JP2738662B2 - Acceleration / angular acceleration measurement device for measuring component force applied to axle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring acceleration and angular acceleration for examining a component force applied to an axle, momentum, and the like.

[0002]

2. Description of the Related Art Analyzing the force and moment (torque) applied to the axle of a vehicle gives important knowledge not only about the mechanical strength of the vehicle and the axle itself, but also about riding comfort and maneuverability. For example, in the case of a passenger car, the motion state of the axle and the vehicle body that suspends the axle is generally analyzed by the model shown in FIG. A vehicle body (usually referred to as a sprung object), an axle portion including a tire and a suspension mechanism (usually referred to as an unsprung object) are usually handled by a one-dimensional model in the vertical direction (x). The spring on the object is defined by the mass m ₂ and the vertical position x _2, unsprung object is defined by the mass m ₁ and vertical position x _1. In this case, between both objects spring force with the damping force and spring constant k ₁ having ζ damping factor acts. In addition, the unsprung object has a vertical position
spring force that can be represented by a spring coefficient k ₂ from the road surface of x ₀ (the elasticity of the tire) receive. In other words, the forces acting on both

[0003]

[Outside 1]

(For example, Automotive Technology Handbook: Japan Society of Automotive Engineers, Vol. 1, 264-268
Page, published December 1, 1990).

[0005] These forces have unique properties. For example, when the sprung mass m ₂ and the spring coefficient are varied, the resonance vibration of the sprung object changes greatly, but the resonance vibration of the unsprung object does not change much. In addition, the unsprung mass m ₁ and the spring coefficient
When k ₂ is changed, the resonance vibration of the unsprung object largely changes, but the resonance vibration of the sprung object does not change much. Therefore, the resonance acceleration of the unsprung object and the sprung object can be considered separately (Automotive Technology Handbook, ibid.).

In the case of a passenger car, a component force applied to an axle system or an unsprung object due to starting, braking, sharp curve running, or riding on a rough road or a curb, that is, a force in three orthogonal directions and a moment in three orthogonal directions (torque) The analysis of ()) is important. The component force applied to the axle system differs greatly depending on whether the wheels are independently suspended or not.

[0007] It is extremely important to analyze the component force applied to the axle of a traveling vehicle, for example, a train, a truck, or the like under various conditions, not limited to an automobile.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an acceleration measuring device capable of reliably and accurately electrically measuring acceleration and angular acceleration applied to an axle or an unsprung object of a vehicle. A further object of the present invention is to provide a detector capable of reliably and accurately detecting acceleration and angular acceleration applied to an axle of a vehicle or an unsprung object.

[0009]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for measuring acceleration and angular acceleration, comprising the steps of: providing a lower portion of a central plane of each plane corresponding to a rectangular parallelepiped or hexagonal block of a detector body; Two acceleration sensors A ₁ and A
₂ ; A ₁ ', A ₂ '; B ₁ , B ₂ ; B ₁ ', B ₂ '; C _1, C ₂ ; C
₁ ′, C ₂ ′ are embedded, in which case, the sensing directions of the two acceleration sensors are in the plane and are orthogonal to each other, coincide with the direction of the ridge of the block, and are in two opposing planes. The problem is solved by a detector in which any embedded acceleration sensors are arranged symmetrically with respect to the center point 0 of the block.

[0010] Further, the above-mentioned problem is that one acceleration sensor A ₁ , A ₁ ', B is provided at the center of each plane corresponding to a rectangular parallelepiped or hexagonal block in the detector main body for measuring acceleration and angular acceleration. ₁ , B ₁ ′, C _1, C ₁ ′ are embedded.
This is solved by detectors in which the sensing direction of each acceleration sensor is in the plane, coincides with the direction of the ridge of the block, and the sensing directions of the three acceleration sensors are symmetrically arranged so that they are orthogonal to each other. .

Furthermore, the above problem is by the invention, the shaft
The axle 1 is rotatably supported via the receiver 4, and
Measure the rotation angle of the axle on the stopped casing 9
The main body of the rotary encoder 6 and the detector 7
Based on the output signals of the rotary encoder 6 and the detector 7 described above, the acceleration, angular acceleration, speed, and angular velocity occurring at the axle 1 with respect to the rotational angle position of the axle 1 are calculated. The problem is solved by an acceleration / angular acceleration measuring device including the calculation unit 20.

Furthermore, the above problem is by the invention, the upper
Is fixedly connected to the axle 1 and the bearing 4 is
The axle 1 is rotatably supported via the shaft, and stops rotating with respect to the vehicle body.
A measurement device for measuring the rotation angle of the axle
Of the rotary encoder 6 and the rotation
The detector 7 and the rotary engine are connected via rolling contact points.
Slip to take out the output signal of coder 6 to connector 10
Pulling 12 and the fixedly connected respectively, on the basis of the output signal of the rotary encoder 6 and the detector 7 to calculate the acceleration and angular acceleration and velocity and the angular velocity generated in the axle 1 with respect to the rotation angle position of the axle 1 operation This is solved by an acceleration / angular acceleration measuring device including the section 20.

[0013] Further advantageous configurations according to the invention are set out in the dependent claims.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the apparatus according to the present invention, as shown in FIG. 2, a component force applied to a rigid system (hereinafter referred to as an axle system) including an axle 1 including wheels 2 is measured. The mass of the axle system and m _1. Then, the Y axis of the orthogonal coordinate system is determined along the axis of the axle, the traveling direction is defined as the X axis, and the vertical direction is defined as the Z axis. The position of the axle system is represented by (X, Y, Z). Further, the rates of inertia around the X, Y, and Z axes are represented by I _X, I _Y,
And I _Z, the rotation angle θ _X, θ _Y, as theta _Z, the wheel 2
Is the rotation angle of φ.

In such a situation, X,
The forces F _X, F _Y, F _{Z in the} Y, Z axis directions and the moments N _X, N _Y, N _Z around the X, Y, Z axes are obtained. At this time, as is well known, the forces F _X, F _{Y, and} F _Z coincide with the corresponding accelerations in the X, Y, and Z axis directions. That is,

[0016]

[Outside 2]

## EQU1 ##

Further, moments N _X, around the X, Y, Z axes
N _{Y and} N _Z coincide with the time derivative of the corresponding angular momentum G about the X, Y and Z axes. That is,

[0019]

[Outside 3]

Here, an underline is used to represent a vector quantity. Therefore, N = (NX _{, NY, NZ} ), and G = (G
_X, G _Y, G _Z ), where G _X, G _Y, G _Z are X,
The angular momentum about the Y and Z axes.

In the arrangement of FIG. 2, the angular momentum G _X about the Y axis
Can be expressed as I _Y d ² θ _Y / dt ² if the mass of the axle system is distributed approximately rotationally symmetrically around the Y axis. Where I _Y
Is the moment of inertia about the Y axis. Further, if the rotational movement around the Z and X axes is relatively small, the rotation does not cause a significant change in the attitude of the axle system, so that the moments of inertia I _{Z and IX} around the Z and X axes are constant. Can be considered.
Therefore, equation (2) has the same form as equation (1),

[0022]

[Outside 4]

Can be rewritten.

[0024] The acceleration A _t (1) out of the equation of the representation, the radial axle acceleration acceleration A _r perpendicular tangential to the direction of the (radial) (tangential direction)
Can be decomposed into That is,

[0025]

[Outside 5]

Here, assuming that r ² = Z ² + X ² ,

[0027]

[Outside 6]

Alternatively,

[0029]

[Outside 7]

It can be expressed as follows.

As shown in FIG. 3B, the velocity and acceleration in the arrangement of the detector rotating with the axle (coordinates are represented by X ', Y', Z ') are represented by the arrangement of the detector as shown in FIG. , Y, Z) to convert to velocity and acceleration, use the following relationship: That is,

[0032]

[Outside 8]

And

[0034]

[Outside 9]

According to the present invention, the component forces, that is, the forces F _X, F _Y, F _Z and the moments N _X, N _Y, N _Z are electrically determined using the acceleration sensor.

[0036]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing preferred embodiments.

FIG. 3 is a schematic diagram showing the main structure of two types of devices according to the present invention. An axle component according to the invention is connected to an axle 1 to which a wheel 2 and a tire 2 'are connected via a test adapter 3 and a bearing 4 connected to the adapter 3 and arranged on the same axis as the axle. The casing 9 of the main body of the measuring device is mounted. This casing 9
Is movable in the X and Z directions (extendable) and Y
A support member (not shown) that is rotatable about an axis is connected to a support portion 8 (only an attachment portion is shown implicitly), and is attached to the vehicle body so as to always maintain a constant posture with respect to the vehicle body. I have. In a device of the type of FIG. 3a, the angle of rotation of the axle 1
Of the rotary encoder 6 and the casing
Acceleration detectors 7 that measure the acceleration of
The axle 1 and the rotary scale disk of the rotary encoder 6 are fixedly connected to the thing 9 via the rotation transmission rod 5. The photoelectric output signal of the rotary encoder 6 and the detection signal of the acceleration detector 7 are connected to an external signal processing circuit via a lead wire (not shown), a connector 10 connected thereto, and an attached cable.

In the case of FIG. 3b, the acceleration detector 7 is an axle.
FIG. 3A shows a configuration in the case of being fixedly connected to FIG.
The same reference numerals used in the above denote members having the same function. This place
The detection signal of the acceleration detector 7 for measuring the acceleration of the axle 1
No. is connected to the slip ring via the attached wire (not shown).
Twelve rotating rotors (not shown),
The fixed end of the slip ring 12 via a point (not shown)
And finally introduced into an external signal processing circuit via the connector 10 and the conductor 11.

In the apparatus shown in FIG. 3A, the acceleration and the angular acceleration when the rotation of the axle 1 is not directly applied can be obtained. In contrast, the device of FIG. 3b can directly determine the acceleration and angular acceleration of the rotating axle.

FIG. 4 schematically shows a main part of a component force measuring device according to the present invention. In this component force measuring device, two acceleration detectors are preferably mounted on each of six planes of a metallic cubic block. As shown in the figure, the directions of detecting the acceleration are different from each other in both acceleration detectors.

An acceleration sensor (B ₁ and B _{2 in} FIG. 4A) arranged in a plane α orthogonal to the X axis has detection sensitivity in the Y and Z directions. Similarly, an acceleration sensor (C ₁ and C _{2 in} FIG. 4A) arranged in a plane β orthogonal to the Y axis has detection sensitivity in the Z direction and the X direction, and has a detection sensitivity in a plane γ orthogonal to the Z axis. The acceleration sensors (A ₁ and A ₂ in the example shown in FIG. 4A) have detection sensitivity in the X and Y directions. The signs of the acceleration sensors arranged in each of the opposing planes α, β, γ of the cube are distinguished by adding a dash to the sign. The detection direction is defined by a right-handed system as shown, and the detection direction of the opposing surface that cannot be seen in FIG. 4a is antiparallel to the direction of the sensor shown. Further, since two acceleration sensors cannot be arranged at the center in one plane, both acceleration sensors are arranged to be shifted from each other as shown in FIGS. 4A and 4B. The drawing of FIG. 4B shows the center of the cube of FIG. 4A cut out parallel to the XY plane.
here,

A ₁ , A ₂ and A ₁ ′ _, A ₂ ′ are arranged symmetrically shifted from the center O within a straight line in the X direction passing through the center of the plane.

B ₁ , B ₂ and B ₁ ′ _, B ₂ ′ are arranged symmetrically shifted from the center O within a straight line in the Y direction passing through the center of the plane.

C ₁ , C ₂ and C ₁ ′ _, C ₂ ′ are arranged symmetrically shifted from the center O within a straight line in the Z direction passing through the center of the plane.

In the arrangement shown in FIG. 4B, when the sense is positive or negative in a direction parallel to the paper, the direction of the arrow is indicated. Shown.

In such an arrangement of acceleration sensors, X,
The time derivative of the accelerations F _X, F _Y, F _Z and the angular momentums G _X, G _Y, G _Z around the X, Y, Z axes or each of X,
The time twice differentiation (angular acceleration) of the rotation angles θ _X, θ _Y, θ _Z around the Y and Z axes can be expressed as follows. That _{F X α A 1 + A 1} '+ C 2 + C 2' F Y α B 1 + B 1 '+ A 2 + A 2' (8) F Z α C 1 + C 1 '+ B 2 + B 2' and G _X α C ₁ - C ₁ '+ A ₂ -A ₂ ' G _Y ＡA ₁ -A ₁ '+ B ₂ -B ₂ ' (9) G _Z ∝B ₁ -B ₁ '+ C ₂ -C ₂ ' Each force F _X, F _Y, F _Z and angular momentum G _X, G _Y, G _Z
Are usually determined experimentally based on values proportional to the mass of the axle system and the moment of inertia of the corresponding shaft, respectively.

Further, an acceleration sensor corresponding to the third and fourth terms on the right side of the equations (8) and (9), that is, an acceleration sensor corresponding to the subscript 2 with a subscript is used as a simple arrangement of detecting elements advantageous for manufacturing. The removed configuration is also conceivable. _{That, F X α A 1 + A} 1 'F Y α B 1 + B 1' (10) F Z α C 1 + C 1 ' and _{G X α C 1 -C 1'} G Y α A 1 -A 1 '(11 ) when G _Z α B ₁ -B ₁ 'this is the acceleration sensor, as shown in FIG. 5, each face of the cube of the detector 7 alpha, gamma, each being located in the center of the beta, the detection direction of the acceleration Make it as shown.

According to the present invention, the component force measuring device uses a piezoelectric element as the acceleration detector, and arranges these piezoelectric elements together with the attached inertial mass member, which is a pressure-sensitive part, in the above-described arrangement to form a hexagonal element. Incorporate into metal block of body. Then, the electric charge proportional to the acceleration generated in the piezoelectric element is converted into a voltage value by an appropriate first-stage amplifier, and simultaneously the impedance conversion is performed. It is very advantageous to incorporate this first-stage amplifier inside the metal block.

FIG. 6 shows acceleration sensors A ₁ , A ₂ , A ₁ ′ _, A ₂ ′, B ₁ , B ₂ , B ₁ ′ _, B ₂ ′, C ₁ , C corresponding to the arrangement of FIG.
₂ , C ₁ ′, C ₂ ′, and accelerations F _X, F _Y, F
A circuit for determining _Z and angular acceleration d G / dt is shown.
According to equations (8) and (9), the acceleration sensors A ₁ and A ₁ ′ are provided with an addition circuit S ₁ and a subtraction circuit D for respectively providing an addition value and a subtraction value.
₁ is connected. In that case, the output terminal of the acceleration sensor A ₁ 'amplifier F ₁ can be varied gain (in this regard are simply indicated implicitly by the schematically a variable resistor symbol) is connected, the amplifier F ₁ subtraction output end the adding circuits S ₁
Connecting to the input terminals of the circuit D _1. The same applies below
Adder circuit S ₂ and the reduced that comes with the acceleration sensor A _2, A ₂ 'pairs
The output of the amplifier F ₂ in the input terminals of the calculation circuit D ₂ is connected,
Such relationships acceleration sensor C _2, C ₂ 'to the adder circuit S
₆ and the output of the amplifier F ₆ to the input terminals of the subtracting circuit D ₆ is tangent
Has been maintained to continue. Of the variable amplifier F ₁ to F ₆
The amplification factor is the corresponding subtraction when no acceleration is applied.
Circuit D ₁ to D 0 output signal at the test point TP ₁ to TP ₆ of ₆
It is adjusted so that The force F thus obtained
_The analog acceleration signals S _{1 to} S ₆ corresponding to _X, F _Y, F _Z and the time derivative d G / dt of the angular momentum are respectively added to an adder circuit H
Obtained from the output terminal of the ₁ to H _6.

The analog acceleration signals S _{1 to} S ₆ are introduced into the arithmetic processing circuit 20 and subjected to various arithmetic processings to determine actual accelerations or forces F _X, F _{Y, and} F _Z in the X, Y, and Z axis directions. it can. Similarly, the time derivative d of the actual moment (torque) N _X, N _Y, N _Z about the X, Y, Z axes or the angular momentum d
G / dt can also be determined. Furthermore, by integrating the forces and moments which such time, the axle system of X, Y, the moving speed v _x of the Z-axis _direction, v _y, v _z and angular momentum G _x, G _y, be determined G _Z it can. Then, all of these physical quantities can be obtained for each of the rotational angle positions φ of the axle.

In the arrangement of the acceleration sensors corresponding to FIG. 5, since all the acceleration sensors corresponding to the subscript 2 are eliminated, the circuit corresponding to FIG. 6 is further simplified. Therefore, test points TP _2, TP _4, TP ₆ is not required, addition circuits H ₁ to H ₆ is not necessary, is introduced to the arithmetic processing circuit 20 is a simple direct connection conductor.

Further, the A-phase, B-phase and Z-phase signals which are the output signals of the rotary encoder 6 are waveform-shaped, and the count value corresponding to the angle is introduced to the count input terminal C of the reversible counter 22. In this case, whether the up-count or down-count is determined based on the advance / delay of the phases of the A and B phases, and resetting the counter by introducing a Z signal indicating one rotation of the rotary encoder to the reset terminal R of the reversible counter each time. Then, the rotation angle is newly counted. A digital value corresponding to the rotation angle of the axle is introduced into the arithmetic processing circuit 20 from a circuit 23 that appropriately encodes the count value.

As shown in the figure, the output signal of the arithmetic processing circuit 20 includes the axle position (X, Y, Z) and the rotation angle (θ _X, θ _Y,
θ _Z ) is output as the acceleration, speed, and actual rotation angle φ of the axle and its speed. Based on the mechanical model of the axle system, a processing circuit (not shown) prepared by the user initially outputs The dynamic characteristics of the axle can be analyzed using appropriate assumptions such as the one-dimensional model described above or equations of forces and moments derived based on experiments. Of course, the output acceleration, velocity, angular acceleration, and angular velocity can be calculated by the above equations (1) to (1) according to the detector arrangement (FIG. 3A or 3B) or the decomposition in the radial and tangential directions. 7)
Use These operations are performed by a microprocessor, R
The processing is executed by the arithmetic processing circuit 20 including an OM storage unit, a RAM storage unit, and an appropriate interface and bus system. The output signal of the arithmetic processing circuit 20 can be output as an analog signal and / or a digital signal having a predetermined number of bits. Although these circuit configurations are not particularly shown, they can be easily realized by well-known electrical design techniques.

Further, the acceleration detector described above is incorporated in a hexagonal block, but the shape of the block is not limited to a hexagon and may be a rectangle. Furthermore, other shapes, such as a circular shape and an elliptical shape, may be used. In that case, the arrangement of the piezoelectric elements needs to correspond to the positions described above.

Further, in the above description, all of the velocity, acceleration, angular velocity, and angular acceleration in the X, Y, and Z directions were obtained. However, if necessary, to detect only components in one or two specific directions (for example, only speed and acceleration in the X direction), a corresponding acceleration sensor (for example, equation (10))
And so it can be determined from _{(11), B 1, B} 1 ', C 1, C 1')
May be appropriately eliminated, and the addition and subtraction circuits of the corresponding electric circuits may be eliminated.

[0056]

As described above, when the acceleration measuring device and the acceleration detector according to the present invention are used, the acceleration and the angular acceleration applied to the axle or the unsprung object of the vehicle can be reliably and accurately electrically measured. it can

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a one-dimensional model for analyzing dynamic dynamic characteristics of a passenger car,

FIG. 2 is a schematic diagram for defining coordinates of an axle system and a detection system;

FIG. 3 is a cross-sectional view in which a component force measuring device is arranged, (a) a case where the detector is fixed to the vehicle body, and (b) a case where the detector is fixed to the axle.

FIG. 4 is a view showing the arrangement of a detection block and an acceleration sensor, (a) a perspective view, (b) a sectional view,

FIG. 5 shows another advantageous arrangement of the detection block and the acceleration sensor,

FIG. 6 is an overall connection diagram of a component force measuring device.

[Explanation of symbols]

 Reference Signs List 1 axle 2 wheel 2 'tire 3 adapter 4 bearing 5 rotation transmission rod 6 rotary encoder 7 acceleration detector 8 support 9 casing 10 connector 11 cable 12 slip ring 20 arithmetic processing unit 21 waveform shaping circuit 22 reversible counter 23 encoding circuit

Claims (7)

(57) [Claims] An acceleration sensor (A ₁ , A _{1) is provided} near the center of each plane corresponding to a rectangular parallelepiped or hexagonal block in a detector body for measuring acceleration and angular acceleration.
_{A 2; A 1 ', A} 2'; B 1, B 2; B 1 ', B 2'; C 1, C 2;
C ₁ ′, C ₂ ′), and receive the two acceleration sensors.
The sense directions are orthogonal to each other in the plane, and
A detector, wherein acceleration sensors embedded in two opposing planes , each of which coincides with the direction of the ridge, are symmetrically arranged with respect to the center point (0) of the block. 2. An acceleration sensor (A ₁ , A ₁ ′, B ₁ , B _{1) at} the center of each plane corresponding to a rectangular parallelepiped or hexagonal block in the detector body for measuring acceleration and angular acceleration.
₁ ′, C _1, C ₁ ′) are embedded , and the sensing direction of each acceleration sensor is in the plane, matches the ridge direction of the block, and 3
A detector characterized in that the sensing directions of the two acceleration sensors are symmetrically arranged so as to be orthogonal to each other. 3. An acceleration is obtained by adding output signals of a corresponding acceleration sensor in an opposing plane of the block, and an angular acceleration is obtained by subtracting the acceleration signal.
Or the detector according to 2. 4. A piezoelectric element is used as the acceleration sensor, and all the piezoelectric elements are connected to a first-stage amplifier for converting a piezoelectric charge generated according to acceleration into a voltage value and simultaneously performing impedance conversion. The detector according to claim 1, wherein an amplifier is incorporated in the block. 5. The method according to claim 1, wherein when the measurement direction is one direction or two directions, only an acceleration sensor required for detection is incorporated in the detector body. 2. The detector according to 1. 6. An axle (1) is rotatable via a bearing (4).
Casing supported by Noh and stopped against the body
(9) Rotary encoder that measures the rotation angle of the axle
(6) and any one of claims 1-5.
Fixed detectors (7), respectively, and
Output signals of the encoder (6) and the detector ( 7)
Based on the rotation angle position of the axle (1)
An acceleration / angular acceleration measuring device, comprising: a calculation unit (20) for calculating acceleration and angular acceleration, and velocity and angular velocity occurring in the vehicle. 7. Any one of claims 1 to 5 defined above.
A detector (7) fixedly connected to the axle (1),
The axle (1) is rotatably supported via (4), and
The rotation of the axle is added to the casing (9)
A main body of a rotary encoder (6) for measuring an angle,
The detector via a rotary sliding contact provided on a rotary rotor
(7) and the output signal of the rotary encoder (6)
Slip ring (12) to be taken out to connector (10)
Are fixedly connected to each other, and the acceleration, angular acceleration, and speed generated on the axle (1) with respect to the rotational angle position of the axle (1) based on the output signals of the rotary encoder (6) and the detector (7). And an arithmetic unit (2) for calculating the angular velocity
0) An acceleration / angular acceleration measuring device characterized by comprising: