JP3134570B2 - Method of correcting origin of moving amount detecting device and moving amount detecting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for correcting the origin of a moving amount detecting device and a moving amount detecting device.
A movement amount detection device for measuring a movement amount of an object that performs one-dimensional movement such as a brake pedal of an automobile, and an origin correction method that can measure the movement amount immediately after the object starts moving, and executing the method. And a moving amount detecting device.

[0002]

2. Description of the Related Art Conventionally, there has been provided a movement amount detecting device for measuring a movement amount of an object performing one-dimensional movement. This kind of moving amount detecting device detects the moving amount of an object by a moving amount sensor such as a differential transformer, and outputs the detected moving amount as an electric signal such as a voltage.

[0003] In the above-mentioned movement amount sensor, even though the object has not started to move, the elapse of time has occurred due to an error at the time of attachment, a change in electric output due to the influence of temperature drift, gain, and the like. , The detected movement amount may fluctuate. Therefore, in this type of movement amount detection device, it is necessary to perform origin correction for the fluctuation of the detection movement amount caused by the temperature drift and the like.

In this case, if there is a switch for switching on / off depending on whether or not the object whose movement amount is to be detected is at the initial position (object origin position), the origin can be easily corrected. However, in reality, it is difficult to adjust the position of the switch means (switch position) so as to coincide with the object origin position. In particular, if the switch position is set on the opposite side to the object moving direction with respect to the object origin position, the switch means is always on or always off, and there is no point in providing the switch means.

[0005] Therefore, in this type of movement amount detection device,
The switch position is set at a predetermined interval from the object origin position in the moving direction of the object, and the origin correction is performed using the detected movement amount when the object passes through the switch position as the origin correction amount.

[0006]

However, in the above method, the origin correction amount cannot be obtained unless the object passes through the switch position. However, there is a disadvantage that the origin cannot be corrected and the moving amount of the object cannot be measured.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem in the movement amount detecting device. Even when an object exists between the object origin position and the switch position, the origin correction amount can be reduced. It is intended to be able to measure the amount of movement as soon as the object starts moving.

[0008]

SUMMARY OF THE INVENTION Therefore, the present invention provides a detection movement amount X which is a movement amount of an object detected by a movement amount sensor.
And an origin correction amount XO, wherein the difference Y (Y = X−XO) is regarded as a true movement amount of the object, wherein the object moves from the origin position of the object to the moving direction of the object. A switch means for detecting that the object has passed through a switch position set at a predetermined distance, and before the object passes through the switch position, the origin correction amount XO is set to a predetermined following speed with respect to the detected movement amount X. A moving amount detecting device, wherein after the object has passed the switch position, the origin correction amount XO is held at the original point correction amount XO at the time when the object passed the switch position. Is provided.

More specifically, the present invention relates to the origin correction amount X
The _{O, XO n = XO n-} 1 + (X n -XO n-1) / k (XO n is the origin correction amount in control operation period of time, X
O _{n -1} is calculated from the origin correction amount in the previous control operation cycle, X _n is the detected movement amount in the current control operation cycle), and the constant k in the above equation is determined by the following speed of the origin correction amount XO. In a range of k> 1 such that the speed follows a gradual change in the detected movement amount X due to the influence of temperature or the like on the amount sensor, but does not follow a rapid change in the detected movement amount X due to the movement of the object. To set.

Further, the present invention provides a moving amount sensor for detecting a detected moving amount X of an object whose sensor origin position is set in a direction opposite to the moving direction of the moving object from the origin position of the object, A switch means for detecting that the vehicle has passed a switch position set at a predetermined distance in the movement direction of the object from the origin position of the object, and arithmetic processing means connected to the movement amount sensor and the switch means; There prior to passing through the switch position, origin correction values XO of _{XO n = XO n-1 +} (X n -XO n-1) / k (XO n is the origin correction amount in control operation period of time, X
On _-1 is obtained from an equation of origin correction amount in the previous control operation cycle, and _Xn is obtained from an equation (detected movement amount in the current control operation cycle). K so as to follow the detected movement amount X at a following speed that does not follow a gradual change in the detected movement amount X due to the influence of temperature or the like but does not follow a sudden change in the detected movement amount X due to the movement of the object. > 1 range,
After the object has passed the switch position, the origin correction amount X
Movement O is held at the origin correction amount XO when the object passes through the switch position, and the difference Y (Y = X-XO) between the detected movement amount X and the origin correction amount XO is regarded as the true movement amount of the object. A quantity detecting device is provided.

[0011]

In the origin correction method of the movement amount detecting device according to the present invention, before the object passes through the switch position set at a predetermined distance from the origin position as described above, the origin correction amount depends on the influence of temperature or the like. Following the change in the detected movement amount,
Following the detected movement amount at a speed that does not follow the change in the detected movement amount due to the movement of the object, change the detected movement amount, and after passing the switch position, keep the origin correction amount at a constant value without changing it Therefore, the origin correction amount is obtained before the object passes through the switch position, and the corrected movement amount is obtained from the time when the object starts moving.

[0012]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. Movement detection device 1 shown in FIG.
Is an application of the origin correction method according to the present invention to the measurement of the amount of depression of a brake pedal 2 of an automobile brake.

The brake has a well-known structure, in which a lever 7 is connected to a rod 6 connected to a piston 5 which slides in a master cylinder 4, and a brake pedal 2 attached to the tip of the lever 7 is used. When the driver steps, the piston 5 moves to the right side (plus side) in the figure according to the amount of stepping.
Go to

The moving amount detecting device 1 includes a moving amount sensor 10, switch means 11, and arithmetic processing means 12.

The moving amount sensor 10 is, for example, a known differential transformer type moving amount sensor. When the rod 6, which is the object of the moving amount detection, moves to the plus side, the moving amount sensor 10 is proportional to the moving amount. The output voltage is output. The object to be detected for the movement amount is not limited to the rod 6, but the piston 5 and the lever 7 that move together with the rod 6 by the movement amount sensor 10.
May be measured.

The object, that is, the rod 6, is located on the leftmost side (minus side) in the state shown in FIG. 1, and is in the initial position where it cannot move further to the minus side. As shown in FIG. 2, the sensor origin position O, which is the measurable limit of the movement amount sensor 10, is set at a predetermined distance to the minus side from the initial position of the rod 6 (object origin position S). is there.

The detected movement amount X when the rod 6 is at the object origin position S, that is, the measured value of the object origin position S as viewed from the sensor origin position O is determined by the influence of mounting accuracy, temperature drift, gain, and the like. Although it may fluctuate over time, the sensor origin position O needs to be set so that at least the object origin position S can always be measured.

The switch means 11 is a switch for turning on and off a stop lamp (not shown). When the driver depresses the brake pedal 2 by a predetermined amount and the rod 6 passes the switch position W set from the object origin position S to the plus side at a predetermined distance from the minus side toward the plus side, the switch means 11 is turned on. Turns on. On the other hand, the switch means 11 is turned off when the rod 6 passes the switch position W from the plus side to the minus side. Distance between object origin position S and switch position W (switch detection movement amount)
Is guaranteed to be smaller than a certain set error limit value, but the actual value cannot be measured by the movement amount detection device 1. The switch means 11 is not limited to the stop lamp lighting changeover switch, but may be an object (see FIG. 1).
Then, any rod that can detect that the rod 6) has passed the switch position W may be used.

The arithmetic processing means 12 is composed of a microcomputer, and is connected to the movement amount sensor 10 to receive the detected movement amount X and to input the detected movement amount X.
And a switch signal SW indicating whether the switch means 11 is in the on state or the off state is inputted, and based on these, the origin correction of the movement amount detection device 1 is performed as described below.

That is, the arithmetic processing means 12 executes the processing shown in FIG. 3 at a predetermined control arithmetic cycle at the same time that the ignition switch (not shown) of the automobile is turned on and the moving amount detecting device 1 is connected to the power supply. Perform each time. In FIG. 3, the subscript n indicates the number of control operation cycles.

First, in step # 1, the detected movement amount X _n output by the movement amount sensor 10 to the arithmetic processing means 12
Read. Next, in step # 2, the switch signal SW is read from the switch unit 11 into the arithmetic processing unit 12.

Subsequently, in step # 3, the switch signal SW is inspected. If the switch signal SW is not on, that is, if the rod 6 is located between the object origin position S and the switch position W, the process proceeds to step # 3. Shift to # 4.

[0023] In step # 4, and calculates an origin correction amount XO _n from the following equation (1).

[0024] _{XO n = XO n-1 +} (X n -XO n-1) / k (1)

The above formula (1) is a formula for performing a so-called exponential filter operation, origin correction amount XO _n calculated by the equation (1) changes to follow the detected amount of movement X _n.

In the above equation (1), the origin correction amount X
Rate O _n to follow the detected movement amount X _n (following speed) is determined by the constant k. This constant k is set in the range of k> 1, while the origin correction amount XO _n varies more sensitive to change in the detected movement amount Xn faster the following speed as constant k is small, the larger the constant k The following speed becomes slower, and it responds more gently to a change in the detected movement amount _Xn .

The temporal variation of the detected movement amount _Xn due to the temperature drift, the gain, and the like is relatively slow, but the rod 6 actually moves when the driver steps on the brake pedal 2. The change speed of the detected movement amount _Xn due to this is rapid. In this embodiment, the origin correction amount XO
_n is the detected movement amount X _n for the temperature drift, gain, etc.
The above constant is set so as to follow the detected movement amount _Xn at such a slow speed that it cannot follow the change in the detected movement amount _Xn due to the actual movement of the rod 6. Set k.

[0028] In step # 5, the output was detected moving amount X _n of origin compensation amount XO _n and moving amount sensor 10 calculated in step # 4, obtaining a correction moving amount Y _n from the following equation (2). At this time, the detected movement amount X _n and the origin correction amount XO
The relationship between _n and the movement correction amount Y _n shown in FIG.

[0029] _{Y n = X n -XO n (} 2)

In this embodiment, when the switch means 11 is turned off as described above, that is, before the rod 6 passes the switch position W, the detected movement amount _Xn is calculated by the above-mentioned equation (1) due to temperature drift or the like. since the set origin compensation amount XO _n following the temporal change, the rod 6 is the switch position W
It is possible to obtain a corrected movement amount Y _n plus origin correction previously passing on the detected movement amount X _n of the rod 6.

On the other hand, if the switch signal SW is ON in step # 3, that is, if the rod 6 has passed the switch position W, in step # 6,
Correcting the origin position XO _n and hold the corrected home position XO _n-1 in the control operation period of the previous seek correction moving amount Y _n by the above formula (2) in step # 5.

[0032] That is, after the rod 6 has passed the switch position W in the present embodiment maintains an origin correction amount XO _n at the time when the switch means 11 is turned on, performs the origin correction using this value.

[0033] Since the rod 6 as described above, after passing through the switch position W, origin correction amount XO _n is the value of the time the switch means 11 is turned on is maintained, origin correction amount XO _n
Is the detected movement amount X _n when the rod 6 is located at the switch position W, that is, the sensor origin position O and the switch position W
It cannot be longer than the distance between.

[0034] In this embodiment, even when the object as described above is present between the object home position S and the switch position W, it is possible to obtain a correction moving amount Y _n, the driver of the brake pedal 2 depression Immediately after starting, the amount of depression can be known.

Although not shown in FIG. 3, the origin correction amount XO after turning on the ignition switch is set.
The initialization of the value of _n is performed, for example, as follows.

First, it is set to "1" when the ignition switch is turned on, and is set to "0" when initialization is completed.
Is provided (first flag first). The detected movement amount Xn shown in steps # 1 and # 2 in FIG.
After reading the switch signal SWn, the first flag first is detected. When the first flag first is "0", since the initialization has already been completed, the steps # 3 to # 3 in FIG. The process shown in # 6 is performed.

On the other hand, when the first flag first is "1", the switch signal SW is checked, and when the first flag first is off, the origin correction amount XOn is set to the detected movement amount Xn, initialization is performed, and the first flag first is set to "1". 0 ".

When the initial flag first is "1" and the switch signal SWn is on, initialization is not performed, and the value of the origin correction amount XOn is set to the detected movement amount Xn or the detection movement amount Xn when the rod 6 is at the object initial position S. It is set to the sensor origin position O, and in this case, the initial flag remains “1”.

That is, in the above example, when the ignition switch is turned on, the origin correction amount XOn is not initialized if the switch is on, and the origin is corrected when the switch is turned off.

The present invention is not limited to the above embodiment, and various modifications are possible. Set the constant k to a value in the above formula (1), if the origin correction amount XO _n tried to follow gently the detection movement amount X _n, the second term on the right side value of the formula (1) , i.e., for _{(X n -XO n-1)} / number of digits k increases, it is necessary to increase the number of significant digits origin compensation amount XO _n in order to prevent cancellation. In this case, the origin correction amount XO
If disadvantageous a large number of significant digits _n, performed once every one of the control operation period a plurality of times to calculate the origin correction amount XO _n by the above formula (1), control operation period of the plurality of times Of the remaining control calculation cycles, the origin correction amount XOn _-1 of the previous control calculation cycle may be held.

Further, origin correction amount XO _n between the rod 6 is present in the switch position W from the object home position S is not always necessary to calculate the above equation (1), the origin correction amount XO _n, temperature drift while to follow for change in the detected amount of movement X _n by like may be determined in such a way as not to follow the relative change in the detected amount of movement X _n by reality the rod 6 is moved.

[0042]

As is apparent from the above description, in the method of correcting the origin of the moving amount detecting apparatus according to the present invention, before the object passes through the switch position, the detected moving amount caused by temperature drift, gain, and the like is reduced. The object follows the change, but does not follow the change in the detected movement amount due to the actual movement of the object.The origin correction amount changes at a gentle speed following the detected movement amount. Even when the position is between the switch position and the switch position, the origin can be corrected and a corrected movement amount can be obtained.

Therefore, for example, when the origin correction method according to the present invention is applied to a movement amount detecting device for detecting an amount of depression of a brake pedal of an automobile, the pedal is immediately started when the driver starts to depress the brake pedal. You can know the amount of depression.

[0044] In the present invention, in order to follow the detected amount of movement correction movement amount as described _{above, XO n = XO n-1} +
When the origin correction amount is set by the equation ( _Xn- XOn _-1 ) / k, a desired following speed can be obtained by appropriately setting the value of the constant k.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a movement amount detection device that performs an origin correction method according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a relationship among an origin position, an object initial position, and a switch position of the movement amount sensor of FIG. 1;

FIG. 3 is a flowchart illustrating an origin correction method according to an embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 movement amount detection device 2 brake pedal 4 master cylinder 5 piston 10 movement amount sensor 11 switch means 12 arithmetic processing means X detection movement amount XO origin correction amount Y correction movement amount O sensor origin position S object origin position W switch position

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-7630 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01B 21/00-21/32 B60T 7 / 02

Claims (2)

(57) [Claims] 1. A difference Y (Y = X−) between a detected movement amount X, which is a movement amount of an object detected by a movement amount sensor, and an origin correction amount XO.
XO) is a method of correcting the origin of a movement amount detecting device that regards the movement amount of the object as a true movement amount, wherein the object passes through a switch position set at a certain distance from the origin position of the object in the moving direction of the object. and a switch means for detecting that was, previous to the object passes through the switch position, the origin correction amount _{XO, XO n = XO n-} 1 + (X n + XO n-1) / k (XO n this time X in the control calculation cycle of X
O _n-1 is obtained from the following equation: X _n is the amount of origin correction in the previous control operation cycle, X _n is the detected movement amount in the current control operation cycle, and the constant k in the above equation is the following speed of the origin correction amount XO. K> 1 so that the speed can follow a gradual change in the detected movement amount X due to the influence of temperature or the like on the movement amount sensor, but not follow a rapid change in the detected movement amount X due to the movement of the object. After the object passes through the switch position, the origin correction amount X
A method of correcting an origin of a movement amount detecting device, wherein O is held at an origin correction amount XO at the time when an object passes a switch position. 2. A movement amount sensor for detecting a detected movement amount X of an object whose sensor origin position is set in a direction opposite to the moving direction of the moving object from the origin position of the object, and wherein the object is located at the origin position of the object. Switch means for detecting that the object has passed a switch position set at a predetermined distance in the moving direction of the object, and arithmetic processing means connected to the movement amount sensor and the switch means; Before passing, the origin correction amount XO
_{The, XO n = XO n-1} + (X n + XO n-1) / k (XO n is the origin correction amount in control operation period of time, X
On _-1 is obtained from an equation of origin correction amount in the previous control operation cycle, and _Xn is obtained from an equation (detected movement amount in the current control operation cycle). K so as to follow the detected movement amount X at a following speed that does not follow a gradual change in the detected movement amount X due to the influence of temperature or the like but does not follow a sudden change in the detected movement amount X due to the movement of the object. After the object has passed the switch position, the origin correction amount X
Movement O is held at the origin correction amount XO when the object passes through the switch position, and the difference Y (Y = X-XO) between the detected movement amount X and the origin correction amount XO is regarded as the true movement amount of the object. Quantity detection device.