JP2014077239A - Opening/closing body control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly change a pinching detection threshold according to a surrounding environment such as a road surface condition, thereby improving accuracy of detecting a pinched object.SOLUTION: Acceleration detection means 10 calculates acceleration of a motor 3 on the basis of a signal of an encoder 4. Threshold determining means 11 sets a threshold on the basis of an amount of change in vertical direction per unit time, which has been input from an image processing device 9. Pinching detection means 12 detects that an object has been pinched, upon determination that the acceleration of the motor 3 has exceeded the threshold during forward drive of the motor 3. The image processing device 9 determines a shift amount so that mean squared errors of both two vehicle front frame images captured by a camera 8 are minimum, while shifting one image data in lateral and vertical directions, and determines the lateral shift amount as an amount of vertical change of a vehicle per unit time. The amount of change can be determined by phase-only correlation.

Description

  The present invention relates to an opening / closing body control device provided in a vehicle.

  2. Description of the Related Art Conventionally, there are devices that detect foreign object pinching during closing operations of vehicle power window devices, sunroof devices, and the like. This apparatus detects the amount of fluctuation in the rotational speed of the motor and the amount of fluctuation in the movement of the opening / closing member, and detects the occurrence of a foreign object when the amount of fluctuation reaches a predetermined threshold value. For example, the opening / closing member control device described in Patent Document 1 determines whether the vehicle is stopped, leveling, or rough road, and the above-described pinching detection threshold is set according to the determination result. It has a configuration for switching.

Japanese Patent No. 4888856

  When the vehicle starts traveling, the above-described device switches the pinching detection threshold value so that the detection sensitivity becomes dull. When the amount of fluctuation in the rotational speed of the motor or the amount of movement fluctuation of the opening / closing member exceeds the disturbance threshold value while the vehicle is traveling, it is determined that the vehicle is traveling on a rough road, and the detection sensitivity is further reduced. Switch to be. That is, the threshold value can be switched in three stages.

  However, since the apparatus indirectly determines the vibration state of the vehicle, which is a great disturbance for the motor, it is difficult to accurately detect the actual vibration state. In addition, the disturbance threshold value of the above device is a fixed value, and the threshold value can be changed only in two stages during traveling, and adaptive threshold value switching according to the environment outside the vehicle such as road surface conditions is insufficient. is there. Therefore, there is still a possibility that erroneous detection of pinching may occur.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to open and close with improved detection accuracy of foreign object pinching by adaptively switching the threshold value of pinching detection according to the environment outside the vehicle such as a road surface condition. The object is to provide a body control device.

  According to a first aspect of the present invention, there is provided an opening / closing body control apparatus comprising: a driving means for driving an opening / closing body provided in a vehicle to open / close by a motor; an acceleration detection means for detecting an acceleration of the motor or the opening / closing body; And a pinching detection means for detecting pinching when the distance exceeds. An imaging unit that captures an image around the vehicle is fixed to the vehicle. The computing means computes the displacement amount per unit time of the vehicle in the direction in which the opening / closing body is opened and closed based on the images of the first frame and the second frame photographed by the imaging means. The threshold value determining means determines the threshold value according to at least one of the calculated displacement amount and the change rate of the displacement amount.

  Unlike the prior art that indirectly estimates the vibration state of the vehicle using a driving device for the opening and closing body, this configuration is based directly on the image around the vehicle taken by the imaging means fixed to the vehicle. The vibration state of the vehicle can be detected continuously (or discretely). For this reason, the threshold value for pinching detection can be adaptively switched according to the vehicle vibration state depending on the environment outside the vehicle (for example, road surface condition), vehicle speed, etc., and the pinching detection accuracy can be improved as compared with the conventional technology. Can do.

The block diagram of the opening-closing body control apparatus which is one Embodiment of this invention Nipping detection control flowchart Diagram showing motor acceleration and threshold setting values (A) is a window glass, (b) is a sunroof, (c) is a figure which shows the imaging | photography direction of a camera in the case of detecting pinching of an electric slide door. The figure which shows the picture ahead of the vehicle when vertical and horizontal shift displacement occurs Diagram showing an image when vertical displacement occurs The figure which shows the image when the displacement of the left-right direction occurs Diagram showing phase-only correlation function The figure which shows an image when rotational displacement is further added to the image shown in FIG. The figure which shows the image when the displacement of rotation occurs Diagram showing an image when enlargement displacement occurs Equivalent to FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A control device 1 shown in FIG. 1 is an opening / closing body control device that drives a window glass 2 (opening / closing body) of a vehicle to open and close in the vertical direction and detects a foreign object being caught during the closing operation of the window glass 2. When the motor 3 rotates, the window glass 2 moves up and down by a driving mechanism (not shown). A rotary encoder 4 that is a rotation detector is attached to the motor 3. The switch 5 (5U, 5D) is an operation switch (up switch, down switch) for performing the raising / lowering operation of the window glass 2, and is provided corresponding to the window glass 2 of each seat in the vehicle interior.

  The control device 1 includes a control circuit 6, a drive circuit 7, a camera 8, and an image processing device 9. The control circuit 6 is mainly configured by a known microcomputer including a CPU, a memory (RAM, ROM, flash memory, etc.), an input / output port, a communication circuit, an interrupt controller, and the like. The ROM stores a control program for driving the window glass 2 to open and close in the vertical direction in accordance with the operation of the switch 5 and detecting a foreign object. The acceleration detection means 10, the threshold value determination means 11, and the pinch detection means 12 shown in FIG. 1 represent functions realized by the CPU of the control circuit 6 executing a control program.

  The drive circuit 7 (drive means) drives the motor 3 according to a command from the control circuit 6. For example, as shown in FIG. 4A, the camera 8 (imaging means) is fixed to the front portion of the vehicle, and continuously captures images in front of the vehicle at a predetermined frame rate. The image processing device 9 (calculation means) is a vehicle (vehicle body) unit in the vertical direction in which the window glass 2 opens and closes based on the images of two frames taken by the camera 8 while the window glass 2 is raised. Calculate displacement per hour.

  Next, the operation of this embodiment will be described with reference to FIGS. When the up signal is input from the switch 5U, the control device 1 drives the motor 3 in the forward direction to perform the closing operation to raise the window glass 2. When the down signal is input from the switch 5D, the control device 1 moves the motor 3 in the reverse direction. An opening operation for driving and lowering the window glass 2 is performed. When the switch 5U is turned on, the control circuit 6 starts pinching detection control of the power window device shown in FIG. This pinching detection control is executed only while the window glass 2 is moving up (step S1; YES). Subsequent steps S2 to S9 are processes in which the control circuit 6 determines the threshold value M, which will be described later.

  If a foreign object is caught between the window frame and the window glass 2 during the closing operation, the load on the motor 3 increases and the rotational speed in the forward rotation direction decreases. That is, the motor 3 generates a negative acceleration with respect to the forward rotation direction. The control circuit 6 as the acceleration detecting means 10 calculates the acceleration of the motor 3 based on the A-phase / B-phase pulse signal output from the encoder 4. The control circuit 6 serving as the pinching detection means 12 is driving the motor 3 in the forward rotation direction and before the window glass 2 reaches the fully closed position, the acceleration of the motor 3 exceeds the threshold value M (<0). If it is determined that the foreign object has been detected, it is detected that foreign matter is caught (step S10). When the sandwiching is detected (step S10; YES), the control circuit 6 performs an opening operation to drive the motor 3 in the reverse direction and lower the window glass 2 (step S11). If pinching is not detected (step S10; NO), the process returns to step S1.

  The motor 3 is subjected not only to foreign object pinching but also to fluctuations in load due to the environment outside the vehicle such as the road surface condition and the vibration of the vehicle caused by the vehicle traveling at high speed. When vibration is generated in the vehicle and the acceleration of the motor 3 exceeds the threshold value M, the window glass 2 starts to descend despite no foreign matter being caught. On the other hand, if the threshold value M is set large so that the acceleration of the motor 3 does not exceed the threshold value M even if vibrations occur in the vehicle, detection when a foreign object is actually caught is delayed or detected. There will be situations where it will not be possible. Accordingly, it is necessary to adaptively switch the threshold value M according to the vibration of the vehicle.

  The control device 1 captures an image of the surroundings of the vehicle using an in-vehicle camera 8 that has recently been installed in many vehicles, and uses the image processing device 9 to per unit time of the vehicle (vehicle body) due to vibration of the vehicle. The amount of displacement (hereinafter sometimes simply referred to as the amount of displacement) is accurately detected. Then, a threshold value M is set according to the amount of displacement (steps S2 to S9). FIG. 3 shows the acceleration waveform of the motor 3 and the set value of the threshold value M when the road surface state and the vehicle speed change while the motor 3 is driven in the forward rotation direction.

  The control circuit 6 as the threshold value determining means 11 inputs the displacement amount D (> 0) per unit time from the image processing device 9 (step S2). The control circuit 6 sets the threshold value M by comparing the displacement amount D with the three reference values D1, D2, and D3 (D1 <D2 <D3). That is, if D <D1, “NO” is determined in step S3, and the threshold value M is set to M1 in step S6.

  If D1 ≦ D <D2, “YES” is determined in step S3, “NO” is determined in step S4, and the threshold value M is set to M2 in step S7. If D2 ≦ D <D3, “YES” is determined in step S4, “NO” is determined in step S5, and the threshold value M is set to M3 in step S8. If D3 ≦ D, “YES” is determined in the step S5, and the threshold value M is set to M4 in a step S9. Here, M1 to M4 are negative values, and there is a relationship of | M1 | <| M2 | <| M3 | <| M4 |.

  The threshold value M set so as to increase as the displacement amount D increases in this way accurately reflects the load fluctuation amount applied to the motor 3 in accordance with the vibration of the vehicle detected based on the captured image of the camera 8. It becomes. Here, the threshold value M is switched to four levels, but it is also possible to switch to more levels or to change it continuously. As a result, even if the vehicle vibration state changes due to changes in road surface conditions or vehicle speed, the threshold value M is a value that is larger by a predetermined margin (as an absolute value) than the negative maximum acceleration of the motor 3 caused by vehicle vibration. Can be set to As a result, it is possible to reliably detect the foreign object and to prevent erroneous detection.

  Next, calculation of the displacement amount D by the image processing device 9 will be described. In the power window device that drives the window glass 2 in the vertical direction, the vibration component in the vertical direction of the vehicle causes a load fluctuation of the motor 3 as described above. In order to detect the vertical displacement of the vehicle from the image of the camera 8, the camera 8 is perpendicular to the operating direction of the window glass 2, that is, in the front, rear, left, or right direction of the vehicle. It is preferable to take an image. In the present embodiment, as shown in FIG. 4A, an image in front of the vehicle is taken by the camera 8.

  When the opening / closing body is a sunroof, as shown in FIG. 4 (b), the image in the left (or right) direction, which is a direction orthogonal to the opening / closing in the front / rear direction, and the opening / closing in the left / right direction It is preferable to take an image in the front (or rear) direction that is an orthogonal direction (use one of the cameras 8 shown in the figure). There are vertical directions in the front-rear direction and the direction orthogonal to the left-right direction, but images above (the sky) and below (the ground) of the vehicle are not appropriate because it is difficult to detect displacement. Similarly, when the opening / closing body is an electric sliding door that opens and closes in the front-rear direction, it is preferable to take a left (or right) image as shown in FIG.

  FIG. 5 is an example of an image in front of the vehicle taken by the camera 8. The image processing device 9 calculates the amount of displacement by sequentially selecting two frames having a time difference that can appropriately calculate the amount of displacement based on the difference between the images from the captured frames. The image shown in FIG. 5 shows a case where the vertical displacement (y direction) shown in FIG. 6 and the horizontal displacement (x direction) shown in FIG. 7 occur simultaneously. The amount of displacement required to set the threshold value M is the amount of displacement in the up-down direction, which is the operation direction of the window glass 2.

  In this case, the image processing device 9 calculates the shift displacement amount in the vertical direction using one of the following two methods. The image data of frame 1 (first frame) and frame 2 (second frame) is, for example, a two-dimensional array having pixel values of 8 bits (0 to 255).

(1) Method of minimizing the mean square error The image data of frame 2 is shifted by Δx and Δy sequentially in the orthogonal first axis direction (x direction; left and right direction) and second axis direction (y direction; vertical direction). Meanwhile, the mean square error between the image data of frame 1 and the image data of frame 2 subjected to the shift process is calculated. The shift position where the calculated mean square error is the minimum is the corresponding point of frames 1 and 2, and the shift amount in the vertical direction among the shift amounts is the displacement amount in the vertical direction of the vehicle per unit time.

(2) Method Using Phase Only Correlation Method The image processing apparatus 9 calculates the shift amount using the phase only correlation method described in the following document or the like.
Takafumi Aoki and three others, “High-Precision Machine Vision Based on Phase-Only Correlation: Toward Image Sensing Technology that Transcends Pixel Resolution”, IEICE Fundamentals Review, Vol.1, No.1, pp.30- 40, July 2007

  The image processing device 9 performs two-dimensional discrete Fourier transform on the image data of frame 1 and the image data of frame 2, respectively, and calculates a normalized mutual power spectrum of the two-dimensional discrete Fourier transform. Then, the normalized mutual power spectrum is subjected to a two-dimensional inverse discrete Fourier transform to obtain a phase-only correlation function r (x, y), which is a two-dimensional array of value ranges 0 to 1 as shown in FIG. The value “x” illustrated in FIG. 8 represents any number from 0 to 9.

  When the image of frame 2 is shifted in parallel to the image of frame 1 as in the image shown in FIG. 5, a correlation peak value appears at a position corresponding to the shift amount. That is, coordinates (X, Y) having a correlation peak value correspond to the displacement amount X in the x direction (up and down direction) and the displacement amount Y in the y direction (left and right direction), respectively.

  Although the displacement due to the parallel shift has been described above, FIG. 9 shows an example of an image in which the displacement due to the rotation is added in addition to the right shift and the downward shift. In an actual image obtained by the camera 8, a displacement due to enlargement / reduction may be added in addition to the displacement due to the rotation. The image shown in FIG. 10 shows a case where only displacement due to rotation occurs, and the image shown in FIG. 11 shows a case where only displacement due to enlargement occurs. Such displacement due to rotation and displacement due to enlargement / reduction are errors in obtaining the amount of shift displacement in the vertical direction using the methods (1) and (2) described above. In such a case, the image processing apparatus 9 calculates the shift displacement amount in the vertical direction using the method described below.

(3) A method using the method (1) after calculating the rotation angle and the enlargement / reduction ratio using the phase only correlation method and canceling the displacement of the rotation and enlargement / reduction. The data and the image data of frame 2 are each subjected to two-dimensional discrete Fourier transform, and their amplitude spectra are converted to logarithmic polar coordinates to calculate a normalized mutual power spectrum. Then, the normalized mutual power spectrum is subjected to two-dimensional inverse discrete Fourier transform to obtain a phase-only correlation function r (x, y), which is a two-dimensional array of value ranges 0 to 1 as shown in FIG. Here, the x coordinate represents the rotation angle, and the y coordinate represents the enlargement / reduction ratio. That is, by performing logarithmic polar coordinate conversion of the amplitude spectrum of the image and using the phase-only correlation method, the rotation and enlargement / reduction of the image can be replaced with a two-dimensional parallel shift.

  The image processing device 9 corrects the image data of the frame 1 or the frame 2 so that the rotation of the image generated between the frame 1 and the frame 2 is returned to zero and the enlargement / reduction is returned to the same magnification. Thereafter, by using the method described in (1) above, it is possible to calculate the amount of displacement in the vertical direction from which an error due to rotation or enlargement / reduction has been eliminated.

(4) Method of calculating the rotation angle and the enlargement / reduction ratio using the phase-only correlation method, and canceling the rotation and enlargement / reduction displacement, and then using the method of (2). By performing logarithmic polar coordinate transformation of the amplitude spectrum and using the phase only correlation method, rotation and enlargement / reduction of the image are obtained. Then, the image data is corrected so that the rotation of the image generated between the frame 1 and the frame 2 is returned to zero and the enlargement / reduction is returned to the same magnification. Thereafter, by using the method described in (2) above, it is possible to calculate the amount of displacement in the vertical direction from which errors due to rotation or enlargement / reduction have been eliminated.

  As described above, the control device 1 of the present embodiment can directly and accurately detect the vibration state of the vehicle based on the image around the vehicle taken by the camera 8 fixed to the vehicle. In the case of opening / closing driving of the window glass 2, a load corresponding to the amount of displacement per unit time of the vehicle in the vertical direction is applied to the motor 3 to change its acceleration. Therefore, by setting a threshold value M by adding a predetermined margin to the detected displacement amount (disturbance), it is possible to adapt to changes in the road surface condition and vehicle speed without deteriorating the detection sensitivity. Can be reliably detected.

  Since the control device 1 can set (switch) the threshold value M in multiple steps or continuously based on an accurate displacement amount, it can improve adaptability to the environment outside the vehicle, the vehicle speed, etc. Can be detected. In addition, since the camera 8 can be shared with a vehicle-mounted camera (front view camera, back view camera) used for other purposes, the introduction cost of the control device 1 can be reduced.

As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to embodiment mentioned above, A various deformation | transformation and expansion | extension can be performed within the range which does not deviate from the summary of invention.
The acceleration detection means 10 may detect the acceleration of the window glass 2 instead of the acceleration of the motor 3, and the pinching detection means 12 may detect the pinching by comparing the detected acceleration with the threshold value M.

  The threshold value determining means 11 determines the threshold value M based on the displacement amount D per unit time of the vehicle, but determines the threshold value M based on the rate of change of the displacement amount D per unit time. Also good. The threshold value M may be determined based on the displacement amount D and the rate of change of the displacement amount D. In these cases, the threshold value M (absolute value) is set to increase as the rate of change of the displacement amount D increases.

  For example, in the case of a sunroof or an electric sliding door that opens and closes in the front-rear direction, when a left-right image is taken by the camera 8, the displacement amount D per unit time increases as the vehicle speed increases. Therefore, in such a case, the threshold value M may be determined based on the change rate of the displacement amount D. Further, the threshold value M may be determined based on a value obtained by subtracting the displacement amount corresponding to the average value of the vehicle speed from the calculated displacement amount D.

  In the methods (3) and (4) described above, the image processing device 9 first converts the image data of frame 1 and the image data of frame 2 into logarithmic polar coordinates, and each of the converted image data is two-dimensional discrete Fourier transform. To do. Then, the normalized mutual power spectrum of these two-dimensional discrete Fourier transform is calculated, and the normalized mutual power spectrum is two-dimensionally inverse discrete Fourier transformed to obtain a phase-only correlation function in polar coordinates, thereby rotating and scaling the image. You may ask for.

The camera 8 preferably captures an image in a direction perpendicular to the operating direction of the opening / closing body, but may capture a direction deviating from the vertical.
Although the case where the opening / closing body is the window glass 2 has been mainly described in the above embodiment, the same applies to the case of a sunroof or an electric slide door.

  In the drawings, 1 is a control device (opening / closing body control device), 2 is a window glass (opening / closing body), 3 is a motor, 7 is a drive circuit (drive means), 8 is a camera (imaging means), and 9 is an image processing device ( (Calculation means) 10 is an acceleration detection means, 11 is a threshold value determination means, and 12 is a pinching detection means.

Claims (6)

Drive means (7) for driving the opening / closing body (2) provided in the vehicle to open and close by a motor (3);
Acceleration detecting means (10) for detecting acceleration of the motor or the opening / closing body;
Imaging means (8) fixed to the vehicle and capturing an image around the vehicle;
A calculation means (9) for calculating a displacement amount per unit time of the vehicle in a direction in which the opening and closing body is opened and closed based on images of the first frame and the second frame taken by the imaging means;
Threshold value determining means (11) for determining a threshold value according to at least one of the displacement amount and the rate of change of the displacement amount;
An opening / closing body control device comprising: pinching detection means (12) for detecting pinching when the detected acceleration exceeds the threshold value.   The opening / closing body control device according to claim 1, wherein the imaging unit captures an image in a direction perpendicular to a direction in which the opening / closing body is opened and closed.   The arithmetic means sequentially changes the shift amount of the image data of the second frame in the first axis direction and the second axis direction orthogonal to each other, and performs the shift process on the second frame of the image data of the first frame. An average square error with respect to the image data is calculated, and a shift amount in a direction in which the opening / closing body is opened / closed out of a shift amount that minimizes the average square error is defined as the displacement amount. The opening / closing body control apparatus according to claim 1 or 2.   The computing means calculates a normalized mutual power spectrum between a two-dimensional discrete Fourier transform of the image data of the first frame and a two-dimensional discrete Fourier transform of the image data of the second frame, and calculates the normalized mutual power spectrum. The opening / closing body control according to claim 1 or 2, wherein a coordinate in a direction in which the opening / closing body moves in an opening / closing direction is set as the displacement amount among coordinates having a correlation peak value of a phase-only correlation function obtained by conversion. apparatus.   The arithmetic means performs a two-dimensional discrete Fourier transform of the image data of the first frame and a two-dimensional discrete Fourier transform of the image data of the second frame, converts their amplitude spectra into logarithmic polar coordinates, and normalizes mutual power Rotation of an image generated between the first frame and the second frame based on polar coordinates having a correlation peak value of a phase-only correlation function obtained by calculating a spectrum and performing two-dimensional inverse discrete Fourier transform on the spectrum The image data is corrected so that the image data is returned to zero and the enlargement / reduction is set to the same magnification, and then the shift amount in the first axis direction and the second axis direction of the corrected second frame image data is sequentially changed. While changing, an average square error between the corrected first frame image data and the shifted second frame image data is calculated, and the average square error is calculated. The closing body is opening and closing member control apparatus according to claim 1 or 2, wherein the shift amount in the direction of opening and closing movement to said displacement amount of the smallest shift amount.   The arithmetic means performs a two-dimensional discrete Fourier transform of the image data of the first frame and a two-dimensional discrete Fourier transform of the image data of the second frame, converts their amplitude spectra into logarithmic polar coordinates, and normalizes mutual power Rotation of an image generated between the first frame and the second frame based on polar coordinates having a correlation peak value of a phase-only correlation function obtained by calculating a spectrum and performing two-dimensional inverse discrete Fourier transform on the spectrum The image data is corrected so as to return to zero and enlargement / reduction to the same magnification, and then the two-dimensional discrete Fourier transform of the corrected first frame of image data and the two-dimensional of the corrected second frame of image data Calculate the normalized mutual power spectrum with the discrete Fourier transform, and the locus with the correlation peak of the phase-only correlation function obtained by two-dimensional inverse Fourier transform Opening and closing member control apparatus according to claim 1 or 2, wherein said movable member is said displacement of the coordinate in the direction of opening and closing movement of the.

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