JPH0443909A - Dynamic displacement quantity measuring instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a dynamic displacement measurement device that is applied to, for example, a vehicle basic characteristic tester and measures the dynamic displacement of an object to be measured.

[Problems to be solved by the prior art and the invention] Vehicle basic characteristic testing machines mainly measure the static rigidity around the axle and suspension,
It is used to measure characteristics and mainly applies force from each axle (tire), and has functions that allow measurement and control of force and displacement in the x, y, z, and θ axes. Conventionally,
Previously, only static tests were performed using basic vehicle characteristic testing machines, but recently there has been an increasing demand for tests that extend to dynamic ranges. The reason why tests in the dynamic range have not been conducted until now is that there is no practical displacement sensor that can accurately measure the movement of an object from static to dynamic.

Generally, non-contact sensors that can measure up to a high cycle range have a small effective measurement span.

Furthermore, non-contact sensors that can measure large swing widths are special, expensive, and impractical.

Therefore, in view of the above-mentioned conventional problems, it is an object of the present invention to provide a dynamic displacement measurement device that is non-contact and capable of measuring displacement over a long span.

[Means for Solving the Problems] In order to solve the above-mentioned problems, a dynamic displacement measuring device according to the present invention includes an actuator, a movable part of the actuator, which is disposed facing the object to be measured; A non-contact displacement sensor for short span measurement that measures the distance to the body and generates a signal corresponding to the distance; A displacement sensor for long span measurement that measures the amount, a target signal that is preset in response to a signal of a predetermined level generated by the displacement sensor for short span measurement, and a signal generated by the displacement sensor for short span measurement. servo control means for determining a deviation and servo-controlling the actuator; and addition means for adding a signal generated by the short-span measurement displacement sensor and a signal generated by the long-span measurement displacement sensor; The method is characterized in that the amount of dynamic displacement of the object to be measured is measured based on the output signal of the means.

[Function] In general, the frequency spectrum distribution of velocity or acceleration of vibrations that the object to be measured, such as a vehicle, receives from the road surface is approximately -, and the object to be measured moves in a large amplitude displacement range in a short period of time. There's nothing to do. In other words, when the frequency becomes high, the displacement (
(width) becomes smaller.

Further, the frequency response characteristic of the servo control means of the actuator generally has a sufficiently large response in a range of about 2 or less determined by the sprung mass constant of the vehicle, as shown in FIG.

Therefore, large displacements in a frequency range that can be tracked by the servo control means are handled by a displacement sensor for long span measurements, and small displacements in a frequency range that cannot be tracked by the servo control means are handled by a displacement sensor for short span measurements. Since it is detected, obtained by the above configuration,
By the addition signal of the signal generated by the displacement sensor for short span measurement and the signal generated by the displacement sensor for long span measurement,
It is possible to measure displacement from static to dynamic.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing an embodiment of the dynamic displacement amount measuring device according to the present invention. In the figure, X is an object to be measured, and this object to be measured It is a part of the vehicle that is placed on the vehicle, and is displaced by the vibrations applied to the vehicle by the vehicle basic characteristics tester. l is placed facing the object to be measured X, and measures the distance between the object and the object to be measured. This is a non-contact type displacement sensor for short span measurement that generates signals that change in one direction or ten opposite directions around the zero level, and can be measured with high accuracy for the displacement of the object to be measured (xLy) within a predetermined range. It outputs an electrical signal corresponding to the distance between it and the body X, and has a sufficiently high frequency response. As this non-contact displacement sensor 1 for short span measurement, a laser displacement sensor as shown in FIG. 2 is preferably applicable.

In the above laser displacement sensor, as shown in the figure, the laser beam emitted from the semiconductor laser C1 is transmitted through the aspherical transparent lens C1.
2 and irradiates the reflector C3.

The irradiated laser beam passes through a reflector C fixed to the object to be measured
A part of this diffusely reflected light passes through the light receiving lens C4 and forms a spot on the optical position detection element (PSD) C5.
5, this amount of movement is determined to be the distance to the reflector C3. PSDC5 is a sensor for detecting the position of a light spot using a silicon photodiode, and since it is a non-divided type, a continuous electric signal can be obtained.

The principle is as shown in FIG. 3, when a light spot is incident on the PSDC 5, a charge proportional to the light energy is generated at the incident position. The generated charge passes through the resistance layer (P layer) as a photocurrent and is output from the electrode. The resistance layer is divided and taken out in inverse proportion to the distance gI (resistance value) to the electrode. Here, the distance between the electrodes is 2L, and the photocurrent is I(1,
The current taken out from the electrode is 11. If I2, the photocurrent ■.

-I I+Tz, and if the center of PSDC5 is the origin, I+ = Io (L XA) / 2'LT2 = 1° (
L+xa)/2 L(12-I+)/(1,-I2)=xA/LII
The formula /Ig = (L-XA)/(LfXA) holds true.

The above-mentioned laser displacement sensor, as shown in FIG.
The output is zero when the distance to the reflector C3 is a predetermined 4Mio, and linearly within a predetermined range -ffi to +12 in the positive direction as the distance increases and in the negative direction as the distance decreases. They each operate to output varying voltages, and no valid signal can be obtained outside this predetermined range.

The displacement sensor 1 for short span measurement is supported by a movable part 2a of an actuator 2, and the distance between it and the object to be measured X is adjusted by driving the actuator 2. The actuator 2 has the movable part 2a
and a servo motor 2b that drives the movable part 2a, and a pinion gear 2c fixed to the output shaft of the servo motor 2b is meshed with a rack 2d formed on the movable part 2a, and the servo motor 2b The rotation of the movable part 2a and the short span measurement displacement sensor 1 supported by the movable part 2a are moved.

The displacement sensor 1 for short span measurement generates an electrical signal according to the distance to the object to be measured X, and this electrical signal is sent to the sensor amplifier 3.
It is supplied to the one-man power of addition point 4 and the ten-man power of addition point 5 through. Addition point 4, 10-man power, applies a zero voltage corresponding to the level of the electrical signal generated by the short span measurement displacement sensor 1 when the distance to the object to be measured X is a predetermined value i0. It is connected to the. A deviation signal, which is the difference between the electrical signal of the output of the sensor amplifier 3 obtained at the output of the summing point 4 and the ground potential, is supplied to the servo motor 2b via the servo amplifier 6. It is rotated so that the output electrical signal is at zero potential. That is, the rack 2d is driven via the pinion gear 2C in the direction in which the level of the electric signal generated by the short span measurement displacement sensor 1 becomes zero, and the actuator 2
The movable part 2a and the displacement sensor l for short span measurement supported by the movable part 2a are moved.

As described above, the summing point 4 and the servo amplifier 6 are configured so that the target signal (earth potential) set in advance corresponds to the signal of a predetermined level generated by the displacement sensor 1 for short span measurement and the displacement sensor 1 for short span measurement. It functions as a servo control means that servo-controls the actuator 2 by determining the deviation from the generated signal.

A long span measurement displacement sensor 7 for measuring the amount of displacement of the movable part 2a is connected to the movable part 2a that supports the short span measurement displacement sensor 1. The long span measurement displacement sensor 7 is composed of a contact type sensor, and generates an electric signal of a magnitude corresponding to the amount of displacement of the movable part 2a,
This is applied via the sensor amplifier 8 to the ten-man power of the addition point 5. As a result, the output of the summing point 5 is the object to be measured
Outputs an electrical signal corresponding to the amount of displacement.

In the configuration described above, the operation of the device will be explained below. When all the objects to be measured X are stationary at arbitrary positions, the short span measurement displacement sensor l is moved by the actuator 2 so that its output becomes zero. The distance between the object to be measured Set it.

In such a state, when the measured object X is displaced as shown in FIG. The long span measurement displacement sensor 7, which is servo-controlled and measures the displacement of the actuator 2, generates an electrical signal as shown in FIGS. However, due to the frequency response of the servo control system, the movement of the short-span measurement displacement sensor l by the actuator 2 does not follow the displacement of the measured object X, and the electrical signal output from the long-span measurement displacement sensor 7 It does not follow the displacement of X, and an electrical signal as shown in FIG. 5(C) corresponding to the displacement that cannot be followed is generated at the output of the short span measurement displacement sensor 1. Therefore, by obtaining the electrical signal shown in FIG. 5(d), which is the sum of the electrical signal of the output of the displacement sensor 1 for short span measurement and the electrical signal of the output of the displacement sensor 7 for long span measurement, the The amount of displacement can be accurately measured.

As described above, a long span actuator 2 for long span measurement is provided, and a non-contact displacement sensor l for short span measurement is attached to the tip of the movable part 2a of the actuator 2 for long span measurement. There is. The distance between the non-contact type displacement sensor I for short span measurement and the object to be measured X can be measured by monitoring the output of the displacement sensor 1 for short span measurement. Further, the long span measurement displacement sensor 7 attached to the long span actuator 2 is of a contact type, and the movement of the movable part 2a of the actuator 2, that is, the short span measurement displacement sensor 1, is accurately measured by this output. be able to. Therefore, the distance between the short span measurement displacement sensor 1 on the movable part 2a of the actuator 2 and the measured object X, that is, the true measurement value, is the distance between the long span measurement displacement sensor 7 and the short span measurement displacement sensor 1. It can be determined from the sum of the outputs.

By the way, the short span measurement displacement sensor l is controlled to zero tracking by the actuator 2 supporting it so that its output signal is always zero.

That is, the actuator 2 is servo-controlled so that the distance between the short-span measurement displacement sensor 1 supported on the movable part 2a and the measured object X is io, but as is clear from the characteristic diagram in FIG. Since the response time of the servo control is finite, a speed deviation will occur depending on the moving speed of the object X to be measured. The displacement deviation caused by this speed deviation is within the effective measurement range of the short span measurement displacement sensor l. ~+12
Accurate distance measurement is possible when inside the
Even if the measured object X includes a high-frequency component and is displaced with a large amplitude, the true measurement value can be obtained from the sum of the outputs of the long-span measurement displacement sensor 7 and the short-span measurement displacement sensor 1. I can do it.

〔effect〕

As explained above, according to the present invention, since the non-contact type displacement sensor for short span measurement and the displacement sensor for long span measurement are used in combination, the signal generated by the short span measurement displacement sensor and the long span measurement displacement sensor are used in combination. By adding the signal to the signal generated by the span measurement displacement sensor, even a non-contact type sensor can measure the amount of displacement over a long span from static to dynamic.

[Brief explanation of drawings]

1e is a diagram showing an embodiment of the dynamic displacement amount measuring device according to the present invention-2, FIG. 2 is a diagram showing details of the displacement sensor for short span measurement in FIG. 1, and FIG. Figure 4 is a graph showing the output characteristics of the sensor in Figure 2. Figure 5 is a waveform diagram showing the state of each part during operation of the device in Figure 1. The figure is a graph showing the frequency characteristics of the servo system. DESCRIPTION OF SYMBOLS 1... Displacement sensor for short span measurement, 2... Actuator, 2a... Movable part, 3... Sensor amplifier, 4
... addition point, 5 ... addition point, 6 ... servo amplifier, 7 ... displacement sensor for long span measurement, X ... object to be measured. Figure 3 Figure 4 Figure 20

Claims (1)

[Claims] An actuator, and a non-contact type short circuit that is disposed on a movable part of the actuator to face an object to be measured, and that measures the distance between the object and the object and generates a signal according to the distance. a displacement sensor for measuring a span; a displacement sensor for long span measurement that is linked to the displacement sensor for short span measurement and measures the amount of displacement of the displacement sensor for short span measurement; and a predetermined displacement sensor generated by the displacement sensor for short span measurement. servo control means for servo-controlling the actuator by determining a deviation between a target signal preset in response to a level signal and a signal generated by the short-span measurement displacement sensor; It is characterized by comprising an adding means for adding the generated signal and the signal generated by the long span measurement displacement sensor, and measuring the amount of dynamic displacement of the object to be measured based on the output signal of the adding means. Dynamic displacement measuring device.