KR0131310B1 - Speed calculation method for a vehicle - Google Patents

Abstract

Since the period of pulses applied for a given time is calculated on average, it is possible to calculate the speed of the vehicle according to the pulse signal applied quickly and accurately without being affected by noise. Computing the wheel speed by using the counted pulse number output from the unit, and setting the state flag value: Detecting the application time of the pulse signal output from the speed detection unit, the pulse signal is applied within the minimum set time Calculating a driving speed of the vehicle by using the far speed value calculated in all sections and the wheel speed value calculated above; Calculating a current wheel speed by using the wheel speed calculated for all the sections when the application time of the pulse signal output from the speed detection unit is applied between the minimum setting time and the maximum setting time; Setting the wheel speed of the vehicle to zero when the application time of the pulse signal output from the speed detection unit exceeds the maximum setting time; Determining whether the state of the calculated wheel speed is actually a wheel speed of a vehicle that can occur; If a speed at which the calculated wheel speed cannot actually occur is calculated, determining whether it has been calculated twice consecutively; When a speed at which the calculated wheel speed cannot actually occur is calculated for the first time, correcting a value of the current wheel speed close to the wheel speed calculated in all the sections, and calculating the current wheel speed; In the case where the speed that the calculated wheel speed cannot actually occur is calculated twice in succession, the currently calculated wheel speed is determined as the normal state, and the average value with the calculated wheel speed in all sections is calculated as the current wheel speed. Consists of more.

Description

How to calculate car speed

1 is a block diagram of a vehicle speed calculating apparatus according to an embodiment of the present invention,

2 is an operation flowchart of a speed calculator according to an embodiment of the present invention.

3 is an operation flowchart of a time measuring unit according to an embodiment of the present invention.

The present invention is a method for calculating the driving speed of a vehicle using a signal output from the vehicle speed sensor, in particular, the speed is calculated by checking the period of the pulse to calculate the speed and averages the speed proportional to the speed to calculate the speed The present invention relates to a vehicle speed calculation method.

In the method of detecting the speed of the vehicle, the speed of the vehicle is calculated by checking a pulse signal proportional to the rotational speed of the wheel of the vehicle output from the mounted sensing device to detect the vehicle speed.

The method used to calculate the speed of the vehicle as described above is a counting method for calculating the speed of the vehicle by counting the number of pulses applied within a predetermined time, and calculating the speed of the vehicle by calculating the period of the applied pulse signal The periodic calculation method is used.

The counting method calculates the speed by counting the number of pulses applied within a predetermined time, so it is easily compatible with other processing devices without being affected by the noise problem caused by processing signals at a certain time interval. It takes a lot of calculation time depending on the number of pulses to be applied, which can cause a rapid process, which causes problems.

In addition, the periodic calculation method calculates the speed by calculating the period each time a pulse signal is applied, and the processing time is very short, but very weak to noise, so it is possible to process wrong information due to noise, and the applied pulse time is applied to the speed. Since the operation time is also changed, it is not compatible with other devices, and in order to minimize the influence of noise, the detection device is very precise so that the accurate pulse can be output from the speed detection device that detects the rotational speed of the automobile wheel. The manufacturing process is very strict as it must be configured correctly.

Therefore, an object of the present invention is to solve the above-mentioned problems, and calculates the average period of the pulse applied for a given time constant, so that the speed of the vehicle according to the pulse signal applied quickly and accurately without being affected by noise An object of the present invention is to provide a method of calculating a vehicle speed, which enables calculation.

According to one aspect of the present invention, there is provided a method including: setting a state flag value after calculating a wheel speed using a counted pulse number output from a speed detector for a given time when a set time is reached;

Detecting the application time of the pulse signal output from the speed detection unit, if the pulse signal is applied within the minimum set time step of calculating the driving speed of the vehicle using the wheel speed value calculated in all the zones and the wheel speed value calculated above Wow;

Calculating a current wheel speed by using the wheel speed calculated for all the sections when the application time of the pulse signal output from the speed detection unit is applied between the minimum setting time and the maximum setting time;

Setting the wheel speed of the vehicle to zero when the application time of the pulse signal output from the speed detection unit exceeds the maximum setting time;

Determining whether the calculated state of the wheel speed is actually a wheel speed of a vehicle that can occur;

If a speed at which the calculated wheel speed cannot actually occur is calculated, determining whether it has been calculated twice consecutively;

When a speed at which the calculated wheel speed cannot actually occur is calculated for the first time, correcting a value of the current wheel speed in proximity to the calculated wheel speed in all sections, and calculating the current wheel speed;

In the case where the calculated speed cannot be actually generated twice in succession, the currently calculated wheel speed is determined to be in a steady state, and the average value with the calculated wheel speed in all sections is calculated as the current wheel speed. It consists of more.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention;

1 is a block diagram of a vehicle speed calculating apparatus according to an embodiment of the present invention, FIG. 2 is an operation flowchart of a speed calculating unit according to an embodiment of the present invention, and FIG. 3 is an operation of the time measuring unit according to an embodiment of the present invention. Flowchart.

Referring to the configuration of the present invention with reference to FIG. 1, a speed detector 1, a time measurer 3 connected to the speed detector 1, and a speed connected to the time measurer 3 are described. It consists of a calculating part (2).

First, a pulse signal having a frequency proportional to the rotational speed of an automobile wheel is output from the speed detecting unit 1 and applied to the time measuring unit 3, and the time measuring unit 3 is input from the speed detecting unit 1. The start point of the pulse and associated data are generated and transmitted to the speed calculating section 2, and the speed calculating section 2 calculates the speed as the data input from the time measuring section 3 at regular intervals.

Referring to Figure 2 looks at the operation of the speed calculator 2 for calculating the vehicle speed.

First, in order to calculate the speed of the vehicle, the process proceeds from the start step 10 to the setting time determination step 20 and determines whether the counted time reaches an arbitrarily set time using an internal timer built in the speed calculating unit 2. do.

When the time counted sequentially by the internal timer in the setting time determination step 20 reaches the setting time, the process proceeds to the first operation step 30 for calculating the speed of the vehicle wheel.

In the first operation step 30, the counter value icnt at the last input point within the setting time of the previous step, the counter value fcnt at the last input point in the setting time, and the pulse applied for the set setting time. The wheel speed is calculated by reading the number NTR and using the equation given in the following equation (1).

Where NTR is the number of pulses applied,

icnt is the counting value at the start,

fcnt is the counting value at the end.)

Using the equation (1), the average period of the pulses applied for the given set time is calculated to calculate the speed of the rotating car wheels, so that the time measurement section 3 can recognize that the operation has been performed. In step 40, the state flag value is set to recognize that the wheel speed calculation operation is performed, and then the input pulse detection step 50 is reached.

If the speed of the vehicle is very slow, the frequency of the signal applied from the speed detector 1 is very small, so that a pulse signal having a period greater than the set time is output from the speed detector 1, There is a case where the wheel speed of the vehicle cannot be calculated because it is not input, and a problem arises in that the vehicle speed in all the sections must be used continuously.

Therefore, the purpose of counting the pulse application time by detecting the pulse applied in the input pulse detection step 50 is to calculate the speed of the vehicle more accurately when the speed is very low.

Therefore, after calculating the wheel speed of the vehicle according to the calculation formula in the first operation step 30 at the predetermined set time, if the pulse signal is applied within a predetermined time after the set time, the input pulse detection step 50 The process proceeds to the first average processing step 110 to calculate the speed of the car by taking the average value of the speed of the car calculated in the previous state and the wheel speed in the current state.

At this time, calculating the speed of the vehicle by using the average value of the two speeds is to reduce the influence of noise by correcting an error of calculation due to noise.

However, if the driving speed of the vehicle is very slow after calculating the wheel speed in the input pulse detection step 50 and there is no pulse signal detected within a predetermined time, the process proceeds to the comparison time judging step 60 and is applied after the set time. Compare the elapsed time that passes without the pulse signal with the set minimum set time.

When the elapsed time determined in the elapsed time comparison determination step 60 does not exceed the minimum set time, that is, when the pulse signal is input within the minimum set time, the process proceeds to the second operation step 80 (2). The wheel speed is calculated by the speed prediction method set in the equation.

Wheel speed = vehicle speed of all wheels-derivative of full wheel speed --------- (2).

Where the derivative of the front wheel speed is the derivative of the elapsed time from the calculated wheel speed in all states.

Therefore, it is possible to reduce the range of error due to the speed of the uncalculated portion.

However, if the elapsed time until the pulse signal is input is present between the minimum set time and the maximum set time, that is, if the pulse signal is applied within the maximum set time after the minimum set time has passed to the third operation step 90 Using the constant value already set according to the vehicle, the speed of the automobile wheel is calculated as in the following (3).

Wheel speed = vehicle speed in all wheels-constant ----------------- (3).

However, if the time elapsed without inputting the pulse signal exceeds the maximum set time, the process proceeds to the fourth operation step 100 and the wheel speed is calculated as 0, so that the vehicle is completely stopped.

Therefore, even when the vehicle is traveling at a very low speed as described above, by using a plurality of operation operations set for each situation, it is possible to more accurately approach the actual speed of the vehicle.

When the wheel speed is calculated by using the second to fourth calculation steps 80 to 100 set according to the driving conditions as described above, the process proceeds to the first average processing step 110 and at the speed and the count range of the car calculated in all the sections. The average value of the calculated wheel speed is calculated as the speed of the car.

In order to determine whether the vehicle speed calculated in the first average processing step 110 is a physically acceptable value, that is, a speed that can occur in an actual driving state, the process proceeds to the sealing occurrence determination step 120.

The calculation result is judged to be inaccurate when the difference between the speed calculation value and the difference between the speed calculation values is not physically understood due to problems such as noise generated during the calculation process of the vehicle speed. It will be corrected to a reasonable value.

Therefore, if it is determined that the vehicle speed calculated in the first average processing step 110 is an operation value that is a driving speed that is generally generated without departing from the range of the error set in the sealing generation determination step 120, the vehicle speed is returned to a normal state instead of a sealing state. Judgment is used as the speed value of the car.

However, if the sealing is out of the range of the error set in the determination step 120, that is, if the condition that can cause the sealing is passed to the sealing count determination step 130 to calculate the number of occurrences of the sealing.

Since it is less likely that an unreasonable operation value outside the set error range may occur twice in succession, when it is determined that the second sealing is performed in the sealing count determination step 130, the value calculated in the first average processing step 110 is a normal vehicle. It is regarded as a value corresponding to the speed, and the process proceeds to the second average processing step 150 to take the average value of the speed of the car calculated in all sections and the wheel speed obtained in the section and use it as the speed of the car.

However, if the number of seals generated in the sealing number determination step 130 is not the second consecutively, the first time is shifted to the sealing correction step 140, and the vehicle speed between the light bulbs and a predetermined error may be generated by using a predetermined formula. After calculating so as to correct the calculated speed of the vehicle, the process returns to the set time determination step 20 and repeats the above operation.

Next, an operation of the time measuring unit 3 for calculating data used when the speed calculating unit 2 calculates the speed of the vehicle as described above will be described with reference to FIG.

First, when a signal corresponding to a car wheel rotating in the speed detecting unit 1 is applied to the time measuring unit 3, the counting value icnt at the first start time, the counting value fcnt at the last end point, and the applied pulse are applied. In order to calculate the number NTR, the process proceeds to the flag state determining step 11 for checking whether the speed calculating operation is performed in the speed calculating section 2 in the starting step 31.

If the state flag is set in the flag state determination step 11, it means that the speed measurement unit 2 has used the speed calculation unit 3 using the data value previously calculated, and if the state flag is not set, the speed flag In the calculator 2, the time measurer 3 has not yet used the previously calculated data value.

Therefore, if the flag is set in the flag state determination step 11, the process proceeds to the flag clearing step 12 to clear the state flag value, and the process proceeds to the pulse number initial setting step 13 and the value of the number of pulses applied during the setting time (ntr). ) To 1

The process proceeds to the start time counting value setting step 14, and sets the counter value when the last pulse is applied to all the sections as the start time counter value icnt, and proceeds to the first error number correcting step 15. The number of over-overflowers is the number of times overflowing during the period of the pulse signal as long as a timer is built in the speed calculator 2 and operated with a predetermined bit.

Therefore, the number of times the timer is underflowered is counted each time a pulse is applied to the total counting value tcnt representing the total number of times the internal timer is over-flushed during the vehicle speed calculation operation. The counting number scnt automatically counted by the measurement unit 3 is stored.

Then, the process proceeds to the end point counter value setting step 18 and stores the counter value when the pulse is applied to the last end point counter value fcnt, and proceeds to the timer overflow initial screen step 19 to execute the timer during the period of one pulse. After initializing the counting value scnt of the overflow number to 0, the process proceeds to the flag state determining step 11 for a new pulse signal to be applied again.

If the state flag is not set, however, when a pulse is applied, the process proceeds to the pulse number increasing step 16, where the value of 1 is added to the value of the current pulse number NTR.

The total counting value ttcnt until all pulses are applied to the total counting value ttcnt that is overflushed and the new counting overflowed while the new pulse is applied Store the sum of (scnt).

Therefore, when the state flag is not set, that is, when the speed calculation unit 2 does not perform the speed calculation, the total number of overflows with the number of applied pulses NTR is corrected without correcting the starting counter value icnt. Only the counting value tcnt is corrected.

The process proceeds to the end point counter value setting step 18 and the timer overflow initializing step 19, sets the values in the same manner as described above, and returns to the flag state determining step 11 each time the pulse signal is applied. Repeat one action.

Therefore, the counter value (icnt) at the initial time, the counter value (fcnt) at the end point, the number of over-firers (tcnt) and the number of counters applied during the set time each time a pulse is applied according to the state of the flag in the same manner as described above. (NTR) is calculated so that the wheel speed of the car can be calculated.

Therefore, the effect of the present invention operating in the above manner is to calculate the speed by calculating the average period of the pulse applied for a predetermined time, it is very easy to link with other algorithms because the speed is calculated at a certain time, The speed calculation is faster than the counting method, and the speed is calculated by calculating the average period of several pulses to compensate for errors caused by noise.

And when the speed of the car is very slow and the calculation of the speed of the car is impossible due to the formula or the wrong calculation result is output due to noise, the new speed of the vehicle can be approximated with the actual speed. In order to increase the reliability of the user, it is possible to increase the accuracy of each system operation using the speed of the car.

Claims (4)

Calculating a wheel speed using the counted pulses output from the speed sensor for a given time when the set time is reached, and then setting a state flag value; Detecting the application time of the pulse signal output from the speed detection unit, if the pulse signal is applied within the minimum set time step of calculating the driving speed of the vehicle using the wheel speed value calculated in all the zones and the wheel speed value calculated above Wow; Calculating a current wheel speed by using the wheel speeds calculated during the whole period when an application time of the pulse signal output from the speed detection unit is applied between the minimum setting time and the maximum setting time; Setting the wheel speed of the vehicle to zero when the application time of the pulse signal output from the speed detection unit exceeds the maximum setting time; Determining whether the state of the calculated wheel speed is actually a wheel speed of a vehicle that can occur; If a speed at which the calculated wheel speed cannot actually occur is calculated, determining whether it has been calculated twice consecutively; When the speed at which the calculated wheel speed cannot actually occur is calculated for the first time, correcting the value of the current wheel speed in proximity to the calculated wheel speed in all sections, and calculating the current wheel speed; In the case where the calculated speed cannot be actually generated twice in succession, the currently calculated wheel speed is determined to be in a steady state, and the average value with the calculated wheel speed in all sections is calculated as the current wheel speed. Car speed calculation method, characterized in that further comprises. 2. The method of claim 1, wherein the method for calculating a variable value used to calculate a wheel speed of the vehicle comprises: determining whether a flag is set; Clearing the state of the flag if the flag is set, and substituting 1 for the pulse number NTR if a pulse is applied; Substitute the counting value of the timer when the last pulse is applied to the start counter value (icnt) and the overflowing counting value (sent) of the counter while the pulse is applied to the total overflow counting value (tcnt). Assigning a counting value when a pulse is applied to an end point counter value fcnt; Initializing the overprobe counting value scnt to 0 and returning to the first step for a new pulse signal; If the flag is not set, increasing the value of the pulse number NTR when a pulse is applied; After substituting the total overflow counting value (tcnt) plus the counter overflow counting value (scnt) as the new total overfloor counting value (tcnt), the counting value when the pulse is applied is counted as the end counter value ( fcnt); Vehicle speed calculation method comprising the step of initializing the value of the number of over-power (scnt) to 0 and back to the first step. The method of claim 1, wherein the following equation is used to calculate the wheel speed by using the number of pulses counted from the speed detector during the time period. Where NTR is the number of pulses applied, icnt is the counting value at the start, and fcnt is the counting value at the end.) According to claim 1, If the current wheel speed is calculated according to the application time of the pulse signal output from the speed sensor, further comprising the step of calculating the average value with the wheel speed calculated in the entire section as the current wheel speed Car speed calculation method characterized in that.