JP4901579B2 - Angle detector - Google Patents

Description

  The present invention relates to a rotation angle detection device around a rotation axis, and more particularly to an angle detection device that outputs an absolute rotation angle using a semi-absolute type angle detector that outputs a relative rotation angle.

  Accurate detection of the rotation angle around the rotation axis is indispensable for control of a device having a rotation mechanism. For example, in a gimbal function including an imaging device, in order to calculate the position of the target object relative to the device provided with the gimbal mechanism by rotating the imaging device following the movement of the target object to be imaged, each rotation axis It is necessary to detect the rotation angle around.

A conventional angle detection device for detecting such a rotation angle is configured using an absolute angle detector that detects an absolute rotation angle around a rotation axis (for example, Patent Document 1).
Japanese Patent No. 2602908

  However, a high-accuracy absolute angle detector is expensive, raising the problem of increasing the product price.

  On the other hand, the semi-absolute type angle detector has a problem that it cannot be used as it is because it is inexpensive but does not output an absolute rotation angle but only outputs a certain angle repeatedly.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an inexpensive angle detection device that detects an absolute rotation angle with high accuracy.

  In order to achieve this object, the present invention provides a stopper for stopping the rotation of the rotating member rotated by the rotating motor, a semi-absolute type angle detector for detecting the rotation of the rotating shaft of the rotating motor, and a calculation by the rotating motor. A control unit that controls the rotary motor, and this control unit rotates the rotary motor until the rotary member is stopped by the stopper, and initializes the detection angle output by the semi-absolute type angle detector as a reference angle. After this initialization, the reference angle is calculated from the sum of the product of the pitch number, which is the rotation speed of the semi-absolute angle detector, and the pitch angle, which is the maximum detection angle of the semi-absolute angle detector, plus the measured detection angle. Provided is an angle detection device that calculates a subtracted difference as an absolute rotation angle.

  According to the present invention, a semi-absolute angle detector is used in the angle detection device, and the output of the semi-absolute angle detector is further processed to calculate an absolute rotation angle. Therefore, there is an effect that it is possible to provide an angle detection device that calculates the absolute rotation angle with high accuracy at low cost.

  Hereinafter, an embodiment of an angle detection device according to the present invention will be described in detail with reference to the drawings.

<Details of Embodiment>
FIG. 1 is a schematic diagram showing a configuration when the angle detection device of the present embodiment is installed in a gimbal mechanism. As shown in FIG. 1, the angle detection device 101 of this embodiment is provided in a gimbal mechanism that rotates a rotating member 109 around two gimbal rotating shafts that are a rotating shaft 102 and a rotating shaft 103 that are orthogonal to each other.

  The angle detection device 101 detects rotations of the rotary shafts of the rotary motors 104 and 105 and outputs a pitch angle which is an angle smaller than 360 °. Semi-absolute type angle detector 108 (the other one is not shown); rotation of the rotating member 109 so that the rotating member 109 rotated by these rotating motors 104 and 105 does not rotate beyond a predetermined angle. And a control unit (not shown) for controlling the rotation of the rotary motors 104 and 105 and calculating the absolute rotation angle of the rotary member 109 from the detection angle input from each semi-absolute type angle detector. And comprising;

  In FIG. 1, the stoppers 106 and 107 are provided as protrusions on the rotating member, but the rotation of the rotating member 109 is stopped so that the rotating member 109 does not rotate more than a predetermined angle. Any installation position or shape may be used.

  Further, in FIG. 1, each semi-absolute type angle detector is provided on the opposite side across the rotating member 109 of each rotating motor 104, 105, but the same side with respect to each rotating motor 104, 105 and rotating member 109. Each semi-absolute type angle detector may be provided.

  FIG. 2 is a view of the gimbal mechanism in which the angle detection device 101 according to the present embodiment is installed as seen from the direction of the arrow A in FIG. As shown in FIG. 2, the stopper 106 is provided at a position where the rotation of the rotating member 109 is stopped so that the rotating member 109 does not rotate more than a predetermined angle by hitting the support member 201.

  FIG. 3 is a view of the gimbal mechanism in which the angle detection device 101 of the present embodiment is installed as seen from the direction of arrow B in FIG. As shown in FIG. 3, the stopper 108 is provided at a position where the rotation of the rotating member 109 is stopped so that the rotating member 109 does not rotate more than a predetermined angle by hitting the support member 301.

  Here, the semi-absolute type angle detector will be described. The semi-absolute type angle detector used in the present embodiment detects a rotation angle and outputs an electrical signal. The absolute type angle detector outputs an absolute angle in one rotation. On the other hand, the semi-absolute type angle detector repeatedly outputs, for example, 0 ° to 60 ° as the rotation shaft rotates in a certain direction. As described above, the maximum value of the angle output from the semi-absolute type angle detector is referred to as a pitch angle.

  When the pitch angle is 60 °, the semi-absolute type angle detector outputs the pitch angle six times as the rotation axis rotates in a certain direction. Thus, the number of times the pitch angle is output is referred to as the number of pitches.

  An example of a semi-absolute type angle detector is an incremental rotary encoder.

  FIG. 4 is a graph showing the relationship between the detection angle X of the semi-absolute type angle detector and the rotation angle of the rotating shaft. Here, the pitch angle is represented by (360 / n), where n is the number of pitches in one rotation. Thus, the semi-absolute type angle detector repeatedly outputs 0 ° to X ° when the rotation shaft rotates in a certain direction.

  Next, the connection configuration of the angle detection apparatus 101 of this embodiment will be described. As shown in FIG. 5, the angle detection device 101 according to the present embodiment includes a first motor 501, a first transmission unit 503 that transmits rotation of the rotation shaft of the first motor 501, and the first transmission. A first semi-absolute angle detector 502 that can transmit the rotation from the unit 503, a second motor 504, a second transmission unit 506 that transmits the rotation of the rotation shaft of the second motor 504, and the second A second semi-absolute angle detector 505 that can transmit rotation from the transmission unit 506 and a control unit 507 are provided.

  Each of the first transmission unit 503 and the second transmission unit 506 can use a reduction gear such as a gear, but without using the first transmission unit 503 and the second transmission unit 506, the rotation shaft of each motor. The rotating part of the semi-absolute angle detector may be directly attached to.

  The control unit 507 includes a signal processing unit 508 that performs calculation and a motor control unit 509 that controls each motor. The control unit 507 can be configured using, for example, a CPU that is an arithmetic device and a memory that is a storage device.

  Outputs from the first semi-absolute angle detector 502 and the second semi-absolute angle detector 505 are input to the signal processing unit 508 of the control unit 507, respectively. The signal processing unit 509 outputs a motor control signal to the motor control unit 509. The signal processing unit 508 outputs an absolute rotation angle 510 as will be described later.

  Next, the operation of the control unit 507 of the angle detection apparatus 101 of this embodiment will be described. In order to simplify the life expectancy, first, a semi-absolute type angle detector 108 installed to detect the rotation of the rotating shaft 102 of the first motor 104 will be described.

  The control unit 507 rotates the rotary motor 104 in the first direction until the rotating member 109 is stopped by the stopper 106, and inputs from the semi-absolute angle detector 108 when the rotating member 109 is stopped by the stopper 106. The detection angle is set to the reference angle and the pitch number is initialized, that is, set to “0”.

  After this initialization, the control unit 507 sets the control detection angle, which is the detection angle input from the semi-absolute angle detector 108, when the rotary motor 104 is rotated in the second direction opposite to the first direction in advance. When a predetermined value, that is, the pitch angle is reached, the pitch number is added to obtain the detected pitch number.

  The control unit 507 outputs the difference obtained by subtracting the reference angle α from the sum of the product of the control detection angle β and the detected pitch number k multiplied by the pitch angle P as the absolute rotation angle D. That is, the absolute rotation angle D is calculated by the following equation (1).

D = β + k × P−α (1)
In equation (1), the number of detected pitches k is multiplied by the pitch angle P. When the control detection angle exceeds the pitch angle, the absolute rotation angle D is calculated by accumulating the pitch angle to the absolute rotation angle. You may comprise.

  That is, after initialization, the pitch is detected when the control detection angle input from the semi-absolute type angle detector 108 exceeds the pitch angle when the rotary motor 104 is rotated in the second direction opposite to the first direction. The angle may be cumulatively added to the absolute rotation angle, and a difference obtained by subtracting the reference angle from the sum of the control detection angle and the absolute rotation angle may be output as the absolute rotation angle.

  When the control detection angle β is larger than the immediately preceding control detection angle when the rotation unit 104 is rotated in the first direction after rotating the rotary motor 104 in the second direction, the control unit 507 calculates “ It may be configured to subtract 1 ″ to obtain the detected pitch number k.

  This will be specifically described with reference to FIG. FIG. 6 is a flowchart showing the operation of the control unit 507. In step S601, the control unit 507 rotates the first motor 104 in the first direction.

  In step S602, the control unit 507 determines whether the first motor 104 has missed rotation. The determination method is, for example, comparing the value output from the first semi-absolute angle detector 502 at regular intervals with the value output from the first semi-absolute angle detector 502 immediately before, and the difference between them is If it is less than or equal to a predetermined threshold, it is determined that the vehicle is stopped. When it is determined that the control unit 507 has not stopped, the control unit 507 returns to step S601. When it is determined that the control unit 507 has missed, the control unit 507 proceeds to step S603.

  In step S603, the control unit 507 sets the detection angle output from the first semi-absolute angle detector 502 to the reference angle α. In step S604, the control unit 507 sets “1” to the pitch number k.

  In step S605, the control unit 507 rotates the first motor 104 in the second direction opposite to the first direction. In step S606, it is determined whether the control detection angle β at this time is equal to the pitch angle. The control unit 507 proceeds to step S607 when determining that they are equal, and proceeds to step S608 when determining that they are not equal.

  In step S607, the control unit 507 adds “1” to the pitch number. In step S608, the control unit 507 calculates and outputs the absolute angle using the above-described equation (1), and returns to step S605.

  The operation related to the semi-absolute type angle detector 108 installed so as to detect the rotation of the rotating shaft 102 of the first motor 104 of the control unit 507 has been described above, but the operation of the second motor 105 of the control unit 507 is described. The operation related to the semi-absolute type angle detector installed so as to detect the rotation of the rotating shaft 103 is similar.

<Effect of embodiment>
As described above, the angle detection device 101 of the present embodiment uses a semi-absolute angle detector, sets the reference angle based on the angle at which the rotation is stopped by the stopper, initializes the number of pitches, and then detects the angle. The absolute rotation angle is calculated from the number of pitches, the pitch angle, the control detection angle, and the reference angle. For this reason, there exists an effect that it becomes possible to provide a highly accurate angle detection apparatus at low cost.

<Possibility in the embodiment of the present invention>
Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

It is a schematic diagram which shows the structure at the time of installing an angle detection apparatus in a gimbal mechanism. It is the figure which looked at the gimbal mechanism which installed the angle detection apparatus from the direction of the arrow A of FIG. It is the figure which looked at the gimbal mechanism which installed the angle detection apparatus from the direction of arrow B of FIG. It is the graph which showed the relationship between the detection angle X of a semi-absolute type angle detector, and the rotation angle of a rotating shaft. It is the block diagram which showed the connection of the angle detection apparatus. It is a flowchart which shows operation | movement of a control part.

Explanation of symbols

101: Angle detection device,
102, 103: rotating shaft,
104, 105: Rotating motor,
106, 107: stopper,
108: Semi-absolute type angle detector,
109: Rotating member.

Claims (6)

A rotation motor that rotates about a rotation axis;
A semi-absolute type angle detector that detects the rotation of the rotary shaft of the rotary motor and outputs a pitch angle that is smaller than 360 °;
A stopper for stopping the rotation of the rotating member so that the rotating member rotated by the rotary motor does not rotate more than a predetermined angle;
A control unit that controls the rotation of the rotary motor and calculates the absolute rotation angle of the rotating member from the detection angle input from the semi-absolute type angle detector;
An angle detection device comprising:
The control unit is
The rotation motor is rotated in the first direction until the rotating member is stopped by the stopper, and the detection angle input from the semi-absolute type angle detector when the rotating member is stopped by the stopper is a reference angle. And initialize the number of pitches,
After the initialization, a control detection angle that is a detection angle input from the semi-absolute angle detector when the rotary motor is rotated in a second direction opposite to the first direction is a predetermined value. When the number reaches, the number of pitches is added to obtain the number of detected pitches.
An absolute rotation angle is calculated and output from the control detection angle, the number of detected pitches, the pitch angle, and the reference angle,
An angle detection device characterized by that. A rotation motor that rotates about a rotation axis;
A semi-absolute type angle detector that detects the rotation of the rotary shaft of the rotary motor and outputs a pitch angle that is smaller than 360 °;
A stopper for stopping the rotation of the rotating member so that the rotating member rotated by the rotary motor does not rotate more than a predetermined angle;
A control unit that controls the rotation of the rotary motor and calculates the absolute rotation angle of the rotating member from the detection angle input from the semi-absolute type angle detector;
An angle detection device comprising:
The control unit is
The rotation motor is rotated in the first direction until the rotating member is stopped by the stopper, and the detection angle input from the semi-absolute type angle detector when the rotating member is stopped by the stopper is a reference angle. And initialize the number of pitches,
After the initialization, a control detection angle that is a detection angle input from the semi-absolute angle detector when the rotary motor is rotated in a second direction opposite to the first direction is a predetermined value. When the number reaches, the number of pitches is added to obtain the number of detected pitches.
The difference obtained by subtracting the reference angle from the sum of the product of the control detection angle multiplied by the detected pitch number and the pitch angle is output as an absolute rotation angle.
An angle detection device characterized by that. A rotation motor that rotates about a rotation axis;
A semi-absolute type angle detector that detects the rotation of the rotary shaft of the rotary motor and outputs a pitch angle that is smaller than 360 °;
A stopper for stopping the rotation of the rotating member so that the rotating member rotated by the rotary motor does not rotate more than a predetermined angle;
A control unit that controls the rotation of the rotary motor and calculates the absolute rotation angle of the rotating member from the detection angle input from the semi-absolute type angle detector;
An angle detection device comprising:
The control unit is
The rotation motor is rotated in the first direction until the rotating member is stopped by the stopper, and the detection angle input from the semi-absolute type angle detector when the rotating member is stopped by the stopper is a reference angle. Set to
After the initialization, when the rotary motor is rotated in a second direction opposite to the first direction, a control detection angle, a control detection angle, which are detection angles input from the semi-absolute type angle detector, An absolute rotation angle is calculated and output from the pitch angle and the reference angle,
An angle detection device characterized by that. A rotation motor that rotates about a rotation axis;
A semi-absolute type angle detector that detects the rotation of the rotary shaft of the rotary motor and outputs a pitch angle that is smaller than 360 °;
A stopper for stopping the rotation of the rotating member so that the rotating member rotated by the rotary motor does not rotate more than a predetermined angle;
A control unit that controls the rotation of the rotary motor and calculates the absolute rotation angle of the rotating member from the detection angle input from the semi-absolute type angle detector;
An angle detection device comprising:
The control unit is
The rotation motor is rotated in the first direction until the rotating member is stopped by the stopper, and the detection angle input from the semi-absolute type angle detector when the rotating member is stopped by the stopper is a reference angle. Set to
After the initialization, a control detection angle that is a detection angle input from the semi-absolute angle detector when the rotary motor is rotated in a second direction opposite to the first direction is a predetermined value. The pitch angle is cumulatively added to the absolute rotation angle when
A difference obtained by subtracting the reference angle from the sum of the control detection angle and the absolute rotation angle is output as an absolute rotation angle.
An angle detection device characterized by that. Provided in a gimbal mechanism that rotates the rotating member around two gimbal rotation axes that are orthogonal to each other;
The two rotary motors rotate the rotary member for each gimbal rotary shaft,
The control unit outputs an absolute rotation angle around the two gimbal rotation axes of the rotation member;
The angle detection device according to any one of claims 1 to 4, wherein the angle detection device is configured as described above.   6. The angle detection device according to claim 1, wherein the semi-absolute type angle detector is an incremental rotary encoder.

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