JP2002362709A - Stacker crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve weight balance, to allow high acceleration/deceleration running, and to compact a carrier by miniaturizing individual running motors. SOLUTION: Front and rear running motors 15 to 18 are disposed on respective lower and upper carriers 4 and 6 of a stacker crane 2, and the carriers 4 and 6 are interconnected through a mast 12 having a truss structure. Running motors 15 and 16 in the lower part are synchronously controlled, running motors 17 and 18 in the upper part are also synchronously controlled, and the upper and lower motors are controlled to vertically stack up the carriers 4 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacker crane, and more particularly, to a stacker crane having a traveling motor on each of an upper and lower truck.

[0002]

2. Description of the Related Art It is known that a traveling motor is provided on each of upper and lower bogies of a stacker crane. In such a stacker crane, a traveling motor is arranged either before or after the upper and lower bogies, and a mast is arranged on the other. However, since the mast and the traveling motor have different weights, there is a problem in the weight balance of the stacker crane.
In addition, since there is a limit in the size of a traveling motor that can be mounted, there is a limit in high acceleration / deceleration traveling in combination with poor weight balance.

[0003]

SUMMARY OF THE INVENTION A basic object of the present invention is to provide a stacker crane which has a good weight balance of a bogie, is compact, and can be easily driven at high acceleration / deceleration.
3). An additional object of the present invention is to reduce the load applied to the connection between the mast and the bogie during high acceleration / deceleration running.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a stacker crane provided with a mast so as to connect an upper bogie and a lower bogie to each other. Wherein the mast is disposed between the traveling motors (claim 1).

Preferably, a pair of front and rear traveling motors of the lower truck are synchronously controlled with each other, a pair of front and rear traveling motors of the upper truck are synchronously controlled with each other, and the traveling motor of the upper truck and the traveling motor of the lower truck are controlled by: A control system for the traveling motor is provided so as to control the upper and lower carts to overlap in the vertical direction.

Preferably, the mast is mounted so as to be swingable in the running direction with respect to one bogie and to be swingable in the running direction with respect to the other bogie so as to be vertically shiftable. .

[0007]

According to the present invention, a pair of front and rear traveling motors are provided on each of the upper and lower trucks, and the mast is arranged between the front and rear traveling motors, so that the weight balance of the lower and upper trucks is improved. . Also, since a total of four traveling motors are used, high acceleration / deceleration traveling is easy, and since the traveling motors are arranged before and after the bogie, each traveling motor can be downsized, and as a result, the bogie of the stacker crane can be made compact (claim). Item 1).

According to the second aspect of the present invention, the upper and lower traveling motors are controlled so that the upper and lower carts overlap in the vertical direction.
The load applied to the connection between the mast and the bogie can be reduced even during high acceleration / deceleration running. As a result, high acceleration / deceleration traveling can be further facilitated.

According to the third aspect of the present invention, when the upper and lower carriages are displaced from the position where they overlap in the vertical direction, the mast swings in the running direction with respect to the upper and lower carriages, and is applied to the connection between the mast and the carriage. Let out. Here, since the mast can be shifted in the vertical direction with respect to the other bogie, it is also possible to eliminate the unreasonableness due to the change in the height of the mounting portion due to the swing of the mast.

[0010]

1 to 4 show a stacker crane 2 according to an embodiment. In these figures, reference numeral 4 denotes a lower dolly 6
Is an upper truck, which travels along traveling rails 8 and 10 by traveling wheels (not shown). Reference numeral 12 denotes a mast, for example, three or four pillars, which are truss-structure pillars in which the pillars are connected with diagonal members. The mast 12 having a truss structure is lightweight and highly rigid, and has a short natural period, so that it is easy to attenuate vibrations. Therefore, it is suitable for high acceleration / deceleration traveling of the stacker crane 2. 14 is a lifting platform, and mast 1
The traveling motors 15 and 16 are provided on the lower bogie 4, and are provided before and after the lower bogie 4 so as to sandwich the mast 12. Reference numerals 17 and 18 denote a pair of traveling motors provided on the truck 6 on the upper side. Reference numeral 20 denotes an elevating motor for elevating the elevating table 14. As the motors 15 to 20, for example, servo motors are used.

Reference numerals 22 to 24 denote laser distance sensors.
27 is a mirror for the laser distance sensors 22 to 24.
The laser distance sensors 22 to 24 are provided for the position and speed of the lower truck 4, the position and speed of the upper truck 6,
4 is used to determine the height h and the vertical speed, and another position sensor or speed sensor may be used. In the embodiment, the laser distance sensors 22 and 23 are provided at one end of the carts 4 and 6, however, they may be provided at both ends. In addition to this, the traveling motor 1
The rotary motors 5 and 17 and the elevating motor 20 have a rotation sensor such as a rotary encoder. In the measurement interval for measuring the absolute position and the absolute height with the laser distance sensors 22 to 24, the current position and the current height are determined by the signal of the rotary encoder. Now, the running speed and the elevating speed are interpolated.

Reference numeral 28 denotes a pin for attaching the mast 12 to the lower carriage 4 so as to be swingable in the running direction. Reference numeral 30 denotes a limiter for regulating the swing range of the mast 12. Reference numeral 32 denotes a plate-like attachment member provided at the upper end of the mast 12, reference numeral 34 denotes a spring attached to the upper dolly 6, and reference numeral 36 denotes a damper attached to the upper dolly 6. Since the mast 12 is attached to the upper carriage 6 via the attachment member 32, the spring 34, and the damper 36, the mast 12 can swing in the traveling direction. When the mast 12 swings in the traveling direction, the height of the mounting member 32 with respect to the carriage 6 on the upper side changes, but the spring 34 and the damper 36 are slidably mounted on the mounting member 32. The mounting member 32 is vertically shiftable with respect to the carriage 6 on the upper side.

When the upper and lower carts 4 and 6 do not overlap in the vertical direction, the mast 12 swings about the pin 28, and the mast 12 swings with the spring 34 on the upper cart 6 side. The change in height in the vertical direction is received by the damper 36, and the change in height in the vertical direction is absorbed by the shift of the mounting member 32 relative to the carriage 6 on the upper side. Further, vibrations of the mast 12 with respect to the upper and lower carriages 4 and 6 are damped by the damper 36. It is optional whether the pin 28 is provided on the lower bogie 4 side or on the upper bogie 6 side, and the limiter 30 may be provided on the upper bogie 6 side instead of the lower bogie 4 side. 70,7
2 may be provided. Further, instead of providing the mounting member 32 on the mast 12 and providing the spring 34 and the damper 36 on the upper carriage 6, the mounting member 32 is mounted on the upper carriage 6, and the spring 34 and the damper 36 are mounted on the mast 12. Is also good.

A traveling pattern generator 40 generates a traveling speed pattern according to a traveling command given to the stacker crane 2. Reference numeral 41 denotes a lower motor control unit that causes the lower truck 4 to vertically overlap the upper truck 6 and the lower truck to be as faithful as possible to the traveling speed pattern generated by the traveling pattern generator 40. 4 for the two purposes of running
Control. The upper motor control unit 42 includes the upper truck 6
Is vertically overlapped with the bogie 4 on the lower side,
The traveling motors 17 and 18 are controlled such that the upper carriage 6 travels as faithfully as possible with the traveling speed pattern generated by the traveling pattern generation unit 40. Traveling motor 1
The control signals to the drive motors 17 and 1 are denoted by CD.
The control signal to 8 is CU, and the traveling motors 15 and 16 are synchronously controlled with each other, and the traveling motors 17 and 18 are also synchronously controlled with each other.

Here, the synchronous control means, for example, controlling the front and rear traveling motors by a common control signal. For example, adding a control signal having a common signal change pattern to the traveling motors 15 and 16; Traveling motors 17, 18
Means that a common control signal is added with a signal change pattern. Synchronous control, in a narrower sense,
This means that control is performed using a common servo control system.

The elevating pattern generator 44 generates an elevating speed pattern such that the elevating platform 14 arrives at the destination designated for the stacker crane 2 by the time the traveling is completed. The elevation motor 20 is controlled using the height h of the elevation table 14 measured by the distance sensor 24 and the elevation speed pattern.

FIG. 2 shows a control system of the traveling motors 15-18. Reference numerals 50 and 51 denote rotation sensors such as rotary encoders. In synchronous control, rotations of output shafts of the traveling motors 15 and 17 on the master side are detected, and 52 and 53 denote interpolation processing units.
This is for interpolating the positions and velocities of the carts 4 and 6 in the time intervals for obtaining the absolute positions and velocities of the carts 4 and 6 by the laser distance sensors 22 and 23. When the measuring cycle of the absolute position and the speed of the laser distance sensors 22 and 23 is sufficiently short, the rotation sensors 50 and 51 are not necessary.

The double-line arrows in FIG. 2 indicate signals related to the absolute positions of the carts 4 and 6.
Then, the displacement Δ in the running direction is detected, and this displacement signal ± Δ is input to the non-linear converters 55 and 56. The nonlinear conversion unit 55,
56 controls the bogie on the side that is too advanced during acceleration to match the bogie that is late, and controls the bogie on the side that is decelerating during deceleration to match the bogie on the side that is slower. This is for nonlinearly converting the displacement ± Δ into a control amount. During acceleration, the non-linear converters 55 and 5
Numeral 6 generates a relatively large control amount for the leading bogie, and a relatively small control amount for the late bogie. In addition, at the time of deceleration, a relatively large control amount is generated for the bogie on the fast deceleration side, and a relatively small control amount is generated for the bogie on the slow deceleration side.
In this way, during acceleration, the leading bogie is matched with the late bogie, and during deceleration, the bogie on which deceleration is too fast is matched with the bogie on which deceleration is delayed. The displacement Δ along the traveling direction is quickly eliminated.

Using the differentiator 54 and the non-linear converters 55 and 56, a control amount for the displacement between the upper and lower carriages 4 and 6 is generated. Next, the average speed of the upper and lower carriages 4 and 6 is compared with the traveling speed pattern, and a control amount is generated so as to eliminate an error from the traveling speed pattern. 58 is an averaging unit for determining the average speed of the trucks 4 and 6, 60 is a differentiator, 61 and 62 are adders, and a control amount for eliminating displacement between the upper and lower trucks and an average speed are used as a traveling speed pattern. And the control amount for matching. The output of the adder 61 is a control signal CD to the lower traveling motors 15 and 16, and the adder 62
Is the control amount CU to the traveling motors 17 and 18 on the upper side.
Becomes 64 to 67 are servo amplifiers for the traveling motors 15 to 18.

In the embodiment, the interpolation processor 52 and the differentiator 5
4. The lower motor controller is constituted by the nonlinear converter 55, the adder 61, the averaging unit 58, and the differentiator 60, and the controller of the upper motor is constituted by the nonlinear converter 56 and the adder 62. The control system of FIG. 2 is provided with a control system for eliminating the displacement between the upper and lower bogies and a control system for eliminating the error of the average speed from the traveling speed pattern. The configuration of the control system is arbitrary. When these control systems are configured by software, firmware, or the like, there are various configuration methods, control for eliminating displacement between the upper and lower bogies, and running of each bogie at a speed according to a running speed pattern. And control for the operation.

FIGS. 3 and 4 show the mounting of the mast 12 on the carts 4 and 6. FIG. Mast 12 is pin 2 against trolley 4
8, the limiter 30 is provided with a screw 71 or the like so that the position for restricting the swing of the mast 12 can be adjusted. When the screw 71 is provided, the screw 71 is raised to prevent the mast 12 from swinging when assembling or inspecting the stacker crane, and the posture of the stacker crane can be fixed. Instead of the screw 71, any member that can move up and down with respect to the limiter 30 can be used.

Since it is difficult to make the upper and lower traveling carts 4 and 6 always overlap completely vertically, vibration occurs between the mast 12 and the carts 4 and 6. Therefore, this vibration is attenuated by the damper 36, and the change in height of the mounting member 32 due to the swing of the mast 12 is controlled by the spring 34 and the damper 3.
The problem is solved by sliding the attachment member 32 with respect to 6.

The features of the embodiment will be described. The traveling motors 15 to 18 are provided before and after the trucks 4 and 6, and the mast 12 is disposed between the pair of front and rear traveling motors.
Improves weight balance. Also stacker crane 2
Is driven by four traveling motors 15 to 18, so that high acceleration / deceleration traveling is possible. Further, since two traveling motors 15 to 18 are mounted on the carts 4 and 6, respectively,
5 to 18 can be made compact, and as a result, the carts 4 and 6 can also be made compact. Stacker crane 2 for these
At high acceleration / deceleration.

Since a total of four traveling motors 15 to 18 are used and the traveling motors are provided on the upper and lower carriages 4, 6, the control becomes complicated. On the other hand, it is necessary to perform high acceleration / deceleration traveling. Therefore, the lower traveling motors 15 and 16 are synchronously controlled with each other, and similarly, the upper traveling motors 17 and 18 are similarly controlled.
Also control each other synchronously to simplify the control. The lower traveling motors 15, 16 and the upper traveling motors 17, 1
In the control of No. 8, control is performed by two control targets of eliminating displacement between the upper and lower carriages 4 and 6, and running according to the running speed pattern. As a result, even if the four traveling motors 15 to 18 are provided, traveling can be easily controlled, and the displacement between the upper and lower carriages 4 and 6 can be reduced.

Since it is difficult to completely eliminate the displacement between the upper and lower carriages 4, 6, the mast 12 can be swung by the pins 28 with respect to the carriage 4, and the swing range is limited by the limiter 30 and the screw 7
Regulate with 1. Further, the mast 12 is mounted on the carriage 6 via a mounting member 32 and a spring 34 so that the mast 12 can swing in the traveling direction with respect to the carriage 6 and can shift in the vertical direction. Then, the vibration of the mast 12 is damped by the damper 36.

As a result, the compact trolley 4,
6, the stacker crane 2 can be run at high acceleration / deceleration, and the load applied to the connection between the mast 12 and the bogies 4, 6 can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a stacker crane according to an embodiment.

FIG. 2 is a block diagram showing a servo drive system for upper and lower traveling motors in the stacker crane according to the embodiment.

FIG. 3 is a view showing a mast attached to a lower bogie in the stacker crane according to the embodiment.

FIG. 4 is a view showing a mast attached to an upper bogie in the stacker crane according to the embodiment.

[Explanation of symbols]

 Reference Signs List 2 stacker crane 4 carriage 6 carriage 8,10 travel rail 12 mast 14 elevating platform 15,16 traveling motor 17,18 traveling motor 20 elevating motor 22-24 laser distance sensor 25-27 mirror 28 pin 30 limiter 32 mounting member 34 spring 36 Damper 40 Running pattern generation unit 41 Lower motor control unit 42 Upper motor control unit 44 Elevation pattern generation unit 45 Elevation motor control unit 50, 51 Rotation sensor 52, 53 Interpolation processing unit 54 Difference unit 55, 56 Nonlinear conversion unit 58 Averaging unit Reference Signs List 60 Difference device 61, 62 Adder 64 to 67 Servo amplifier 70 Lower frame 71 Screw 72 Upper frame

Claims (3)

[Claims] 1. A stacker crane provided with a mast so as to connect between an upper truck and a lower truck, wherein a pair of front and rear traveling motors are provided for each of the upper truck and the lower truck, and a pair of front and rear traveling motors are provided. A stacker crane, wherein the mast is disposed on a stacker crane. 2. A pair of front and rear traveling motors of a lower truck are controlled synchronously with each other, a pair of front and rear traveling motors of an upper truck are synchronously controlled with each other, and the traveling motor of the upper truck and the traveling motor of the lower truck are vertically controlled. 2. The stacker crane according to claim 1, wherein a control system of a traveling motor is provided so as to control the bogies to overlap in a vertical direction. 3. The mast is mounted so as to be swingable in the running direction with respect to one bogie and to be able to swing in the running direction with respect to the other bogie so as to be vertically shiftable. The stacker crane according to claim 1.