JPS595846B2 - Sway angle measurement device for traveling objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a device for measuring the oscillation angle of a traveling body using a gyroscope, and in particular, a device for measuring the sway angle of a traveling body using a gyroscope, which uses the reaction torque of preset, which is one of the characteristics of the gyroscope, to measure a stable surface around one axis. This invention relates to a sway angle measuring device for a running body that measures changes in the sway angle of the running body with high accuracy by detecting the relative angular displacement between this surface and the surface of a base fixed to the running body.

A running object, such as a railway vehicle, shakes violently in and around each of three orthogonal axes while running, and also receives acceleration in the direction of each axis.

Special requirements are required to accurately measure changes in the oscillation angle of the vehicle during such travel.

This will be discussed below.

It is well known that a normal pendulum, when used in a quiet state, can serve as a standard for accurately measuring the angle of inclination (sway angle), but it cannot be used as a standard when used on a moving object such as a moving vehicle. That's right.

This is because pendulums generally have a short period, so they swing immediately when subjected to horizontal acceleration.

When a pendulum with period T is continuously subjected to acceleration α in the horizontal direction, the swing angle (oscillation angle) β with respect to the vertical line is expressed by the following equation when no damping action is performed.

β-(α7g)(1-cO3(2π/T)×t)...
...(1) Here, J is the gravitational acceleration and t is the elapsed time (units are CGS units).

FIG. 1 is a pendulum characteristic curve diagram showing the relationship between the swing angle β and the elapsed time t depending on the magnitude of the period T of the pendulum, and the curve A
, B, C, and D have longer periods in this order.

Since a general pendulum has a short period T, the swing angle β increases in a short period of time, and eventually it continues to swing between an angle of 2×α/9 with the vertical line.

If the acceleration is applied for a shorter period of time, it will simply not be able to swing to that angle.

If the period T of the pendulum is sufficiently long, the time required for the pendulum to swing to an angle of 2×α/g will be sufficiently long, so it can be assumed that the pendulum will hardly swing under short-term acceleration.

The present invention utilizes this characteristic as one of its special requirements.

Furthermore, in order to determine the attitude of a ship or aircraft, a gyro horizon using a two-axis free gyro is usually used.

However, unlike the present invention, the angle in units of minutes is not a problem, but the precision is much rougher, and this cannot be used for the same purpose as the present invention.

This point will be explained below.

FIG. 2 is an explanatory perspective view showing a general example of such a gyro horizon.

In the figure, 1 is a gyro, 2 is a gyro case housing the gyro 1, and 3.3' is a horizontal case shaft attached to the gyro 2. Both ends of these case shafts 3 and 3' are connected via bearings to a gyro ring ( It is rotatably supported by a ring (hereinafter simply referred to as a ring) 4.

5 and 5' are horizontal gimbal axes fixed to ring 4,
It is perpendicular to the case axes 3, 3'.

The gimbal shafts 5, 5' are rotatably supported by brackets 6.6' through bearings, and the brackets 6.6' are fixed to the base 7.

This horizon is based on the so-called free gyro system, in which the gyro 1 is free on two axes, and the center of gravity of the movable part is at the intersection of the extension lines of the case axes 3, 3' and the gimbal axes 5, 5'. It does not have the vertical directivity of 1.

A gyro horizon is a free gyro with an erecting mechanism added to give it vertical directivity.

There are many types of orthostatic mechanisms, but the main points are:
Using a pendulum, electrolytic level, or other device, detect the difference from the direction of gravity, that is, the tilt, and convert this tilt into an electrical signal to generate a torquer.
The vertical directivity is given to the gyro 1 by applying a torque to the gyro 1 or mechanically giving a torque to the gyro 1.

The one in Figure 2 is an example of a gyro horizon equipped with an electrolytic level and a torquer.

That is, 8.8' are the case shafts 3 and 8 of the gyro case 2, respectively.
3' and an electrolytic level for detecting the inclination angle around the gimbal axes 5, 5' of the ring 4, and 9, 9' are torquers excited by the output thereof, which apply torque to the gyro 1 to cause preset. , gives the gyro 1 an upright motion until the outputs of the electrolytic levels 8 and 8' become 0, respectively.

Reference numerals 10 and 10' denote angle detectors attached to the tips of the case shaft 3 and gimbal shaft 5, respectively, so as to transmit outputs corresponding to the inclination angle of the base 7 to two orthogonal axes based on the attitude of the gyro case 2. be.

In addition, a mechanism for correcting errors caused by the earth's rotation may be added as necessary, but these will be omitted as they are not directly related to the present invention.

Next, we apply the horizontal acceleration α to such a gyro horizon.
Let us consider the case where is applied continuously.

Electrolytic level 8.8' that detects the tilt of gyro case 2
outputs an output signal that indicates that the gyro case 2 is tilted in response to the acceleration α.

As a result, the torquers 9 and 9' act to cause the gyro 1 to begin presetting, and finally tilt to an angle α7g, that is, to the apparent direction of gravity.

For the first time, the outputs of the electrolytic levels 8 and 8' become O, and the tilting of the gyro 1 stops.

The relationship between the elapsed time and the inclination angle at this time differs depending on the standing constant.

This relationship is similar, but not the same, as in Figure 1.

In order to further reduce this inclination due to acceleration, the upright constant may be made smaller.

In the extreme case, the erecting constant is O, that is, the erecting action is eliminated, but since the gyro 1 has the property of not changing its orientation with respect to space, the apparent tilting movement due to the rotation of the earth The gyro 1 will tilt if the standing position is interrupted for a long period of time, as this will cause drift due to torque caused by friction in the bearings or unbalanced balance.

If the traveling direction of the traveling object changes while the gyro 1 is tilted to one side, the attitude of the gyro 1 remains unchanged with respect to the space, but the angular position of the angle detector 10, 10' changes, so the angle cannot be detected. The output of the device 10.10' changes.

Therefore, in a traveling object whose traveling direction changes frequently, unless the gyro 1 is perpendicular to both the case axis 3 and the gimbal axis 5, errors will occur as the direction changes, and this should be avoided. I can't.

Therefore, although the use of a gyro provides a pendulum with a long period, another special requirement is required to avoid this error.

In order to satisfy these special requirements, the present invention uses two gyros to stabilize around one axis so that even if the traveling direction of the traveling object changes, the above-mentioned error does not occur, and the pendulum The period due to the characteristics of the vehicle can be changed continuously as desired in the usage state, and the curve of time versus inclination angle shown in Fig. 1 can be arbitrarily selected to make the period long, and the oscillation angle of the traveling body can be changed. This makes it possible to measure with high precision.

FIG. 3 is an explanatory perspective view showing an embodiment of the present invention.

In the figure, reference numerals 11 and 12 refer to two gyro cases each housing a gyro (not shown) that rotates in opposite directions around the vertical axis.
3.13' and 14.14' are attached, and these two pairs of case shafts 13, 13' and 14.14' are arranged parallel to each other and rotatably attached to the ring 15 via bearings. There is.

The centers of gravity of the gyro cases 11 and 12 containing the gyro are slightly lower than the plane containing the two pairs of case shafts 13, 13' and 14, 14' and the ring 15, forming a pendulum shape.

16 and 16' are sector-shaped pieces fixed to one end of the case shafts 13 and 14, respectively.

The outer arcuate portions of these sector-shaped pieces 16, 16' each form a part of the circumference centered on the case axis 13.14, and these sector-shaped pieces 16.16' maintain a small distance between their two arcuate portions. and connected by two flexible wires 17, 17', 2
It forms a coupling means for coupling the pair of case shafts 13 and 14.

That is, one end of one wire 17 is fixed to the outer periphery near the center of one sector-shaped piece 16, runs along the outer periphery of that sector-shaped piece 16, passes from near the center to the outer periphery of the other sector-shaped piece 16', and then passes through the outer periphery of the other sector-shaped piece 16'. The wire 17' is fixed to the outer periphery near the center of the sector-shaped piece 16' via a spring (not shown), and another wire 17' is also symmetrically fixed in tension between the two sector-shaped pieces 16 and 16' to form a coupling means. are doing.

This coupling means allows the gyro cases 11 and 12 to freely rotate at the same angle in opposite directions with respect to a plane containing the rotation axis of the gyro and the axis of the gyro case, without friction or play. It is.

Reference numerals 18 and 18' denote horizontal gimbal shafts mounted on the ring 15 at right angles to the case axes 13 and 14, respectively, and these gimbal shafts 18 and 18' are rotatably mounted on brackets 19 and 19' via bearings. There is.

Reference numeral 20 denotes a base on which brackets 19 and 19' are fixed, and is attached to the traveling body whose inclination angle change is to be measured.

Reference numeral 21 denotes an angle detector that is attached to the end of the gimbal shaft 18 and detects the angular difference between the ring 15 and the base 20, and is made of synchro electric equipment or the like.

When the direction of the gimbal axis 18, 18' is installed parallel to the traveling direction of the traveling object, the output of the angle detector 21 indicates the lateral oscillation angle, and when it is installed at right angles to this, the output of the angle detector 21 The output shows the pitch angle.

22 is an acceleration detector such as an accelerometer or an electrolyte level gauge attached to the ring 15, and the detection direction is the case axis 13.1.
The direction is parallel to 4'.

This output passes through an amplifier 23 and excites a torquer 24.

The rotor of the torquer 24 is fixed to the end of the gimbal shaft 18', the stator is fixed to the bracket 19', and the rotor of the torquer 24 is fixed to the end of the gimbal shaft 18'.
4 is excited, the torque of the torquer 24 causes the two gyros in the gyro cases 11 and 12 to undergo preset via the ring 15.

As a result, the gyro cases 11 and 12 are connected to the case shaft 13.
13' and 14. They rotate in opposite directions using 14' as rotation axes.

At this time, the ratio between the output of the acceleration detector 22 and the output torque of the torquer 24 can be arbitrarily changed by adjusting the gain of the amplifier 23, which is one of the effects of the present invention.

The direction of this torque is that the gyro is currently stopped, there is no acceleration in the horizontal direction, and the ring 15 is aligned with the gimbal axis 18.
．． 18', it is as if the center of gravity of the ring 15 is directly below the surface of the ring 15 and the surface of the ring 15 is returned to horizontal by the restoring torque due to gravity. It has become.

In other words, it has the same property as the restoring torque of a pendulum with its center of gravity downward.

Reference numeral 25 denotes an angle detector made of a synchro electric machine or the like, the rotor of which is fixed to the end of the case shaft 13' and fixed to the stator ring 15.

When the rotation axis of the gyro is perpendicular to the plane of the ring 15, the output from the detector 25 is O, but when the gyro is tilted, an output having a magnitude and phase corresponding to the angle and direction is produced.

This output enters the amplifier 23 and is combined with the output of the acceleration detector 22 to excite the torquer 24, applying torque to the ring 15 about the ring axis 18, 18', causing the gyro to preset, and 11 and 12 to a position perpendicular to the plane of the ring 15.

However, this effect is not an essential element of this invention.

Next, the operation of this surface mounting will be explained.

The gimbal axis 18.18' is the y-axis, the horizontal axis perpendicular to this is the y-axis, and the two axes are the axes perpendicular to the xy plane.

A case will be described in which the traveling direction when this device is attached to a traveling object is the y-axis direction.

In this case, the angle detector 21 measures the height difference (change in slope) with respect to the traveling direction, that is, the change in the slope angle around the X-axis.

It will be explained that this device has the characteristics of a long-period pendulum and that the period can be changed as appropriate.

Now, the base 20 is horizontal and the ring 15 is aligned with the gimbal axis 18.
．． Suppose that it is tilted by an angle β around 18'.

The acceleration detector 22 outputs an output proportional to the component βy of the gravitational acceleration I (assuming that the magnitude of β is equal to sinβζβ), which is output via the amplifier 23 to the torquer.
24 is excited to give the gyro a torque of βg (K is a variable constant) around the gimbal axis 18.18'.

On the other hand, the gyro cases 11 and 12 containing the gyro have a pendulum shape with a slightly lowered center of gravity.

One mass is m1 center of gravity and fulcrum (case shaft 13, 13
', 14. If the distance from 14' is a, then gimbal 1
The restoring torque due to the ring 15 being tilted at an angle β around 8.18' is 2 mga·β.

The angular momentum of one gyro is H1 gyro case 1L12
Let ψ be the inclination angle around the case axes 13 and 14, the following equation of motion can be obtained from the relationship: (angular momentum) x (preset angular velocity) = (torque).

When the gyro case 1L12 is tilted at an angle ψ, a torque of mgaψ is applied to each gyro around the case axes 13 and 14, respectively.
Preset around 8.

That is, −Hdβ/dt=mgaψ (2)
In this way, the initial inclination of the ring 15 gradually decreases and then begins to incline in the opposite direction.

When the sign of the angle β changes, the direction of the torque (K+2ma) gβ changes, the direction of the gyro preset changes and the tilt angle ψ begins to decrease, and then when the ring 15 tilts in the opposite direction, the ring 15 returns to the initial tilt angle β. Return to the direction.

In this way, the inclination of the ring 15 around the gimbal axis 18 and the inclination of the gyro cases 11 and 12 around the case axes 13 and 14 create a oscillating motion with a constant period while repeating causes and effects of each other. .

Then, if ψ is eliminated from equations (1) and (2), we get, and when we calculate the period T from equation (3), we get.

And by choosing K) 2ma, it becomes substantially.

Since the constant can be changed during operation by adjusting the gain of the amplifier 23, the period T can be changed at any time.

That is, when it is desired to reduce the deflection angle of the ring 15 due to the forward and backward acceleration of the traveling object, the constant K should be made small, and the error due to the friction of the gimbal shafts 18 and 18' is mainly due to the error in the zero point position of the ring 15 when the traveling object is stopped. If you want to reduce , you can set the constant K to be a dog.

Note that the ring 15 does not always need to be horizontal during measurement.

Even when the device is performing a shaking motion consisting of angles β and ψ, if the period is as long as several tens of minutes, if the measurement time is short compared to that period, the shaking This is because the amount of change in output can be ignored or eliminated.

This is exactly the same as in the case of seismometers.

Another feature of this device is that the output of the angle detector 21 does not change even if the base 20 of this device is tilted around the y-axis or around two axes.

This is a feature for using two gyros.

That is, when the base plate 20 is tilted around the y-axis, the orientation of the two gyros in the gyro case 11 and 12 is changed, so a torque is generated around the gimbal axis 18 due to the principle of preset, but the gyro Since the directions of rotation of the two torques are opposite to each other, the directions of the two torques are also opposite to each other and cancel each other out, so that the ring 15 does not tilt.

Furthermore, when the base 20 is rotated around two axes (this corresponds to a change in the traveling direction of the traveling object), it is natural that no change occurs when the two gyro axes are in the two axes directions. However, when the gyro is tilted from the two axes,
That is, when the angle ψ is not 0, the gyro generates torque around the case axes 13 and 14 due to the rotation.

However, since the directions of rotation of the gyro are opposite to each other,
The directions of the two torques are also opposite to each other and cancel each other out, so that the gyro case 1L12 does not tilt and the output of the angle detector 21 does not change.

As is clear from the above description, the present invention uses a gyro to lengthen the period of the pendulum type oscillation, and also allows the period to be adjusted each time during operation, taking into account the influence of acceleration and the accuracy of the zero point. Moreover, since it is not affected by oscillation or turning around axes other than the gimbal axis to be measured using two gyros, when using the device of the present invention, the oscillation angle of the traveling object can be measured. can be measured with high precision, and its effectiveness is extremely unique.

[Brief explanation of the drawing]

Fig. 1 is a pendulum characteristic curve diagram showing the relationship between swing angle β and elapsed time depending on the period T of the pendulum, Fig. 2 is an explanatory perspective view showing a general example of a gyro horizon, and Fig. 3 is a diagram of the present invention. It is an explanatory perspective view showing an example. 11.12: Gyro case, 13, 14: Case axis,
15 Nishinpal ring, 16.16' Sector-shaped piece constituting two coupling means, 17.17': Flexible wire constituting coupling means, 18.18' Nishinpal shaft, 20: Base, 21:
Angle detector, 23 Two amplifiers, 24: Torquer-6

Claims (1)

[Claims] 1. Two gyro cases each housing a gyro that rotates in opposite directions around the vertical axis, and two pairs of horizontal case shafts fixed to each of these gyro cases, which are arranged parallel to each other and can rotate freely. a gimbal ring supported on the gyro, and a space between the two pairs of case shafts so that the two pairs of case shafts can be rotated at the same angle in opposite directions with respect to a plane including the rotation axis of the gyro and the case shaft. A case shaft coupling means to be coupled, a base horizontally rotatably supporting the gimbal shaft fixed to the gimbal ring at right angles to the case axis, and a base mounted to the gimbal ring to allow acceleration in a direction parallel to the case axis. an acceleration detector for detecting the angle of inclination of the gimbal ring with respect to the base; A device for measuring the sway angle of a traveling body, comprising an angle detector for detecting the angle.