JPH03239687A - Method and device for controlling car speed - Google Patents

Abstract

PURPOSE:To correct the target speed value with high precision without resorting to a pulse encoder and a pulse counter by calculating the actual speed on the basis of the time while a car has run for a certain specified distance, and thereupon making speed control in conjunction with the speed correction value calculated from the target speed and actual speed. CONSTITUTION:A car 3 runs at the target speed V, and the number of correcting occasions (n) shall be 0 as no speed correction has been made yet. When the car 3 passes a gage 10, a photo-sensor PS senses it and is turned on t actuate clocking with a timer 62. When thereafter the photo-sensor is again turned on, the clocking is ended, and the passage time (t) of the gage 10 for a set reference distance L is determined. Then a speed calculating part 63 calculates the car 3 actual speed V' using the formula V'=L/t. Then the number of speed correcting occasions n becomes 1, and calculation is made through the first time speed correction value Kn+Kn-1.f(V,V'),K0=1 from the speeds V and V'. A speed correcting part 64 gives the speed command voltage Vn=Kn.V0 to a drive control part 60 to serve drive control of a motor 20, and thus the car 3 is controlled to the speed V.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle speed control method and a speed control device;
More specifically, the present invention proposes a method and apparatus for controlling the traveling speed of a vehicle to a target speed with high precision.

[Conventional technology]

For example, a method for automatically correcting the running speed of a vehicle is disclosed in Japanese Patent Application Laid-open No. 63
This is disclosed in Japanese Patent No. 167602, and the moving device is equipped with a pulse encoder that interlocks with the wheels. In addition, a detection target member for correction is provided in the travel path of the moving device, and a detector for detecting the detection target member for correction is provided in the moving device, and this detector detects the detection target member for correction. The pulses emitted by the pulse encoder during this period are counted, the counted pulses are taken as a normal value per predetermined length, and the speed setting value is corrected based on this normal value.

[Problems to be Solved by the Invention] According to the method of automatically correcting the traveling speed of a vehicle as described above,
There is a problem in that a pulse encoder and a pulse counter for counting the pulses transmitted by the pulse encoder are required, which increases the cost.

Further, the control circuit is complicated, and there is a problem that calculation errors are accumulated during the correction process.

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide a vehicle speed control method and speed control device that can correct a target speed with high precision without using a pulse encoder or a pulse counter.

[Means to solve the problem]

A vehicle speed control method according to a first aspect of the present invention is a vehicle speed control method that calculates the speed of a vehicle traveling a predetermined distance S and corrects the traveling speed of the vehicle. The vehicle's actual speed v' based on the time
(S/l), calculate a speed correction value Kn from the target speed V and actual speed V', and perform speed control to achieve the target speed V in relation to the calculated speed correction value Kn. Features.

A vehicle speed control method according to a second aspect of the present invention is characterized in that the actual speed V' is calculated at a plurality of positions on the travel route of the vehicle.

A vehicle speed control method according to a third aspect of the present invention is a vehicle speed control device configured to determine the speed of a vehicle traveling a predetermined distance S and control the traveling speed of the vehicle. A timer means for measuring the running time t, and the actual speed v of the vehicle based on the predetermined distance S and the measured running time t.
a speed calculation unit that calculates a speed correction value based on the target speed V and the actual speed V′, and a speed correction unit that calculates a speed correction value based on the target speed V and the actual speed V′; A drive control unit for controlling the drive control unit.

[Effect]

In the first invention, the vehicle is driven. The actual speed v' (
=S/l). A speed correction value Kn is calculated from the target speed V and the actual speed V', and the calculated speed correction value is
The target speed V is corrected by.

This causes the vehicle to always travel at the target speed.

In the second invention, the actual speed V' is calculated at a plurality of positions on the travel route of the vehicle, and the target speed V is corrected each time.

As a result, the traveling speed of the vehicle becomes the target speed each time.

In the third invention, the timer means measures the time t during which the vehicle travels the predetermined distance S. The speed calculating section calculates the actual speed V' of the vehicle based on the predetermined distance S and the measured running time t. The speed correction section calculates a speed correction value Kn based on the target speed V and the actual speed V'. The drive control section controls the speed of the vehicle based on the calculated speed correction value.

This allows the vehicle to always be controlled to the target speed.

〔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 path when the vehicle speed control method and speed control device according to the present invention are applied to, for example, an automobile assembly process in an automobile factory. In the assembly process, automobile bodies that are being assembled are transported in the following order: front dowel line A, suspension line B1, and rear dowel line C. The front sacrificial line A is the process of first assembling parts onto the painted car body, and the car body is at a low position close to the work floor. Suspension line B
is the process of assembling automobile suspension parts, in which 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 loading line C, the car body is again at a low position close to the work floor.

A 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 I along the transport route, and a plurality of vehicles 3.3... are installed on the track 2 so that they can run according to a travel command signal from the ground side. It is being

A hanger 4 for hanging the car body is attached to the lower side of each vehicle 3, 3..., and each hanger 4, 4...
・A car body 5.5... is suspended. 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 assembly robots 7.7 assemble parts. In the work range M, in order to improve the transport efficiency, the workers 6, 6, etc. can assemble the vehicles 5, 5, and so on without stopping the transport of the vehicle bodies 5, 5, and so on. It is necessary to run at a low speed, 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.

Guide wheels 53a and 53a (only one side is shown) are provided on the lower side of the reducer 33 on its front side and rear side, respectively, by moving the side surfaces of the upper flange 2a of the track 2 so as to sandwich the track 2 therebetween. . The reducer 33 has an upper end of a connector (not shown) attached to the side opposite to the drive wheels 36 (on the back side of the drawing) that can straddle between the upper and lower parts of the track 2 without contacting the track 2. , the lower end of the connector has a track 2
A guide wheel mounting plate 35a located below is attached. The guide wheel mounting plate 35a is provided with guide wheels 53b, 53b (only one side shown) that roll on the side surface of the lower flange 2b of the track 2 and sandwich the track 2 in the same manner as described above. The drive wheel 36 is guided along the track 2 by these guide wheels 53a, 53a, 53b, and 53b, and a guide wheel (not shown) opposing the guide wheels 53a, 53a, 53b, and 53b with the track 2 in between.
I'm trying not to get off track. On the other hand, a driven wheel 32 is disposed at a position that is heated by a suitable distance from the driving wheel 36 so as to roll on the upper surface of the raceway 2 . On the lower side of the driven wheel case 41 to which the driven wheel 32 is attached, there are guide wheels 53c, 53c on the front and rear sides of which the side surfaces of the upper flange 2a of the raceway 2 are transferred so as to sandwich the raceway 2 therebetween.
(only one side 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 has a guide wheel 53d on which the side surface of the lower flange 2b of the track 2 is transferred so as to sandwich the track 2.
, 53d (only one side shown). These guide wheels 53c and 53d and a guide wheel (not shown) that faces them across the track 2 cause the driven wheel 32 to move along the track 2.
The wheels are guided along the track 2 to prevent them from falling off 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 from the respective support shafts 51a, 5.
The vehicle body 50 is rotatably supported by the vehicle body 1b. A speed control section CTR, which will be described later, is connected to a drive control section 60, which will be described later, that drives the motor 20, on the driven wheel 32 side of the vehicle body 50. Vehicle body 5
A hanger 4 for hanging the automobile body is attached to the lower side of the vehicle.

A photosensor PS having a groove and a U-shaped cross section is attached to one side of the guide wheel mounting plate 35a on the driving 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 IO 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. Further, on the web 2c of the track 2, on the side where the gauge 10 is not attached (on the back side of the paper), there is a power line piv that supplies driving power for the motor 20, and a signal line S- that transmits a target speed signal to the speed control unit CTR. and a control line Cl11 for transmitting a command signal for instructing the vehicle 3 to run or stop, respectively, are arranged along the length direction of the track 2 on the side of the web 2C where the gauge 10 is not provided (on the back side of the page). There is. These power lines PW
, the signal line S-, and the control line ch are connected to the speed control section CTR and a drive control section 60, which will be described later, via a collector (not shown) provided in the vehicle 3.

This vehicle 3 supplies driving power via the power line PG11, and when a travel command signal is given by the control curve, the motor 2
0 is driven, the drive wheels 36 begin to rotate, and travel along the trajectory 2 based on the commanded target speed.

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

FIG. 4 is a perspective view of the gauge 10 attached to 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 attached to the web 2C of the track 2 so as to straddle the tips of brackets 11, 11 provided at appropriate distances apart in the length direction of the track 2.

Then, when the aforementioned photosensor PS approaches the gauge 10 from the direction of the arrow and the gauge 10 enters the groove PSs of the photosensor PS, the emitted light (not shown) from the photosensor PS is emitted at one end of the gauge 10. The photosensor PS turns on when the light is blocked. Thereafter, when the photosensor PS reaches one end edge of the notch 10a, the light-blocking state is canceled and the photosensor PS turns off. Furthermore, when the photosensor PS reaches the other edge of the notch 10a, the light is blocked again and the photosensor PS turns on, and when the photosensor PS separates from the other edge of the gauge 10, the photosensor PS turns off again. Therefore, when the vehicle to which the photosensor PS is installed passes the gauge 10, the period from which the photosensor PS turns on until it turns on again, that is, the gauge I
The reference distance is set based on the length from one end edge of O to the other end edge of the notch 10a.

FIG. 5 is a perspective view of the striker 12 attached to the track 2. The striker 12.12 is composed of a rectangular light-shielding plate made of metal, for example, bent into an L shape, and is attached to the web 2C of the track 2 to an appropriate length in the length direction of the track 2, with the tip facing downward. They are placed separately. This striker 12
When a vehicle (not shown) to which a photo sensor PS is attached approaches, and the striker 12 enters the groove PSS of the photo sensor PS, the photo sensor PS is activated at one end of the striker 12, as in the case of the gauge 10 described above. On works. After that, the photo sensor PS is connected to the other edge of the striker 12.
is turned off, and at the next edge of one end of the striker 12 the photosensor PS is turned on, and at the other edge it is turned off.

Therefore, in the case of the striker 12, the reference distance is set as the period from when the photo sensor PS turns on until it turns on again, that is, the distance from one edge of one striker 12 to one edge of the next striker 12. There is.

Figure 6 shows the vehicle speed control unit CT along with its peripheral circuits.
FIG. 2 is a block diagram of main parts of R. The power line P- is connected to the drive control section 60 that controls the drive of the motor 20, and the signal line SW and the control line C- are connected to the multiplex communication section 6 in the speed control section CTR.
Connected to 1. Turn on the photo sensor PS.

The off signal is given to timer 62. The timer 62 measures the time from when the photosensor PS outputs an on signal until when it outputs an on signal again. A signal related to the time measured by the timer 62 is given to the speed calculation section 63. The speed calculating section 63 calculates the actual speed of the vehicle, and a signal related to the calculated actual speed is given to the speed correcting section 64.

This speed correction section 64 is given a signal related to the target speed from the multiplex communication section 61. Speed correction section 64
calculates a speed correction value by comparing the speed instruction voltage corresponding to the target speed and the speed instruction voltage corresponding to the actual speed, and a signal related to the speed correction value is given to the drive control section 60.

Next, a speed control method using this vehicle speed control device will be explained with reference to a flowchart showing the control contents of the speed control section CTR.

Now, when a travel command signal for causing the vehicle 3 to travel and a speed command signal for commanding the target speed V of the vehicle 3 are given to the multiplex communication unit 61 via the control line SW and the signal line CH (SL),
A travel command signal and a target speed signal are provided from the multiplex communication section 61 to the speed correction section 64 . As a result, the speed correction section 64
is the speed instruction voltage ■ corresponding to the target speed V. = f (
v), n=0 (initial value) is outputted (s2) and given to the drive control section 60, so that the vehicle 3 runs at the target speed V. Then, since no speed correction has been performed so far, the number of corrections n is set to 0 (s3>).

Now, when the vehicle 3 travels and passes the gauge 10, the photosensor PS detects the gauge 10. Therefore, photo sensor P
It is checked whether or not S is turned on (S4), and when it is turned on, the timer 62 starts measuring time (S5). Next, it is checked whether the photo sensor is turned on again (S6), and if it is turned on, the time measurement is terminated and the time t for passing the reference distance set by the gauge 10 is determined. Based on the time and the reference distance, the speed calculation unit 63 calculates the actual speed V' when the vehicle 3 passes the gauge IO as follows: v=L/l (1). Subsequently, the number of speed corrections n becomes l (
S9). Then, the first speed correction value Kn is determined by the target speed V and the actual speed V', K, =KM-,・f (v, v') =・(
2) Calculate by K, = t (initial value) (SLO). In other words, a speed correction value of 7 is calculated using a function related to the target speed V and the actual speed V'. The speed correction unit 64 calculates a speed command voltage v7 related to the calculated speed correction value, V, =, VO, (3), and gives the calculated speed command voltage v7 to the drive control unit 60. The motor 20 is driven and controlled to control the speed of the vehicle 3 to reach the target speed V, so that the vehicle 3 travels at the target speed V.

When the vehicle 3 travels in this manner and reaches the next gauge position provided on the travel route and the photosensor PS is activated, the actual speed is determined again by the flow from steps (S4) to (S12) as described above. V' and speed correction value Kn
is calculated, speed control is performed, and the traveling speed is corrected so as to eliminate the difference between the target speed V and the actual speed V' when the vehicle passes the gauge position. This second speed correction value of 7 is f (v, v') for the previous speed correction value of 4 to 1.
is corrected as a function, and the difference between the target speed V and the actual speed V' is canceled by the speed correction value Kn. As a result, the vehicle 3 always travels at the target speed V.

By providing the gauges 10 at multiple positions along the vehicle's travel route, each time the vehicle passes the gauge 10, the actual speed V' and the speed correction value are calculated as 7, which reduces the load on the vehicle while the vehicle is traveling. The target speed V can always be maintained even when the wheels of the vehicle are deformed due to changes in load and the traveling speed changes, or when the wheel diameter changes due to wear.

In addition, a set of two strikers 12 is used instead of the gauge IO.
．． 12 and set the reference distance based on the distance between them (see Figure 5), the actual speed V' and the speed correction value can be calculated in the same way as when the gauge IO is provided. Then, the speed of the vehicle is controlled so that the vehicle 3 travels at the target speed V. Furthermore, by arranging the strikers 12 at multiple positions on the vehicle's travel route, each time the striker 12 is passed, the actual speed V' and the speed correction value of the vehicle are calculated based on the reference distance between the strikers installed in parallel. 7 is calculated, and the vehicle 3 maintains the target speed V.

In this embodiment, the speed command value is given to the drive control unit 60 as the speed command voltage v7, but this is just an example, and either the IT pulse or the voltage pulse or the current pulse is sent to the drive control unit 60 by changing the number of pulses. You may give. Further, although the present invention has been 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 vehicle speed control method and speed control device according to the present invention, the vehicle can be stably run at a target speed without using expensive pulse encoders and pulse counters. Further, even if the wheels of the vehicle are deformed due to a change in the load applied to the vehicle, or the wheel diameter changes due to wear, the present invention provides excellent effects such as being able to maintain the target speed without being affected by the deformation.

[Brief explanation of drawings]

Figure 1 is a plan view of the vehicle body transport route 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 the vehicle installed on the track, and Figure 4 is FIG. 5 is a perspective view showing how the gauge is installed, FIG. 5 is a perspective view showing how the striker is installed, FIG. 6 is a block diagram of the speed control section along with its peripheral circuits, and FIG. 7 shows the control contents of the speed control section. FIG.

Claims (1)

[Claims] 1. In a vehicle speed control method in which the speed of the vehicle traveling a predetermined distance S is determined and the traveling speed of the vehicle is corrected, Based on this, calculate the actual speed v' (S/t) of the vehicle, calculate the speed correction value K_n from the target speed v and the actual speed v',
A method for controlling the speed of a vehicle, characterized in that the speed is controlled to reach the target speed v in relation to the calculated speed correction value K_n. 2. The vehicle speed control method according to claim 1, wherein the actual speed v' is calculated at a plurality of positions on the vehicle travel route. 3. A speed control device for a vehicle configured to determine the speed of a vehicle traveling a predetermined distance S and control the traveling speed of the vehicle, comprising: a timer means for measuring the time t during which the vehicle travels the predetermined distance S; , a speed calculation section that calculates the actual speed v' of the vehicle based on the predetermined distance S and the measured traveling time t, a speed correction section that calculates the speed correction value K_n based on the target speed v and the actual speed v', and the calculated speed. A speed control device for a vehicle, comprising: a drive control section that controls the speed of the vehicle to achieve a target speed v using a correction value K_n.