JP2551320B2 - Steering origin alignment device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering origin position adjusting device for performing steering origin position adjustment, which is a basis for controlling wheels of an automatic device that automatically travels on a floor such as an automated guided vehicle. .

[0002]

2. Description of the Related Art An automatic device such as an automatic guided vehicle that automatically travels on a floor surface steers in the direction in which the wheels are oriented in order to adjust the traveling direction. It is necessary for a control device that controls the steering to adjust the origin of the steering, which is the basis of the steering control, before starting the driving and at any time during the driving.

FIG. 3 is a perspective view showing a wheel portion of an automatic guided vehicle. The wheel 1 is rotatably held by a wheel receiver 2. The wheel receiver 2 is attached to the drive shaft of the speed reducer 3 and rotates in the horizontal direction. The decelerator 3 is attached to a servo motor 4, which is a steering motor, and an incremental encoder 5 that detects rotation of a drive shaft of the servo motor 4 is attached to an upper portion of the servo motor 4.
The lower end of the decelerator 3 is provided with two limit sensors 6 and 7, which are proximity sensors or reflective photoelectric sensors, and detects a dock 8 projecting on the upper surface of the wheel receiver 2.

As shown in FIG. 4, when the limit sensor 6 detects the dock 8, the wheel 1 cannot rotate further clockwise (wheel 1a), and when the limit sensor 7 detects the dock 8, the wheel 1 rotates. Cannot rotate any further in the counterclockwise direction (wheel 1b). Wheel 1
Has a swivel range of about 200 degrees.

A controller for an unmanned guided vehicle (not shown) uses the limit sensors 6 and 7 to adjust the origin position before starting the operation or at any time during the operation. That is, the control device drives the servo motor 4 to rotate the wheel 1 clockwise or counterclockwise, and the incremental encoder 5 when either the limit sensor 6 or 7 detects the dock 8 is detected.
The value of was stored and used as the origin position.

[0006]

According to such a home position alignment method, the servo motor 4 must be driven, and the position where the wheel 1 is rotated and stopped is used as the home position. When the limit sensors 6 and 7 were accidentally detecting the dock 8 when trying to go, a malfunction occurred.

[0007] Therefore, an object of the present invention is to provide a steering origin alignment device which has a simple structure and is capable of accurately performing origin alignment without malfunction.

[0008]

In order to achieve the above object, the present invention provides an incremental encoder for detecting rotation of a drive shaft of a steering motor, and a limit sensor for detecting two limits of steering of a wheel. The rotation direction detecting means for detecting the steering direction of the wheel from the AB phase signal of the incremental encoder and the Z phase of the incremental encoder are turned ON, the limit sensor detects one limit, and the limit sensor detects the limit. Of the gate means for stopping the power supply to the steering motor when the rotation direction detecting means detects that the wheel is rotating toward the steering wheel, and the incremental encoder when the steering motor is stopped by the gate means. And a storage means for storing the value as the origin position. To constitute a grayed home position alignment device.

[0009]

Since the present invention has the above-mentioned structure, it has the following effects.

According to the steering origin alignment device of the present invention, when the steering origin alignment is performed, power is first supplied to the steering motor,
Steer the wheels. As a result, the turning direction detecting means for detecting the steering direction of the wheel from the AB phase signal of the incremental encoder detects which direction the wheel is turning. As the wheel rotates, the limit sensor detects one of the limits. If the Z phase of the incremental encoder is turned on while the limit is being detected, and the rotation direction detected by the rotation direction detecting means is toward the limit detected by the limit sensor, the gate means is provided. Is activated, and power supply to the steering motor is stopped. The value of the incremental encoder when the steering motor is stopped is stored as the origin position and used for control.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments shown in the drawings will be described below.

FIG. 1 is a block diagram showing the configuration of an embodiment of a steering origin alignment device according to the present invention.

In FIG. 1, the AB phase output of the incremental encoder 5 for detecting the rotation of the servo motor 4 for steering the wheels is connected to a set of a CW rotation detector 9 and a CCW rotation detector 10 and a controller 11. ing. The Z-phase output of the incremental encoder 5 is AN
It is connected to the D gates 12 and 13.

The limit sensor 6 for detecting the clockwise limit of the wheel is connected to the AND gate 12, and the limit sensor 7 for detecting the counterclockwise limit of the wheel is connected to the AND gate 13. AN
The outputs of the D gates 12 and 13 are connected to the OR gate 14. The output of the OR gate 14 is connected to the set of the latch 15, and the inverted output of the latch 15 is connected to the AND gate 16.

The output of the AND gate 16 is connected to the controller 11 and the servo driver 17 for driving the servo motor 4, and the servo driver 17 is connected to the AND gate 16.
The power supply to the servo motor 4 is stopped by the output from.

The controller 11 controls the drive of the servo driver 17, and when the servo driver 17 is driven, the CW
Rotation detector 9, CCW rotation detector 10, latch 15, A
Sends a signal to the ND gate 16 to detect the CW rotation detector 9, CC
The W rotation detector 10 and the latch 15 are reset. The control device 11 is also connected to a RAM 18 that stores the encoder value of the steering origin position.

Next, the operation of this embodiment will be described with reference to the time chart of FIG.

When the steering origin is adjusted, t
At s, the control device 11 drives the servo driver 17. As a result, the CW rotation detector 9 and the CCW rotation detector 1
The output of 0 becomes 0, and the inverted output of the latch 15 becomes 1. Almost at the same time, the output of the AB phase of the incremental encoder 5 causes the output of either the CW rotation detector 9 or the CCW rotation detector 10 to become 1. Here, the CW rotation detector 9 outputs 1 assuming that it is rotated clockwise.

When the servo driver 17 is driven,
The Z phase of the incremental encoder 5 is periodically turned on. When the wheel is further rotated, the wheel reaches the limit, the limit sensor 6 detects the clockwise limit, and is turned on. When the rotation is further continued, the Z phase of the incremental encoder 5 is turned on at te, whereby the CW rotation detector 9, the limit sensor 6, and the Z phase of the incremental encoder are all turned on, so that the AND gate 12 outputs the output. To do.

The output of the AND gate 12 causes the OR gate 14 to output, and the inverted output of the latch 15 becomes 0, so that the output of the AND gate 16 also becomes 0. The output of the AND gate 16 forcibly turns off the power supply to the servo driver 17, and the controller 11 causes the servo driver 1 to turn off.
It is recognized that the power supply of 7 has been turned off, the value of the AB phase of the incremental encoder 5 at this time is stored in the RAM 18, and the steering origin position is set.

If the origin position is to be adjusted, Z
Even if the phase and limit sensor 6 is turned on, the servo driver 17 once outputs and the output of the servo driver 17 is stopped when the CW rotation detector 9 is turned on, so that no malfunction occurs.

The above procedure is the same when rotated in the counterclockwise direction.

As described above, according to the steering origin alignment device according to this embodiment, the origin alignment can be accurately performed with a simple structure, and the CW rotation detector 9,
Since the origin position is detected by turning on the CCW rotation detector 10, it is possible to detect a state in which the wheels are not rotating, and there is no malfunction.

Further, ON / OFF of the servo driver 17
Since only the signal needs to be output on the control side, it is easy to handle. Further, since the wheel rotation is forcibly stopped by hardware, there is no time error.

The embodiment of the present invention has been described above.
It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be appropriately modified within the scope of the gist of the present invention.

[0026]

As described above, according to the steering origin position adjusting device of the present invention, the origin position can be accurately adjusted with a simple structure, and the wheels are rotated by the rotation direction detecting means. Since it is possible to detect a non-existent state, there is no malfunction. Further, since the control side only needs to output the ON / OFF signal of power supply to the steering motor, the handling is easy. Further, since the wheel rotation is forcibly stopped by hardware, there is no time error.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a steering origin alignment device according to the present invention.

FIG. 2 is a time chart of the output of each device in the embodiment of FIG.

FIG. 3 is a perspective view showing wheels of an automatic guided vehicle to which the embodiment of FIG. 1 can be applied.

FIG. 4 is a diagram showing a range of rotation of the wheels of FIG.

[Explanation of symbols]

 4 Servo Motor 5 Incremental Encoder 6 and 7 Limit Sensor 9 CW Rotation Detector 10 CCW Rotation Detector 11 Controller 12 and 13 AND Gate 14 OR Gate 15 Latch 16 AND Gate 17 Servo Driver 18 RAM

Claims (1)

(57) [Claims] 1. An incremental encoder for detecting rotation of a drive shaft of a steering motor, and a limit sensor for detecting limits of two steering positions of wheels.
The rotation direction detecting means for detecting the steering direction of the wheel from the AB phase signal of the incremental encoder and the Z phase of the incremental encoder are turned ON, the limit sensor detects one limit, and the limit sensor detects the limit. Of the gate means for stopping the power supply to the steering motor when the rotation direction detecting means detects that the wheel is rotating toward the steering wheel, and the incremental encoder when the steering motor is stopped by the gate means. A steering origin alignment device, comprising: a storage unit that stores a value as an origin position.