JPS6270103A - Mobile object position detection device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to position detection*ii'l for detecting the position of a moving body 1 running on a track, such as a star car crane or a trolley in an automated warehouse. related.

Background of Departure] In automated warehouses, moving objects such as styker cranes and tracked trolleys for loading and unloading are controlled to accurately stop at a predetermined stop position of 4n. Accurate position detection is a prerequisite for practical implementation.

Conventionally, pulse encoders that generate pulses in conjunction with the movement of the moving body are attached to the wheels of the moving body, and the current position of the moving body is known by counting the number of pulses generated by the pulse encoder. In this case, the counter that counts the pulses from the pulse encoder is reset to zero when the moving body returns to its home position (origin) to prevent counter errors from accumulating. However, in this case, unless the moving object returns to its home location, the counter error, that is, the position detection device of the moving object, will accumulate, which is not preferable.

Special 1. Like a stacker crane in an automated warehouse.

When a vehicle travels a very long distance and stops, the position detection error cannot be ignored. Conventionally, in order to eliminate such problems, a coarse address detecting object and a plurality of objects arranged at small intervals in the moving direction are used to correspond to each stopping place set on the moving route of the moving object. A coarse address detector is provided on the movable body side for detecting a coarse address detection object.

A precision address detector is installed to detect the detection object for precision addresses.
It is known to detect the current position of a moving object based on the detected coarse address and fine address. This is shown, for example, in Japanese Unexamined Patent Publication No. 56-82706.

However, the method described above requires that 2s types of detected objects (detected objects for S addresses and multiple detected objects for fine addresses) be thrown at each stop location on the moving route of the moving object. However, the equipment costs are high, and the objects to be detected must be placed accurately at each stop position! The installation work is difficult. In particular, the installation of the object to be detected at each stop position must be done carefully because the accuracy of the installation position directly affects the accuracy of position detection of the moving body.

[Purpose of the invention]

An object of the present invention is to provide a position detection device for a moving body that has a simple configuration and can detect the position of a moving body with high accuracy.

[Essentials of invention]

The present invention provides each joint position if of a track laid on a travel route.
An object to be detected for joint position detection is provided, and on the moving body side,
A pulse encoder that generates pulses in conjunction with the movement, a joint position detector that detects the detected object, a memory that stores a learned value of the distance between the joints of the trajectory, and counts the pulses generated by the pulse encoder. The current position of the moving object is determined by inputting a position counter that is reset each time a seam position is detected, the seam position detection output of the seam position detector, the count value of the position counter, and the learning value stored in the memory. and a calculation device that calculates the learned value up to the seam position detected immediately before, and uses this calculation value and the count value of the position counter to determine the current state of the moving body. It is characterized by calculating the position.

Embodiments of the Invention] Hereinafter, the present invention will be described in detail based on specific embodiments shown in FIGS. 1 to 4. FIG. 1 is a schematic block diagram of position detection and position control in one embodiment of the present invention. Fig. 2 is a plan view showing the load capacity of the shelves of the automated warehouse and the stacker crane, and Fig. gJ3 is its side view. FIG. 4 is a diagram showing how the pulse encoder is attached to the stub car crane.

First, the schematic configuration of the automated warehouse facility will be explained with reference to FIGS. 2 and 3. 1 is a three-dimensional warehouse shelf, and 2 and 3 are upper and lower running tracks of the stub car crane 4. The stacker crane 4 is a moving body that is disposed between the shelves 1 and runs on a running track 3, and includes 5, 6a, 6b, 7a, 7b, which will be described later.
It consists of 8.11-17, 18a-18c, and 19.20. 5 is a traveling device, 6a is a stand section, 6b is an upper structure section,
7a and 7b are support columns. 8 is a lifting body, 11 is a fork attached to the lifting body, g1112 is a rope for lifting the lifting body, 13 is a lifting device y that raises and lowers the lifting body 8 by hoisting and lowering the lifting rope, and 614 is an on-machine control. It is a panel with built-in control equipment for controlling the traveling of the stub car crane, the elevation control of the elevating body, and the operation control of the fork jig. 15 is a traveling mechanism of the traveling device 5; 16 is a lift detector for detecting a lift position; and 17 is a steady rest mechanism of the crane. 18a to 18c are running wheels, and in this example only 18a is running! The configuration I driven by ff5 is performed. 19 indicates a guide roller. Reference numeral 9 indicates a shelf, and reference numeral 10 indicates a load S placed on a lifting body stop.

Next, an overview of the installation of the object to be detected for joint detection on track 3, the pulse encoder that generates pulses according to the movement of the moving body, and the track joint position detector will be explained using Figures 2 to 4. . First, the objects to be detected are installed corresponding to each joint position r24a-24e of the track 3, as shown in FIG. A seam position detector n that senses the detected object n and detects the seam position is installed on the movable body side. The pulse encoder is similarly installed (installed on the moving body side). Specifically, the pulse encoder 21, as shown in FIG.
A roller attached to one end of the arm extending from the detector support is directly connected to that shaft. Measuring roller ah, due to the spring force, a moderate contact force with the track 3 can be obtained c-n
I try to do that. Therefore, the measuring roller n rotates due to the movement of the moving body, and in response to this rotation, the pulse encoder 21 directly connected to the shaft generates a pulse. Note that in this embodiment, the object to be detected is used to block light (O
Turn on the light (FF) as a seam position detector.

It uses a photoelectric switch that detects off (OF). The equipment installed to detect track joints may be any device as long as it can detect joints; for example, equipment that uses mechanical contact such as a striker or i2, or equipment that uses electromagnetic coupling. Proximity switches can be used.

Next, the position of the stacker crane whose equipment has been sheared as described above is detected, and four-position control is performed based on this position detection.
This will be explained using figures. In FIG. 1, the stub car crane 4 travels by transmitting the rotational driving force of the traveling device 5 to the traveling wheels 18a via the traveling mechanism.

Note that the traveling mechanism includes a brake that performs braking and stopping in response to a stop command signal from the computing device 5, and a transmission mechanism that transmits rotational driving force. The encoder generates pulses in response to the rotation of the motor. The speed counter Shio is
The generated pulses are input, pulse counts are repeated within a unit time, and the running speed is detected. Running gear W5
is controlled by the output of a comparator that calculates the difference between the set speed, which is the output of the speed pattern generator 26, and the actual speed, which is the output of the speed counter 4.The calculation device 1r25 is set from the outside. The difference between the target stopping position 3 of the moving body and the current position of the moving body is determined and output to the speed pattern generation *M2B, and when this difference becomes zero, a stop command signal is output. 25 calculates the current position of the moving body necessary for the above control using the count value of the position counter (9), the output of the joint position detector n, and the distance between each joint of the trajectory stored in the memory υ. The calculation is performed using the learned value of the number of generated pulses of the corresponding pulse encoder.

Hereinafter, position detection of a moving body, which is directly related to the present invention, will be explained in detail. The position counter counts the pulses generated by the pulse encoder 4. Arithmetic unit 5ij2
Position calculation of moving object (stub car crane) 4 by 5)
At this time, the distance Jl (i=
0-n) using the pulse encoder 21 and memorize it in the memo IJ 27. Since the distance Ji between each joint does not substantially change, it is best to calculate it once and store it in the memory γ (as long as it is possible, and learning is not required when detecting the position of a moving object. The following explanation assumes that the learning value li has already been stored in the memory.Assuming that the stub car crane 4 starts traveling from 0 to the reference position 8, the pulse encoder 21
A pulse is generated, and this pulse is counted up by a position counter (9). During this travel, the output of the position counter directly functions as the current position of the moving body until the joint position Mlii output device n detects 1 at the first joint. That is, the arithmetic unit 25 determines the count value eo of the input position counter force as the current position i11L of the moving body. When the seam position detector n detects the first seam, it can be detected that the moving object has moved from the reference position to the seam position by a distance 1+ corresponding to . Even if the count value of the position counter I at this time is e1', the arithmetic unit 25 takes the learning value (in this case 1.>) stored in the memory n and calculates the movement at that point. Determine the current position of the body as i+. At the same time, reset the position count value to zero. If the moving body continues to travel beyond that position, the 1 position counter (9) will count again from zero. Seam position detection During the period after the device n detects 2 at the first joint and until it detects 2 at the second joint, the arithmetic unit 6 calculates the current position of the moving object as the sum of 11 and the count value of the position counter I. .When the moving body moves further and the seam position detector n detects 2 at the seam, the sum of the learned value 12 of the distance from the seam to 2 and the above 11, that is, the learned value up to that n. Calculate the cumulative total of , and use this as the current position ftL of the moving body at that point (in other words, when the moving body reaches the joint 2).At this point, the position counter is reset to zero. Moving body When the moving object moves from the joint 2 to the next joint in three directions, the position counter (9) again counts the pulses generated by the pulse encoder. The current position of the moving object is obtained as a linear equation.

L=It+12+lc・・・・・・・
(1) However, when the count value of the position counter (9) and the moving object reaches 3 at the next joint, the current position of the moving object calculated by the calculation device 5 is 1. It will look like this: L = 11+12+ 13 However, 7, l! 3; Learning value for the distance between 2 and 3 at seam When the moving object advances from seam 3 to the next seam K, the position counter concave similarly performs a count after rearing. In this case, the current value of the moving body calculated by the calculation device 2 is a linear expression.

L = 11 + 12 + 13 + lc The calculation formula for the current position ILL of such a moving object is as follows as a general formula.

In other words, each seam (9) up to the seam position detected immediately before
By calculating the sum with the count value (lc) of
The current position of the moving body at that time is obtained. Therefore, the calculation device 6 calculates the distance traveled by the moving object from the reference position, that is, the current position of the moving object by calculating the equation (41). In this case, the position counter is reset at the time of each seam position detection. The reset I of the position counter may be directly reset using the seam position detection signal from the seam position detector n.

According to the embodiment described above, an object to be detected is installed at each joint of the trajectory where errors are likely to occur when detecting a relative position using a pulse encoder, and thereby the pulses generated by the pulse encoder are counted. The position counter is reset to prevent cumulative errors. Therefore, the decrease in detection accuracy at track joints is compensated for, and the accumulated error in count values between joints is also eliminated, so that highly accurate position detection of the moving object can be realized over the entire length of the traveling track.

In addition, only a simple object to be detected for joint detection is provided at each joint of the traveling track, and the installation position is not directly related to the stopping position of the moving object, so the installation work is extremely simple. It is. Furthermore, the stopping position can be arbitrarily set at any position on the running track, and no new construction work is required to change or add the stopping position of the moving body.

〔Effect of the invention〕

As described in detail above, according to the present invention, the position of a moving body can be detected with high accuracy with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing a schematic configuration of automated warehouse equipment. l! FIG. 4 is a diagram showing the mounting state of the detector.

Claims (1)

[Claims] 1. A detected object for detecting the joint position is provided at each joint position of the track laid on the travel route, and a pulse encoder that generates pulses in conjunction with the movement of the moving object and a pulse encoder that detects the detected object are provided on the moving body side. a joint position detector for detecting a joint position; a memory for storing a learned value of the distance between joints of the trajectory; a position counter that counts pulses generated by the pulse encoder and is reset each time a joint position is detected; The seam position detection signal, the count value of the position counter, and the learned value stored in the memory are input, and each time the seam position detection signal is input, the cumulative total of the learned values up to the seam position is calculated, and the calculated value and 1. A position detection device for a moving object, comprising: an arithmetic unit that calculates the current position of the moving object from the count value.