JP7418931B2 - Conveyor tracking correction system and workpiece retrieval method using it - Google Patents

Description

The present invention relates to a tracking correction system for a conveyor and a method for taking out a workpiece using the same, and more particularly, the present invention relates to a tracking correction system for making the measured displacement of an encoder follow the feed amount of an endless belt, and a method for taking out a workpiece using the same. This invention relates to a method for taking out a workpiece.

2. Description of the Related Art As a conveyance device for conveying an object, a conveyor is known that includes an endless belt and a guide roller that guides the endless belt. Among these, for example, there is one in which an encoder for detecting the feed amount of the endless belt is attached to the upstream guide roller.
In such a conveyor, the encoder is capable of detecting the amount of displacement caused by the rotation of the upstream guide roller when feeding out the endless belt. That is, in such a conveyor, it is possible to recognize the amount of feed of the endless belt based on the amount of displacement of the encoder.

However, when a conveyor is used for a long time, tracking deviation may occur due to elongation of the endless belt itself, slippage between the endless belt and guide rollers, and the like.
That is, during actual measurement, the amount of feed of the endless belt on the conveyor and the amount of actual displacement of the corresponding encoder value may deviate from each other.
In this case, there will be a discrepancy between the actual position of the conveyed object being conveyed to the conveyor and the position information based on the measured displacement of the encoder, so the robot will take out the conveyed object based on the position information on the downstream side of the conveyor. A situation arises in which it is no longer possible to process the conveyed object, and it is also no longer possible to process the transported object.

In contrast, conventionally, when a tracking deviation occurs, the position of the belt or the amount of displacement of the encoder is generally corrected artificially.

Incidentally, the following techniques are known as other measures against misalignment.
For example, an endless belt with an encoder slit in the belt conveyance direction, a position sensor for detecting the position of the encoder slit, a zero point sensor that detects the position once per rotation of the endless belt, and an encoder slit for the belt conveyance. A belt conveyance position control method is known that includes a control section that controls the belt conveyance position even if there is a break in the direction (for example, see Patent Document 1).
In addition, if the conveyor carrying the tire components to be transported to the tire molding machine is run in advance and stopped, and if the actual stopping position and the set position, which is the preset stopping position, deviate, the amount of deviation will be Based on this, there is a known method for adjusting the origin position/feed amount of a conveyor, which resets the origin position or feed amount of the conveyor, which is input to a control device that controls a servo motor attached to the conveyor moving mechanism. (For example, see Patent Document 2).

Patent No. 4234895 JP2009-34972A

As described above, in the past, correction of tracking deviation (hereinafter referred to as "tracking correction") was performed manually, which had the disadvantage of being time-consuming and prone to human error.
Furthermore, the methods described in Patent Documents 1 and 2 described above have the disadvantage that they are time-consuming and the conveyance capacity is significantly reduced.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a tracking correction system for a conveyor that can easily perform tracking correction and does not reduce conveyance capacity, and a method for taking out a work using the same. shall be.

After intensive study to solve the above problem, the inventor of the present invention has discovered that the upstream side detection section and the downstream side detection section are arranged at a certain distance, and when both detect an arbitrary point, the encoder value detection section We have discovered that the above problem can be solved by calculating a scale factor from the amount of displacement between the belts and correcting the measured displacement amount based on the scale factor without correcting the feed amount of the endless belt, and have developed the present invention. I ended up completing it.

The present invention provides (1) an endless belt, an upstream guide roller and a downstream guide roller that guide the endless belt, an upstream detection section for detecting arbitrarily set points on the running endless belt, and the upstream guide roller and the upstream guide roller that guide the endless belt. A conveyor tracking correction system comprising a downstream side detection section located downstream of the side detection section and an encoder attached to an upstream guide roller, the conveyor tracking correction system comprising a running command means for running an endless belt; When the upstream side detecting unit detects a point set arbitrarily, the first detection signal is received from the upstream side detecting unit, and the first encoder value of the encoder at the time of reception is measured, a measuring means for receiving a second detection signal from the downstream detection unit when detecting the point set in and measuring a second encoder value of the encoder at the time of receiving the second detection signal, and storing the first encoder value and the second encoder value. and calculating an inter-detection unit displacement amount of the encoder value between the upstream side detection unit and the downstream side detection unit from the stored first encoder value and second encoder value, and calculates the inter-detection unit displacement amount and the stored first encoder value and second encoder value. calculation means for calculating a scale factor from the distance between the upstream side detection section and the downstream side detection section; The endless belt has a plurality of support and guide rollers disposed on the outside thereof to support and guide the lower side of the endless belt, the plurality of support and guide rollers are arranged at equal intervals from each other, and the upper side of the endless belt is It is installed on the upstream guide roller and the downstream guide roller and is flat, and the lower part is maintained in a relaxed state between a plurality of support guide rollers, and the endless belt can be set arbitrarily. The conveyed object is placed at the point where the conveyed object is placed, and the running speed of the endless belt is constant between the upstream side detection section and the downstream side detection section, and the arbitrarily set point is placed through the conveyed object. It is detected by the upstream side detection section and the downstream side detection section, and both the upstream side detection section and the downstream side detection section are reflection type laser sensors that emit laser in the width direction. An arbitrarily set point is detected by irradiating the object, and the measurement of the first encoder value and the measurement of the second encoder value are performed in one conveyance of the conveyed object. , in the calculation means, the scale factor is calculated according to the following formula,
Q1=P2-P1 (Q1: displacement amount between detection parts, P1: first encoder value, P2: second encoder value)
SF=L1/Q1 (L1: distance between upstream detection section and downstream detection section, SF: scale factor)
In the calculation means, calculation of the corrected movement amount by tracking correction in which the measured displacement amount of the encoder value is multiplied by the scale factor is based on the following formula,
L2=Q2×SF (Q2: Actual displacement amount, L2: Corrected movement amount)
By repeatedly calculating the corrected movement amount using tracking correction, the conveyance continues without correcting the feed amount of the endless belt itself, and the robot takes out the object being conveyed or The problem lies in the tracking correction system for the conveyor that performs processing.

The present invention provides ( 2 ) the conveyor tracking according to (1) above, wherein the encoder is an incremental rotary encoder, and the encoder value is a value obtained by counting a pulse signal obtained by converting the rotation amount of the upstream guide roller. It is in the correction system.

The present invention provides ( 3 ) a conveyor in which the frames disposed on both sides of the endless belt support both ends of the upstream guide roller, the downstream guide roller, and the plurality of support guide rollers, and The present invention resides in the conveyor tracking correction system according to ( 1 ) above, wherein the downstream detection section is mounted and fixed at a fixed distance along the conveyance direction.

In the conveyor tracking correction system of the present invention, the conveyor used has a simple configuration including an endless belt, an upstream guide roller, a downstream guide roller, an upstream detection section, a downstream detection section, and an encoder. Since there is no need to perform any special processing on the endless belt or any special equipment, it is highly versatile.

In the conveyor tracking correction system of the present invention, the upstream side detection section and the downstream side detection section are arranged at a certain distance, and when both detect an arbitrary point, the amount of displacement between the detection sections of the encoder value is calculated. Since the calculation means calculates a scale factor that is a ratio of the distance to the encoder value, the measured displacement amount can be corrected by using the scale factor. That is, even if a tracking deviation occurs, the actual measured displacement amount of the encoder can be corrected to match it without correcting the feeding amount of the endless belt.

In this way, according to the above conveyor tracking correction system, tracking correction can be easily performed, so that highly accurate conveyance can be performed with respect to positional information. Furthermore, since the feed amount of the endless belt is not corrected, the conveyance capacity is not reduced.
As a result, the feed amount of the conveyor and the corrected movement amount corrected by the actual measured displacement of the encoder will almost match, so the robot can pick up objects with high precision based on the corrected movement amount. This also makes it possible to process objects with high precision.
Further, by repeating the tracking correction described above, highly accurate conveyance can be continuously performed.

Here, the calculation by the calculation means is performed using the above formula. Then, the corrected movement amount is calculated by multiplying the measured displacement amount of the encoder value by the scale factor.
This makes it possible to reliably perform the tracking correction described above.

In the conveyor tracking correction system of the present invention, an incremental rotary encoder is preferably used as the encoder. In this case, the encoder value is a value obtained by counting pulse signals obtained by converting the amount of rotation of the upstream guide roller.
Thereby, the degree of rotation of the upstream guide roller can be recognized by the pulse signal.

In the conveyor tracking correction system of the present invention, by placing the conveyed object at an arbitrarily set point on the endless belt, the position at which the upstream side detection section and the downstream side detection section detect the conveyed object can be set at the above arbitrary point. Since this is the set point, it becomes possible to easily detect the arbitrarily set point.
At this time, if both the upstream side detection section and the downstream side detection section are reflective laser sensors that irradiate the laser in the width direction, the conveyed object can be detected instantaneously, making it easier to detect arbitrarily set points. It can be done with high precision.

The workpiece retrieval method of the present invention uses the above-mentioned conveyor tracking correction system and causes the robot to grip the workpiece based on position information based on the corrected movement amount, so it is possible to prevent errors caused by positional deviation of the workpiece. can.

FIG. 1 is a perspective view schematically showing a conveyor in which a tracking correction system according to the present embodiment is used. FIG. 2 is a block diagram for explaining the conveyor tracking correction system according to this embodiment. FIG. 3 is a flowchart showing a method for taking out a workpiece according to this embodiment. FIG. 4 is an explanatory diagram for explaining a method for taking out a workpiece according to this embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are designated by the same reference numerals, and redundant explanations will be omitted. In addition, the positional relationships such as top, bottom, left, and right are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the illustrated ratios.

The conveyor tracking correction system according to the present embodiment is a system that allows the conveyor to follow the actual measured displacement amount of the endless belt on the conveyor by correcting the measured displacement amount of the encoder value, regardless of the presence or absence of tracking deviation.
Note that the correction by the conveyor tracking correction system may be performed periodically during setup change or the like, or may be performed continuously during conveyance of the conveyed object.

Here, in this specification, "upstream" means upstream in the conveying direction of the conveyed object, and "downstream" means downstream in the conveying direction of the conveyed object.
In addition, the "calculated feed amount" of the endless belt means the calculated feed amount of the unauthorized belt 1 due to the rotation of the upstream guide roller, and the "feed amount" of the endless belt refers to the calculated feed amount of the endless belt. It means the amount of deviation due to tracking deviation added to the sending amount of .
In addition, "the amount of displacement between the encoder values between the detection parts" particularly means the amount of displacement of the encoder values between the upstream side detection part and the downstream side detection part, and the "actually measured displacement amount of the encoder values" means any This means the amount of displacement of the encoder value with respect to the amount of feeding of the endless belt. That is, the measured displacement amount changes depending on the amount of feed of the endless belt.

First, a conveyor in which a tracking correction system according to this embodiment is used will be described.
FIG. 1 is a perspective view schematically showing a conveyor in which a tracking correction system according to the present embodiment is used.
Note that the conveyor 10 in FIG. 1 is shown with the frame F being transparent.
As shown in FIG. 1, the conveyor 10 includes an endless belt 1, a plurality of guide rollers 2 that guide the endless belt 1, and an upstream side detector for detecting a point P arbitrarily set on the running endless belt 1. section 3a and the downstream detection section 3b, an encoder E attached to the upstream guide roller 2 (hereinafter also referred to as "upstream guide roller 2a"), and the downstream guide roller 2 (hereinafter also referred to as "downstream guide roller 2a"). 2b"), and a frame F for supporting both ends of the guide roller.
A rectangular parallelepiped-shaped conveyed object B is placed at an arbitrarily set point P on the endless belt 1.

The tracking correction system according to this embodiment has excellent versatility because the conveyor 10 that uses it has a simple configuration, and there is no need for special processing on the endless belt or special equipment. It is.

In the conveyor 10, specific examples of the endless belt 1 and the upstream guide roller 2a and downstream guide roller 2b on which the endless belt 1 is installed are not particularly limited, but include, for example, a flat belt, a pulley, a toothed belt, It can be used in combination with toothed pulleys, chains, sprockets, etc. as appropriate.
Moreover, these materials are not particularly limited, and may be made of metal or resin.

In the conveyor 10, the endless belt 1 is annular in side view.
Here, for convenience, the upper part of the conveyor 10 that advances in the transport direction of the transported object B is referred to as the upper part 1a, and the lower part of the conveyor 10 that advances in the opposite direction to the transport direction of the transported object B is referred to as the lower part. The side portion 1b is defined as the side portion 1b.

In the endless belt 1, the upper side portion 1a is flat, and the belt moves in the conveying direction with the conveyed object B placed on an arbitrarily set point P on the upper surface. Note that the arbitrarily set point P is appropriately set on the upper side portion 1a using the values of the X axis in the width direction and the Y axis in the conveyance direction of the endless belt.
On the other hand, the lower part 1b of the endless belt 1 is configured to move in the opposite direction to the conveyance direction of the conveyed object B while maintaining a relaxed state between support guide rollers 2c, which will be described later. .
In this way, in the conveyor 10, by keeping the lower part 1b of the endless belt 1 in a relaxed state, tension is applied to the upper part 1a of the endless belt 1 by its own weight.

In the conveyor 10, the guide roller 2 includes an upstream guide roller 2a and a downstream guide roller 2b that are arranged inside the endless belt 1, and a guide roller 2 that is arranged outside the endless belt 1 and supports the lower part 1b of the endless belt 1. It has a plurality of support guide rollers 2c for guiding.
That is, the endless belt 1 is installed over an upstream guide roller 2a and a downstream guide roller 2b, and the loosened lower portion 1b is supported by a plurality of support guide rollers 2c.

In the conveyor 10, an encoder E is attached to the upstream guide roller 2a.
Here, as the encoder E, an incremental rotary encoder is employed.
In this case, the encoder E converts the mechanical displacement caused by the rotation of the upstream guide roller into a pulse signal. Therefore, the encoder value obtained by the encoder E is a value obtained by counting the pulse signal with a counter.

In the conveyor 10, the amount of rotation of the upstream guide roller 2a can be recognized from the encoder value (count number of pulse signals) of the encoder E.
That is, the amount of rotation of the upstream guide roller 2a can be calculated from the encoder value, and from the amount of rotation, it is possible to calculate the calculated feed amount of an arbitrarily set point on the endless belt 1.

In the conveyor 10, a motor M and a reduction gear (not shown) are attached to the downstream guide roller 2b.
That is, the downstream guide roller 2b is a so-called drive roller that incorporates a motor M and a reduction gear.
As a result, the endless belt 10 is driven and rotated on the conveyor 10.

In the conveyor 10, a plurality of support guide rollers 2c are arranged at equal intervals between the upstream guide roller 2a and the downstream guide roller 2b.
As described above, the lower part 1b of the endless belt 1 is in a slack state between the adjacent support guide rollers 2c. Note that the lower part 1b may be loosened at one location between the support guide rollers 2c or at all locations.

In the conveyor 10, the frame body F is arranged on both sides of the endless belt 1.
The frame F supports both ends of the guide rollers 2 (upstream guide roller 2a, downstream guide roller 2, and support guide roller 2c).
Further, two detection units are attached and fixed to the frame F so as to extend along the conveyance direction.
That is, one detection section (hereinafter referred to as "upstream detection section 3a") is attached and fixed to the frame F, and the other detection section (hereinafter referred to as "upstream detection section 3a") is attached and fixed at a certain distance L1 downstream of the upstream detection section 3a. (referred to as "downstream detection section 3b") is attached and fixed.

In the conveyor 10, the upstream detection section 3a and the downstream detection section 3b both employ reflective laser sensors that emit laser light in the width direction perpendicular to the conveyance direction.
Therefore, when the conveyed object B placed at an arbitrarily set point P is conveyed and reaches the upstream detecting section 3a, the upstream side detection section 3a detects the conveyed object by irradiating the conveyed object with a laser. B can be detected instantly.
Similarly, when the conveyed object B placed at an arbitrarily set point P is conveyed and reaches the downstream detecting section 3b, the downstream detecting section 3b irradiates the conveyed object with a laser. B can be detected instantly.

The conveyed object B is placed at an arbitrarily set point P on the endless belt 1.
Note that the position where the conveyed object B is placed may be an arbitrarily set point P.
As a result, a point P arbitrarily set on the endless belt 1 is detected via the conveyed object B by the upstream side detection section 3a and the downstream side detection section 3b. As a result, it becomes possible to easily detect the arbitrarily set point P.

Although the shape of the conveyed object B is not particularly limited, it is preferably rectangular parallelepiped from the viewpoint of ease of detection by the upstream side detection section 3a and the downstream side detection section 3b.
Furthermore, the conveyed object B may be a processed product that is actually processed or has been processed.

Next, a tracking correction system using the above-mentioned conveyor 10 will be explained.
FIG. 2 is a block diagram for explaining the conveyor tracking correction system according to this embodiment.
As shown in FIG. 2, the tracking correction system T for the conveyor 10 according to the present embodiment includes a running command means T1 for running the endless belt, a detection signal that is received at the time of detection by the detection unit, and an encoder at the time of reception of the detection signal. A measurement means T2 for measuring the encoder value, a storage means T3 for storing the encoder value, and an inter-detection part displacement amount of the encoder value between the upstream side detection part and the downstream side detection part is calculated from the stored encoder value. It also includes calculation means T4 that calculates a scale factor from the amount of displacement between the detection parts and the distance between the upstream detection part and the downstream detection part.

The tracking correction system T for the conveyor 10 is performed using a normal computer equipped with a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an external storage device, an input section, and an output section. be exposed.

The running command means T1 issues a running command for causing the endless belt 1 to run in the conveyance direction.
The specific running speed of the endless belt 1 at this time is not particularly limited, but it is preferably a substantially constant speed at least between the upstream side detection section 3a and the downstream side detection section 3b.
When the travel command means T1 issues a travel command, the motor M of the conveyor 10 rotates the downstream guide roller 2b based on the travel command. As a result, the endless belt 1 rotates, and the upper side portion 1a of the endless belt 1 runs in the conveying direction.
Further, the running command means T1 issues a stop command when stopping the rotation of the endless belt 1.
Thereby, the motor M stops the rotation of the downstream guide roller 2b.

The measuring means T2 detects a detection signal (hereinafter referred to as a "first detection signal") from the upstream detection section 3a when the upstream detection section 3a detects the conveyed object B (arbitrarily set point P). ).
Then, the encoder value of the encoder E at the time of receiving the first detection signal (hereinafter referred to as "first encoder value") is measured.
Further, after that, when the downstream detecting section 3b detects the transported object B (point P arbitrarily set), the measuring means T2 receives a detection signal (hereinafter referred to as "second") from the downstream detecting section 3b. Detection signal) is received.
Then, the encoder value of the encoder E at the time of receiving the second detection signal (hereinafter referred to as "second encoder value") is measured.
That is, the measuring means T2 measures the encoder values at the time when the upstream detecting section 3a and the downstream detecting section 3b detect the conveyed object B, respectively.
Note that the measurement of the first encoder value and the measurement of the second encoder value are performed when the object B is transported once.

The storage means T3 stores at least the first encoder value and the second encoder value measured by the measuring means T2.
Note that the stored first encoder value and second encoder value can also be displayed by a display means.

The calculation means T4 reads the first encoder value and the second encoder value stored in the storage means T3, and calculates the inter-detection unit displacement amount of the encoder value between the upstream side detection unit 3a and the downstream side detection unit 3b from these. calculate.
That is, when the first encoder value is P1 and the second encoder value is P2, the displacement amount Q1 between the detection parts is
Q1=P2-P1
Calculated by

Furthermore, a scale factor is calculated from the displacement amount between the detection sections and the distance between the upstream detection section and the downstream detection section.
That is, when the distance between the upstream detection section 3a and the downstream detection section 3b is L1, the scale factor SF is
SF=L1/Q1
Calculated by That is, the scale factor SF is calculated as the distance (feed amount) per one count. Note that when a tracking shift occurs, although the distance L1 is constant, the first encoder value P1 and the second encoder value P2 change, so the scale factor SF also changes.

Then, the measured displacement amount of the encoder E is corrected using the obtained scale factor SF.
When the endless belt 1 is fed by an arbitrary feed amount, the corrected movement amount is calculated by multiplying the actual measured displacement amount of the encoder value by a scale factor.
That is, when the measured displacement amount is Q2, the corrected movement amount L2 is
L2=Q2×SF
Calculated by
The obtained corrected movement amount L2 corresponds to the above-described arbitrary feed amount of the endless belt 1.

In this way, in the tracking correction system T for the conveyor 10, tracking correction is performed by calculating an arbitrary feed amount of the endless belt 1 as the corrected movement amount L2.
In this case, even if a tracking deviation occurs, the feeding amount of the endless belt itself is not corrected, so that the conveyance capacity is not reduced.
Furthermore, since the position of the transported object can be recognized with high precision, it becomes possible for the robot to take out the object and also to process the object.
Further, by repeating the tracking correction described above, highly accurate conveyance can be continuously performed.

Next, a method for taking out a workpiece using the above-mentioned tracking correction system for the conveyor 10 will be explained.
FIG. 3 is a flowchart showing a method for taking out a workpiece according to this embodiment.
As shown in FIG. 3, the workpiece takeout method according to the present embodiment includes a transport step S1, a takeout step S2, and a placement step S3.
By going through these steps, the transported workpiece can be reliably taken out.
Note that the workpiece may be flat or three-dimensional as long as it can be gripped by the robot.

FIG. 4 is an explanatory diagram for explaining a method for taking out a workpiece according to this embodiment.
As shown in FIG. 4, in the workpiece retrieval method, first, the workpiece W placed on the endless belt 1 is transported to the retrieval position X1 (transport step S1).
At this time, the above-mentioned tracking correction system is used in the transport step S1.
Therefore, the corrected movement amount obtained by correcting the actual displacement amount measured by the encoder E is obtained as the position information of the workpiece W to be transported.

Next, the robot R grasps and takes out the work W that has been transported to the take-out position X1 (take-out step S2).
At this time, in the take-out step S2, the position set for the robot to grip the workpiece is based on the corrected movement amount. That is, the robot R is caused to grip the work W based on the position information based on the corrected movement amount.
Thereby, in the workpiece retrieval method, even if tracking deviation occurs during long-term use, it is possible to prevent a retrieval error due to positional deviation of the workpiece from occurring.
Moreover, in the method for taking out the workpiece, the conveyance capacity is not reduced.

Then, the robot R places the workpiece W on the placement section X2, and thereby the workpiece W is taken out (placing step S3).
Here, a lifter is employed as the mounting portion X2.
Therefore, a so-called stack S is formed by stacking the works on the lifter.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

In the conveyor tracking correction system according to the present embodiment, the endless belt 1 is used as the belt of the conveyor 10, but the present invention is not limited to this, and it is also possible to use a linear belt.
Note that tracking deviation is more likely to occur with the endless belt 1.

In the conveyor tracking correction system according to the present embodiment, by keeping the lower part 1b of the endless belt 1 in a relaxed state, tension is applied to the upper part 1a of the endless belt 1 by its own weight. , the configuration is not limited to this, as long as it is possible to apply tension.
For example, tension may be applied to the endless belt 1 by attaching a tension adjustment roller that guides the endless belt 1 and moving the tension adjustment roller without loosening the lower part 1b of the endless belt 1.

In the conveyor tracking correction system according to the present embodiment, an incremental rotary encoder is employed as the encoder E, but the present invention is not limited to this, and an absolute rotary encoder may also be employed.

In the conveyor tracking correction system according to the present embodiment, two detection units are attached and fixed to the frame F along the conveyance direction, but the detection units are only attached and fixed to the frame F. Not done. It is also possible to install it by attaching it to a separate component from the conveyor 10.

In the conveyor tracking correction system according to the present embodiment, the upstream side detection section 3a and the downstream side detection section 3b both employ reflective laser sensors that emit laser in the width direction perpendicular to the conveyance direction. However, the present invention is not limited to this, and it is also possible to employ surveillance cameras, photoelectric sensors, etc.

In the conveyor tracking correction system according to this embodiment, the scale factor SF is the distance per count, but it can also be the time per count.
However, in this case, it is necessary to keep the conveyance speed constant and set the time required for conveyance between the upstream side detection section and the downstream side detection section.

In the method for taking out the workpiece W according to this embodiment, the robot R takes out the workpiece, but instead of the robot R, it is also possible to employ an orthogonal clamping device (gantry) or the like.

In the method for taking out the workpiece W according to the present embodiment, a lifter is used as the placement part, but instead of the lifter, it is also possible to use a fixed table, a pallet, another conveyance device, etc. .

The conveyor tracking correction system of the present invention is used for a conveyor that conveys objects.
According to the conveyor tracking correction system of the present invention, tracking correction can be easily performed and the conveyance capacity is not reduced.

1...Endless belt 10...Conveyor 1a...Upper side part 1b...Lower side part 2...Guide roller 2a...Upstream guide roller 2b...Downstream guide roller 2c... Support guide roller 3a... Upstream detection section 3b... Downstream detection section B... Object to be transported E... Encoder F... Frame L1... Distance M... Motor P... Points set arbitrarily R...Robot S1...Transportation step S2...Takeout step S3...Placement step T...Tracking correction system T1...Travel command means T2...Measurement means T3 ... Storage means T4 ... Calculation means X1 ... Take-out position X2 ... Placement section W ... Workpiece

Claims (3)

An endless belt, an upstream guide roller and a downstream guide roller that guide the endless belt, an upstream detecting section for detecting arbitrarily set points on the running endless belt, and a downstream side of the upstream detecting section. A conveyor tracking correction system comprising: a downstream detection section located at the upstream side guide roller; and an encoder attached to the upstream guide roller.
a running command means for running the endless belt;
receiving a first detection signal from the upstream detection unit when the upstream detection unit detects the arbitrarily set point, and measuring a first encoder value of the encoder at the time of reception; Measuring means for receiving a second detection signal from the downstream detection section when the detection section detects the arbitrarily set point, and measuring a second encoder value of the encoder at the time of receiving the second detection signal;
storage means for storing the first encoder value and the second encoder value;
An inter-detection unit displacement amount of the encoder value between the upstream side detection unit and the downstream side detection unit is calculated from the stored first encoder value and the second encoder value, and the inter-detection unit displacement amount and Calculation means for calculating a scale factor from the distance between the upstream detection unit and the downstream detection unit;
has
In the conveyor, the guide roller includes, in addition to the upstream guide roller and the downstream guide roller, a plurality of support guide rollers that are arranged outside the endless belt and support and guide the lower side of the endless belt. have,
The plurality of support guide rollers are arranged at equal intervals from each other,
The upper part of the endless belt is stretched over the upstream guide roller and the downstream guide roller and is flat, and the lower part is in a relaxed state between the plurality of support guide rollers. is maintained,
A conveyed object is placed at an arbitrarily set point on the endless belt,
The running speed of the endless belt is a constant speed between the upstream side detection section and the downstream side detection section,
The arbitrarily set point is detected by the upstream detection section and the downstream detection section via the conveyed object,
Both the upstream side detection section and the downstream side detection section are reflective laser sensors that irradiate a laser in the width direction, and by irradiating the conveyed object with the laser, the arbitrarily set point is set. is detected,
The measurement of the first encoder value and the measurement of the second encoder value are performed in one conveyance of the conveyed object,
In the calculation means, the calculation of the scale factor is based on the following formula,
Q1=P2-P1 (Q1: displacement amount between detection parts, P1: first encoder value, P2: second encoder value)
SF=L1/Q1 (L1: distance between upstream detection section and downstream detection section, SF: scale factor)
In the calculation means, calculation of the corrected movement amount by tracking correction in which the measured displacement amount of the encoder value is multiplied by the scale factor is based on the following formula,
L2=Q2×SF (Q2: Actual displacement amount, L2: Corrected movement amount)
By repeatedly calculating the corrected movement amount by the tracking correction, conveyance is continuously performed without correcting the feed amount itself of the endless belt,
A conveyor tracking correction system in which a robot takes out a conveyed object or processes the conveyed object based on the corrected movement amount. The encoder is an incremental rotary encoder,
2. The conveyor tracking correction system according to claim 1, wherein the encoder value is a value obtained by counting pulse signals obtained by converting the amount of rotation of the upstream guide roller. In the conveyor, frame bodies disposed on both sides of the endless belt support both ends of the upstream guide roller, the downstream guide roller, and the plurality of support guide rollers, and
The conveyor tracking correction system according to claim 1 , wherein the upstream side detection section and the downstream side detection section are mounted and fixed at a fixed distance along the conveyance direction.

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