JPH03248954A - Distance specifying device - Google Patents

Abstract

PURPOSE:To prevent the generation of an error in a rotation amount of a wheel detected at a given distance even when a wheel is deformed by selecting the length of a distance specifying device, located on a running route to specify a distance range in which a rotation amount of a wheel is detected, to a value being integral number times as long as the outer peripheral length of a wheel. CONSTITUTION:A gauge 10 for correcting a speed serving as a distance specifying device is mounted on a track 2 and on the inlet side of a wheel device line in an automobile assembly process. The gauge is formed of a long stripform light shield plate, a rectangular notch part 10a opened downward is formed closer to the one end thereof, and the gauge is mounted on a web 2c of a track 2 through brackets 11 and 11. A photo sensor PS located in the vicinity of the drive wheel of a vehicle running on the track 2 is caused to approach the gauge 10, and ON and OFF signals are output. In this case, a period between ON-operation of the photo sensor PS and re-ON-operation, namely, length between the one edge of the gauge 10 and the other edge of the notch part 10a is selected to a value being an integral number times as long as the outer peripheral length of a drive wheel to specify a reference distance L.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distance defining device provided on a travel route of a vehicle in order to define a distance range in which the amount of rotation of a wheel provided on the vehicle is to be detected.

[Conventional technology]

The applicant has already filed an application for a method of controlling the speed of a vehicle by outputting pulses from a pulse encoder according to the amount of rotation of wheels running on a track, and detecting the number of pulses. FIG. 10 is a side view of a vehicle traveling on a track using the speed control method.

A driving wheel 36 and a driven wheel 32 of the vehicle 3 are provided to roll on the track 2, and the driving wheel 36 is driven by the motor 20 via a speed reducer 33. The motor 20 includes a pulse encoder 3 that outputs a number of pulses corresponding to the amount of rotation of the drive wheels 36, that is, the amount of travel of the vehicle 3.
It has 4 built-in.

On the drive wheel 36 side, guide wheels 53a, 53a, 53b, 53b (-
The upper mounting part to which the guide wheels 53a and 53a are attached and the lower mounting part to which the guide wheels 53b and 53b are attached are connected to a connecting tool ( (not shown). Also, on the driven wheel 32 side, like the driving wheel 36 side, guide wheels 53c, 53c, 53d,
53d and a connector. Drive wheel 3
The 6 side and the driven wheel 32 side are rotatably connected to each end of a vehicle body 50 located below the track 2, and the vehicle body 50 is provided with a hanger 4 for suspending, for example, an automobile body in the process of being manufactured. It is installed. A speed control unit CTR is attached to the vehicle body 50 on the driven wheel 32 side, and an engine sensor PS is attached on the drive wheel 36 side.

A strip-shaped speed correction gauge 10 having a notch 10a is attached to one side of the web 2C of the track 2, and a power line PW, (8-segment line SW) is attached to the other side of the web 2C.

A control line C- is provided in the length direction of the track 2. Power line P
W is connected to the motor 20 via a collector and speed control unit CTR (not shown), and a signal line SK and a control line CW+
It is connected to the speed control unit CTR via a current collector (not shown).

Next, the speed control operation of this vehicle will be explained. When a travel command signal and a speed signal are given to the speed control unit CTR via the control line CW and signal line SW, the motor 20 is driven according to the speed No. 13, and the vehicle 3 moves along the track 2 in the direction of the arrow. Run to. As the vehicle travels, the pulse encoder 34 outputs a number of pulses corresponding to the number of revolutions of the drive wheels 36, that is, the number of legs the vehicle travels, to the speed control unit CTl1.

When the photosensor PS provided in the vehicle 3 detects the front end of the speed correction gauge 10, the light emitted from the bottom sensor IIS is blocked and the photosensor PS is turned on, and the notch 1. Oa
When the front end of the photo sensor PS is detected, the light shielding state is released and the light is turned off, and the light shielding state is again restored at the rear end of the notch 10a, and the photo sensor PS
Turn on. The speed control unit CTR detects such an operation of the bottom sensor PS, and the reference distance I is from the time when the photosensor PS is turned on to the time when it is turned off once and then turned on again.
, and the pulse encoder 3 within that time.
The speed control unit CTR counts the number of pulses of 4, and calculates the actual speed of the vehicle 3 from the time and the number of pulses. Then, the speed control unit CTR drives the motor 20 to cause the vehicle to travel at a constant speed so as to eliminate the difference between the calculated actual speed and the set speed.

[Problem to be solved by the invention]

Both the driving wheels 36 and the driven wheels 32 of the vehicle 3 described above are made by covering the outer peripheral surface of a short cylindrical core metal part M with a hard urethane elastic body NT having a predetermined thickness. This prevents the generation of noise when the vehicle is running. By the way, when the vehicle 3 is run on an assembly line with a partially assembled automobile body suspended from the hanger 4, the applied load changes as parts are attached during the run.

As a result, the elastic portions N of the driving wheels 36 and driven wheels 32 are compressed and partially deformed. By the way, when the drive wheels 36 are deformed, the amount of travel of the vehicle 3 relative to the predetermined amount of rotation of the drive wheels changes. Further, even if the drive wheel 36 has run-out during manufacture, the amount of travel of the vehicle relative to the predetermined amount of rotation changes depending on the rotation angle.

FIG. 11 is an explanatory diagram showing a state in which an error occurs in the travel distance due to deformation of the drive wheels 36. As is clear from this figure, when the outer peripheral side of the drive wheel 36 with the shorter radius d is located at a predetermined position X on the track 2 and the DJ transport 36 rotates twice in the direction of the arrow, However, if the outer circumferential side of the drive wheel 36 where the radius d is longer is located and the drive wheel 36 rotates -12 in the direction of the arrow, the travel distance of the vehicle 3 becomes β'. This results in a running difference of e'-e. Therefore, the number of pulses that the pulse encoder 34 outputs depending on the amount of travel during the period when the vehicle 3 travels a predetermined distance will differ if the drive wheel 36 is deformed, and the number of pulses of the vehicle 3 detected based on the number of pulses will differ. An error occurs in the amount of travel. Therefore, if the actual speed of the vehicle is calculated from the number of pulses detected during the period of traveling a predetermined distance, that is, the amount of travel, and the travel time, an error will occur in the actual speed, and the set speed of vehicle 3 cannot be corrected with high accuracy. There is a problem.

In order to deal with this problem, the number of pulses output when the vehicle 3 travels a predetermined distance is periodically measured, and the number of pulses output while traveling a predetermined distance is corrected to match the actual speed. Calculations are made to avoid errors. However, in this case, there is a problem in that troublesome measurement work is forced on a regular basis.

SUMMARY OF THE INVENTION In view of this problem, it is an object of the present invention to provide a distance determining device that does not cause an error in the amount of rotation of a wheel detected at a predetermined distance even if the wheel is deformed.

[Means for Solving the Problems] A distance defining device according to the first invention defines a distance range in which the amount of rotation of a wheel is to be detected (in a distance defining device provided on a traveling route of a vehicle, The length is selected to be an integral multiple of the outer circumference length.

In the distance determining device according to a second aspect of the invention, the wheels are J drive wheels.

The distance determining device according to the third invention uses steel or a material with a thermal expansion coefficient approximately similar to that of the steel material.

[Effect]

In the first invention, the wheels of the vehicle rotate an integer number of times to move a predetermined distance defined by the distance defining device.

As a result, even if the wheel is deformed, no error occurs in the amount of rotation of the wheel obtained within a predetermined distance.

In the second invention, the drive wheels of the vehicle rotate an integer number of times to move a predetermined distance defined by the distance defining device.

As a result, even if the drive wheel is deformed, no error occurs in the amount of rotation of the drive wheel within a predetermined distance.

In the third invention, the distance defining device that defines the predetermined distance expands and contracts with a thermal expansion coefficient substantially equal to the thermal expansion coefficient of the steel material.

As a result, even if the ambient temperature changes, the predetermined distance changes less.

〔Example〕

The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 1 is a plan view of a vehicle body transport route in which the distance defining device according to the present invention is applied, for example, to an automobile assembly process in an automobile factory. [Assembly] - During the assembly process, automobile bodies that are being assembled are transported in the order of front mounting line A, suspension line B, and rear mounting line C. The front assembly line A is the process of first assembling parts onto the painted car body, and the car body is placed at a low position close to the work floor. Suspension line B is a process for attaching the suspension parts of automobiles, and the automobile body is suspended from a hanger and placed at a high position where workers and assembly robots can work from the underside of the suspended vehicle body. At rear dosing line C, the vehicle body is again at a low position close to the work floor.

A speed correction gauge 10, which will be described later, is provided on the inlet side of the suspension line B.

FIG. 2 is a side view showing the conveyance state in the suspension line B. A track 2 is installed at a high place above the work floor 1 along the conveyance route, and the track 2 is provided so that a plurality of vehicles 3, 3, . It is being

There is a hanger 4 (=J) on the underside of each vehicle 3, 3... that can hang the car body, and each hanger 4, 4...
An automobile body 5.5... is suspended from .... In this suspension line B, there is a work range M in which workers 6, 6, . . . assemble parts, and a work range R in which the assembly robot 77 assembles parts. and work area M
Now, in order to increase the transport efficiency, the vehicles 3, 3... are moved at low speed so that the workers 6, 6... can perform the assembly work without stopping the transport of the vehicle bodies 5, 5... Moreover, it is necessary to run at a constant speed and at a constant pitch.

Further, in the work area R, the vehicles 3, 3 are stopped at fixed positions to ensure the assembly by the assembly robot 7.7.

When the assembly work is completed, it is necessary to run the vehicle 3 in a tact manner, in which the vehicle 3 is rapidly accelerated, then rapidly decelerated, and then stopped at the next predetermined position in order to increase the transport efficiency.

Furthermore, the vehicle 3 needs to satisfy conditions such as high stopping accuracy, no impact, and no runaway.

FIG. 3 is a side view of a vehicle installed on the track 2 so that it can run. The track 2 is made of, for example, an aluminum member having an H-shaped cross section and is installed with the web 2c oriented vertically. Therefore, the track 2 has an upper flange 2a and a lower flange 2b of equal length extending in a direction perpendicular to the length direction of the track 2 at its upper end and lower end, respectively. The drive wheels 36 of the vehicle 3 are arranged to roll on the upper surface of the track 2, and the rotating shaft 36a to which the drive wheels 36 are attached is connected to the motor 20 attached to the reducer 33 via the reducer 33. Connected to the rotating shaft. A pulse encoder 34, which is a pulse generator that outputs a constant pinch pulse in relation to the rotation of the drive wheel 36, is built into the front end of the motor 20. On the lower side of the reducer 33, on the front and rear sides thereof, there are rungs 2a (above the track 2).
The guide wheel 5 is moved around the side of the track 2 so as to sandwich the track 2.
3a and 53a (only one side is shown) are provided, respectively. The reducer 33 has a track 2 on the opposite side of the drive wheel 36 (on the back side of the paper).
One end of a connector (not shown) is attached to the lower end of the connector, which can span between the upper and lower parts of the track 2 without contacting the upper and lower parts of the track 2. A guide wheel mounting plate 35a is attached. Number of guide wheels A] Plate 35a
In the same manner as described above, guide wheels 53b and 53b (
Only one side is shown). And these guide wheels 5
3a, 53a, 53b and 53b, and a guide wheel (not shown) opposing them with the track 2 in between, the drive wheel 36 is guided along the track 2 and is prevented from coming off the track 2.

On the other hand, a driven wheel 32 is arranged at a position a suitable distance ahead of the driving wheel 36 so as to roll on the upper surface of the track 2. On the lower side of the driven wheel case 41 to which this driven wheel 32 is attached BJ, guide wheels 53c roll on the side surfaces of the upper flange 2a of the raceway 2 on the front and rear sides thereof so as to sandwich the raceway 2. , 53c (only one side is shown). The driven wheel case 41 has an upper end of a coupling device similar to the drive wheel 36 side attached to the side opposite to the driven wheel 32, and a guide wheel mounting plate located below the track 2 is attached to the lower end of the coupling device. 35b is installed. The guide wheel mounting plate 35b is provided with guide wheels 53d, 53d (only one side shown) that roll on the side surface of the lower flange 2b of the track 2 and sandwich the track 2 therebetween. The driven wheels 32 are guided along the track 2 by these guide wheels 53c, 53d and a guide ring (not shown) opposing the guide wheels 53c and 53d with the track 2 in between, so that the driven wheel 32 is prevented from coming off the track 2. The driving wheel 36 side and the driven wheel 32 side straddle support shafts 51a, 51b provided on the guide wheel mounting plates 35a, 35b and extending downward -1 from each, and are rotatable on the support shafts 51a, 51b. The vehicle body 50 is supported by the vehicle body 50. A speed control unit CTR, which will be described later, is connected to the motor 20 and the pulse encoder 34 on the driven wheel 32 side of the vehicle body 50.

A hanger 4 for hanging the automobile body is attached to the lower side of the vehicle body 50. A photosensor PS having a groove and an eye-shaped cross section is attached to an example side surface of the guide wheel mounting plate 35a on the drive wheel 36 side with the groove facing upward.

The photosensor PS is structured to project emitted light from one side to the other side so as to cross the groove. The web 2c of the track 2 is provided with a long strip-shaped gauge 10 whose longitudinal direction is parallel to each of the side and bottom surfaces of the track 2, and at a position where it can pass through the groove of the photosensor ps without contact. Selected and installed. In addition, the web 2c of the track 2 has a power line section that supplies driving power for the motor 20 on the side to which the gauge 10 is not attached (on the back side of the page), a signal wire section that transmits a set speed signal to the speed control section CTR, and Control lines CW for transmitting command signals for instructing the vehicle 3 to run and stop are arranged along the length direction of the track 2, respectively. These power line section, signal line SW and control line CW are connected to the speed control section CT via a collector (not shown) provided in the vehicle 3.
R and a drive control section 60 which will be described later.

When this vehicle 3 is supplied with driving power through a power supply line section and a travel command signal is given through a control line C, the motor 20 is driven and the drive wheels 36 begin to rotate. It will travel along track 2.

In addition, in the section where the track 2 is curved, the driving wheels 36 and the driven wheels 32 side swing in response to the curve of the track 2, that is, the driving wheels 36 side and the driven wheels 32 side perform a swinging motion similar to that of a bogie bogie. The vehicle moves smoothly and runs as smoothly as on a straight section.

FIG. 4 is a perspective view of a speed correction gauge (hereinafter referred to as gauge) 10, which is a distance determining device installed on the track 2. The gauge 10 is made of a light-shielding plate made of e.g. metal in the shape of a long strip, and has a rectangular notch 10a opening downward near one end thereof. This gauge 10 is
The brackets 11 and 11 are attached to the web 2c of the track 2 so as to straddle the tips of the brackets 11 and 11, which are provided at appropriate distances in the length direction of the track 2. Then, the photo sensor PS described above approaches the gauge 10 from the direction of the arrow, and the photo sensor PS
Groove PS.

When the gauge 10 enters, one edge of the gauge 10 blocks the light emitted from the photosensor PS (not shown), and the photosensor PS turns on. Thereafter, when the photosensor PS reaches one end edge of the notch 10a, the light-blocking state is resolved and the photosensor PS turns off.

Further, when the photo sensor PS reaches the other edge of the notch 10a, the light is blocked again and the bottom sensor PS is turned on.
Thereafter, when the photosensor PS separates from the other end of the gauge 10, the photosensor PS is turned off again.

Therefore, the vehicle with the photo sensor PS installed is gauge 1.
When passing 0, the period from when the sensor PS turns on until it turns on again, that is, the length from the - edge of gauge 0 to the other edge of the notch 10a, is determined by the outer periphery of the drive wheel 36. The reference distance is specified by selecting an integral multiple of the length.

FIG. 5 is a perspective view of a speed correction striker (hereinafter referred to as a striker) 12 which is a one-digit distance regulating device installed on the track 2. The striker 12 has a bent structure, and is arranged on the web 2c of the track 2 with the tip facing downward at an appropriate distance apart in the length direction of the track 2.A vehicle in which the photo sensor PS is attached to this striker 12 (not shown) approaches and the striker 12 hits the groove PS of the photosensor PS.
When the slider enters the state, the photo sensor PS is turned on at one end of the slider 12 in the same manner as in the case of the gauge 10 described above.

Thereafter, the photo sensor PS is turned off at the other edge of the striker 12, the photo sensor PS is turned on at one edge of the next striker 12, and turned off at the other edge. Therefore, in the case of the striker 12, the photo sensor PS
The reference distance is defined as an integral multiple of the outer circumferential length of the drive wheel 36, which is the period from when the switch is turned on until it is turned on again, that is, the distance from one end edge of the striker 12 to one end edge of the next striker 12. are doing.

FIG. 6 is a block diagram of the main parts of the vehicle speed control section CTR. The power line section is a drive control section 6 that drives and controls the motor 20.
0, and the signal line S- and control line C- are connected to the multiplex communication section 61. The multiplex communication unit 61 provides a signal to the control unit 62, and the control unit 62 provides a signal to the multiplex communication unit 61. The output signal of the control section 62 is given to the drive control section 60. An on/off signal from the photosensor PS attached to the vehicle 3 is given to the control section 62 .

The pulses output by the pulse encoder 34 are transmitted to the control section 6.
given to 2.

Next, the principle of using the gauge 10 configured in this manner so that no error occurs in the detected traveling distance even if the drive wheel 36 is deformed will be explained with reference to FIG.

Now, if the outer circumferential side of the drive wheel 36 with the shorter radius d is located at the predetermined position When the outer circumferential side of the driving wheel 36 where the radius d is longer is located and the driving wheel 36 rotates twice in the direction of the arrow, the traveling distance of the vehicle 3 becomes p', and the traveling distance difference is ff' - #. arise.

However, if the reference pressure ML defined by the gauge 10 is selected as the outer circumferential length of the drive wheel 36, even if the drive wheel 36 is deformed, when the drive wheel 36 rotates once, the distance traveled will be the same. Therefore, the drive wheel 3 is located at the tip of the gauge 10.
Even if the outer circumferential side of the gauge 6 where the radius d is shorter (longer) is located, the number of pulses obtained during the period of travel on the gauge 10 is the same. As a result, errors in detecting travel distance caused by deformation of the drive wheels 36 are eliminated.

Now, a method of correcting the traveling speed of the vehicle using the gauge 10 described above will be explained with reference to flowchart 1 showing the control contents of the control section 62 in the speed control section CTR.

Now, when the vehicle 3 is traveling (Sl) and the photosensor PS reaches the position of the gauge 10, the photosensor PS detects the gauge 10. Thereby, it is checked whether or not the photo sensor PS is turned on (S2), and if it is turned on, the pulses output by the Lapulse encoder 34 are counted at the time when the photo sensor PS is turned on (S3), and then the photo sensor PS is turned off. After that, it is checked whether it has been turned on again (S4), and when it has been turned on, the pulse counting is finished (S5). Also, the time measurement from the time when the Botosenza PS is turned on until the time when it is turned on again is finished (S6).
. Thereafter, the running speed of the vehicle 3 when traveling the distance specified by the gauge IO is calculated by dividing the counted number of pulses, that is, the distance, by the time measured (S7).

A signal related to the difference between the calculated speed and the set speed is given to the drive control section 60 to drive the motor 20 and drive the vehicle 3.
Correct the set speed. As a result, vehicle 3 has drive wheels 36
The set speed can be corrected with high precision without being affected by the deformation of. Therefore, the set speed of vehicle 3 is gauge 1
When traveling at the 0 position, the vehicle 3 is corrected and travels at a constant speed.

Note that when the pulse encoder 34 is provided to interlock with the driven wheels 32 of the vehicle 3 (see FIG. 3), the gauge 1
A similar effect can be obtained by selecting the reference distance defined as 0 to be an integral multiple of the outer circumferential length of the driven wheel 32.

Figure 9 shows the encoder carrier with the encoder attached.
FIG. 3 is a side view of the vehicle 3 provided on the driving wheel 36 side. The arm Y is connected to the driven wheel 32 from the part near the track 2 of the 36 driving wheels.
It extends toward the side, and an encoder carrier EC that rolls on a track 2'' is installed at its tip. This encoder carrier EC has a much smaller diameter than the diameter of the drive wheel 36.

A pulse encoder 3 similar to the pulse encoder 34 attached to the drive wheel 36 is mounted on the encoder carrier EC.
I got a 4. As a result, when the vehicle 3 travels, the pulse encoder 34 outputs pulses corresponding to the amount of travel. The structure of the other nine vehicles 3 is the same as that shown in Fig. 3.

When the pulse encoder 34 is attached to the Konin encoder carrier EC in this way, the same effect as described above can be obtained by making the reference distance defined by the gauge 10 an integral multiple of the outer circumference length of the encoder gear carrier EC. is obtained.

In addition, by constructing the gauge 10 from a material with a thermal expansion coefficient that is approximately the same as that of the prepared material or steel material, changes in the reference distance due to changes in ambient temperature can be minimized, and the distance traveled by the vehicle can be constantly monitored with high accuracy. can be detected.

The reference distance can be defined using a striker 12 (see FIG. 5) instead of the gauge 10 described above. In that case, the reference distance between the pair of sliders 12 and 12 is determined by the driving wheel 36. It is selected to be an integral multiple of the outer circumferential length of the driven wheel 32 or the encoder carrier EC. Even when the striker 12 is used in this way, the same effect as when the gauge 10 is used can be obtained.

In this embodiment, the number of pulses corresponding to the travel distance of the vehicle is obtained from the pulse encoder, but the present invention is not limited to the pulse encoder. In addition, the reference distance 0 L was set as 1 times the outer circumference of the wheel, but it was also set as 2 times the outer circumference, 3 times the outer circumference
It may be doubled. Further, in this embodiment, the speed of the vehicle is corrected based on the determined rotation amount of the wheels, but the speed control is not limited to this, and the distance from the vehicle to the target position or the traveling position of the vehicle can be corrected.

Although the present invention is applied to an automobile assembly line, this is merely an example and is not limited thereto.

〔Effect of the invention〕

As described in detail above, according to the present invention, even if the wheels of the vehicle are deformed, no error occurs in the amount of rotation of the wheels detected within a predetermined distance, and the amount of travel of the vehicle can be accurately detected. As a result, the set speed of the vehicle, the vehicle position, or the distance from the vehicle to the target position can be corrected with high precision, and excellent features such as driving at the set speed, detecting the vehicle position, and accurately commanding the distance to the target position can be achieved. be effective.

[Brief explanation of drawings]

Figure 1 is a plan view of the vehicle body transport path in the automobile assembly process, Figure 2 is a side view showing the state of vehicle body transport on the suspension line, Figure 3 is a side view of a vehicle installed on a track so that it can run, Fig. 4 is a perspective view showing the mounting state of the gauge, Fig. 5 is a perspective view showing the striker in the first state, Fig. 6 is a block diagram of the speed control section, and Fig. 7 is a flow chart showing the control contents of the control section. , FIG. 8 is an explanatory diagram of the principle of eliminating the detection error of the traveling distance, FIG. 9 is a side view of the vehicle showing another embodiment of the vehicle, FIG. 10 is a side view of the vehicle running on the track, and FIG. FIG. 6 is an explanatory diagram of a state in which a detection error occurs in the travel distance due to wheel deformation. 2...Track 3...Vehicle 4...Hanger 1o
... Gauge 12 ... Striker 20 ... Motor 32 ... Driven wheel 34 ... Pulse encoder 3
6... Drive wheel 50... Vehicle body 60... Drive control section ps... Photo sensor 4... Power line or...
...Signal line CW...Control line EC...Encoder carrier

Claims (1)

[Scope of Claims] 1. In a distance defining device provided on a traveling route of a vehicle to define a distance range in which the amount of rotation of a wheel is to be detected, the length is selected to be an integral multiple of the outer circumference of the wheel. A distance regulating device characterized by: 2. The distance determining device according to claim 1, wherein the wheels are drive wheels. 3. The distance determining device according to claim 1, which uses steel or a material with a thermal expansion coefficient substantially equal to the thermal expansion coefficient of the steel material.