JP2008175674A - Traveling vehicle, and measuring method of its wheel abrasion quantity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure a wheel abrasion quantity of a trackless type traveling vehicle during traveling. <P>SOLUTION: A distance measuring means for measuring a distance to a traveling surface is mounted on a carriage frame of the traveling vehicle. A horizontal surface capable of supporting rolling surfaces of the whole wheels of the traveling vehicle on the same plane is formed on a prescribed spot of the traveling surface. The traveling vehicle is guided onto the horizontal surface, and the distance to the horizontal surface is measured by the distance measuring means. The measured distance is compared with a value just after wheel replacement, and the wheel abrasion quantity is determined from the difference. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for detecting the amount of wheel wear of a traveling vehicle, and more particularly to a technique suitable for measuring the amount of wheel wear of a trackless traveling vehicle.

  In today's highly automated factories, traveling vehicles that carry products and semi-finished products on a loading platform and unattended transport to designated locations are often used. Such traveling vehicles include a tracked vehicle that travels on a track and a trackless vehicle that travels on a flat floor while steering itself. Most of the traveling vehicles of any system use an encoder to detect the rotational speed of the wheel. Then, the travel distance from the reference position is calculated by multiplying the detected rotational speed by the wheel outer circumference length, and the unmanned travel is performed according to the program stored in advance while confirming the current position by the value.

  In such a method of obtaining the moving distance from the number of wheel rotations, it is important to accurately grasp the wheel diameter that is the basis for calculating the wheel outer peripheral length. The wheels are made of a material such as iron, urethane, rubber, etc., all of which are worn by running to reduce the wheel diameter. If the wear of the wheels is ignored, an error occurs in the calculated moving distance, and a deviation occurs in the stop position and the travel route. Since there is a problem of inspection time and man-hours in checking the amount of wheel wear manually, it is desirable that automatic measurement can be performed during operation or between operations.

  In a tracked traveling vehicle that travels on a track as a conventional technique, marks are provided at two reference positions that are separated by a predetermined distance along a straight track, and detectors that detect these marks are attached to the traveling vehicle. And many methods are employed in which the number of wheel rotations while traveling between these two reference positions is detected by an encoder to calculate the traveling distance per one wheel rotation, and the wheel diameter is calculated backward from that value.

  This method adopted in a tracked traveling vehicle can measure the actual wheel diameter during operation, and can increase the measurement accuracy by increasing the distance between the two reference positions. However, there are many problems in applying this method to trackless traveling vehicles. Many trackless traveling vehicles travel along these while detecting induction wires such as light reflecting tape and magnetic tape affixed to the floor, and electric current lines laid directly under the floor. Therefore, it is also possible to run the vehicle in a straight line by stretching the guide wire in a straight line. However, even in this case, the traveling vehicle repeats delicate steering so as not to deviate from the guide line, and the traveling direction of the wheels slightly swings around the direction of the guide line. As a result, an error occurs even if the wheel speed is detected while traveling between two reference positions along a straight path. For this reason, it is difficult to accurately measure the amount of wheel wear by this method.

  The present invention has been made in order to solve such problems of the prior art, and the subject thereof is a technique for measuring the amount of wear of wheels of a traveling vehicle, and in particular, the wheels of a trackless traveling vehicle that travels unattended. The object is to provide a technique suitable for measuring the amount of wear during operation or between operations.

  The invention according to claim 1 for achieving the above object is a method for measuring the amount of wheel wear of a traveling vehicle, wherein the wheel rolls on a carriage frame of the traveling vehicle or a surface parallel to the traveling surface. A distance measuring means for measuring the distance between the traveling vehicle and the traveling surface where the traveling vehicle travels is formed at a predetermined position on the traveling surface, and a plane that can support the rolling surfaces of all the wheels of the traveling vehicle on the same surface is formed. The traveling vehicle is guided on the plane, and the distance measuring means measures the distance between the plane or a parallel plane spaced apart from the plane, and compares the measured distance with the value immediately after the wheel replacement. This is a method of measuring the amount of wheel wear of a traveling vehicle.

  According to such a measuring method, even if it is a trackless traveling vehicle, it is possible to automatically measure the amount of wheel wear without any human intervention during operation or between operations. If the amount of wear is known, the actual wheel diameter at that time can also be found, so when calculating the amount of movement based on the encoder signal that emits a pulse synchronized with the rotation of the axle, the amount of movement can be accurately grasped by using that value. can do.

  The invention according to claim 2 is a traveling vehicle that travels by rolling wheels on the traveling surface, and is attached to the carriage frame of the traveling vehicle and between the traveling surface or a surface parallel to the traveling surface. A distance measuring means for measuring the distance of the vehicle and a wheel wear amount calculating means. The wear amount calculating means inputs a distance measurement instruction to the running surface or a plane parallel to the running surface and information indicating that the wheel has been replaced. Receiving means, and a storage means for storing the distance measured by the distance measuring means and the wheel replacement information received by the input means. When receiving a distance measurement instruction via the input means, the distance measurement is performed. Instruct the means to perform distance measurement with the running surface or a plane parallel to the running surface, and compare the obtained measurement value with the distance measurement value stored first by the storage means after receiving the wheel replacement information input It is configured to calculate the amount of wheel wear by It is traveling vehicle characterized by.

  According to the traveling vehicle having such a configuration, even if the vehicle is a trackless type, it is possible to measure the distance to the horizontal plane on the horizontal plane during operation or between operations, thereby eliminating wheel wear without human intervention. The amount can be measured automatically. If the amount of wear is known, the actual wheel diameter at that time can also be found, so when calculating the amount of movement based on the encoder signal to generate a pulse synchronized with the rotation of the axle, the value is used to accurately determine the amount of movement. I can grasp it.

  According to a third aspect of the present invention, in the traveling vehicle according to the second aspect, the distance measuring means is attached to a bogie frame close to a driving wheel of the traveling vehicle.

  Since the wear of the wheel is more severe on the driving wheel than on the driven wheel, if the distance measuring means is attached to the bogie frame near the driving wheel, the replacement time of the wheel can be determined more accurately.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a traveling vehicle and a method for measuring the amount of wheel wear according to the present invention will be described with reference to the drawings. In the present embodiment, an unmanned forklift will be described as an example of a traveling vehicle. 1 and 2 are a front view and a side view of the unmanned forklift 1. The unmanned forklift 1 is a trackless type and travels unmanned while rolling a wheel 3 on a flat floor 2 to carry a load. The right direction in FIG. 1 is the forward direction when the vehicle travels unattended.

  The unmanned forklift 1 includes a lower bogie frame 5, a vehicle body main body 6 mounted on the front side in the traveling direction, and a fork device 7 mounted on the rear side. The fork device 7 is a cargo loading / unloading device comprising an L-shaped fork 8 and a drive mechanism 9 for moving the L-shaped fork 8 up and down and back and forth. The transported luggage is carried on the fork 8.

  The vehicle body 6 contains a travel control device 31, a wheel wear amount calculation circuit 45, a laser distance meter 50, a power supply device and the like which will be described later. A travel warning lamp 11 and an obstacle detection sensor 12 are attached to the front surface of the vehicle body main body 6. A pair of side frames 14 extending obliquely upward from both sides of the upper portion of the vehicle body main body 6 are attached, and an upper frame 15 is horizontally attached to the upper ends thereof. A laser projector / receiver 16 is attached to the upper frame 15.

  3 and 4 show the mounting relationship between the bogie frame 5 of the unmanned forklift 1 and the wheels on the lower surface side thereof, FIG. 3 is a plan view showing the positional relationship of the wheels, and FIG. 4 is a cut surface of FIG. It is sectional drawing seen from line AA. In addition, the code | symbol 18 in FIG. 3 has shown the horizontal board installed in the predetermined place of a driving | running | working surface for the wheel abrasion amount measurement of the unmanned forklift 1. FIG.

  The unmanned forklift 1 travels on four wheels. As shown in FIG. 3, traveling drive wheels 3a are attached to the front left side in the traveling direction, driven wheels 3b are attached to the front right side, and driven wheels 3c and 3d are attached to the rear left and right sides. As shown in FIG. 4, the traveling drive wheel 3a and the driven wheel 3b are respectively attached to wheel support frames 22a and 22b that are freely attached to the carriage frame 5, and the traveling drive wheel 3a has a reduction gear attached coaxially. It is driven by the travel motor 20. The driving wheel 3a is steered by a steering mechanism (not shown). A caster is used for the driven wheel 3b.

  As a feature of the unmanned forklift 1 of the present embodiment, a laser rangefinder 50 is attached downward through a hole formed in the bogie frame 5 on the bogie frame 5 near the traveling drive wheel 3a. A laser distance meter (corresponding to a distance measuring means) 50 is based on a time difference, a phase difference, etc. between the laser light irradiated toward the floor surface 2 and the reflected light reflected by the floor surface (traveling surface) 2 and returned. This is a device for measuring the distance to the floor surface 2.

  FIG. 5 shows the configuration of the control device 30. The control device 30 includes a travel control device 31, a laser distance meter 50 for calculating a wheel wear amount unique to the present embodiment, and a wheel wear amount calculation circuit (corresponding to a wear amount calculation means) 45.

  The travel control device 31 also controls the fork device 7 in addition to the travel control of the unmanned forklift 1. The control circuit 32 as a core is configured using a microcomputer. The control circuit 32 includes a wireless device 33, a laser projector / receiver 16, an obstacle detection circuit 35, an encoder circuit 36, a travel motor drive circuit 37a, a steering mechanism drive circuit 37b, a travel warning light drive circuit 38, and a travel sound alarm drive. A circuit 39, a fork device drive circuit 40, and the like are connected.

  The control circuit 32 receives the conveyance command sent from the ground command device by the wireless device 33. Based on the command, the travel motor drive circuit 37a is operated to drive the travel drive wheel 3a, and the steering mechanism drive circuit 37b is operated to steer the travel drive wheel 3a to guide the unmanned forklift 1 to a target location. For guidance, a layout map of the traveling space stored in advance, current position information detected using the laser projector / receiver 16, and a pulse signal from an encoder (not shown) attached to the traveling motor 20 are encoded by an encoder circuit 36. This is performed based on the movement distance information from a predetermined point obtained by counting in step (b). The current position detection using the laser projector / receiver 16 is based on the principle of triangulation by projecting laser light onto a plurality of reflectors attached to the wall surface of the traveling space and detecting the distance and direction from the reflected light. This is done by calculating its own position.

  The wheel wear amount calculation circuit (corresponding to the wear amount calculation means) 45 includes an arithmetic circuit 46, a storage circuit 47, and an interface (IF) circuit 48. The arithmetic circuit 46 is configured using a microcomputer. The interface circuit 48 is used for data communication with the control circuit 32, and is an input means described in the claims. The storage circuit (corresponding to storage means) 47 is for storing the distance to the floor 2 measured by the laser distance meter 50 and the wheel replacement time received via the interface circuit 48. It is configured using.

  Next, a method for measuring the amount of wheel wear under the above configuration will be described. The measurement starts by notifying the wheel wear amount calculation circuit 45 that the wheel has been replaced with a new one. Information on the exchange is transmitted from the ground command device to the control circuit 32 of the travel control device 31 wirelessly. The information is output from the control circuit 32 to the interface circuit 48 of the wheel wear amount calculation circuit 45 and transmitted to the arithmetic circuit 46. The arithmetic circuit 46 stores in the storage circuit 47 that the wheel has been replaced.

  Subsequently, the command device issues an instruction to move the unmanned forklift 1 to a measurement location prepared for measuring the amount of wheel wear and to perform measurement. Receiving the instruction, the travel control device 31 guides the unmanned forklift 1 to the prepared measurement location and stops it. At the measurement location, a horizontal plane that can support the rolling surfaces of all the wheels of the unmanned forklift 1 on the same plane and reflects the irradiated laser beam well is formed. For example, as shown in FIGS. 3 and 4, a thick horizontal plate of stainless steel whose surface is polished is laid.

  After the unmanned forklift 1 is guided to the measurement location and stopped, the traveling control device 31 instructs the wheel wear amount calculation circuit 45 to start measurement. Receiving the instruction through the interface circuit 48, the arithmetic circuit 46 instructs the laser distance meter 50 to measure the distance to the floor 2 and receives the value. The arithmetic circuit 46 stores the received measurement value in the storage circuit 47. In the first measurement after wheel replacement, the wheel wear amount is not calculated.

  When the cumulative operating time of the unmanned forklift 1 reaches a predetermined value, a command for measuring the wheel wear amount is issued from the ground command device to the travel control device 31. The measurement instruction may be issued manually by an operator or periodically from the commanding device. Moreover, you may make it the traveling control apparatus 31 put out automatically whenever it passes a measurement place. When a measurement instruction is issued, the traveling control device 31 guides the unmanned forklift 1 to the measurement location and stops it, just after the wheel replacement described above, and issues a measurement start instruction to the wheel wear amount calculation circuit 45. The arithmetic circuit 46 instructs the laser distance meter 50 to measure the distance to the floor 2 and receives the value. The arithmetic circuit 46 stores the received measurement value in the storage circuit 47. At the same time, the current measurement value is compared with the measurement value immediately after the wheel replacement, and the difference is grasped as the wheel wear amount. The grasped wear amount is transmitted to the travel control device 31 via the interface circuit 48. The traveling control device 31 wirelessly transmits the received value to the ground command device.

  In this way, the ground commanding device can grasp the wheel wear amount without manual intervention only by wirelessly transmitting a wheel wear amount measurement instruction. If the amount of wheel wear is known, the necessity of wheel replacement can be determined from the value. Further, if the wheel wear amount is known, the actual wheel diameter at that time is also found. Therefore, when calculating the amount of movement based on the encoder signal that generates a pulse synchronized with the rotation of the axle, the amount of movement can be accurately calculated by using the numerical value of the wheel diameter that has been found.

It should be noted that wheel wear is more severe on the drive wheels than on the driven wheels. Therefore, it is preferable that the laser distance meter 50 is attached to a carriage frame near the drive wheel as in the above embodiment. Further, when there are a plurality of driving wheels, the laser distance meter 50 may be attached to each driving wheel.
Moreover, in the said embodiment, although the measurement of the amount of wheel wear was performed on the horizontal board 18, the board 18 does not necessarily need to be horizontal and may incline a little.
In the above embodiment, the distance to the horizontal plate 18 is measured. However, a surface parallel to the horizontal plate 18 is formed above or below the horizontal plate 18 and the distance to the surface is measured. Good.

Further, the wheel wear amount calculation circuit 45 may be integrated with the travel control device 31 instead of being provided separately from the travel control device 31. In that case, the control circuit 32 is caused to execute the functions of the arithmetic circuit 46 and the interface circuit 48 in FIG.
In the above embodiment, a trackless traveling vehicle has been described. However, the present invention can also be applied to a tracked traveling vehicle. In that case, a track having a certain height may be laid on the horizontal plate 18 shown in FIGS. 3 and 4 and the distance to the surface of the horizontal plate 18 may be measured periodically by the laser distance meter 50.

1 is a side view of an unmanned forklift (traveling vehicle) 1. FIG. 1 is a front view of an unmanned forklift (traveling vehicle) 1. FIG. It is a top view which shows the positional relationship of the wheel attached to the trolley | bogie frame. It is sectional drawing seen from the cut surface line AA of FIG. 2 is a configuration diagram of a control device 30. FIG.

Explanation of symbols

  In the drawings, 1 is an unmanned forklift (traveling vehicle), 2 is a floor surface (traveling surface), 3a is a traveling drive wheel (wheel), 3b is a driven wheel, 5 is a carriage frame, 16 is a laser projector / receiver, and 18 is a horizontal plane. (Horizontal plate), 31 is a traveling control device, 45 is a wheel wear amount calculation circuit, and 50 is a laser distance meter.

Claims (3)

A method for measuring a wheel wear amount of a traveling vehicle, wherein a distance measuring means for measuring a distance between a traveling surface on which a wheel rolls or a surface parallel to the traveling surface is attached to a bogie frame of the traveling vehicle,
Forming a plane capable of supporting the rolling surfaces of all the wheels of the traveling vehicle on the same surface at predetermined locations on the traveling surface on which the traveling vehicle travels;
Guiding the traveling vehicle onto the plane and measuring the distance between the plane or a parallel plane spaced apart from the plane by the distance measuring means;
A method for measuring a wheel wear amount of a traveling vehicle, wherein the measured amount of wear of the wheel is calculated by comparing the measured distance with a value immediately after the wheel is replaced. A traveling vehicle that travels by rolling wheels on a traveling surface,
A distance measuring means attached to the carriage frame of the traveling vehicle and measuring a distance between the traveling surface or a surface parallel to the traveling surface; and a wheel wear amount calculating means.
The wear amount calculating means includes an input means for receiving an instruction to measure a distance to the running surface or a plane parallel to the running surface, and an information input indicating that the wheel has been replaced, the distance measured by the distance measuring means, Storage means for storing the wheel replacement information received by the input means, and when receiving a distance measurement instruction via the input means, the distance measurement means is instructed to the travel surface or the travel surface The distance measurement with the parallel plane is executed, and the measured value obtained is compared with the distance measurement value stored first by the storage means after receiving the wheel replacement information input, thereby determining the amount of wear of the wheel. A traveling vehicle configured to calculate.   3. The traveling vehicle according to claim 2, wherein the distance measuring means is attached to the bogie frame close to a driving wheel of the traveling vehicle.