JPH0635282B2 - Stacker crane movement speed control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control method for traveling, ascending / descending speed, and positioning of a stacker crane used for loading / unloading a load in a three-dimensional warehouse or an automated warehouse.

(Prior Art) Conventionally, in the method of controlling the speed and positioning of the traveling and ascending / descending of the stacker crane, the acceleration / deceleration control is treated as the number of times, and the speed is controlled according to the time. For example, 2 seconds after the start, a speed of 2 meters per second, and then 5
After a second, it is controlled like a speed of 10 meters per second. The final stop on the target shelf is made by a mechanical brake.

As still another method, a method of gradually controlling the speed based on the information of the shelf address or the number of shelves, a method of determining the deceleration start point from the shelf immediately before the start of deceleration and determining the speed by a timer, and the like are adopted. .

(Problems to be Solved by the Invention) The conventional speed control method with a small number of times has a drawback in that an error is likely to occur at the deceleration end point / stop position due to variations in initial speed, load, and the like. In addition, since the final stop is the mechanical brake, it depends on the variation in the operating time of the mechanical brake ON / OFF control, the change over time of the brake, the influence of the surrounding environment such as the temperature and humidity of the braking force, and the change and consumption of the brake shoe. There is a problem that the final stop position varies due to variations in braking force, load, variation in stopping distance due to variation in initial speed, and the like.

Further, since the conventional control method of controlling the speed based on the position / distance information from only the shelf address or the number of shelves can perform only the rough stepwise speed control, the speed control / position control with high accuracy cannot be performed. Also, even if the control method of
There is a problem that the error of the deceleration start point becomes large due to the variation of the initial speed and the like, and it is not possible to perform the speed / position control with high accuracy as described above.

A control method of this type is disclosed in Japanese Patent Laid-Open No. 12226/51.
9 PR, JP 63-47210 PR, JP 50
Japanese Patent Publication No. 37154 discloses a method of measuring the distance from the rotation of the drive system to control the movement of a crane or the like, and a method of detecting the position of a shelf to control the movement, but only by the distance from the rotation of the drive system. When the movement is controlled, slips and instrument errors are accumulated during long distance travel, and a considerable distance measurement error occurs. High-speed control is also required. Further, there is a problem that it is difficult to perform accurate control in the shelf section of the acceleration / deceleration section by the method of controlling only the shelf position. In addition, the final stop positioning is not sufficient in terms of accuracy if only two types of control are performed.

The problem to be solved by the present invention is to solve these conventional problems, to shorten the loading / unloading cycle of the stacker crane, improve the stop position accuracy, and reduce the number of times of periodical replacement of the brake shoes.

(Means for Solving the Problems) The gist of the present invention which has solved the above problems is as follows: 1) A designated speed value required for a series of operations such as acceleration, constant speed, deceleration, and stop of a stacker crane is set as the number of distances. Calculate and store the relationship between the distance and speed in a storage device in advance, calculate the distance information from the measured value of the rotational speed of the shaft of the drive system such as wheels and motors, and based on the calculated distance information. In addition to controlling the speed of each running or ascending / descending with the speed pattern of the above-mentioned distance number calculated in advance, in a long distance moving section where there is one constant speed moving distance or more, up to the shelf position immediately before deceleration or acceleration starts Calculate the distance by counting the number of shelves, prioritize the calculated distance as the distance information in that section, and use two non-contact type distance sensors near the moving side of the stacker crane. In addition, mountain-shaped symmetrical dogs are arranged so as to face each other on the fixed side of shelves, warehouses, stations, etc., and a stacker is used so that the difference between the measured values of the symmetrical dogs of the two distance sensors becomes zero. A stop positioning control method for a stacker crane, wherein final positioning is performed by controlling a traveling motor of the crane.

It is in.

(Operation) In the present invention, the designated value of the speed is set as the number of distances, the distance speed pattern is stored in advance, distance information is actually measured from the rotation speed of the wheel or the like by means such as a pulse generation circuit, and the distance information is obtained. The method of controlling the speed is adopted. Initial speed
Factors such as load do not affect the value of the distance actually measured from the rotation speed, the distance at the correct position can be calculated, and the speed control becomes accurate. Also, instead of stepwise speed control by shelf address and number of shelves, continuous or highly accurate digital control of speed by continuous distance / position information can be performed, enabling high speed / position control.

Here, in the case of a long distance movement such that the constant speed movement distance is one shelf or more, the number of shelves is counted in the constant speed shelf section,
If the method of determining the number of shelves or the number of the shelf and maintaining a constant speed up to the shelf position immediately before deceleration or acceleration, and then controlling the speed by the distance actually measured from the number of rotations described above is used, the control is simplified and an error occurs. Can be reduced.

Furthermore, when the stacker crane is stopped at a predetermined position, by using two distance sensors and a mountain-shaped symmetric dog, the difference between the two distance sensor measurement values is the center of the mountain dog and the distance between the two distance sensors. If the traveling motor of the stacker crane is controlled so that the difference between the measured values of both sensors becomes zero, the stop positioning can be accurately performed with simple control.

(Example) Hereinafter, an example will be described with reference to the drawings.

This embodiment used to control the speed and position of the stacker crane for loading and unloading of a multi-storey warehouse having a large number of shelves and frontages is an embodiment that embodies all the inventions described in each claim in the section of the claims. is there.

In the figure, (1) is a microcomputer for performing central control and storage of the present invention, (2) is a D / A converter, (3) is a signal switch,
(4) is an amplifier, (5) is a motor controller, (6) is a traveling motor,
(7) is a pulse generator that measures the rotational speed of the wheel shaft, (8) is a non-contact distance sensor, (9) is a mountain-shaped symmetrical dog provided for each shelf, (10) is a comparator, (11) ) Is an amplifier.

In this embodiment, the number of revolutions of the traveling motor (6) for driving the wheels of the stacker crane is converted into the number of pulses by the pulse generator (7), input to the microcomputer (1), the number of pulses is counted, and Is multiplied and corrected to calculate the distance. From the calculated distance, the target speed corresponding to the distance speed pattern set and stored in the RAM or ROM built into the microcomputer (1) is read out and output as an analog signal via the D / A converter (2), Amplified (4) to the required signal level,
Input to the motor control unit (5). The motor control unit (5) controls the traveling motor (6) to the target speed according to the input value.

Here, the distance / velocity pattern set and stored in the microcomputer (1) is created by an external command (12) of this computer or by a move command at a required rack position from an internal command.

An acceleration / deceleration speed pattern suitable for the crane is stored in advance in the ROM or RAM in the microcomputer (1). These acceleration / deceleration patterns are stored so that the position and the predetermined speed at that time can be sequentially understood. These patterns are stored in ROM when the crane is installed.
May be stored in the RAM, or may be calculated each time immediately before the crane starts and stored in the RAM.
It may be sent from the parent computer.

When the microcomputer (1) is instructed to move to the target shelf, the distance (pulse number) to the target shelf is calculated.

Next, it is determined whether the calculated distance is longer or shorter than the distance required for acceleration / deceleration up to the MAX speed (constant speed range). If you don't have the distance to accelerate to MAX speed,
The previously stored pattern is calculated so that the sum of the acceleration distance and deceleration distance matches the movement distance, and the acceleration / deceleration demarcation point (1/2 if acceleration / deceleration is on the same curve) Accelerate along and decelerate thereafter.

When the target value is farther than the acceleration / deceleration distance, the remainder obtained by subtracting the distance required for acceleration / deceleration from the target value is taken as the constant speed section at the MAX speed. First, the vehicle accelerates to the MAX speed according to the acceleration pattern, and moves from that point at the MAX speed by the distance calculated above. Next, the vehicle is decelerated according to the deceleration pattern.

If the traveling section at MAX speed is more than one shelf, only the shelves are moved to the distance sensor (8) when moving at MAX speed.
The microcomputer (1) commands to maintain the constant speed up to the shelf position immediately before the start of deceleration. When the constant speed running section is long as described above, the pulse signal of the pulse generator (7) is not used, so that errors due to wheel slip and wheel wear in the pulse signal can be suppressed to a minimum. When the constant-speed shelf section ends and the acceleration / deceleration shelf section is entered, the distance is calculated from the number of revolutions by the pulse generator (7) in the same manner as described above, and the speed is controlled to the distance-speed pattern corresponding to the distance. Furthermore, at the end of deceleration, put the signal switch (3) on the side of the distance sensor (8), the two distance sensors (8) detect the chevron-shaped symmetrical dog (9), and output with a signal according to the distance. The output signals of both distance sensors (8) are compared by the comparator (10), the difference is amplified and input to the motor control unit (5), and the travel motor (6) is connected to the two distance sensors ( Operate so that the signal of 8) becomes the same value, and stop when it converges to the same value.

In such a stop positioning control method, wheel slip,
There is no deviation from the shelf position due to wear, and it can be stopped accurately at an absolute position.

(Effect of the invention) As described above, according to the present invention, the speed is stored as the number of distances, and the speed is controlled by obtaining the distance based on the measured value of the rotation speed of the wheel or the like. It is possible to obtain high speed / position control accuracy without being affected by.
Also, if the final stop is controlled based on the difference between the measured values of the symmetrical dog and the distance sensor, it will be affected by the variation in the operating time of the mechanical brake ON / OFF control, the change in braking force over time, and the influence of the surrounding environment of braking force. It is possible to accurately stop at an absolute position regardless of variations. Furthermore, in the section where the constant speed moving distance is one shelf or more, instead of controlling the distance speed,
If the constant speed maintenance control is performed only by counting the number of shelves, it will not be affected by the slip and wear state of the wheels, and the speed and accuracy of
Position control can be enabled.

[Brief description of drawings]

 FIG. 1 is a control block diagram of an embodiment of the present invention. (1): Microcomputer (2): D / A converter, (3): Signal switcher (4), (11): Amplifier, (5): Motor controller (6): Travel motor, (7) : Pulse generator (8): Distance sensor, (9): Symmetric dog (10): Comparator

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Toshiya Goto 1 868 Kubo, Koga-cho, Kasuya-gun, Fukuoka Prefecture Seibu Electric Co., Ltd. (72) Teruaki Takahata 1-868 Kubo, Koga-cho, Kasuya-gun, Fukuoka (56) References JP-A-51-122269 (JP, A) JP-A-63-47210 (JP, A) JP-A-50-37154 (JP, A) JP-A-61-106389 ( JP, A) JP 58-197102 (JP, A) JP 61-203008 (JP, A) JP-B-4-22802 (JP, B2)

Claims (1)

[Claims] [Claim 1] Acceleration / constant speed / deceleration of stacker crane
Calculate the speed specified value required for a series of operations such as stopping as the number of distances, store the relationship between the distance and speed in a storage device in advance, and store the distance information in the axes of drive systems such as wheels and motors. Calculated from the measured value of the number of revolutions, and control the speed of every running or ascending / descending according to the calculated distance information with the speed pattern of the above-mentioned distance number, and the constant speed movement distance is 1 shelf or more In a certain long-distance travel section, the number of shelves is calculated to calculate the distance to the shelf position immediately before the start of deceleration or acceleration, and the calculated distance is prioritized and used as distance information for the section. Two non-contact type distance sensors are installed close to the moving side of the crane, and a mountain-shaped symmetrical dog is arranged on the fixed side of a shelf, warehouse, station, etc. so as to face each other, and two distance sensors are placed. Pair of Stacker crane stop positioning control method and performing final positioning by the difference between the measured value of the detection of the type dog controls the traveling motor of the stacker crane so that zero.