WO2015045587A1 - Vehicular reflective optical sensor - Google Patents

Abstract

The purpose of this invention is to provide a vehicular reflective optical sensor whereby detection precision can be increased. Said vehicular reflective optical sensor is provided with a control unit (6) that: emits pulses of detection light (2) from an exterior panel of a vehicle towards a detection region (1) set outside said vehicle; and, if the amount of reflected light (3) from the detection region (1) exceeds a prescribed detection threshold, detects that a detection target (4) has entered the detection region (1). To determine whether the threshold has been exceeded, for each detection interval consisting of a pulse group comprising an appropriate number of pulses, the control unit (6) compares the detection threshold to the difference between the total amount of light received by a light-receiving unit (5) when light was being emitted and the total amount of light received by said light-receiving unit (5) when light was not being emitted.

Description

Reflective optical sensor for vehicles

The present invention relates to a vehicle reflective optical sensor.

As a vehicle door opening / closing control device that uses an infrared sensor to control a vehicle door opening / closing operation, a device described in Patent Document 1 is known. In this conventional example, a foot detection sensor that outputs a signal such as an infrared ray is mounted on the vehicle, and the user is detected by the foot detection sensor that is driven after the portable wireless terminal possessed by the user is authenticated. When it is detected, the door is opened and closed.

JP 2005-133529 A

In general, an optical sensor is configured to detect a detection target based on the amount of reflected light with respect to an output signal (emitted light). However, when used as a foot sensor of a vehicle as in the above-described conventional example, the following problems occur. is there.

In other words, since the vehicle is parked in various places with different optical conditions, if the detection is made only by the amount of reflected light with respect to the irradiated light, the difference in the optical environment at the parking place acts as disturbance light, so the detection accuracy is high. There is a problem of lowering.

The present invention has been made to solve the above-described drawbacks, and an object of the present invention is to provide a vehicle reflection type optical sensor capable of enhancing detection accuracy and a vehicle door opening / closing control device using the same.

According to the present invention, the object is
When the pulsed detection light 2 is projected from the vehicle outer wall portion toward the detection region 1 set outside the vehicle, and the amount of the reflected light 3 from the detection region 1 exceeds a predetermined threshold for detection determination A reflective optical sensor for a vehicle including a control unit 6 for detecting the entry of the detection object 4 into the detection region 1,
The determination of the threshold excess state in the control unit 6 is performed by using a pulse group composed of an appropriate number of pulses as a determination unit, and the total amount of light received by the light receiving unit 5 during light emission and the light receiving unit 5 during non-light emission. This is achieved by providing a vehicle reflective optical sensor which is performed by comparing the difference between the total received light quantity and the total with a predetermined threshold value for detection determination.

As described above, the vehicle does not specify the optical environment of the stop position, the brightness of the detection area 1 varies depending on the stop position, and snowfall, rain, sunshine, etc. may occur when the same position is an outdoor stop. In order to always change, if only the amount of reflected light during light emission is used as a criterion, detection reliability is extremely lowered.

On the other hand, as in the present invention, it is possible to reliably prevent a decrease in determination accuracy due to variations in the brightness of the detection region 1 by using the difference in the amount of reflected light between light emission and non-light emission as a determination target. become.

In addition, the detection light 2 is emitted in units of a pulse group composed of a plurality of pulses, and the determination of an over-threshold state is made in units of pulse groups. The tolerance is improved and the determination accuracy is also improved. Furthermore, since the accuracy of the determination unit is high, it is possible to increase the emission interval of the pulse group without reducing the accuracy, which is effective for power saving.

Moreover, the control part 6 of the reflective optical sensor for vehicles is
For each pulse group, a deviation sum of squares corresponding to the difference between the total amount of received light in the light receiving unit 5 during light emission and the total amount of received light in the light receiving unit 5 during non-light emission is less than a predetermined test threshold value. It is possible to configure such that only the effective detection light is used as the determination target reflected light by performing the verification that the effective detection light is used only in the case.

As in the present invention, the determination accuracy is further improved by performing the test for the pulse group and using only the effective pulse group as the determination target.

Further, the control unit 6 of the vehicle reflective optical sensor shortens the emission interval of the detection light 2 when the amount of reflected light from the detection region 1 exceeds the threshold value, and a predetermined number of times within a short cycle period. It can be configured to return the light emission interval to a long period after outputting the detection confirmation signal upon detection of the threshold excess state.

In the present invention, the emission interval of the detection light 2 is shortened only until the detection confirmation signal is output after the threshold excess state is detected, and after the detection confirmation signal is output, the long cycle again. Therefore, it is possible to save power.

Also, since the detection confirmation signal is output by confirming the state of exceeding the threshold value a plurality of times, the influence of noise becomes as small as possible, and the detection reliability becomes high.

Further, in order to output the detection confirmation signal, the threshold excess state needs to be detected a predetermined number of times within a short cycle period in which the emission interval of the detection light 2 is shortened. Since it becomes possible to increase the number of times of detection of an over-value state, the detection reliability is further improved.

Further, the control unit 6 of the reflective sensor
It can be configured to shift to a short cycle period when a threshold excess state is detected a predetermined number of times after detection of the first threshold excess state.

Although the transition to the short cycle period can be started immediately after detecting the threshold excess state, the transition to the short cycle due to the influence of noise can be prevented by configuring as in the present invention. it can.

Moreover, the vehicle door opening / closing control device using these vehicle reflection type optical sensors is
A vehicle reflective optical sensor (A);
A door control unit 9 that opens the vehicle door 8 by operating the actuator 7 on condition of a detection confirmation signal of the detection target 4 in the vehicle reflection type optical sensor (A) can be configured.

In the present invention, when the door control unit 9 receives the detection confirmation signal, the door control unit 9 is in a locked state on condition that a predetermined other condition such as that the unlocking operation authority is authenticated by an appropriate authentication unit is satisfied. The release and opening operation signal of the vehicle door 8 is output to the actuator 7, and the opening operation of the door is performed. As a result, the door can be opened simply by inserting a load, a hand, etc. into the detection area 1 in a state where the unlocking conditions are satisfied, so that convenience is improved.

According to the present invention, since the amount of received light when not emitting light is taken into account when determining the presence or absence of a detection target, the determination accuracy can be increased.

It is a figure which shows the vehicle by which the vehicle door opening / closing control apparatus was used, (a) is a rear view, (b) is a side view, (c) is the 1C-1C sectional view taken on the line of (a). It is a block diagram of a reflection type optical sensor. It is a timing chart which shows operation | movement of a control part. It is a timing chart which shows the detection timing of a threshold value excess state. It is a timing chart which shows the detection timing of threshold value excess state cancellation. It is a timing chart explaining examination resumption conditions.

Fig. 1 shows a vehicle using a vehicle door opening / closing control device. In this example, the vehicle door opening / closing control device is configured as a back door control device for controlling the opening / closing operation of the power back door driven by the actuator 7 such as a damper device, and is fixed to the back door 8 of the vehicle. A vehicle reflection type optical sensor (A), and a door control unit 9 for controlling the actuator 7.

As will be described later, the reflection type optical sensor (A) is configured to output a detection confirmation signal when detecting the entry of the detection target 4 into the predetermined detection area 1 where the detection light 2 is projected. And fixed to the ceiling wall portion of the license plate mounting recess surrounded by the license plate finisher 10. In FIG. 1, reference numeral 11 denotes a license plate.

Further, in this example, in order to position the center of the detection region 1 of the reflective optical sensor (A) in the license plate mounting recess, the optical axis of the detection light 2 is slightly inclined toward the vehicle inner side (angle θ). . As a result, the detection ability outside the concave portion of the license plate is lowered, so that the reflective optical sensor (A) may react inadvertently when a person other than the user, an animal, garbage, or the like approaches the vehicle. Can be prevented.

In this example, when a detection confirmation signal is output from the reflection type optical sensor (A), the door control unit 9 first performs authentication of an electronic key possessed by the user, detection of the state of the back door, locking / unlocking operation, etc. After performing the preparatory operation, the actuator 7 is driven. The authentication of the electronic key is performed by communicating with an authentication device (not shown) and authenticating the authentication code output from the electronic key. When the authentication is established, the back door 8 is in a closed condition on the condition that the back door 8 is in a closed state. After unlocking operation, the actuator 7 is driven to start the door opening operation.

Therefore, in this embodiment, even if the hand is blocked by a luggage or the like, the bag can be moved only by bringing the luggage or the like to be detected 4 close to or near the license plate mounting recess set as the detection area 1. Convenience is improved because the door can be opened.

As shown in FIG. 2, the reflective optical sensor (A) includes a light emitting unit 12 using an infrared LED as a light source, a light receiving unit 5 including a light receiving circuit including an infrared light receiving element, and a control unit 6. The control unit 6 includes a light emission control unit 6a that controls the light emission timing of the light emission unit 12, a light reception control unit 6b that controls the light reception timing of the light reception unit 5, and a calculation unit 13 that includes a threshold value calculation unit 13a. .

As shown in FIG. 3, the light-emitting unit 12 is controlled by the light-emission control unit 6a to generate the detection light 2 in units of a pulse group (PLS) composed of an appropriate number (eight in this example) of pulses (pls). Fire at predetermined intervals (T1, T2 in FIG. 3). *

The light receiving control unit 6b activates the light receiving circuit from the sleep state in accordance with the light emission timing of the pulse group (PLS) in the light emitting unit 12 for power saving, and at the time of light emission and non-light emission for each light emission pulse (pls). The amount of received light in the light receiving unit 5 is acquired. The acquisition of the amount of light received at the time of light emission with respect to the light emission pulse (pls) takes into account the delay time until the light emission is started after the light emission control unit 6a sends the light emission request of each pulse (pls) to the light emission unit 12. Then, it is performed at the timing when the reflected light 3 for each light emission pulse (pls) reaches the peak, and the value is acquired as the light reception light amount (H) during light emission.

Further, the received light amount when not emitting light is acquired at the timing when the light emitting unit 12 transitions from the light emitting state to the non-emitting state and the afterglow at the time of emitting light disappears, and the value is set as the received light amount (L) when not emitting light. The

On the other hand, the calculation unit 13 calculates the amount of reflected light in units of pulse groups (PLS) based on the amount of light received by the light receiving unit 5. The reflected light amount (P) of the pulse group (PLS) is

Is given by.

As shown in equation (1), in calculating the amount of reflected light, the inclusion of the received light amount (H ₁ , L ₁ ) for the _first pulse and the received light amount (H ₈ , L ₈ ) for the last pulse should be excluded. This eliminates instability in the transient state.

The effectiveness of the reflected light 3 of each pulse group (PLS) obtained as described above is determined by the calculation unit 13. Effectiveness is the evaluation of the mixing of disturbance elements by the homogeneity of the amount of reflected light within the same pulse group (PLS). The variation of each pulse in the pulse group (PLS), specifically equivalent to the sum of squared deviations value if larger than the predetermined validity test threshold (Th _val) is invalid data.

The deviation sum of squares equivalent value is a so-called deviation sum of squares given as the sum of the squares of the difference between the received light amount (P) for each pulse light and the average value, or a variance obtained by dividing the deviation square sum by the number of data. Furthermore, it is possible to use a standard deviation or the like obtained as the square root of the variance. In this example, as shown in the equation (2), the absolute value of the difference between the received light amount of each pulse and the average value is used. The total of the values is substituted and the burden on the control unit 6 is reduced.

Further, the calculation unit 13 compares the amount of reflected light of the pulse group (PLS) described above with a predetermined threshold value for detection determination (Th _on ), detects a threshold excess state, and eliminates the threshold excess state. When the detection, further, the entry of the detection object 4 to the detection area 1 is determined, and the entry of the detection object 4 to the detection area 1 is detected, a detection confirmation signal is output for a predetermined time, and further the detection confirmation signal A confirmation signal output flag indicating that has been output is set.

This confirmation signal output flag satisfies a predetermined cancellation condition when a threshold exceeding state is detected within a predetermined period after the confirmation signal is output and when a threshold exceeding state is not detected within a predetermined period. If the confirmation signal output flag is in the reset state, the calculation unit 13 executes the threshold value excess state detection step.

The threshold value for detection determination (Th _on ), which is a criterion for determining the above threshold excess state, is obtained as the sum of a preset fixed value (Th _onfix ) and an adjustment value (Th _cal ). The fixed value (Th _onfix ) is set to about 20 to 30 percent of the validity test threshold value (Th _val ).

The adjustment value (Th _cal ) is an average value of the received light quantity of a predetermined number (10 in this example) preceding the determination target pulse group (P _n ), as shown in FIGS. 4 and (3). And is calculated by the threshold value calculation unit 13a in the calculation unit 13. In this example, the fixed value (Th _onfix ) is set to about 20 to 30 percent of the validity test threshold value (Th _val ).

In the present example, the adjustment value (Th _cal ) is shown by the arithmetic average of the appropriate number of received light amounts, but if it is a statistical representative value, for example, the mode value, the median value, etc. Can be used.

In addition to the validity test for each pulse group (PLS), the calculation unit 13 performs noise determination using the adjustment value (Th _cal ), and when noise is detected, the threshold calculation unit 13a.

The noise determination is performed by determining the received light amount (P _n ) of the noise determination target pulse group (PLS) and the average value of the ten received light amounts preceding the received light amount (P _n ), that is, the adjustment value (Th _cal ). And a predetermined noise determination threshold value (Th _nz ) are compared, and it is determined as noise light by satisfying either of the expressions (4) and (5). In this example, the noise determination threshold (Th _nz) is 5 to the Th _Onfix is set to about 8%.

The threshold value calculation unit 13a notified of the occurrence of noise observes the amount of received light thereafter and determines the stability of the received light amount. Whether or not the stability is satisfied satisfies (6) with respect to an appropriate number (20 in this example) following the noise pulse group (PLS), that is, the amount of reflected light is a noise determination threshold value. It is determined whether or not it is non-noise light that falls within (Th _nz ), and when the expression (6) is satisfied, it is determined that the subsequent pulse group (PLS) is stable.

When the threshold value calculation unit 13a determines that there is stability with respect to the subsequent pulse group, as shown in the equation (7), the ten light receptions preceding the determination target pulse group (P _{n + 21} ). If it is determined that there is no stability using the average light intensity as the adjustment value (Th _cal ), the average of the 10 received light quantities preceding the noise pulse group (P _n ) is adjusted as shown in equation (8). A threshold value for detection determination (Th _on ) is determined as a value (Th _cal ).

The operation of the control unit 6 is shown in FIG. First, when the door control unit 9 or a control device such as an in-vehicle computer (not shown) detects that the start condition of the detection operation by the optical sensor (A) is satisfied, the door control unit 9 or the like detects the optical sensor (A). A drive signal is output and the optical sensor (A) is powered on. The detection start condition of the optical sensor (A) is set as appropriate, for example, the stop of the vehicle detected by the shift lever position of the vehicle.

When the optical sensor (A) is turned on, the CPU of the control unit 6 is initialized for a predetermined time (step S1), and then calibration initialization is performed by the threshold value calculation unit 13a (step S2). During the calibration initialization, the light emission control unit 6a maintains the firing interval (T1) of the pulse group (PLS) at about 15 (ms).

In the calibration initialization, a predetermined number (10 in this example) of pulse groups (PLS) are fired to obtain the reflected light amounts (P ₁ , P _2... P ₁₀ ) for each pulse group (PLS). The average value is set as an initial adjustment value (Th _cal ).

When the calibration initialization process is completed, the calculation unit 13 shifts to the threshold excess state in a state in which the light emission control unit 6a maintains the light emission interval of the detection light 2 in the intermittent mode with a long period of about 117 (ms). Is monitored (step S3).

As shown in FIG. 4, in the excess state detection mode, the calculation unit 13 compares the threshold value for detection determination (Th _on ) with the amount of reflected light (P) as described above.
Pn => Th _on
= Th _onfix + Th _cal (9)
Is satisfied, it is determined that the threshold value is exceeded.

When the calculation unit 13 detects an over-threshold state (step S4), an excess state verification process is then executed (step S5). The verification step is for knowing whether or not the detected threshold excess state is an intentional entry operation of the detection target 4 by the user into the detection region 1, and includes a detection including an excess state. Whether or not the threshold value for detection determination (Th _on ) has been exceeded continuously (four times in this example) is used as a test pass / fail criterion.

The threshold value for detection determination (Th _on ) in this verification process is the one used when a threshold excess condition is detected to prevent a decrease in verification accuracy due to a change in the adjustment value (Th _cal ) during verification. Therefore, satisfying all of the following formulas (10) to (13) is a condition for passing the test.

If it is determined that the test is passed as the intended operation satisfying the above conditions (step S6), after setting the confirmation signal output flag, the detection confirmation signal is output for a predetermined time (T4) (about 150 msec) (step S7). ).

On the other hand, in the verification process, if invalid received light exceeding the verification threshold value (Th _v ) based on equation (2) is observed before the condition is met, the verification process is terminated and the monitoring mode is restored. To do.

In addition, when the threshold value excess state is detected in the verification step, the light emission control unit 6a sets the pulse group (P _{n + 1} ) immediately after the detection pulse group (P _n ) to the long cycle mode with the interval (T2). (Step S51), the light emission interval (T3) is shifted to the short cycle mode shortened to about 20 (msec) (step S52), and after waiting for the output of the detection confirmation signal, the excess state canceling detection mode is set. Transition is made (step S8).

As shown in FIG. 5, the excess state elimination detection mode (step S8) monitors the elimination of the excess state while emitting a pulse group (PLS) in the long period mode. Determination of excessive state persists, the amount of reflected light with respect to pulse group (PLS) was below the detection resolving determining threshold value _{(T off = Th offfix + Th} cal) successively (4 times in this example) a predetermined number of times, That is, it is a condition that all the expressions (14) to (17) are satisfied. In this example, Th _offfix is set to about 5 to 8 percent of Th _onfix , similarly to Th _nz .

When the excess state cancellation is detected in step S8 (step S80), the calculation unit 13 resets the confirmation signal output flag, and returns to the excess state detection mode to prepare for the detection of the excess state (step S3). In the threshold value for detection determination (Th _on ) in step S3, the subsequent pulse group (P _{m + 4} , P _{m + 5} ...) Whose initial value is the adjustment value used in the excess state elimination detection mode is used. The average value is used.

On the other hand, as shown in FIG. 6, when the excess state cancellation is not detected in step S8, the arithmetic unit 13 cancels the threshold excess state on condition that the detection restart condition is satisfied. The detection restart condition is that a predetermined number (20 in this example) of non-noise light defined by the equation (6) continues, and a confirmation signal is output by eliminating the threshold excess state due to the satisfaction of the detection restart condition. The flag is reset and returns to the excess state detection mode again to prepare for the detection of a new threshold excess state (step S9). As the adjustment value (Th _cal ) of the threshold value for detection determination (Th _on ) in step S9, the value obtained by the equation (7) is used.

The detection resumption condition can be determined for each single pulse group (PLS). In this example, in order to reduce the burden on the system, the equation (18) is used. , Continuous condition matching can be inferred by evaluating the entire 20 pulse groups (PLS).

DESCRIPTION OF SYMBOLS 1 Detection area 2 Detection light 3 Reflected light 4 Detection object 5 Light-receiving part 6 Control part 7 Actuator 8 Vehicle door 9 Door control part A Reflection type optical sensor

Claims (5)

1. Pulse-shaped detection light is projected from the outer wall of the vehicle toward the detection area set outside the vehicle, and when the amount of reflected light from the detection area exceeds a predetermined threshold value for detection determination, It is a vehicle reflection type optical sensor provided with a control unit that detects entry of a detection target into the vehicle,
   The determination of the threshold excess state in the control unit is performed by using a pulse group composed of an appropriate number of pulses as a determination unit, and the total amount of light received by the light receiving unit during light emission and light reception by the light receiving unit during non-light emission. A reflective optical sensor for a vehicle, which is performed by comparing a difference with a total light amount with a predetermined threshold value for detection determination.
2. The control unit, for each pulse group, a deviation square sum equivalent value for a difference between the total amount of received light in the light receiving unit during light emission and the total amount of received light in the light receiving unit during non-light emission is equal to or less than a predetermined test threshold value. 2. The vehicular reflective optical sensor according to claim 1, wherein the test is performed with the effective detection light only in the case of the above, and only the effective detection light is adopted as the determination target reflected light.
3. When the control unit detects that the amount of light reflected from the detection area exceeds the threshold value, the detection interval is shortened, and a detection confirmation signal is detected by detecting the threshold value excess state a predetermined number of times within a short period. The vehicle reflection type optical sensor according to claim 1, wherein the light emission interval is returned to a long cycle after the output of.
4. 4. The vehicle reflection type optical sensor according to claim 3, wherein the control unit executes transition control to a short cycle period when the threshold excess state is detected a predetermined number of times after the first threshold excess state is detected.
5. A vehicle reflective optical sensor according to claim 1;
   A vehicle door opening / closing control device comprising: a door control unit that operates an actuator to open and close a vehicle door on condition of a detection confirmation signal of a detection target in a vehicle reflection type optical sensor.

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