JPH0477321B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a non-contact, omnidirectional movable trolley that can be used to reduce load fluctuations such as light and heavy loads, changes in road surface conditions due to irregularities on the floor, and changes in wheel diameter due to vehicle wear of omnidirectional movable trolleys. The present invention relates to a fixed-point stop position detection device for an omnidirectional movable cart that can improve the position accuracy of fixed-point stops without being affected by fluctuations.

Conventionally, a pick-up is provided at the bottom of the vehicle body of a moving dolly, and the pick-up coil detects a magnetic field indicating the stop position, or an image sensor installed at the bottom of the vehicle body detects a pattern indicating the stop position, and the moving dolly is stopped at a fixed point. However, since a moving trolley has inertia while it is running, it is necessary to decelerate and stop it. Therefore, in conventional methods, the starting position of deceleration is also determined by using a magnetic field generator or pattern. must be instructed. But like this,
Even if the deceleration position was correctly instructed, the deceleration control would not be sufficient depending on load fluctuations, road surface conditions, and the degree of wheel wear, and the positional accuracy of fixed-point stopping could not be said to be good.

The present invention provides an optical position indicator that displays the stop position on a wall surface along the running road surface of the omnidirectional movable trolley, and an optical position indicator that can detect the stop position using an optical signal from the position indicator. The object of the present invention is to provide a fixed-point stop position detector for an omnidirectional movable trolley that can solve the above-mentioned problems, based on the idea that the stop position detector is attached to the body of the omnidirectional movable trolley.

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 illustrates a case where a fixed-point stop position detector 1 for an omnidirectional movable cart (hereinafter referred to as the device 1 of the present invention) is adopted as a flexible production system for machining. The movable carts 2 are loading devices for storing and storing workpieces, and are arranged along the traveling road surface of the omnidirectional movable cart 1, for example, facing each other. 3...
... are machining centers that machine workpieces in a predetermined order, and a plurality of machining centers are arranged along the running road surface of the omnidirectional movable cart 1. 4...
is a general-purpose machine tool other than a machining center that machine workpieces in a predetermined order, and a plurality of machines are arranged along the running surface of the omnidirectional movable trolley 1, and a central processing unit is installed on the back of one cargo handling device 2. Place 6. An optical position indicator 5 is provided on the vertical wall surface of the cargo storage device 2 . . . , the machining center 3 . . . , and the general-purpose machine tool 4 .

In addition, the omnidirectional movable trolley 1 is as shown in FIG.
An optical stop position detector 12 capable of receiving an optical signal such as a light beam from the position indicator 5 is attached to the center of the vehicle body 10 on the side surface of the omnidirectional movable trolley 1 facing the traveling path. Optical distance measuring devices 13, 13 are installed to detect the distance from the wall by receiving light such as scattered light from the wall. Note that each distance measuring device 13 is installed at a position lower than the stop position detector 12 to prevent mutual interference of optical signals. Furthermore, a cargo handling mechanism 1 is provided on the upper surface of the vehicle body 10.
1 is attached to enable workpieces to be carried in and out of the loading device 2, machining center 3, and general-purpose machine tool 4.

The position indicator 5 uses a light emitting diode that lights up with a light beam projected from the omnidirectional movable trolley 1, and as shown in FIG. 2, the position indicator 5
The optical receiver 5a receives the light beam from the light projecting section 12a of the stop position detector 12, and the optical receiver 5
It can be formed from a transistor TR that amplifies the signal of a, and a light emitting diode LD that is turned on by the output signal of the transistor TR and can send a light beam to the light receiving section 12b of the stop position detector 12. .

The stop position detector 12 is connected to the light projector 12a.
and a plurality of, in this example two, light receiving sections 12b, 12b.
The light receiving section 12b also includes a well-known light spot position detector 12P that can detect the displacement of the light incident position without scanning, and a lens 12L of an optical system. As shown in FIG. 4, each of the light receiving sections 12b and 12b includes a light spot position detector 12P1 and a light spot position detector 12P1, respectively.
12P2, and the two lenses 12L are disposed parallel to the running center line of the vehicle body, and the light spot position detectors 12P1 and 12P2 are arranged at right angles to the running center line and at the rear thereof by a positional deviation amount f1. , f
2, they are placed in a shifted position. With this, it is possible to cooperatively receive optical signals from position indicators 5 located near and far. Note that a cylindrical lens is used as the lens, making it possible to expand and contract the light beam. Note that the light receiving section 12a can project a light beam toward the position indicator 5 to cause the position indicator 5 to emit light.

The operating principle of the light spot position detector 12P will be explained.

The distance between electrodes A and B of the light spot position detector 12P is
DA, resistance is Rl, distance from electrode A to light incident position P is DA/2+△L1, resistance of that part is
Rx, the photogenerated current generated at the light incident position P reaches the resistance layer as a photocurrent proportional to the incident energy of the light, and is inversely proportional to the resistance value from the incident position P to each electrode A, B. It is divided into two parts and taken out from electrodes A and B. If the photocurrent generated by the incident light is Io, and the currents taken out to electrodes A and B are IA and IB, then IA=Io・(Rl−Rx)/Rl IB=Io・Rx/Rl (1) , when the resistance layer is uniform and the length and resistance value are proportional, IA=Io×{DA−(DA/2+△L1)}/DAIB=Io×(
It is expressed as DA/2+△L1)/DA...(2).

Therefore, finding the ratio of IA and IB, IA/IB=DA−(DA/2+△L1)/DA/2+△
L1=DA/DA/2+ΔL1)-1...(3) The incident position P of the light can be detected from the values of IA and IB regardless of the incident energy. Therefore, the distance L1 between the wall surface and the omnidirectional movable trolley 1
Or, when L2 is known and the omnidirectional moving cart 1 is parallel to the wall surface, the distance ΔL1 or ΔL2 of the light spot position detector 12P1 or 12P2 where the incident position P exists and the positional deviation amount f1 or f2
The distance L1 or L2 of a right triangle whose two sides are
The distances l1 and l2 of the traveling method from the center of each optical length position detector 12P1 or 12P2 to the position indicator 5 are determined as the similarity ratio of . Thereby, control for deceleration and stopping is sequentially performed according to the displacement of the incident position P, and it becomes possible to stop at a fixed point with high precision.

Note that as in this embodiment, the light spot position detector 12P
By providing a pair of 1 and 12P2 shifted back and forth, the incident position P of the optical signal from the position indicator 5 on the light spot position detector 12P can be detected over a wide range and accurately, and deceleration and stop can be performed. Smooth control and improve stopping accuracy.

As shown in FIG. 5, the distance measuring device 13 has the same configuration as the stop position detector 12 in this embodiment,
a light projecting unit 13a that emits a light beam toward a wall surface;
A light receiving section 13b using a well-known light spot position detector 13P that can receive the scattered light from the wall surface and detect the displacement of the light incident position without scanning, and in this example, the light receiving section 13b has two The two light spot position detectors 13P1 and 13P2 are arranged front and back and shifted in position, making it possible to obtain optical signals in the far field and near field. In addition, the light projecting section 13a has a light emitting diode LD, and has an arithmetic processing section and a control section 15.
are connected together.

The principle of the distance measuring device 13 will be explained.

Displacement of light incident position P according to subject distance △L1
is, △L1=Lb1・f1/L1...(4) L1: Subject distance from the center of the lens 12L to the wall surface Lb1: Length between the base line points from the center of the light emitter 13a and the light receiver 13b f1: The length of the light receiver lens Focus distance DA: length between electrodes A and B of light spot position detector 13b, then the output current of light spot position detector 13b is: I1OCDA/2-△L1=DA/2-Lb1・f1/L1 I2OCDA /2+△L1=DA/2+Lb1・f1/L1 Therefore, if we take the ratio of output currents I1 and I2, we get the following output:
The near-field position signal of PL1 can be obtained.

PL1= Io・I1/I2=IoDA/2−Lb1・f1/L1/DA/2+Lb1・
f1/L1...(7) Similarly, △L2=Lb2・f2/L2...(8) △L2: Displacement of light incident position according to subject distance f1: Focal length of light receiving lens, PL2=Io・I1/I2= Io・DB/2−Lb2・f2/L2/DA/2−Lb2・f2/L2 In other words, it is possible to obtain the far-field position signal of the output PL2, and accurately calculate the distance from far to near. can be measured.

However, in the case of the omnidirectional movable trolley 1 stopping,
The stop position detector 12 is activated by a signal from the central processing unit 6 that determines that it is necessary to supply the workpiece.
By making the light emitting unit 12a emit light, the light emitting diode of the position indicator 5 provided on the wall surface of the machining devices 3 and 4 that require workpiece supply is lit as illustrated in FIG. . The light position detector 12P of the running omnidirectional movable trolley 1 receives the optical signal from this lighted light emitting diode, and as the omnidirectional movable trolley 1 moves, the light spot position detector 12P
The upper incident position moves. This light spot position detector 1
Omnidirectional movable trolley 1 due to the displacement of the incident position on 2P
It measures the position in the running direction and decelerates and stops the vehicle. This displacement corresponds to the wall surface of the machining devices 3 and 4 (the wall surface facing the running road surface of the omnidirectional movable trolley 1).
It is also influenced by the attitude angle α of the omnidirectional movable trolley 1 relative to the direction. Therefore, as described above, the distance measuring device 13 consisting of the light projecting section 13a and the light receiving section 13b having the light spot position detectors 13P1 and 13P2 is installed at both ends of the body of the omnidirectional movable trolley 1, and the stop position detector 12 is installed at both ends of the vehicle body of the omnidirectional movable trolley 1. They are provided at a distance (distance C/2 in FIG. 6) from the center. As a result, as shown in FIG. 6, the distance Lx from each distance measuring device 13 to the wall surface,
Using the difference Lx-Ly of Ly and the arctangent of the ratio to the distance C, the central processing unit 6 can easily calculate the attitude angle α of the omnidirectional movable cart 1 with respect to the wall surface. Therefore, when tilting at this attitude angle α,
The position of the position indicator 5 at which the stop position detector 12 detects the position indicator 5 (FIG. 6 shows the case where the position indicator 5 is detected on the center of the stop position detector 12); Stop position detector 12 on the vehicle body
The stop position detector 1 can easily determine the deviation X in the running direction from
The displacement of the light receiving point P on the second light spot position detector 12P can be corrected.

As mentioned above, the present invention is an optical type, is resistant to noise, and can decelerate and stop the omnidirectional moving carriage by changing the incident position of the light spot position detector, and can control the omnidirectional moving carriage without contact. It is possible to stop at a fixed point without being affected by changes in the load loaded on the truck, changes due to road surface conditions, or changes in wheel diameter due to wear of the wheels of the omnidirectional movable cart, improving its accuracy. Further, the stop position detector includes a light receiving section and a light projecting section, and the light receiving section uses a lens and a plurality of light spot position detectors arranged apart from the lens, and The device includes an optical receiver that receives the light beam from the light projecting section of the stop position detector, a transistor that amplifies the signal, and a light beam that is lit by the output signal of the transistor and transmits the light beam to the light receiving section of the stop position detector. By consisting of a light emitting diode that sends a light beam, the stop position detector can receive a light signal from the position indicator that is synchronized with this detection operation, and the signal to light the light emitting diode in the position indicator It is possible to secure a wide detection area without cables, and the stop position in the moving direction of the mobile cart can be detected with high precision using the stop position detector and position indicator. In addition, since the position indicator has an optical transmission/reception function and an amplification function, if it receives a small portion of the light transmitted from the stop position detector, it can transmit an optical signal amplified by the transistor and reflect the light. Reduces changes in the reflectance characteristics of the object's reflective surface due to dirt etc. when using a reflective plate.
It is possible to achieve effects such as obtaining constant distance measurement characteristics.

In addition, by providing a distance measuring device, it is possible to correct the influence of the attitude angle and distance on the displacement of the incident position, further improving the fixed-point stopping accuracy and smoothing the supply of workpieces to the machining equipment. Moreover, since it is a trackless type, it is easy to change the course, the layout of ground equipment can be easily changed, and the flexibility of the flexible factory system is further improved, such as reducing and shortening the construction period. In addition to the above-mentioned production systems, it can also be widely used in assembly lines, storage warehouse systems, etc.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the entire mechanical processing flexible production system in which the apparatus of the present invention can be adopted;
Fig. 2 is a plan view showing an example of a position indicator that can be used in the device of the present invention, Fig. 3 is a side view illustrating an omnidirectional movable cart that can be used in the device of the present invention, and Fig. 4 is a diagram showing a stop position detector. FIG. 5 is a plan view showing an example of a distance measuring device, and FIG. 6 is a diagram illustrating correction based on attitude angle. 1... Omnidirectional movable trolley, 2... Loading device, 3...
...Machining center, 4...General-purpose machine tool, 5...
Position indicator, 6...Central processing unit, 10...Vehicle body, 11...Cargo handling mechanism, 12...Stop position detector, 13...Distance measuring device.

Claims (1)

[Claims] 1. A cargo storage device, a machining device, etc. arranged along the running road surface of the omnidirectional moving trolley, which is arranged facing the running road on the wall surface of the position where the omnidirectional moving trolley should stop. and an optical position indicator capable of displaying the stop position, an optical stop position detector for receiving an optical signal from the position indicator and detecting the stop position on the omnidirectional movable cart, and a side surface facing the wall surface. The stop position detector includes a light receiving part and a light projecting part, and the light receiving part uses a lens and a light spot position detector disposed apart from the lens, and The device includes an optical receiver that receives the light beam from the light projecting section of the stop position detector, and a transistor that amplifies the signal.
A fixed-point stop position detection device for an omnidirectional movable trolley, comprising a light emitting diode that is turned on by an output signal of the transistor and sends the light signal to a light receiving section of the stop position detector. 2. The light receiving section includes a plurality of lenses disposed parallel to the traveling center line of the omnidirectional movable cart, and a plurality of lenses arranged at right angles to the traveling center line from the lenses. The fixed point stop position detection device according to claim 1, characterized in that a light spot position detector is used.