JPH01226482A - Position matching method for conveyor synchronizer - Google Patents

Abstract

PURPOSE:To correct position measurement error in carrying direction caused through positional shift of a body in the direction perpendicular to the carrying direction by arranging an optical sensor and a distance sensor on a conveyor synchronizer and measuring the position of the body in carrying direction. CONSTITUTION:When a body B is carried through a slat conveyor 1 to a predetermined position, a portion of the body contacts with a limit switch 9 to turn a distance sensor 4, on optical sensor 5 and a light source switch ON thus starting synchronous control. The distance sensor 4 measures the distance to the body B while the optical sensor 5 detects light emitted from a light source 7 arranged obliquely rearward and detects the portion where the light is blocked by means of a center pillar. A servo motor 2a is started based on the detection signal to advance the conveyor synchronizer 2 thus starting travelling through the slat conveyor 1.

Description

[Detailed description of the invention] Industrial application field of automobiles! The present invention relates to a method for highly accurately aligning the relative positions of a conveyor dowj device and a vehicle body on a conveyor in an I-loading roughing line or the like.

Conventional technology In a car body assembly line, etc., when a conveyor synchronizer mounted on a work machine or the like is run in synchronization with the conveyor, there is a method for aligning the relative positions of the car body on the conveyor and the conveyor synchronizer, for example. Light is irradiated onto the center pillar of the car body being transported, and the horizontal illuminance distribution of the reflected light is detected by an optical sensor installed on the conveyor synchronizer so as to be perpendicular to the center pillar surface. Conventionally, a method has been adopted to adjust the position by adjusting the position of the conveyor synchronizer and the position of the conveyor body during conveyance by detecting special parts such as the stepped part of the center pillar. The positioning was performed by controlling the running speed of the conveyor synchronizer based on the measured value.

Problems to be Solved by the Invention However, in general, the same Sa assembly line handles many types of car bodies with different podium colors, and since the amount of reflected light differs depending on the podium color, the conventional positioning method described above is difficult to visually detect. Sensing is difficult, and the amount of reflected light changes due to differences in day and night, seasons, etc. due to the influence of external light, making stable lζ measurement difficult. ζ
Since positional misalignment in the direction perpendicular to the conveyance direction of the car body is ignored, the accuracy of measuring the amount of relative positional deviation between the car body on the conveyor and the conveyor synchronizer decreases, which adversely affects the alignment. There was a risk that it would

Furthermore, in order to prevent malfunctions when a single optical sensor is used and improve the reliability of position detection, the center pillar position detection and the position of other specific parts of the vehicle body such as the wheel house with respect to the transport direction are This is also carried out together with the detection of deviation.
A method for controlling the running of a conveyor synchronizer by measuring the positional deviation of a vehicle body in the conveying direction during conveyance
34868), but since the position of the center pillar is detected using reflected light, the amount of reflected light changes due to differences in body color, day and night, and seasonal differences, which affects the measurement accuracy. There was a problem.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to provide a positioning method that accurately detects and corrects errors in the relative positions of the vehicle body being transported and the conveyor synchronizer, thereby achieving highly accurate synchronized travel. It is said that

Means for Solving the Problem 1. Means for Solving the Problem This amount of light is generated when the conveyor synchronizer is placed opposite the conveyor synchronizer with the car body in between when the conveyor synchronizer runs in synchronization with the conveyor that conveys the car body. Detects specific parts of the vehicle body, such as the center pillar, by receiving transmitted light emitted diagonally from a light source placed on the side by an optical sensor placed on the conveyor synchronizer. to measure the position of the car body in the transport direction, and also measure the position of the car body in the direction perpendicular to the transport direction using a distance sensor installed on the conveyor synchronizer, and based on both measurement values, the conveyor synchronizer moves. It is characterized by positioning by controlling speed.

Effect According to the above method, the distance of the vehicle body being transported in a direction perpendicular to the transport direction is repeatedly measured using a distance sensor, and a specific part of the vehicle body such as a center pillar is moved diagonally forward or backward with respect to the transport direction. detecting the center pillar using transmitted light from the center pillar, and correcting the detected position of the center pillar in the conveyance direction according to the position of the center pillar in the direction perpendicular to the conveyance direction of the vehicle body by the distance sensor, thereby determining the accurate position;
Since the traveling speed of the conveyor synchronizer is controlled based on the determined accurate position, highly accurate positioning is performed.

EXAMPLE Hereinafter, an example in which the method of the present invention is applied to a method for positioning a conveyor synchronizer in an i-equipment assembly line for automobile bodies will be described with reference to FIGS. 1 to 5.

One side of the slat conveyor 1 that conveys the car body B (
On the lower side in Fig. 3), a conveyor synchronizer 2 equipped with a working machine (not shown) for sacrificial assembly of parts to the car body B is driven by a servo motor 2a to move the traveling rail 3 above the ground. It is disposed so as to be able to move forward and backward in the conveying direction (left and right direction in FIG. 1, ie, the direction of arrow X) in a direction parallel to the slat conveyor 1.

Further, on the conveyor synchronizer 2, there is a distance sensor 4 for measuring the distance in a direction perpendicular to the conveying direction of the heavy body B (in the vertical direction in FIG. An optical sensor 5 for measurement is provided at a predetermined height by vertically erected columns 4a and 5a, respectively, and the light receiving part of the optical sensor 5 is located at a predetermined angle rearward from the direction perpendicular to the slat conveyor 1. It is set towards. Furthermore, an encoder 6 for detecting the position of the conveyor synchronizer 2 running on the running rail 3 is provided on the running rail 3 side.

On the other hand, on the opposite side of the conveyor synchronizer 2 and the slat conveyor 1, a light source 7 such as a fluorescent pair having a length of a certain length or more in a direction parallel to the slat conveyor 1 is installed at the same height as the optical sensor 5. The slat conveyor 1 is supported by a pillar 7a, emits light toward the optical sensor 5, and is driven by a servo motor 7b on a rail 8 so as to be able to move forward and backward in a direction parallel to the slat conveyor 1. The fixed part of the slat conveyor 1 has the conveyor synchronizer @2.
Limit switches 9 and 10 are provided at the starting point (on the left side in FIG. 1) and the ending point of the optical measurement section. In addition,
The reference numeral 11 is a front wheel attached to the vehicle body B, and the reference numeral 12 is a rear wheel.

When the vehicle body B being conveyed by the slat conveyor 1 reaches a predetermined position, a part of the vehicle body B (for example, a front wheel
1), the switches of the distance sensor 4, optical sensor 5, and light source 7 are turned ON and synchronous control is started, and the distance sensor 4 detects the distance (
In Fig. 3, the distance 1) in the direction of arrow Z is measured, and the optical sensor 5 detects the transmitted light of the light source 7 from diagonally rearward in the conveyance direction, and the transmitted light is detected by the two examples of the conveyor synchronizer of the vehicle body B. By detecting the part blocked by the center pillar P, when a specific part (one point such as the center of gravity position) on the center pillar P is detected, the servo motor 2
a starts and the conveyor synchronizer 2 moves forward in the conveying direction,
The slat conveyor 1 starts to run in synchronization with the vehicle body B being transported, and the servo motor 7b is started to move the light source 7 forward in the transport direction to follow the forward movement of the conveyor synchronizer 2.

After the conveyor synchronizer @2 starts running synchronously, the distance sensor 4 measures the distance in two directions again. tllll is determined, the optical sensor 5 detects a specific part on the center pillar P to measure the relative position between the vehicle body B being conveyed and the conveyor synchronizer 2 that is traveling synchronously, and the distance sensor The actual positional deviation of the conveyor synchronizer 2 in the X direction is calculated from the measured value of 4 and the relative position measured by the optical sensor 5, and the calculated value
In order to synchronize the conveyor synchronizer 2 with the slat conveyor 1 that conveys the slat conveyor 1, a new running speed of the conveyor synchronizer 2 is determined, and the speed of the servo motors 2a and 7b is controlled to perform synchronization control of the conveyor synchronizer 2 with respect to the slat conveyor 1. In this way, the limit switch 10 at the end point of the optical measurement section determines the relative position between the conveyor body B being conveyed and the conveyor synchronizer 2 which is traveling synchronously by the distance sensor 4 and the optical sensor 5. This is repeated until the passage of point B is detected, and by controlling the speed of the servo motors 2a and 7b and performing synchronous control, the deviation in relative position is repeatedly corrected and synchronous traveling is performed with high precision alignment. During this synchronous running, a predetermined dovetailing work on the vehicle body B is carried out and completed using a work rack mounted on the conveyor synchronizer 2.

When the limit switch 10 at the end point of the optical measurement section detects the passage of the rear wheel 12 of the vehicle body B, the synchronous running of the conveyor synchronizer 2 is stopped, and the conveyor synchronizer 2 and the light source 7 are connected to the servo motors 2a, 7b. The distance sensor 4 is driven backward and returned to its original position, and then the distance sensor 4
and the operation switches of the optical sensor 5iB and the light source 7 are OFF.
F, the synchronization ilIl1m ends, and the process waits until the limit switch 9 detects the next vehicle body to be conveyed by the slat conveyor 1.

Further, since the optical sensor 5 detects the position of the center pillar P in the X direction of the vehicle body using transmitted light from a predetermined angle rearward from a direction perpendicular to the conveyance direction, and measures the relative position, If the distance to the car body B being conveyed by the slat conveyor 1 is different from the reference value, that is, if the position of the car body B shifts in 7 directions (directions perpendicular to the II feeding direction), the conveyor synchronizer An error occurs in the position of the vehicle body B in the X direction, making it impossible to determine the actual position, and as a result, highly accurate positioning cannot be achieved. By correcting the distance in the X direction measured by the optical sensor 5 according to the difference between the actual measured distance and the reference value, an accurate relative position is determined and synchronous control is performed.

For example, when the vehicle body B is shifted by Zo in seven directions,
To explain the method of correcting the positional deviation in the directions, in FIG.
The position when shifted, d is the actual position of the printer pillar, d
' is the apparent position seen from optical sensor a when the center pillar is at position d, e is the actual deviation amount of the center pillar in the X direction, f is the deviation amount of d as seen from optical sensor a, q
is the distance in the X direction between the center pillar reference position (i) and optical sensor a, h is the center pillar reference position (1)
and the optical sensor a in two directions, i is the reference position of the center pillar.

If the vehicle body B shifts in seven directions, the limit switch 9
Immediately after detecting the arrival of There is a relationship expressed by the following equation between the positional deviation Φf in the direction and the actual positional deviation e.

−f e = f −−X Z O Therefore, the deviation of the vehicle body B in two directions measured by the distance sensor 4 and the apparent X measured by the optical sensor 5
The actual positional deviation amount in the X direction is calculated from the positional deviation amount in the X direction, a new synchronization speed is determined based on the calculated positional deviation amount in the X direction, and the servo motor 2aF3 of the conveyor synchronizer 2 and the light source are The speed of the servo motor 7b of 7 is controlled, and the distance sensor 4 and the optical sensor 5 repeatedly measure the misalignment in two directions and the misalignment in the X direction, and each time a new synchronous speed is determined. By controlling the conveyor synchronizer 2, it is possible to accurately align the position of the conveyor synchronizer 2 and perform highly accurate synchronization control. In addition, Zo
, e and f take negative values, Zo, e
A similar relationship holds between and t.

Next, the case where synchronous control is performed using the above correction method will be explained based on the flowchart shown in FIG.

When the vehicle body B conveyed to the slat conveyor 1 reaches the starting point side of the optical measurement section, the limit switch 9 is turned on and synchronous control is started. First, in step 1, a measurement I is performed by the distance sensor 4, followed by a measurement I by the optical sensor 5 in step 2, and then the process proceeds to step 3.

In step 3, it is checked whether or not a specific part of the vehicle body B (the center of gravity position of the center pillar P) has been detected from the results of the both side chambers I. If it is not detected, the process returns to step 1 and steps from step 1 to step 3 are performed. Repeat each process in step 3. Then, in step 3, the vehicle body B
If the specific site is detected, the process proceeds to step 4.

When the process proceeds to step 4, the servo motor 2a of the conveyor synchronizer 2 and the servo motor 7b of the light source 7 are activated, synchronous travel is started, and the process proceeds to step 5.

When synchronous driving is started, the distance sensor 4 performs measurement (2) in step 5 to find the difference (deviation amount Zo) between the actual measured distance to the vehicle body B and the reference value, and then proceeds to step 6. After measurement (3) is performed by the optical sensor 5 and the apparent positional deviation ff1f of the center pillar P in the X direction is determined, the process proceeds to step 7.

In step 7, the apparent positional deviation If obtained in step 6 is corrected based on the deviation amount zO obtained in step 5, and the correct positional deviation e in the X direction of the center pillar P is calculated. Then proceed to step 8.

In step 8, based on the correct positional deviation e in the X direction calculated in step 7, a new synchronization is established to accurately align the conveyor synchronized bag @2 with the vehicle body B being conveyed by the slat conveyor 1. After the speed is controlled, the process proceeds to step 9.

In step 9, it is checked whether or not the limit switch 10 disposed at the end point of the optical measurement section has been detected. If it has not been detected, the process returns to step 5 because it is within the synchronous running section. By repeating each process from step 5 to step 9, synchronous speed control of the conveyor synchronous bag @ 2 is performed and positional deviation in the X direction is repeatedly corrected, resulting in more accurate positioning and highly accurate synchronous control. be done. When the vehicle body B being conveyed to the slat conveyor 1 passes the limit switch 10 and the end position of the synchronous travel section is detected, the process proceeds to step 10.

When the process proceeds to step 10, both the conveyor synchronizer 2 and the servo motors 2a and 7b of the light source 7 stop, and the synchronized running ends, and the process proceeds to step 11.
At , both the servo motors 2a and 7b rotate in reverse, and the conveyor moves in the same direction! 11'Jt@2 and light source 7 are retreated and returned to their original positions, and then Step 1
Proceed to step 2.

When the process proceeds to step 12, the operation switches of the distance sensor 4, optical sensor 5, and light source 7 are turned off, and the process proceeds to step 13, where the synchronous control ends.

When the limit switch 9 detects the passage of the next vehicle body conveyed by the slat conveyor 1, the synchronous control is started again and each process from step 1 is performed.

In this embodiment, the optical sensor 5 detects the position of the center pillar P on the conveyor synchronizer 2 side of the vehicle body B using the transmitted light of the light source 7 from diagonally backward in the conveyance direction. Compared to the conventional case where position detection is performed using light from a right angle direction, the position can be measured in a wider field of view without being affected by the other center pillar that is closer to the light source, and the center pillar position can be detected using the optical sensor 5. It is possible to prevent accidental ejection of the material.

In this example, the position of the vehicle body B during transportation was measured by detecting the position of the center pillar P.
Position measurement can also be performed using other specific parts of the vehicle body that can be detected by transmitted light from the opposite side, such as the front pillar or rear pillar.

As described in detail, the conveyor synchronizer positioning method of the present invention is such that when the conveyor synchronizer Hfi is run synchronously with the conveyor that conveys the car body, the conveyor synchronizer and the conveyor synchronizer are placed on opposite sides with the car body in between. The optical sensor installed on the conveyor synchronizer receives the transmitted light emitted from the installed light source in a diagonal direction with respect to the conveyance direction, detects specific parts of the vehicle body such as the center pillar, and detects the vehicle body. In addition to measuring the position of the car body in the transport direction, a distance sensor installed on the conveyor synchronizer measures the position of the car body in the direction perpendicular to the transport direction, and the running speed of the conveyor synchronizer is controlled based on both measured values. Since the positioning is performed using
Accurate positioning and highly accurate synchronous control can be performed.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the method of the present invention, in which Figure 1 is a side view showing a state in which the conveyor synchronizer is aligned, and Figure 2 is a rear view of Figure 1. , 3rd
The figure is a plan view of Fig. 1, and Fig. 4 is an X due to misalignment in the Z direction.
FIG. 5 is an explanatory diagram showing the principle of correcting directional positional deviation and suspension, and is a flowchart of synchronous control. DESCRIPTION OF SYMBOLS 1... Slat conveyor, 2... Conveyor synchronizer, 2a... Servo motor, 4... Distance sensor, 5... Optical sensor, 7... Light source, 7b.
... Servo motor, 9.10... Limit switch, B... Vehicle body, P... Center pillar. Applicant Toyota Motor Corporation Agent Patent Attorney Noboru 1) Takehisa (and 1 other person) Figure 1 s5

Claims (1)

[Claims] When a conveyor synchronizer runs in synchronization with the conveyor that transports the car body, transmitted light irradiated diagonally to the transport direction from a light source placed on the opposite side of the conveyor synchronizer and the car body is transmitted. By receiving light with an optical sensor placed on the conveyor synchronizer, specific parts of the car body such as the center pillar can be detected and the position of the car body in the transport direction can be measured. A method for positioning a conveyor synchronizer, characterized in that the position of the vehicle body in a direction perpendicular to the conveyance direction is measured by a distance sensor, and the positioning is performed by controlling the running speed of the conveyor synchronizer based on both measured values.