to load detection when the platform support structure shown in FIG. 15 is employed in place of the double convex loading column type load cells 11-14 shown in FIG. It comes to be.
The restoring force F in this case is expressed by the following equation (28).

When substituting this F into the equation (13), if expressed as k as in the equation (16), the following equation (29) is obtained.

This k may be used in equation (15) instead of equation (16). It is assumed that the axial load cell 63 detects a force in the vertical direction.
Further, when the measurement object 4 is a rigid body, equation (29) may be used instead of k in equation (17) ′ instead of equation (16).

Further, in place of the double convex loading column type load cells 11 to 14 shown in FIG. 3, a dynamic model relating to load detection in the case where the mounting support structure shown in FIG. 16 is adopted is shown in FIG. As shown in
The restoring force F in this case is expressed by the following equation (30).
F = Mg · y ₀ / l (30)
When substituting this F into the equation (13), if expressed as k as in the equation (16), the following equation (31) is obtained.
k = Mg / l (31)
This k may be used in equation (15) instead of equation (16). It is assumed that the tension load cell 71 detects a force in the tension direction according to the inclination.
Further, when the measurement object 4 is a rigid body, the equation (31) may be used by replacing k in the equation (17) ′ with the equation (16).
However, in this case, since the tensile load cell 71 does not detect the force in the vertical direction, the values of ΔW and ΔW _{34 in} the equation need to be corrected as shown in the following equations (32) and (33). is there.

  Since the center-of-gravity height measuring device of the present invention has the characteristic that the center-of-gravity height of a measurement object can be measured at a fixed position, it can be used for measuring the center-of-gravity height of container cargo and cargo trucks. It can be used suitably.

DESCRIPTION OF SYMBOLS 1,1A Center-of-gravity height measuring device 4 Measuring object 5 Mounting stage 11-14 Load cell 15 Elastic body 18 Upper convex surface 19 Lower convex surface 20 Upper receiving member 21 Horizontal seating surface 22 Lower receiving member 23 Horizontal seating surface 24 Hydraulic cylinder 30 Displacement sensor 31 Acceleration sensor 50 Planar center-of-gravity coordinate calculation unit 51 Center-of-gravity height calculation unit 55 Link 61 Leg member 62 Support member 63 Axial load cell 64 Lower pin 65 Suspension ring member 68 Upper pin 69 Suspension ring member 71 Tensile load cell 84 Steel Sphere 84a Spherical surface 85 Upper seat 86 86 Concave seat 87 Lower seat 88 Concave seat

Claims (3)

And the loading table placing the object to be measured of the center of gravity height,
A vibration composed of a horizontal force applying mechanism for applying a horizontal force to the above-mentioned table on which the measurement object is placed and a restoring force generating mechanism for generating a restoring force with respect to the displacement of the above-mentioned table by the horizontal force applying mechanism. Generating means;
While detecting the load while supporting the table, a load cell that bears a part of the restoring force generation mechanism,
Vibration state quantity detecting means for detecting either or both of the displacement and acceleration of the table in the free vibration state;
An apparatus for measuring the height of the center of gravity, comprising: a calculation means for calculating the height of the center of gravity of the measurement object based on the detection signal from the load cell and the detection signal from the vibration state quantity detection means. It said horizontal force applying mechanism, the center of gravity height measuring apparatus according to claim 1, wherein the actuator to provide a horizontal force with respect to the platform. The object to be measured is a vehicle carrying a load,
2. The link according to claim 1, wherein the horizontal force applying mechanism is a link that applies a free vibration to the preceding table in a specific direction by using a force received from the vehicle that has entered the table described above when the vehicle stops. Center of gravity height measuring device.

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