JPS5861470A - Arithmetic device for accelerated and decelerated speeds - Google Patents

Abstract

PURPOSE:To detect accelerated and decelerated speeds in all speed regions from low to high speeds with high accuracy in an arithmetic device for accelerated and decelerated speeds, which operates accelerated and delcerated speeds from the change in the periods of the output pulse of a speed sensor. CONSTITUTION:A titled device is so arranged that the number No for creating the pulse intervals to be calculated in order to execute the operations of accelerated and decelerated speeds without executing said operations until the intervals T1 of the pulses from a wheel speed sensor exceed the prescribed value T0 at which the operations of the accelerated and decelerated speeds are possible and that only when the pulse intervals exceed the value T0 the operations of the accelerated and decelerated speeds are executed. Thus when the intervals of the pulses generated by the wheel speed sensor in the storage of high speeds are extremely short, the pulse intervals are below the value T0; therefore the operations of the accelerated and decelerated speeds for each pulse are not executed and the operations of the accelerated and decelerated speeds are executed only when the number of the pulses giving the pulse intervals generating the periodic differences when the operations of the accelerated and decelerated speeds are possible exceeds the value T0. As a result, the arithmetic processing time for the accelerated and decelerated speeds in the stage of high speeds remain above the detected intervals of the pulses, whereby the errors in the operations of the accelerated and decelerated speeds by the reduction in the pulse intervals occurring in an increase in the speed are considerably reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acceleration/deceleration calculation device that calculates acceleration/deceleration from periodic changes in output pulses of a speed sensor.

As shown in the operation flow f, -r-) of FIG. 1 and the time chart of FIG.
Clock count values A, , B, in the counter when pulse P is output at 1"m.

C3 and the interval between these pulses, i.e. the period T
m, period difference from Tm +* (Tm −) − ITts
), i.e. ((Ct −Bl )−(Bl −A
t')) is a predetermined value (where N is the number of cycles, N
= 2) to find the acceleration/deceleration α, while the value of ((C8-Bl)-(Bl-AI)) is the predetermined value S.
When the value is less than , the count values B, , C, are reset and two pulses P are outputted in the above mode 102 times at time 1. ．． 14 clock count values B,,C, and similarly ((C! Byi) (Bt-At)
) value (however, A.

= A, ) is larger or smaller than a predetermined value 8,
If it is thicker than S, calculate the acceleration/deceleration α by substituting A, B, C, into the α) equation, and if it is smaller than S, shift to mode 8, and even if it finally reaches mode 4, the period will not change. When the difference is smaller than the predetermined value S, the acceleration/deceleration is α.

proposed a method in which the mode is set to zero and returns to mode 1 (Japanese Patent Application No. 55-2148).

According to such an acceleration/deceleration calculation method, even if the period of the pulse P becomes short at high speed and a speed change occurs such that a period difference cannot be extracted in mode 1, the higher-order modes 2 and 8 are sequentially applied. ．． The count value corresponds to the period difference that shifts to ... and exceeds the predetermined value of 8.

Since the calculation of acceleration/deceleration is performed when Ba and C- are obtained, it is possible to detect acceleration/deceleration with high precision in all speed ranges from low speed to high speed.

By the way, in the above device, the number of cycles N for determining the pulse interval is set to N=1, 2.4.8 until the predetermined cycle difference S is obtained.
However, when this is used in a vehicle's anti-skid device, etc., as the vehicle speed increases, for example to 100/H, the pulse generation interval becomes shorter, so the predetermined cycle is increased. When the number of cycles N exceeds the difference S, the mode inevitably becomes a high-order mode, and the processing time required to calculate the acceleration/deceleration relative to the pulse generation interval becomes relatively long.

Therefore, if the acceleration/deceleration calculation processing time exceeds the pulse generation interval, the pulses generated during the calculation processing will be ignored, and the acceleration/deceleration calculation processing will be completed in time for the pulse generation interval. Therefore, there is a risk that accurate acceleration/deceleration cannot be detected.

The present invention has been made by focusing on the above-mentioned problem, and each time a pulse output from a speed sensor is input, the number of pulses is equal to the pulse interval of any number of pulse salts before the Mukuro Hals. In a device that calculates acceleration/deceleration based on each pulse interval when the difference from the pulse interval of the previous pulse salt exceeds a certain value, the pulse interval of the above-mentioned pulses is detected in order to improve calculation accuracy. When the detection interval is below the predetermined value, the number of pulses for detecting the pulse interval is increased until it exceeds the predetermined value, and when the detection interval exceeds the predetermined value, the detection interval is changed to the minimum pulse interval. It is an object of the present invention to solve the above problem by instructing the calculation of the acceleration/deceleration as described above.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 8 is a block diagram showing one embodiment of the present invention, which is applied to an anti-skid device for a vehicle.

First, to explain the configuration, 1 is a wheel speed sensor as a speed sensor that generates a number of pulses proportional to the rotation of the wheel;
2 detects the pulse interval) from the wheel speed sensor l based on the number N of pulses. The pulse interval calculation unit 4) compares the interval detection value Tf1 from the pulse interval calculation unit 8 with a predetermined value TO, and when T11<To, sets the value of the number of pulses N for the pulse prescaler 2 to N= 2.4.8, and when T, )T, the detected value T of the pulse interval at that time is used as the minimum pulse interval to calculate the acceleration/deceleration. Incidentally, the acceleration/deceleration calculation in the comparison calculation section 4 is performed by a method already proposed by the inventors of the present application, as shown in FIG. 1.2.

Here, the predetermined value T set in the comparison calculation section 4.

To clarify, the value of the predetermined value T6 is determined according to the error due to the accuracy of the wheel speed sensor that generates the pulse.

That is, as shown in FIG. 4, the period given by the pulse interval of N pulses is T1. T, and 1 layer.

Assuming that the average speed due to T2 is V,,V,, the acceleration/deceleration α is given by the following equation.

2・ However, it is assumed that ΔT'=T, -T, and T in T1.

Here, the period difference ΔT and the error T@ due to the accuracy of the wheel speed sensor are as follows: ΔT≧T・・・・・・・・・・
Reliable α is calculated only after the relationship (8) is satisfied.

The error T due to this sensor accuracy is Ru.

Therefore, from the above-mentioned (2), (8), (→ formula, however,
k'=,=ni-ni'.

From this equation (5), the period T is as follows, and T cannot be less than the minimum value on the right side of equation (6). In other words, even if the acceleration/deceleration α is calculated using T that is less than the minimum value on the right side, the calculation error is extremely large and cannot be used as a detected value.

On the other hand, the maximum value αm of acceleration/deceleration α predicted when the vehicle is running
Since the value of aX is known in advance, by substituting the predetermined value αmJ1x into the left side of equation (6), it is sufficient to set it as the predetermined value To of the comparison calculation unit 4 in FIG.

Next, the operation of the present invention will be described in the flowchart of FIG.
This will be explained with reference to the time chart shown in the figure.

First, at the beginning of the calculation, N from the comparison calculation section 4 is N-1, and the pulse prescaler 2 outputs the pulse from the wheel speed sensor 1 as it is. A pulse is output from the wheel speed sensor 1, and at time t, 2
The visible pulse is sent to the pulse interval calculating section 8 as a pulse grid scale.
22, the pulse interval T is measured.

That is, as shown in block 5.6.7 of FIG. 5, the pulse interval T is measured at time t1, and N
The pulse interval T is calculated by calculating . The nox interval (NXTI) calculated by the nox interval calculation unit 8 is compared with a predetermined value T in the comparison calculation unit 4 as shown in the determination block 8, and when it is less than the predetermined value T0, Proceeding to block 9, N is set as 2N, and the determination block 8 again compares the magnitude relationship with the predetermined value TO.

At this time, if the value of the pulse interval (which was doubled in block 9) exceeds the predetermined value To, the process proceeds to block 10, where N=N0, and the comparison calculation unit 4 uses the N determined in block 10 as a pulse prescaler. Set to 2.

For this reason, the pulse scale scale 22 outputs pulses from the wheel speed sensor l thinned out according to N set by the comparison calculation unit 4. For example, if the time '*m in FIG.
'Output the Norx signal at timing l, and at this time'
! Based on the pulse given at the timing of +'3, the pulse interval calculation section 8&1 measures each of the pulse intervals T1+Tl' and inputs them to the comparison calculation section 4. The comparison calculation section 4 calculates the absolute value of the difference between the pulse interval detection values T, , T, and ' from the Norms interval calculation section 8, and calculates this difference between the pulse intervals as It is determined whether it is thicker or smaller than the value S, and if it is less than a predetermined value S, a value obtained by doubling N=, =N0 obtained in block 10 in FIG. 5 is set in the pulse scaler 2. For this reason, the pulse prescaler 2 thins out the pulses from the wheel speed sensor l so as to generate pulses at timings 1s and 14 in FIG. Pass/'pass interval'r,.

T! ' are measured and output to the comparison calculation section 4.

The absolute value ITm of the difference between this pulse interval Ta * Tl'
If Ts'l exceeds the predetermined value S, an acceleration/deceleration calculation command is issued in the comparison calculation section 4, and the
1) Execute the calculation shown in the formula and output acceleration/deceleration.

When this acceleration/deceleration calculation is completed, N from the comparison calculation section 4 becomes N=l, returns to the initial state again, and becomes K so that the above operation is repeated.

The calculation of acceleration/deceleration in the comparison calculation section 4 is as follows: 1.
Block 11 in FIG. Determination block 12. Proc 1
As shown in B, 14 and block 15, first, Tk and 'rx are measured in block 11, and in block 12, the absolute value ITm-T-1 of the difference is compared with 8, and if it is less than S, the block Proceed to 1B, double the value of N, set k: k + 1 in block 14, and return to block 11.
So the pulse interval Th+t, T? Forget +x, block 1
When the absolute value of the difference in pulse intervals exceeds the predetermined value S in step 2, the process proceeds to block 15 to calculate the acceleration/deceleration α, and then returns to block 5.

In this way, in the acceleration/deceleration calculation of the present invention, the acceleration/deceleration calculation is not performed until the pulse interval from the wheel speed sensor exceeds the predetermined value To that enables the acceleration/deceleration calculation. The number used to create the pulse interval calculated to perform the calculation is increased sequentially, and the acceleration/deceleration calculation is performed only when the pulse interval exceeds the predetermined value TO. When the interval between the generated pulses is very short, K is the period difference that makes it possible to calculate the acceleration/deceleration without calculating the acceleration/deceleration for each pulse because the Norls separation is less than or equal to the predetermined value T. Acceleration/deceleration calculations are only executed when the number of pulses that gives the pulse interval that produces .
Even at high speeds, the calculation processing time for acceleration/deceleration never falls below the pulse detection interval, and errors in calculation of acceleration/deceleration due to shorter pulse intervals due to increased speed are significantly reduced.

As explained above, according to the present invention, each time a pulse output from a speed sensor is input, the pulse interval of an arbitrary number of pulse salts before the pulse and the same number of pulse salts before the pulse are input. In a device that calculates acceleration/deceleration based on each pulse interval when the difference from the pulse interval exceeds a certain value, when calculating acceleration/deceleration, the pulse interval is first detected, and the detected interval is less than or equal to a predetermined value. At this time, the number of pulses for detecting the pulse interval is increased until it exceeds the predetermined value, and when the detection interval exceeds the predetermined value, the detection interval is set as the minimum pulse interval and the calculation of acceleration/deceleration is commanded. Since the pulse interval is very short (acceleration and deceleration can be calculated even at high speeds), acceleration and deceleration calculations are not performed until the pulse interval detection value is obtained. Since the acceleration/deceleration calculation command is issued only after the possible pulse interval has been detected, the acceleration/deceleration calculation processing time can be used even if the corner between pulse occurrences is short. Therefore, it is possible to calculate acceleration/deceleration with high precision in all speed ranges from low to high speeds. It will be done.

[Brief explanation of the drawing]

Figure 1 is an operation flowchart showing the Calo deceleration calculation method proposed by the inventors of the present application, and Figure 2 shows an example of (Russ interval Q) #! in the calculation method of Figure 1. Fig. 8 & End is a block diagram showing an embodiment of the present invention; Fig. 4 is a time chart used to determine the predetermined value T0 for determining the magnitude of the pulse interval; Figure 5 is a flowchart showing the operation of the present invention σ], and Figure 6 is a time chart showing an example of pulse interval detection according to the present invention. l... Wheel speed sensor 2... No. Pulse prescaler 8...Pulse interval calculation section 4...Comparison calculation section Patent applicant: Nissan Motor Co., Ltd. Representative Patent Attorney Hiroshi Tsuchihashi

Claims (1)

[Claims] Every time a pulse output from the speed controller is input, the pulse interval up to an arbitrary number of pulses before the input pulse, and the pulse interval up to the same number of pulses before the input pulse. When the difference exceeds a certain value, the device that calculates acceleration/deceleration based on the above-mentioned pulse intervals detects the pulse interval of each of the above-mentioned pulses, and when the detection interval is less than a predetermined value, the above-mentioned predetermined value is calculated. The adjustment method is characterized in that the number of pulses for detecting the pulse interval is increased until the pulse interval exceeds the predetermined value, and when the detection interval exceeds the predetermined value, the calculation command means is provided for instructing the calculation with the detection interval as the minimum pulse interval. Speed calculation device.