JP2001047983A - Detector for detecting driver's foot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the moving of a driver's foot, and to allow constant use. SOLUTION: In this detector, a detection area E having a detection center R within an area surrounded by a lower end edge BL of a pad face 32 in an acceleration pedal 3, a left side edge line SL of the pad face 32, a longitudinal center line CL of the pad face 32, and a cabin floor is set in a vehicle with a brake pedal 4 juxtaposed in a left side of the acceleration pedal 3. It is determined that a driver D's foot 1 is positioned on the acceleration pedal 3, when a body exists within the detection area E.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foot detecting device of a driver in each system for detecting a motion of a foot of a driver of a vehicle (hereinafter referred to as a driver) and controlling a vehicle state based on a result of the detection. For example, in an emergency, a driver's foot detection device in a brake assist system or the like that automatically applies a braking force to decelerate the vehicle before the driver depresses a brake pedal, thereby reducing a stopping distance and improving avoidance ability. About.

[0002]

2. Description of the Related Art In recent years, research and development on a brake assist system for reducing a delay in braking effect has been advanced, and is disclosed, for example, in Japanese Patent Application Laid-Open No. 8-80822. The brake assist system detects the accelerator pedal return speed and foot movement, predicts that the driver will depress the brake pedal, and automatically brakes the vehicle or supports vehicle braking (hereinafter, referred to as “brake assist system”). Brake assist).

[0003] In a brake assist system, urgency is determined from the return speed of an accelerator pedal whose depression has been released and the moving speed of a foot that is going to switch from an accelerator pedal to a brake pedal. I do. Further, a driver's intention to step on the brake pedal (hereinafter referred to as a step change intention) is estimated from the positional relationship between the accelerator pedal and the foot, and the accuracy of the brake assist is ensured. As a result, it is possible to shorten the vehicle stopping distance and improve the avoidance ability, which is preferable in terms of safety.

The step change intention is estimated, for example, by detecting the positional relationship between the foot and the accelerator pedal, in particular, detecting that the foot has moved away from the accelerator pedal to some extent. Specifically, a contact-type sensor mounted on the accelerator pedal, a proximity sensor, an optical sensor, or the like, or a contact-type switch provided on the lower floor of the accelerator pedal detects that the foot has left the accelerator pedal to some extent. Was. That is, in the former, the movement of the foot with respect to the accelerator pedal is directly detected, and in the latter, whether the heel is on the floor of the vehicle compartment is detected or not, and the positional relationship between the foot and the accelerator pedal is detected.

[0005]

As described above, when the intention of stepping is estimated from the detection result using the contact type sensor or the proximity sensor, the estimated stepping intention and the driver actually release the brake pedal. It was easy to make a discrepancy with the intention to step. This is because contact sensors and proximity sensors have a narrow range for detecting an object, and if the foot is separated from the accelerator pedal more than necessary, the position of the foot can no longer be detected, making it difficult to determine the movement of the foot. Because it becomes. On the other hand, when the optical sensor is mounted on the accelerator pedal, it is susceptible to the effects of mud, dust, and the like, and its reliability remains questionable.

Further, in the method of detecting the position of the heel of the driver, there is a great difference between the places where the heel is placed, and depending on the person, the position of the heel is the same between when the brake pedal is pressed and when the accelerator pedal is pressed. There is also. In other words, the method of detecting the position of the heel of the driver cannot cope with the individual difference described above, and it is difficult to accurately estimate the intention to change steps. An object of the present invention is, for example, to solve the above-described problem, and to provide a driver's foot detection device that accurately detects movement of a driver's foot and enables constant use. With the goal.

[0007]

According to the present invention, there is provided a vehicle having a brake pedal arranged on the left side of an accelerator pedal, wherein a lower end edge of a pad surface of the accelerator pedal, A detection area having a detection center within a range surrounded by a left edge line, a vertical center line of the pad surface, and a vehicle cabin floor is set, and when an object is present in the detection area, the driver's foot is And a driver's foot detecting device, which determines that the driver's foot is on the accelerator pedal. ADVANTAGE OF THE INVENTION According to this invention, it can respond also to the individual difference of the position which puts a foot, and can detect and judge whether a foot is on an accelerator pedal accurately.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION
This will be specifically described with reference to the drawings. In this embodiment, a driver's foot detection device used in a brake assist system will be described as an example for convenience of explanation.
However, the driver's foot detection device according to the present invention is not limited to the case where the device is used for a brake assist system, but may be applied to various systems that control the vehicle state from the position of the driver's foot that operates the accelerator pedal. Can be used.

FIG. 1 is a schematic side view of a vehicle cabin showing a state in which a driver depresses an accelerator pedal, and also shows a configuration of a brake assist system. When the vehicle V is running, the driver D sitting in the driver's seat S
Normally, the accelerator pedal 3 is depressed with the right foot 1 (hereinafter referred to as a foot). Then, if necessary, the foot 1 is changed to a brake pedal to brake the running of the vehicle.

When a sudden danger occurs or an object to be avoided suddenly appears while the vehicle is running, the driver D applies a sudden brake to avoid the danger or the like. When such an emergency is required, the driver D needs to release the accelerator pedal 3 that has been depressed and immediately depress the brake pedal. However, stepping on the foot 1 of the driver D involves a certain time loss, and it is necessary to reduce this loss time as much as possible. The brake assist system BS is a system for reducing such a time loss and automatically braking and decelerating the vehicle V. First, the schematic configuration and operation of the brake assist system BS will be described. FIG. 2 is a flowchart showing the operation of the brake assist system BS.

As shown in FIG. 1, the brake assist system BS according to the present embodiment includes an accelerator pedal return speed detecting device 5 (hereinafter, referred to as an urgency detecting device 5), a brake control device 7, and a foot detecting device 2. . The urgency detection device 5 includes a detection unit and a determination unit. The detector detects the amount of rotational displacement per unit time of the pivotal support 31 that pivotally supports the accelerator pedal 3, and detects the return speed. When the accelerator pedal 3 that has been depressed attempts to return to a position in a no-load state, the direction of the pivot 31 that rotates is a positive return speed, and the opposite is a negative return speed. That is, when the return speed is positive, the depression of the accelerator pedal 3 is released, and when it is negative, the depression of the accelerator pedal 3 is increased.

As shown in FIG. 2, the determining unit determines the urgency based on the result detected by the detecting unit (S1). This determination will be specifically described. An urgency area for the return speed is set in the determination unit in advance. Then, when the return speed detected by the detection unit is within the urgency area, it is determined to be urgent. If it is determined that the emergency is urgent, a signal indicating the urgency is sent to the brake control device 7.

When an emergency signal arrives at the brake control device 7, the brake control device 7 performs first-stage brake braking (S2). The first-stage brake braking is a relatively light braking or a preliminary preparation for braking the vehicle V. After determining the urgency, the foot detection device 2 determines the intention of stepping on the foot 1 within a predetermined time (S
3). Incidentally, the determination of the intention to change the foot 1 is to determine whether or not the change of the foot 1 is going to be performed from the accelerator pedal 3 to the brake pedal. When it is determined that there is an intention to change the foot 1, the fact is transmitted to the brake control device 7 as a signal.

When the brake control device 7 receives a signal indicating that there is an intention to change the brake pedal, the brake control device 7 performs the second-stage brake braking (S4). The second-stage brake braking is stronger than the first-stage brake braking, and automatically decelerates the vehicle V. The above is the outline of the brake assist system BS according to the present embodiment. Of the brake assist system BS, the foot detecting device 2 of the driver D embodying the present invention will be described in further detail.

The foot detecting device 2 according to the present embodiment has a structure shown in FIG.
As shown in FIG. The distance sensor 21 uses an optical signal. First, the distance sensor 21 will be described.
FIG. 3 is an enlarged side view of a main part schematically showing the structure of the distance sensor.

The distance sensor 21 is located above and behind the accelerator pedal 3 as shown in FIG.
Only the foot 1 on which the step change operation is performed exists as an obstacle between the passenger compartment floor F to which the vehicle 1 faces. Incidentally, in the present embodiment, the distance sensor 21 is provided on the lower surface of the dash lower cover 9 which is the foot of the driver D. If the distance sensor 21 is located at this position, the distance sensor 21 is less likely to be affected by dirt or the like, and the accuracy of the distance sensor 21 and the constant use thereof can be secured.

The distance sensor 21 has an infrared light emitting diode 21a (hereinafter, referred to as a diode 21a) and a position detecting element (hereinafter, referred to as a PSD) 21b. Then, the diode 21a transmits an infrared ray corresponding to an optical signal, and the PSD 21b receives a reflected signal of the infrared ray. The infrared rays transmitted from the diode 21a are reflected on the object as shown in FIG.

The cover 21c covering the PSD 21b includes:
The slit 21d is formed, and the infrared light reflected on the object reaches the PSD 21b through the slit 21d. This infrared light is transmitted to the PSD 21 by the slit 21d.
An image is formed at one point on b. This imaging position changes depending on the position of the object, specifically, the distance between the diode 21a and the object. In the PSD 21b, the voltage between the output terminals changes according to the imaging position. That is, if the output voltage for a certain distance (hereinafter, referred to as a reference distance) is set as the reference voltage, the distance from the diode 21a to the object can be confirmed from the ratio between the reference voltage and the output voltage.

FIG. 4 is a side view schematically showing the relationship between the depression of the accelerator pedal and the distance sensor. FIG. 5 is a plan view schematically showing the state of the driver's feet. In the distance sensor 21 according to the present embodiment, FIG.
The light source of the diode 21a is the accelerator pedal 3
It is directed to a nearby vehicle floor F, that is, a vehicle floor F located below the accelerator pedal 3. The transmission center line R of the infrared light emitted from the light source passes through a predetermined position behind the accelerator pedal pad 32 as shown in FIG. This predetermined position will be described in detail.

Normally, when the accelerator pedal 3 is depressed,
There are individual differences. Therefore, if this individual difference cannot be dealt with, the reliability of the foot detecting device 2 is lost. In addition, a certain regularity can be seen in this individual difference. That is, when the brake pedal 4 is provided in parallel to the left side of the accelerator pedal 3,
As shown in FIG. 5, the heel 11 of the foot 1 is likely to be located at a position slightly shifted to the left with respect to the rear position of the accelerator pedal 3. This regularity is considered to be caused by a layout in which the accelerator pedal 3 is disposed at a position on the right outside with respect to the front of the driver D, and the brake pedal 4 is disposed on the left of the accelerator pedal 3. Can be

The position where the transmission center line R passes is determined in consideration of this regularity. In other words, the rear edge BL of the pad surface 32 of the accelerator pedal 3, the left edge line SL of the pad surface 32, the longitudinal center line CL of the pad surface 32, and the area surrounded by the vehicle floor F (hereinafter, a detection reference range) ) Passes through the transmission center line R. In the present embodiment, the transmission center line R corresponds to a “detection center”.

If the transmission center line R passes through the detection reference range, the foot 1 on the accelerator pedal 3 can be accurately captured. In the present embodiment, the pad surface 32 of the accelerator pedal 3 in the half throttle state is used as a reference. When it is urgent to release the accelerator pedal 3,
The foot 1 moves leftward from a state in which the accelerator pedal 3 is depressed (see the band arrow in FIG. 5), and depresses the brake pedal 4. In other words, based on the pad surface 32 in the half throttle state in which the accelerator pedal 3 is depressed to some extent, stepping on the foot 1 in an emergency state can be performed.
More accurate judgment can be made.

The transmission center line R according to the present embodiment
Is 28 mm from the rear edge BL of the pad surface 32 and 12 mm from the left edge line SL of the pad surface 32.
This position corresponds to the foot 1 where the driver D steps on the accelerator pedal 3.
Is based on the result of a sampling experiment for the position of. That is, at this position, even if there is an individual difference, it can be detected with high accuracy.

The transmitted infrared rays have a certain spread (hereinafter referred to as a transmission range E), and a part of the transmission range E corresponds to the foot 1. In the present embodiment, the transmission range E corresponds to a “detection area”. Transmission range E is also foot 1
It is necessary to set an appropriate range so as to be able to respond to individual differences.
In the present embodiment, particularly, a person whose foot 1A is relatively small, specifically, the length d1 of the foot 1A is 210 mm, and
A width d2 of A is set on the basis of a person of 85 mm. The heel 11A of the foot 1A is on the left side of the accelerator pedal 3,
It is assumed that the vehicle is located at a limit position where the driver can depress to the half throttle state. In setting the transmission range E, the first
Is a range in which the foot 1A placed at the limit position is captured. At least a part of the foot 1A overlaps the transmission range E.

FIG. 6 shows a state in which the toe 12 of the foot 1 which has been depressed to the half throttle state is lifted around the heel 11 as a fulcrum. When the toe 12 is lifted, the heel 11 does not move and remains on the passenger compartment floor F. In the present embodiment, the lifting angle α
Is 20 degrees. Transmission range E is diode 2
It has a certain extent from 1a. Here, as shown in FIG. 6, the toe 12 may be lifted and the accelerator pedal 3 may be released. In this case, if the spread of the transmission range E is too large, it may be determined that the foot 1 is present even though the accelerator pedal 3 is released.

In order to reduce such a problem, the transmission range E is set based on the following second condition. That is, first, the size of the reference foot 1 is determined, and this foot 1
Specifies the place where the heel 11 can be depressed to the half throttle state. Next, with the heel 11 placed in a specific place, a predetermined range in which the toe 12 can be lifted by a predetermined angle with the heel 11 as a fulcrum is specified. Then, the transmission range E is set so that the transmission range E and the foot 1 overlap only within this predetermined range.

In this embodiment, the predetermined angle at which the toe 12 is lifted is 20 degrees. This is the upper limit value at which the toe 12 can be relatively easily lifted within the movable region of the foot 1 (the movable region of the toe 12 with the heel 11 as a fulcrum). If it is necessary to lift the toe 12 beyond the upper limit of 20 degrees, the heel 11
Is no longer considered to be in a certain place,
Normally, in such a case, the foot 1 falls out of the transmission range E.

That is, it is generally considered sufficient to determine a predetermined range in which the transmission range E and the foot 1 overlap with each other based on the upper limit of 20 degrees. In addition, when it is necessary to consider special circumstances, it is not necessary to specify the transmission range E based on the upper limit. In such a case, the reference can be freely set from the movable region of the human foot 1 (the movable region of the toe 12 with the heel 11 as a fulcrum).

The distance sensor 21 according to the present embodiment
In FIG. 4, the distance between the diode 21a and the passenger compartment floor F is set as the reference distance L1. Further, a distance area indicated by a symbol B is an accelerator depression range B. The accelerator depression area B is a distance from a state in which the foot 1 fully depresses the accelerator pedal 3 (see the foot 1 shown by a two-dot chain line in FIG. 4) to a moment when the accelerator pedal 3 is released. On the other hand, the distance region indicated by the reference symbol A is the vehicle interior floor range A. The passenger compartment floor range A will be described in detail.

The cabin floor range A according to the present embodiment is:
This is a distance range having a width of 80% of the distance on the transmission center line R from the passenger compartment floor F to the fully depressed accelerator pedal 3, and is allowed upward with reference to the reference distance L1. Distance range. That is, in the passenger compartment floor range A, since the passenger compartment floor F is used as an object of the distance measurement, no obstacle exists between the diode 21a and the passenger compartment floor F. That is, the foot 1 is no longer present on the accelerator pedal 3, and this is a distance range in which it can be determined that a step change has been performed.

The width of the cabin floor area A is given as described above, for example, in consideration of the effects of floor mats and the like laid on the cabin floor F and the effects of dirt on the cabin floor F. . The reason why the width is set to 80% is to eliminate as much as possible the possibility that the foot 1 is determined to be the passenger compartment floor F when the accelerator pedal 3 is fully depressed.

FIG. 7 is a graph (hereinafter referred to as a sensor output characteristic graph) in which the horizontal axis represents the distance from the diode 21a to the object and the vertical axis represents the output voltage. Further, in this sensor output characteristic graph, when the distance is short, the output voltage is high, and the output voltage is low in inverse proportion to the distance. The result detected by the distance sensor 21 is sent to the step change determination unit 22. FIG. 8 is a flowchart of a determination operation performed by the step change determination unit. The determination operation of the step change determination unit 22 (see FIG. 1) will be described with reference to FIGS.

The step change determination section 22 (see FIG. 1) presets an output voltage area A 'corresponding to the cabin floor area A (S31). Then, the output voltage of the distance sensor 21 is compared with the output voltage area A 'to determine whether or not the output voltage is within the range of the output voltage area A' (S32). The output voltage regions A ′ and B ′ correspond to the vehicle floor area A and the accelerator depression area B shown in FIG. 4, respectively.

In the step change determining section 22, the distance sensor 21
Is not within the range of the output voltage area A ', it is determined that the foot 1 exists (S33), and the output voltage area A' is determined.
It is determined that there is no foot 1 when the distance is within the range (S3).
4). When the step change determination unit 22 determines that there is no foot 1, it determines that there is a step change intention, and sends a signal to that effect to the brake control unit 7. In addition, there is this foot 1,
“Not present” means that it is on the accelerator pedal 3 or not.

FIG. 9 is a graph showing the relationship between the output voltage output by the distance sensor over time and the determination as to whether or not the foot is on the accelerator pedal. And the lower determination graph correspond on the time axis. When the foot 1 is on the accelerator pedal 3, the output voltage is usually in the output voltage region B '. However, when the foot 1, specifically, footwear or the like worn by the driver D is close to a mirror, infrared rays cause irregular reflection, and an erroneous signal different from a regular reflection signal is generated by the PSD.
21b.

When an erroneous signal is transmitted to PSD 21b, PS 21
D21b outputs an output voltage corresponding to a distance longer or shorter than the distance between the diode 21a and the foot 1. Therefore, in the step change determination unit 22, the distance sensor 21
Is widely included not only in the output voltage region B 'but also when the output voltage is not included in the output voltage region A'. As a result, the influence of the erroneous signal is reduced, and the accuracy of determination of the intention to change over is improved.

The foot detecting device 2 of the driver D according to the present embodiment has been described above. Also, this foot detecting device 2
Is to judge whether the foot 1 is on the accelerator pedal 3 by using the distance sensor 21 using the PSD 21b. However, the driver's foot detecting device according to the present invention is not limited to the distance sensor 21 using the PSD 21b, but may be an embodiment using an ultrasonic sensor.
However, this ultrasonic sensor is easily affected by the hardness of the measurement object. On the other hand, the distance sensor 21 using the PSD 21b is preferable because it hardly affects the hardness and color of the measurement target.

Further, in the foot detecting device 2 according to the present embodiment, brake braking is performed based on the result of determination as to whether the foot 1 is on the accelerator pedal 3 or not. But,
The foot detecting device 2 of the driver D according to the present invention is not limited to the above embodiment, and may be used for a system that issues an alarm such as an acoustic signal or a visual signal based on a determination result.

[0039]

According to the present invention, it is possible to detect the position of the foot corresponding to the individual difference, specifically, the detection of the foot on the accelerator pedal, and whether or not the foot is on the accelerator pedal. Accuracy of the determination can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a vehicle cabin showing a state in which a driver depresses an accelerator pedal, and also shows a configuration of a brake assist system.

FIG. 2 is a flowchart showing the operation of the brake assist system.

FIG. 3 is an enlarged side view of a main part schematically showing the structure of a distance sensor.

FIG. 4 is a side view schematically showing a relationship between depression of an accelerator pedal and a distance sensor.

FIG. 5 is a plan view schematically showing a state of a driver's foot.

FIG. 6 shows a state in which the toe of the foot which has been depressed to the half throttle state is lifted with the heel as a fulcrum.

FIG. 7 is a sensor output characteristic graph in which the distance from an infrared light emitting diode to a target is plotted on the horizontal axis and the output voltage is plotted on the vertical axis.

FIG. 8 is a flowchart of a determination operation performed by a step change determination unit.

FIG. 9 is a graph showing the relationship between the output voltage output by the distance sensor over time and the determination of whether or not the foot is on the accelerator pedal. Correspond to each other on the time axis.

[Explanation of symbols]

 1: foot 2: foot detection device 3: accelerator pedal 32: pad surface BL: lower edge SL: left edge line CL: vertical center line F: vehicle floor R: transmission center line (detection center) E: detection range ( (Detection area) D: Driver

Claims (1)

[Claims] 1. A vehicle in which a brake pedal is juxtaposed on the left side of an accelerator pedal, wherein a lower edge of a pad surface of the accelerator pedal, a left edge of the pad surface, a longitudinal center line of the pad surface, and a vehicle. A detection area having a detection center within a range surrounded by a room floor, and determining that the driver's foot is on an accelerator pedal when an object is present in the detection area. Foot detection device.