JPS6350730A - Car speed following filter device for on-vehicle measuring device - Google Patents

Abstract

PURPOSE:To remove noise according to a wide range of a car speed, by performing the follow adjustment of the band of a notch filter according to the running state of a vehicle. CONSTITUTION:The resetting of a counter 26 and the latching of a latch 28 are performed by a timing unit 34. Notch filters 54-60 are connected in series and an input signal is supplied to a filter 54 from an input terminal 52a and a signal wherein the primary band following the predetermined running state of a vehicle is removed as noise is outputted as a primary output signal from an output terminal 52b. In the same way, the output of the filter 54 is supplied to the filter 56 to be taken out as a secondary output signal from an output terminal 52c and ternary output is outputted from a terminal 52d through the filter 58. Band control signals are supplied to the band control input terminals of the filters 54-58 from the respective stages of a counter unit 24 and the band characteristics of the filters 54, 58 are adjusted by car speed following type band control and optimum noise removal according to the running state of the vehicle can be performed automatically.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is a vehicle speed tracking filter device for on-vehicle measuring instruments, in particular, a filter device with variable band characteristics such as a notch filter, which automatically adjusts the band characteristics according to the driving condition of the vehicle. This invention relates to an improvement of a filter device that changes the speed according to the vehicle speed.

[Prior art] In actual vehicle driving measurement tests, various H1 measuring instruments are mounted on the vehicle to collect data under actual vehicle driving conditions.
This test is extremely important because, unlike stationary tests, various unpredictable results can be obtained.

Such actual driving measurement tests are conducted for all kinds of items, and various types of Hil devices are prepared depending on the required test items, but all use electrical measuring means.

A major problem with this type of actual driving measurement test is that noise generated from various parts of the vehicle, especially rotating parts, mixes into the closed-side data during measurement, which is the main factor that significantly degrades the quality of the measurement data. . Such noise often arises from the driving conditions, especially the rotation of the vehicle tires, and in many cases, the noise generated from the rotation of the vehicle tires was often a nuisance during the second engine performance test, which is the subject of Test 1. .

Normally, in conventional noise removal, an electrical detection signal is sent to a processing circuit via a filter, and this filter is formed from a band elimination filter, that is, a notch filter, and the band to be removed is set in advance using a digital switch or the like. was.

Therefore, according to this conventional device, the noise frequency determined from the vehicle speed expected at the time of the test is set in advance as the band adjustment number 1g in the notch filter, and the noise that is affected by the driving condition is removed.

[Problems to be Solved by the Invention] However, in the conventional filter installation described above, it is necessary to adjust the band characteristics of the notch filter in advance (even if it is, the band is fixed for each test, so In order to determine the measured value of ``J■,'' the test driver must measure the vehicle speed while keeping it in line with the preset expected vehicle speed during the test drive, and the accelerator work for this is troublesome. There was also the problem that data collection under optimal conditions or while changing vehicle speed was slow.

In the past, several attempts have been made to adjust the band of the notch filter according to the vehicle speed - C tracking control ■1, but in the past, it has been difficult to realize such improvements, and it has been difficult to realize such improvements due to vehicle specifications such as tires. It has not been possible to obtain a device that can respond to changes in the effective radius or differential ratio, etc.

The present invention was made in view of the above-mentioned conventional problems, and its purpose is to install an improved filter that can remove noise in a wide range of vehicle speeds by adjusting the band of the notch filter according to the vehicle running condition. We are committed to providing this.

[Means for Solving the Problems] In order to achieve the above object, the present invention captures the width side running signal as a pulse signal, modulates this pulse signal at a predetermined interval for a certain period of time, and converts it into a band The present invention is characterized in that a sampling signal is output as an adjustment signal, the band adjustment signal is further supplied to an adjustment input of a notch filter, etc., and a band corresponding to the running state of the vehicle is set to follow at the sampling interval.

The driving state detection signal, for example, an electrical pulse signal detected according to tire rotation, can be arbitrarily corrected according to the tire diameter, differential ratio, etc., and the pulse signal can be used by a counter and a latch circuit to detect the driving state. Since the band adjustment signal according to the state is counted and held and outputted as a notch filter → thick filter, the notch filter has the advantage that its band characteristic can be arbitrarily adjusted according to the driving state of the vehicle.

[Embodiments] Preferred embodiments of the present invention will be explained below based on the drawings.

FIG. 1 shows a preferred embodiment of the filter installation according to the present invention, which can be used by connecting to any side equipment.

The running signal horn part 10 includes an input terminal 10a that detects the running state of the vehicle and receives it as an electrical input pulse. For example, it can receive an input signal that electrically detects the number of rotations of a tire. .

The signal input from the input terminal 10a is input to the input amplifier 1.
2, and is further outputted from the input section 10 through the register A multipliers 16, 18, and 20 connected in three stages via the changeover switch] 4 connected externally to the input section 10.

In the input section 10 in the embodiment, signal correction is performed by the ratio multipliers 16 to 22 connected in three stages,
For example, corrections are made in response to other changes such as tire diameter and differential ratio.

Said correction is actually applied to each ratio multiplier 16°, 18.
Measure the settings of the digital switch 22 connected to 20,
This initial correction is accomplished by selectively applying calibration pulses by means of the changeover switch 14.

The pulse signal output from the running signal input section 10 is
In the present invention, the counter unit 24 counts and outputs the sampled signal as a band adjustment signal.

In this embodiment, the counter unit 24 has a three-stage configuration in order to remove primary, secondary, and tertiary noise in the detected running state.
Each of the tertiary counter units is designated by reference numerals 24a and 24.
b and 24G, and the circuit configuration itself is the same, so in the following explanation, only the primary counter unit 24a will be explained, and the other units 24b and 24 will be explained.
Regarding C, it will be omitted.

The basic configuration of the counter unit 24 consists of a counter 26 and a latch 28 that holds its output.In the embodiment, the latch output is sent to a decoder for the operator to visually check or correct the band adjustment signal. It is displayed on an LED display 32 via 30.

As described above, the counter unit 24 counts the pulse signal from the running signal input section 10 for a certain period of time and outputs the pulse signal at a predetermined sampling period. A timing 1-34 is provided between the running signal input section 10 and the counter unit 24.

The timing unit 34 not only controls the counter unit 24 but also performs the initial calibration at the running signal input 8 [S]O, receives the reference frequency from the externally connected oscillator 36, and transmits the reference frequency to the frequency dividers 3B and 40. 10 Turn on the predetermined timing signal.

The calibration pulse in the running signal input section 10 is transmitted to the frequency divider 3.
8 to 1q, and this calibration pulse is applied to the changeover switch 1.
40 is supplied from the calibration terminal 148 to the terminal 14G, and the terminal 14G is connected to the running signal input section for correction measurement or for calibration by switching between the measurement terminal 14b supplied from the input non-amplifier 12 and the calibration terminal 14a. can output pulse signals.

On the other hand, the timing unit 34 outputs a timing signal from the frequency dividing jM 40 to the counter unit [~24].
First, the output of the frequency divider 40 is directly used as a gate pulse to pass through one input of the gate circuit 42 (J is applied, and during this gate time, the pulse signal that is the output of the running signal input section 10/) is passed. In the embodiment, this gate time is set to about 0.13 seconds, for example.

The output of the gate circuit 42 is directly supplied to the tertiary counter unit 24c as a counting input signal, and is also supplied to the divider 44.
For example, it is supplied to the input of the primary counter unit 24a as a signal divided into 1/3 via the divider 46, and is further supplied to the count input of the secondary counter 24b as a signal divided into 2/3 via the divider 46. Supplied.

As described above, each counter unit 24 counts the pulse signal input by its counter 26, and simultaneously counts this count value by the latch 28, but the reset and latching of both counters 26 and the notch 28 are not performed in the embodiment. This is done by a timing unit 34.

That is, the output of the frequency divider 40 is supplied from the reset circuit 48 to the reset input of each counter unit 24 via an inverter, and the contents of the counter 26 are reset at a predetermined sampling period. And the latch circuit 50
supplies a latch signal to the latch terminal of each counter unit 24 via an inverter, and the signal 3 latched by the latch circuit 28 is sampled and output as a band adjustment signal, and at the same time, the notched count value at this time is It is displayed on the display 32 via the decoder 30. As described above, the counter unit 24 can output a band adjustment signal according to the driving state of the vehicle at a predetermined sampling period.

The band adjustment signal is also supplied to a notch filter provided in the filter unit 52, and in the embodiment, the filter unit 52 includes three stages of notch filters 54 corresponding to the -order, second-order, and third-order counter units 1 to 3. ,56.
58, and further includes a low-pass filter 60 that does not follow the running state of the vehicle.

Each of the filters 54 to 60 is connected in series, and the input signal detected during the actual driving test is supplied to the filter 54 from the input terminal 52a, and the first-order band according to the predetermined vehicle driving condition jD is used for noise removal. The resulting signal is outputted from the output terminal 52b as -next output signal/3.

Further, the output t of the notch filter 54 is further supplied to the second stage notch filter 56, and a signal from which secondary noise has been removed is taken out as a secondary output signal from the output terminals 52c bX, and is further supplied to the notch filter 56. A tertiary output of the filter 58 is output from a terminal 52d.

Further, the low-pass filter 60 is set to the digital switch 6 in advance.
2, the frequency component determined by z2 is removed, and a signal is output from the output terminal 52e to the subsequent processing circuit.

A band adjustment signal from each stage/JX of the counter unit 24 is supplied to the band adjustment input of each of the notch filters 54 to 58. ? By adjusting A, the band characteristics of each notch filter 54, 56, 58 are strongly adjusted, and noise removal is automatically performed optimally according to the driving condition of the vehicle.

The embodiment of the present invention has the above-mentioned configuration, and will be described below.
Let's explain the effect of rotation (when removing commotion noise).

Assuming that the tire circumference of the sample vehicle is 1.9 (m>) and the maximum vehicle speed is 200 (km/h), the primary noise frequency generated from the tires can be obtained from the tire rotation speed,
In this case, the tire rotates approximately 29 t01 times per second, so 2
9(t-1z) is determined as the first factor wave number to be removed.

If the running state detector of the vehicle is a device that detects 60 pulses per rotation from the tires, the -order noise frequency 29 (t1z) is 29X as the frequency of the detection pulse.
It is determined that 60=1752 (day l).

The detection pulse has the gate time dimension in the embodiment, that is, 0.
．． The number of pulses captured in 13 seconds is 227.8 pulses.

Therefore, the primary input of the counter unit 24a is the passing pulse divided into ]/3, and approximately 75 becomes the band IO and adjustment signal of the primary counter unit 24a.

Here, in order to perform initial correction of the device, select switch 1
4, its terminal 14G is switched to the calibration terminal 14a,
A calibration pulse from timing unit 34 is sent to counter unit 24 .

In this device, the calibration pulse frequency is 1000 (Hz)
The band adjustment signal at this time (yo 1000/1
752x75=42.

Therefore, in this initial correction stage, correction is performed by the digital switch 22 so that "42" is displayed on the display 32 of the negative counter unit 24a, and this correction value is actually 24/42 - 0.690. As expected, the digital switch is operated by the operator so as to obtain the desired band adjustment signal.

When the calibration using the calibration frequency is completed as described above, the band l or adjustment signal of each filter is "29".
, "58" and "87".

Therefore, it is understood that if the selector switch 14 is switched to the measuring switch 14b in this state and a running test is started, the band frequency of each notch filter will automatically change to follow the change in the rotational speed of the tire. be done.

[Effects of the Invention] As explained above, according to the present invention, during an actual driving test of a vehicle, an arbitrary pulse detector is attached to the rotating part of the vehicle, and a pulse signal incremented by 1 is detected from this pulse detector. Since the band adjustment of the notch filter is automatically controlled according to the following, it is possible to remove noise generated from a desired rotating part up to an arbitrary order.

In addition, since the initial correction of the adjustment range is constant and easy, it is possible to perform optimal band adjustment in response to changes in vehicle types.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a preferred embodiment of a vehicle speed tracking filter device for an on-vehicle measuring instrument according to the present invention. DESCRIPTION OF SYMBOLS 10... Running signal input part, 10a... Running signal input terminal 24... Counter unit 34... Timing unit 52... Filter unit 54, 56, 58... Notch filter.

Claims (1)

[Claims] (1) A running signal input unit that electrically detects a running signal according to the running state of the vehicle and outputs it as a pulse signal, and counts the running signal for a predetermined period of time and converts the running state into a band adjustment signal at a predetermined sampling interval. A counter unit that performs sampling output, and a filter unit that can adjust band characteristics each time based on the band adjustment signal,
A vehicle speed tracking filter device for in-vehicle measuring instruments that can follow and change the band characteristics of the filter according to the vehicle's driving conditions.