JP2833440B2 - Moving speed control 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 moving speed control device for controlling the moving speed of a moving device such as a traveling truck, a lifting platform, and a fork of a stacker crane.

[0002]

2. Description of the Related Art The inventors of the present invention have proposed a method of measuring the traveling speed of a traveling vehicle such as a stacker crane, elevating a hoist, elevating a fork, and the like. We have already proposed a method to control the relationship. That is, as shown in FIG.
The preset maximum constant speed V _H of the mobile device and the minimum constant speeds V _LA , V _LD and the maximum acceleration a _A at the time of starting / stopping.
And the maximum deceleration a _D are stored in the storage device, and when the moving distance L is instructed to the speed control device, the constant speeds V _LA , V
_H, deceleration interval t _A between the V _LD, the relationship between time and speed in t _D, without exceeding the maximum acceleration a _A and maximum deceleration a _D stored in the storage device, taken along a sine curve Calculation is performed so as to obtain a relationship, and a speed command having a value corresponding to time is output from start to stop.

[0003]

According to such a moving speed control, since the acceleration / deceleration becomes zero at the time of transition between the acceleration / deceleration section and the constant speed section, no shock or vibration occurs in the mobile equipment. This has the effect. However, it is actually impossible to completely follow the motor due to slippage of the induction motor. Therefore, an undershoot U and an overshoot O as shown in FIG. 7 occur, which affects the distance accuracy and varies the creep distance. . When the creep distance is increased, the cycle time is adversely affected. If the creep distance is not sufficient, an overrun occurs, or the vehicle stops suddenly at a speed greater than the minimum constant speed V _LD, causing impact or vibration on the mobile device.

Accordingly, an object of the present invention is to provide a moving speed control device capable of improving the distance accuracy of a mobile device regardless of undershoot or overshoot.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a method for correcting each correction at a predetermined time interval from start to stop.
Created based on the actual position measured at each timing and the speed pattern of the time-speed relationship from start to stop
And theoretical positions - currently commanded in the rate tables
Comparing the theoretical position corresponding to the speed, measured positions continue to command the speed of the current instruction if less than the theoretical position is measured position speed theoretical position corresponding to the next theoretical position if more theoretical position - speed The moving speed control device is configured to read out and instruct from the table .

[0006]

The present invention has the above-described structure, and has the following effects.

According to the moving speed control device of the present invention,
The moving speed control device operates at a predetermined time interval from start to stop.
Based on the actual position measured at each correction timing and the speed pattern of the time-speed relationship from start to stop
It created Te theoretical position - in the corresponding table speed
Compare with the theoretical position corresponding to the speed currently being commanded . If the measured position is less than the theoretical position, continue to command the current commanded speed.If the measured position is greater than or equal to the theoretical position, read the speed corresponding to the next theoretical position from the theoretical position-speed table.
Produce and instruct.

[0008]

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

FIG. 1 is a block diagram showing a configuration of an embodiment applied to a traveling truck of a stacker crane of a moving speed control device according to the present invention.

In FIG. 1, a storage device 1 stores a maximum speed v _H , which is a normal operation speed of a traveling truck of a stacker crane,
Minimum speed v _LA during starting, the minimum speed v _LD during stopping, the maximum acceleration a _A, the maximum deceleration a _D are stored. The speed calculation device 2 is provided with a travel distance L from the travel control device 3.
And reads the data from the storage device 1,
Generate a speed pattern of the relationship between speed and time.

The maximum speed v _H is a normal operation speed determined based on the performance and safety of the traveling vehicle. The minimum speed v _LA at the time of starting is the minimum speed that can be reached immediately after starting, and the minimum speed v _LD at the time of stopping. Is the minimum speed that can be stopped immediately by braking. Maximum acceleration a _A and maximum deceleration a _D is determined based on the performance and safety. The running distance L changes each time according to a work instruction.

[0012] speed calculating unit 2 is driven by the start at the minimum velocity v _LA and the maximum speed v accelerating section between a section running at _H, and the maximum speed v interval and stop at the minimum speed to travel at _H v _LD The calculation is performed so that the relationship between the speed and the time becomes a relationship along the sine curve as shown in FIG. 7 in the deceleration section between the creep section and the creep section.

Further, the speed calculating device 2 converts the relationship between the speed V and the time t into the relationship between the speed V and the position x. FIG.
As shown in (1), if the speed pattern calculated based on each data of the storage device 1 is integrated with respect to the time t, the relationship between the time t and the position x can be obtained. Further, the speed V at the position x is obtained, and a speed pattern based on the relationship between the position x and the speed V as shown in FIG. 3 can be obtained.

The traveling control device 3 receives a speed pattern based on the relationship between the position x and the speed V from the speed calculating device 2, activates the inverter 4 according to the speed pattern, and drives the traveling drive motor 5 to drive the traveling vehicle. Move. The encoder 6 for measuring the position of the traveling vehicle is connected to the traveling control device 3.

The data of the speed pattern based on the relationship between the position x and the speed V is actually in the form of a table as shown in FIG. Intermediate speed command value data [n],
The theoretical position dist [n] on the right is a value corresponding to the table number n on the left.

Next, according to the flowchart of FIG. 5, a process of the traveling control performed by the traveling control device 3 while the traveling vehicle is moving will be described.

The travel control device 3 corrects the speed command at every correction timing (for example, every 5 msec) from start to stop. First, it is determined whether or not it is a correction timing (step 1). If not, a speed command value data [n] corresponding to the table number is set as an output value (step 2). According to FIG. 4, at the time of startup, the table number is 0, the speed command value data [0] is 10, and this value does not change until the next correction timing.

When the correction timing comes, the theoretical position dis
t [n] is compared with the actually measured position measured by the encoder 6 (step 3). Measured position is theoretical position dis
If it is less than t “n” , the same speed command value data is continuously
[N] becomes the output value (step 2).

If the measured position is equal to or greater than the theoretical position dist [n] , n = n + 1, and a speed command value data [n] is output (step 4). That is, as shown in FIG.
When the measured position exceeds the theoretical position dist [0] = 43,
n = 0 + 1, and the speed command value data [1] = 11 is the output value.

The output value determined as described above is output from the travel control device 3 to the inverter 4 (step 5), and the above process is repeated until it stops.

According to the above-described control, as shown in FIG. 6, the speed output value is kept constant without changing the speed until the measured position catches up with the theoretical position. The traveling vehicle can be caused to travel in a pattern close to the speed pattern obtained by the above. Therefore, the position accuracy can be increased, and the creep distance for traveling at the minimum constant speed _VLD at the time of stoppage can be kept constant.
Therefore, even if the creep distance is shortened to shorten the cycle time, an accident such as overrun or sudden stop does not occur.

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-described embodiments, and can be appropriately modified and implemented within the scope of the present invention.

For example, the above-described embodiment is applied to the movement of the traveling truck of the stacker crane, but can also be applied to a lifting platform, a slide fork, and other moving devices of the stacker crane. Further, the present invention is also applicable to triangular control or the like generally performed in a traveling truck of a stacker crane, and the relationship between speed and time is not particularly limited to the one following the sine curve in the above embodiment.

[0024]

As described above, according to the moving speed control device according to the present invention, the speed control of the mobile device can be performed without depending on time.
Since the adjustment is performed based on the position, a position error hardly occurs, and the position accuracy can be improved. Therefore, variations in creep distance adversely affect cycle time,
It is possible to prevent an accident such as an overrun or an abrupt stop at a speed greater than the minimum constant speed, causing an impact or vibration on the mobile device. Also, even if the speed output response delay occurs,
Since the speed command is maintained until the measured position reaches the theoretical position, highly accurate traveling drive is possible regardless of the response of the motor.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a moving speed control device according to the present invention.

FIG. 2 is a diagram schematically illustrating a process of converting a speed pattern having a time-speed relationship into a speed pattern having a position-speed relationship in the embodiment of FIG. 1;

FIG. 3 is a diagram showing a velocity pattern of a position-velocity relationship generated by the process of FIG. 2;

FIG. 4 is a diagram illustrating an example of tabulating the data of the speed pattern of FIG. 3;

FIG. 5 is a flowchart illustrating a process of determining an output value of a speed command according to the embodiment of FIG. 1;

6 is a diagram illustrating a relationship between an output value that changes at each correction timing according to the output of the speed command in FIG. 5 and an actual speed;

FIG. 7 is a diagram showing a speed pattern of a time-speed relationship.

[Explanation of symbols]

v Maximum _H speed v Minimum _LA start speed v Minimum _LD stop speed

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-186581 (JP, A) JP-A-2-243403 (JP, A) JP-A-58-137795 (JP, A) 138210 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B60L 15/40 H02P 5/00 G05D 3/00

Claims (1)

(57) [Claims] 1. A supplementary method for a predetermined time interval from start to stop.
It is based on the measured position measured at each positive timing and the speed pattern of the time-speed relationship from start to stop.
Currently commanded in the generated theoretical position-speed table
If the measured position is less than the theoretical position, the current command is continuously commanded, and if the measured position is greater than or equal to the theoretical position, the speed corresponding to the next theoretical position is compared with the theoretical position. A moving speed control device which reads out from a speed table and issues a command.