JPH06233297A - Rotation angle detecting device - Google Patents

Abstract

PURPOSE:To provide a rotation angle detecting device with high reliability, which withstands use for a long period of time. CONSTITUTION:A first index 18 which is arranged on one of the circular arcs of two concentric circles with the rotation center of an object to be detected 9 as a center, the second index 19 which is arranged on the other circular-arc of the concentric circles, a first sensor 14 which optically detects the first index and the second sensor 15 which optically detects the second index are provided so that the first sensor 14 detects information representing the rotation reference position of the object to be detected 9 from the first index 18 and the second sensor 15 detects information representing the relative rotation position of the object to be detected 9 from the second index 19. The rotation angle of the object to be detected 9 is obtained as relative rotation angle which is detected by the second sensor 15 from the rotation reference position which is detected by the first sensor 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle detecting device used for controlling a rotation operation for changing a shooting direction of a camera unit used in a video conference, and particularly, it can endure long-term use and has high accuracy. It is configured to be able to detect.

[0002]

2. Description of the Related Art In a video conference, as shown in FIG. 6, a pattern of a conference is photographed by a camera unit 22 and the image is transmitted to a conference partner at a remote place. The monitor 24 displays the image of the other party or the image projected by the camera unit 22 of the own side. By operating the operation unit 23, the camera unit 22 rotates in the horizontal direction, reflects the participants A, B, and D at the same height while changing the angle in the vertical direction, and the participants in the upright state. Take a picture of C.

As shown in FIG. 5, a conventional camera unit includes a camera unit having a lens 1 and an image pickup device 2 such as a CCD, a vertical rotation motor 3 for rotating the camera unit in a vertical direction (V direction), A vertical rotation angle sensor (rotary potentiometer) 4 for detecting the vertical rotation angle, a vertical drive transmission unit 5 for transmitting the drive in the vertical rotation direction, and a horizontal rotation for rotating the camera unit in the horizontal direction (H direction). The motor 6, the horizontal rotation angle sensor (rotary potentiometer) 7 for detecting the horizontal rotation angle, the horizontal drive transmission unit 8 for transmitting the horizontal drive, the horizontal drive transmission unit 8, the camera unit, etc. A frame 9 for mounting,
It is composed of a housing 11 containing a camera unit and the like, and a fixed support base 10 for supporting the entire camera unit.

As the vertical rotary motor 3 and the horizontal rotary motor 6, pulse motors with high positioning accuracy are used.

The housing 11 also rotates in the same manner as the camera unit rotates in the horizontal direction. However, even if the camera unit and the frame 9 integrated therewith are rotated in the vertical direction, the housing 11
Is immovable. At this time, the lens 1 of the camera unit swings its head up and down, and takes a picture of the outside world through a window that is wide open at the top and bottom of the housing 11 that does not move vertically.

The control mechanism of this camera unit is
As shown in the block diagram of FIG. 7, an operation unit 23 for an operator to input a command, a control unit 25 that controls the operation of each unit of the camera unit in response to the command, and drives the vertical rotation of the camera unit. Vertical rotation motor 3, vertical rotation angle sensor (rotary potentiometer) 4 for detecting the rotation angle, horizontal rotation motor 6 for driving the horizontal rotation of the camera unit, horizontal rotation for detecting the rotation angle Angle sensor (rotary potentiometer) 7
And an image pickup device unit 2 that executes an image pickup operation under the control of the control unit 25.

The vertical rotation motor 3 and the horizontal rotation motor 6 start rotating operation by the control signal of the control unit 25,
The rotary potentiometers 4 and 7 detect the rotation angle of the motor 3 or 6 and transmit it to the control unit 25.
Upon receiving the information from the rotary potentiometers 4 and 7, the control unit 25 stops the rotation of the motor 3 or 6 when the rotation angle reaches a predetermined value.

[0008]

However, since the conventional rotation angle detecting device in the camera unit uses the contact type rotary potentiometer for detecting the rotation angle in the vertical and horizontal directions, it has been used for a long time. Then, there are problems such as contact failure and the like, which lowers the accuracy and causes undetectability, and there is a point that reliability and life are insufficient.

The present invention solves these conventional problems, and an object of the present invention is to provide a highly reliable rotation angle detecting device that can be used for a long period of time.

[0010]

Therefore, in the present invention, the first index arranged on one arc of two concentric circles centering on the rotation center of the object to be detected and the other of the concentric circles on the other arc. And a second sensor disposed optically in the first index, a first sensor that optically detects the first index, and a second sensor that optically detects the second index. First
The rotation angle detecting device is configured to detect the information indicating the rotation reference position of the detected object from the index and the second sensor to detect the information indicating the relative rotational position of the detected object from the second index. is doing.

In this rotation angle detecting device, the second
Comparing operation means for comparing the information detected by the sensor with the information indicating the rotation speed of the rotational drive source of the object to be detected,
And a control means for controlling the rotation of the rotary drive source based on the comparison result of the comparison calculation means.

[0012]

Therefore, the rotation angle of the object to be detected is obtained as the relative rotation angle detected by the second sensor from the rotation reference position detected by the first sensor.

Further, when the rotational speed of the rotational drive source of the object to be detected is higher than usual with respect to the relative rotation angle detected by the second sensor, the object to be detected comes into contact with something and the rotation is hindered. It can be seen that it is in the state of being disturbed (disturbance state). This disturbance state is detected by the comparison calculation means, and the control means controls the rotary drive source.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the rotation angle detecting device of the present invention, the rotation angle is detected by using a photo interrupter which can detect the object without coming into contact with it. This photo interrupter is arranged by combining a light emitting element and a light receiving element, and converts a change in light generated by mechanical movement into an electric signal, which has been known per se.

In the embodiment, the case where this rotation angle detecting device is applied to a camera unit will be described.

This camera unit has the structure shown in FIG. 1 as a mechanism for detecting rotation in the vertical direction, and has the structure shown in FIG. 2 as a mechanism for detecting rotation in the horizontal direction.

As shown in the perspective view of FIG. 1A and the sectional view of FIG. 1B, the mechanism for detecting the vertical rotation of the camera unit is fixed to a support substrate 21 which is immovable in the vertical direction. It consists of two photo interrupters 14 and 15, and a semicircular rib 18 and a dividing rib 19 fixed to the frame 9 that rotates in the vertical direction integrally with the camera unit.

The support substrate 21 to which the photo interrupters 14 and 15 are fixed is fixed to the housing 11 of the camera unit,
It does not follow the vertical movement of the camera unit, but it can rotate in the horizontal direction in the same way as the camera unit.

The rib 18 and the dividing rib 19 are shown in FIG.
As shown in (c), the ribs 18 are arranged along two circles with different radii around the center of rotation in the vertical direction of the camera section, and the rib 18 is a half of the inner circle that is vertically divided. It is located on the circumference of a circle, and its lower end extends into the gap between the light emitting element and the light receiving element of the photointerrupter 14 facing each other.

Further, the dividing rib 19 is located on the circumference of a semicircle which is formed by dividing the outer circle laterally into two. Unlike the rib 18, the dividing rib 19 is divided into a plurality of ribs by slits, and an inner circumferential angle occupied by an arc formed by combining one of the plurality of ribs and one slit is X °. Ribs with an inner peripheral angle of 2X ° are provided at both ends (or one end) of the dividing rib 19, and the dividing rib is equal to the length of the rib.
19 is longer than half a circle. The center of the semi-circular arc of the dividing rib 19 is located in the gap where the light emitting element and the light receiving element of the photo interrupter 15 face each other.

Further, as shown in the perspective view of FIG. 2A and the sectional view of FIG. 2B, the mechanism for detecting the horizontal rotation of the camera unit is provided with two photo units fixed to a stationary support substrate 20. The interrupters 12 and 13 are composed of semicircular ribs 16 and split ribs 17 fixed to the housing 11 that rotates integrally with the camera unit only in the horizontal direction.

The support substrate 20 to which the photo interrupters 12 and 13 are fixed is fixed to the support base 10 of the camera unit.

The rib 16 and the dividing rib 17 are shown in FIG.
As shown in (c), the ribs 16 are arranged along two circles having different radii about the horizontal center of rotation of the camera section, and the ribs 16 are arranged such that the inner circle is parallel to the direction of the camera section. It is located on the circumference of a semicircle divided into two, and one end thereof extends into the facing gap between the light emitting element and the light receiving element of the photointerrupter 12.

The dividing rib 17 is located on the circumference of a semicircle obtained by dividing the outer circle into two in a direction orthogonal to the direction of the camera section. The dividing rib 17 is the dividing rib 19 of FIG.
The center of the half arc of the dividing rib 17 is located in the gap where the light emitting element and the light receiving element of the photo interrupter 13 face each other.

The photo interrupters 14 and 12 detect the rib 18 or 16 to detect the vertical or horizontal reference position (home position) of the camera unit. On the other hand, the photo interrupters 15 and 13 are divided into ribs 19 or
By detecting the number of passages of the plurality of 17 divided ribs, the relative rotation angle of the camera portion in the vertical direction or the horizontal direction is detected, and the inner peripheral angle 2 of the end portion of the divided rib 19 or 17 is detected.
By detecting the X rib, the vertical or horizontal rotation limit of the camera unit is detected. Furthermore, through the detection of the photo interrupter 15 or 13, it is possible to detect a state (disturbance state) in which the camera unit comes into contact with another object to prevent its rotation.

The control mechanism of this camera unit is
As shown in the block diagram of FIG. 3, an operation unit 23 for an operator to input a command, a control unit 25 for controlling the operation of each unit of the camera unit in response to the command, and a control unit 25 built in the photo interrupter. A pulse number calculator 26 that calculates based on the detection information, a vertical rotation motor 3 that is a drive source when the camera unit rotates in the vertical direction, and a vertical home position detection sensor (photointerrupter) that monitors the ribs 18. 14
A vertical relative position / rotational limit / disturbance detection sensor (photointerrupter) 15 for monitoring the divided ribs 19, a horizontal rotation motor 6 that is a drive source when the camera unit horizontally rotates, and ribs 16 Horizontal home position detection sensor (photointerrupter) 12 for monitoring and split rib 17
A horizontal relative position / rotational limit / disturbance detection sensor (photointerrupter) 13 for monitoring the above, and an image pickup device section 2 for executing an image pickup operation under the control of a control section 25.

The home position in the vertical or horizontal direction of this camera unit is a state in which the ends of the ribs 18 or 16 are located in the gaps between the photo interrupters 14 or 12.

As for the vertical direction, when the camera unit starts to rotate vertically downward (clockwise in FIG. 1C) from the state in which the camera unit is facing upward, the photo interrupter 14 will move to the direction shown in FIG.
The intersection line from white to black in (c) is detected to detect the home position. Conversely, when the camera unit starts to rotate vertically upward (counterclockwise in FIG. 1C) from the state in which the camera unit faces downward, the photo interrupter 14 causes the black to white crossing in FIG. 1C. The line is detected and the home position is detected.

The horizontal home position is also detected by the photo interrupter 12 in the same manner.

When the camera unit is positioned at the home position, when the photo interrupter 14 or 12 detects the home position, the camera unit passes the home position to some extent. Controls the vertical rotation motor 3 or the horizontal rotation motor 6.

The rotation angle in the vertical or horizontal direction of the camera unit can be obtained by detecting the rotation angle after the home position in each direction is detected by the photo interrupter 15 or 13. The rotation angle of the camera unit when one of the plurality of ribs in the split ribs 19 and 17 passes through the photo interrupter 15 or 13 is X °. Photointerrupter 15
Alternatively, 13 detects a pulse accompanying the passage of this rib and outputs it to the pulse number calculation unit 26, and the pulse number calculation unit 26 counts the number of pulses and multiplies the number of pulses by X to calculate the number of pulses in the camera unit. Calculate the rotation angle.

When it is necessary to detect the rotation angle of X ° or less, the number of pulses of the rotation motors 3 and 6 of the drive source is counted by the pulse number calculation unit 26 to calculate the rotation angle.

When the camera unit has rotated to the rotation limit, the photo interrupter 15 or 13 detects the 2X ° ribs of the dividing ribs 19 and 17, and notifies the control unit 25 of this.
Stops driving the rotary motor 3 or 6.

The detection of whether or not the camera unit is in a disturbance state is performed by the procedure shown in FIG. First, step 1; the pulse number calculator 26 counts the number of pulses detected by the photointerrupter 15 or 13 associated with the rotation of the dividing rib 19 or 17, and step 2; further, the rotation of the rotary motor 3 or 6. Count the number of pulses associated with. Next, step 3; the pulse number calculator 26 calculates the ratio of the pulse numbers counted in steps 1 and 2.
Under normal conditions without disturbance, the photo interrupter 15 or
The number of pulses generated from the motor is constant while 13 detects one pulse (that is, while rotating by a constant angle X °). However, when a disturbance is occurring, this pulse rate changes. When the pulse number calculator 26 detects this change in pulse rate, step 4;
The control unit 25 controls the rotary motors 3 and 6 to return the camera unit to the home position.

As described above, the control unit 25 moves the camera unit to the home position or maintains the predetermined angle based on the detection information of the photo interrupters 12, 13, 14, and 15. To control. Further, the rotation motors 3 and 6 are caused to take appropriate actions in response to the detection of the rotation limit and the disturbance state.

The rotation angle detecting device of the present invention is not limited to the configuration shown in the embodiment, but various modifications can be made.
For example, the ribs 16 and 18 and the dividing ribs 17 and 19 may be changed to different lengths. The ribs 16 and 18 may be replaced with ribs having a shape in which a slit is provided at the position indicating the home position.

Further, as the non-contact sensor, instead of a transmissive sensor that allows an object to be detected to pass between the light emitting and light receiving elements,
A light emitting / light receiving element may be arranged at a certain angle and a reflection type element for detecting the reflected light of the object may be used. In this case, a black and white striped plate can be used instead of the dividing rib.

When only one of the vertical direction and the horizontal direction is detected, it suffices to use one of the mechanisms shown in FIG. 1 or 2.

When applied to a camera unit, the rotation angle detecting device of the present invention can output information that contributes to the control operation required by the camera unit, and therefore, its effectiveness is maximized. Of course, it can be used for other devices.

[0040]

As is apparent from the above description of the embodiments, since the rotation angle detecting device of the present invention uses a non-contact type photo interrupter for detection, it has a long life and reliability. Therefore, the detection can be performed with high accuracy. Further, it is possible to protect the safety of the device by detecting a disturbance that disturbs the rotation operation of the device.

[Brief description of drawings]

FIG. 1 shows an embodiment of a rotation angle detection device of the present invention,
A perspective view (a), a cross-sectional view (b) and an enlarged view of a main part (c) of a mechanism for detecting rotation in a vertical direction,

FIG. 2 shows an embodiment of the rotation angle detection device of the present invention,
A perspective view (a), a cross-sectional view (b) and an enlarged view of a main part (c) of a mechanism for detecting horizontal rotation.

FIG. 3 is a block diagram showing a control mechanism in the apparatus of the embodiment.

FIG. 4 is a flowchart showing a procedure for performing disturbance detection in the apparatus of the embodiment,

FIG. 5 is a perspective view of a camera unit including a conventional rotation angle detection device,

FIG. 6 is a diagram showing a usage state of a camera unit,

FIG. 7 is a block diagram showing a control mechanism of a camera unit including a conventional rotation angle detection device.

[Explanation of symbols]

 1 Lens 2 Image Sensor 3 Vertical Rotation Motor 4 Vertical Rotation Potentiometer 5 Vertical Drive Transmitter 6 Horizontal Rotation Motor 7 Horizontal Rotation Potentiometer 8 Horizontal Drive Transmitter 9 Frame 10 Support 11 Housing 12-15 Photointerrupter 16, 18 ribs 17, 19 split ribs 20, 21 support substrate 22 camera unit 23 operation unit 24 monitor 25 control unit 26 pulse number calculation unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiichi Yoshiaki 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A first index arranged on one arc of two concentric circles having a center of rotation of a detected body as a center, and a second index arranged on the other arc of the concentric circles. A first sensor that optically detects the first index and a second sensor that optically detects the second index are provided, and the first sensor includes the first index and the second sensor. Rotation angle detection, characterized in that information indicating a rotation reference position of the detected object is detected, and the second sensor detects information indicating a relative rotational position of the detected object from the second index. apparatus. 2. A comparison calculation means for comparing information detected by the second sensor with information indicating a rotation speed of a rotary drive source of the object to be detected, and the comparison calculation means based on a comparison result of the comparison calculation means. The rotation angle detection device according to claim 1, further comprising a control unit that controls the rotation of the rotation drive source.