JP2704266B2 - Travel control device for automatic guided vehicles - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a traveling control device for an automatic guided vehicle, and in particular, generates a driving pattern between both from information on traveling between two points, and generates the driving pattern. The present invention relates to a control device for causing an automatic guided vehicle to travel based on a vehicle.

(Prior Art) Conventionally, a map of a traveling path is stored in advance, and a target point installed at a key point of the traveling path is detected or a traveling distance is calculated, thereby confirming a position on the map. There is an automatic guided vehicle that travels while traveling. When this automatic guided vehicle passes over the target point from the vicinity of the target point or is positioned at the target stop position, conventionally, from the positional relationship between the target position and the automatic guided vehicle, the traveling route between the two is defined as a straight line. The drive means of the automatic guided vehicle is controlled so as to travel on the generated trajectory by generating it as a trajectory of an arc or a curve represented by an interpolation function such as a clothoid function or a spline function.

(Problems to be Solved by the Invention) However, in the case of the above-mentioned generated trajectory, the curvature change is not continuous at the connecting point between the straight line and the circular arc, so that the drive command value to the driving means changes discontinuously at the connecting point. As a result, it becomes difficult for the driving means to follow up, and as a result, there is a problem that it is not possible to reach the target point.

In addition, in the case of the above-mentioned generated trajectory, although the trajectory curvature changes continuously, the trajectory generation does not consider the acceleration / deceleration capability of the driving means. It was difficult to drive accurately.
Furthermore, since the complicated interpolation operation includes repetitive calculations, a large amount of time is required for the calculation of the trajectory generation, and it has been difficult to generate the trajectory according to the situation near the target position in real time.

The present invention has been made in view of the above-described problems of the related art, and provides a travel control device for an automatic guided vehicle, which is capable of generating a trajectory in which curvature changes continuously and in consideration of the capability of a drive system in real time. Aim.

(Description of First Invention) As shown in FIG. 1, the first invention provides position, velocity, and acceleration information at a control start position of the automatic guided vehicle in the X direction on a plane on which the automatic guided vehicle travels, Position and speed and acceleration information on the X direction that the AGV should take at the control end position, and position, speed and acceleration information on the control start position of the AGV on the Y direction that is different from the X direction, Travel information storage means I for storing and outputting position, speed and acceleration information in the Y direction to be taken by the automatic guided vehicle at the control end position, and control start and control end times at the two positions; Based on a predetermined continuous time function, the travel information storage means I
X of the automatic guided vehicle at the two positions output from
With travel information about the direction, the X direction drive pattern generating means II ₁ for generating X-direction drive pattern between the two positions; based on a predetermined continuous time function for the Y direction, the driving information Y-direction drive pattern generation means II for generating a Y-direction drive pattern between the two positions by using traveling information on the Y direction of the automatic guided vehicle at the two positions output from the storage means I
_2; drive means IV and for driving the wheels of the AGV; based on the X-direction and Y-direction drive pattern generating means II _1, II ₂ X and Y directions of the driving patterns are respectively generated by said driving means And a drive command value calculating means III for calculating a drive command value for the IV, and for each of different X and Y directions on the travel plane, a time function determined independently and travel information at two positions are used to calculate X. And a continuous drive pattern in each of the Y and Y directions, whereby the automatic guided vehicle smoothly travels to the target control end position and is accurately guided to the target position. And a device.

The operation of the first invention having such a configuration will be described.

The traveling information storage means I stores the time at the control start position and the control end position for traveling control by trajectory generation, and the position, speed, and acceleration information of the automatic guided vehicle, and each of the two directions of X and Y different from each other. doing.

The X-direction drive pattern generating means II ₁ is configured to output travel information in the X direction from the travel information storage means I based on a predetermined continuous time function in the X direction, that is, the automatic guided vehicle at the control start position and the control end position. Position of,
Using the speed, acceleration information and the time at the two positions,
A drive pattern between the two positions is generated as a function of time. At the same time, the Y-direction drive pattern generation means II ₂ also uses the Y-direction travel information from the travel information storage means I based on a predetermined continuous time function in the same manner as the X-direction drive pattern generation means II _1. , Generating a drive pattern between the two positions as a function of time.

In the drive command value calculating means III, based on the drive patterns in the X and Y directions generated by the X and Y direction drive pattern generating means II ₁ and II ₂ , the drive command value calculating means III drives the drive means IV for driving the wheels of the automatic guided vehicle. Give a command. And driving means IV
Drives the wheels based on the command value given from the drive command value calculating means III, and consequently travels on the traveling route between the control start and control end positions to reach the target position.

In the first aspect of the present invention, the travel information such as the position, the speed, the acceleration, and the time at the control start position and the control end position,
Since the drive pattern is generated based on a continuous time function in each of two different directions, the orbit, speed, and acceleration of the automatic guided vehicle, which smoothly changes from the control start position to the control end position, can be changed in real time. At the same time, the automatic guided vehicle can smoothly and accurately reach the target position.

The X-direction drive pattern, which further embodies the first invention, converts each coefficient of a predetermined continuous time function in the X direction into travel information in the X direction, that is, X.
A time pattern of acceleration in the X direction generated by determining position and velocity and acceleration information at the two positions in the direction and time at the two positions as boundary conditions; Each coefficient of a predetermined continuous time function in the Y direction is
The travel information on the Y direction, that is, the position, velocity and acceleration at the two positions in the Y direction;
A time pattern of acceleration in the Y direction generated by determining the time at two positions as a boundary condition; unmanned conveyance in which the drive command value is determined from the acceleration and speed values in the X and Y directions A second aspect of the present invention, which is a vehicle body speed and a track curvature, can be adopted.

Further, as shown in FIG.
Target trajectory calculating means for calculating the position where the automatic guided vehicle should exist on the target trajectory according to the driving patterns in the direction and the Y direction
VI ₂ a; automated guided between the current position of the automatic guided vehicle from the position measuring unit V from the target track calculating section VI _2; and position measuring unit V which measures the current position of the automatic guided vehicle actually exists A deviation from a position on the target track of the vehicle is calculated, and when the deviation exceeds a predetermined threshold value, a regeneration command is issued to the X-direction and Y-direction drive pattern generation means II ₁ and II ₂ respectively. A comparison means IV ₁ for outputting, and the X-direction and Y-direction drive pattern generation means II ₁ , II
₂ is, by the input of the regeneration command from the comparing means VI ₁ ,
A third aspect of the present invention can be adopted in which X-direction and Y-direction drive patterns are regenerated. That is, at the time of actual traveling, there are various error factors such as unevenness of the traveling floor surface, slippage between the driving wheels and the traveling floor surface, delay due to calculation time, and change in the traveling characteristics of the automatic guided vehicle due to a change in the loaded load. For this reason, while traveling with the generated drive pattern,
Errors from the target trajectory accumulate.

In the present third invention is detected by comparing means VI ₁ of this error. That is, it is expressed as a deviation between the position on the target trajectory where the AGV calculated by the target trajectory calculating means VI ₂ should exist and the current position of the AGV measured by the position measuring means V, and the deviation is predetermined. and when it exceeds the threshold, regeneration command respectively from the comparison means VI ₁ in the X direction and the Y direction drive pattern generating means II _1, II ₂ is output. on the other hand,
The X-direction and Y-direction drive pattern generation means II ₁ and II ₂
When regeneration command is inputted from the comparison unit VI _1, new travel information from the travel information storage unit that time of the AGV position and the AGV is a target position to be reached as the control start position, and a control end position, respectively Is input, and the X-direction and Y-direction drive patterns are regenerated based on the travel information.

The drive command value calculating means III and the drive means IV operate on the basis of the regenerated X-direction and Y-direction drive patterns. As a result, the AGV moves from a position shifted from the target track to a target position to be reached. Guided exactly.

According to the third aspect of the present invention, even if the traveling route deviates from the target track due to various error factors during the actual traveling controlled based on the X-direction and Y-direction driving patterns, the driving in the X-direction and the Y-direction during traveling. Since the pattern is regenerated, the trajectory can be easily corrected, and the automatic guided vehicle can accurately reach the target position.

Further, a fourth aspect of the present invention can be adopted in which the travel information storage means has a time parameter adjusting means for determining a time at the two positions in accordance with the two positional relationships.

The time parameter adjusting means determines the time, that is, the control start time and the control end time, according to the traveling information at the control start position and the control end position. In other words, the drive pattern generated by the X-direction and Y-direction drive pattern generation means using the time can change the amplitude of the pattern with respect to time by changing the time interval between the control start time and the control end time. . Therefore, for example, when the control start time and the control end time are relatively close to each other, by changing the time interval more largely, the drive pattern changes gradually, and the automatic guided vehicle intensifies a sudden drive. It is possible to reach the target position smoothly and accurately without being performed. Further, by making the control start time or the control end time different between the X direction and the Y direction, it is possible to form a state where the automatic guided vehicle travels only on the plane in the X direction or the Y direction, and therefore, is more accurate. Posture control at a desired target position.

According to the fourth aspect, since the determination is made according to the travel information at the control start position and the control end position given to the X-direction and Y-direction drive pattern generation means, it is possible to accurately guide to the target position according to the situation. .

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

First Embodiment The first embodiment further embodies the second invention. FIG. 3 is a schematic configuration diagram of an automatic guided vehicle to which the travel control device according to the first embodiment is applied.

The automatic guided vehicle 1 according to the present embodiment includes optical sensors 13 and 14,
The position measuring computer 15, the traveling control position 12, the driving devices 10, 11, the motors 8, 9, the reduction gears 6, 7, the driving wheels 2, 3, and the driving wheels 2, 3 are arranged coaxially. Measuring wheel 2
5, 25 and encoder 2 for detecting the number of revolutions of measuring wheels 25, 25
6, 26, a storage battery 20, and casters 16, 17, 18, and 19.

The drive wheels 2 and 3 are mounted on the motors 8 and 9 by the motors 8 and 9 fixed to the vehicle at positions equidistant to the left and right from the center of the vehicle on the center axis in the front-rear direction of the vehicle. The unmanned vehicle 1 is driven to rotate independently via the output shafts 4 and 5 of the speed reducers 6 and 7 and the casters 16, 17, 18 and 19 disposed at the four corners of the vehicle body. It can run in all directions.

The optical sensors 13 and 14 are disposed before and after the vehicle body, and measure a distance to a target stop mark. By arranging the optical sensors in front and rear of the vehicle body, the automatic guided vehicle 1 can control traveling in both front and rear directions.

The position measurement computer 15 calculates the current position of the automatic guided vehicle 1 with respect to the target position and the azimuth based on the distance information from the optical sensors 13 and 14 and the moving distance obtained by integrating the rotation speeds of the left and right measurement wheels 25 and 25. Calculate the bearing.

The traveling control device 12 generates a traveling trajectory of the automatic guided vehicle based on the current position and azimuth information of the automatic guided vehicle from the position measurement computer 15, and calculates instantaneous speed commands of the left and right driving wheels 2, 3. Then, it outputs to the driving devices 10 and 11. Drive devices 10 and 11 are based on a speed command from travel control device 12,
The rotation speed of the motors 8 and 9 is controlled. As a result, the automatic guided vehicle 1 travels on a predetermined track and reaches a target position.

FIG. 4 shows a system block diagram of the travel control device 12. As shown in FIG. The travel control device 12 includes a travel information storage device 24, X-direction and Y-direction acceleration generation devices 21 and 22, a clock 38, and a control command value calculation device 23. The X-direction and Y-direction acceleration generators 21 and 22 have the same configuration and handle information in the X-direction and the Y-direction, respectively. The Y-direction acceleration generator 22 is omitted in the following description.

The travel information storage device 24 stores the position measurement computer 15
Current X-direction acceleration alpha _xs in the position, velocity v _xs AGV 1 output from the position coordinates x _s, the time t _xs and, acceleration in the X direction at the target stop position alpha _xd, velocity v _xd, position coordinates x _d , time t _xe, and accelerations α _ys , α _yd , velocity v _ys , v _yd , position coordinates y _s , y _d , time t _ys , t _ye in the Y direction at the current position and the target stop position are stored. ing.

The X-direction acceleration generation device 21 receives the travel information α _xs , α _xd , v _xs , v _xd , x _s ,
x _d , t _xs , t _xe are input, and the continuous acceleration pattern required to reach the target position from the current position is represented by a third-order time function f _x
X-direction acceleration pattern generator 32 generated as (t)
And X generated by the X-direction acceleration pattern generator 32.
From time t ₁ Metropolitan sequentially output from the clock 38 and the direction of the acceleration pattern f _x (t), an X-direction acceleration calculator 36 and outputting the acceleration command value alpha _x momentary X-direction direction.

The control command value calculating device 23 outputs the X-direction and Y-direction momentarily output from the X-direction and Y-direction acceleration calculators 36 and 37.
The direction acceleration command values α _x and α _y are input, and a vector integrator 39 that integrates the _{instantaneous} vehicle speed vector command value v _sd and the X-direction and Y-direction acceleration calculators 36 and 37 output X. The direction and Y-direction acceleration command values α _x , α _y and the vehicle speed vector command values x _x , v _y output from the vector integrator 39 are input, and the vehicle speed of the automatic guided vehicle | ▲ ▼
| And a vector calculator 40 for calculating the curvature f _d, the driving wheel speed calculator for calculating a speed command value of the left and right drive wheels 2 and 3 based on the vehicle speed and the curvature is output from the vector calculator 40
Consists of 41.

The automatic guided vehicle 1 measures stop marks placed at target stop positions and preset positions by the optical sensors 13 and 14. The position measurement computer 15 calculates the position and direction of the target stop position and the current position and direction of the automatic guided vehicle based on the sensor information,
Output to 12.

This calculation is performed as follows. Position measurement computer 15
When the optical sensors 13 and 14 detect a stop mark, the relative positions (x _m , y _m ) and the azimuth θ _m between the stop mark and the target stop position and azimuth stored in advance are determined. First, an X direction and a Y direction that are linearly independent are set. These two directions can be arbitrarily taken,
In this embodiment, the target stop position 47 as shown in FIG.
0), the X-axis as a reference to the target direction 44 following the stop,
Further, an XY orthogonal coordinate system in which a direction 45 at 90 ° to the X axis is set to the Y axis is set on the traveling plane 41. In the following description of the embodiment, simply the X direction and the Y direction refer to the directions shown in FIG. 5 at the target stop position.

Next, when the automatic guided vehicle 1 comes right beside the stop mark,
By using the relative distance 1 and the azimuth angle theta _r between the automatic guided vehicle 1 and the stop mark obtained by the distance information from the optical sensors 13 and 14, the current position to the target stop position of the AGV (X _s , y _s ) and the azimuth θ _s are calculated by the following equations.

_{θ s = θ m + θ r} x s = x m +1 · sin θ m y s = y m -1 · cos θ m addition, the current vehicle speed v _s of the automatic guided vehicle, the output from the encoder 26 Speed v of certain left and right measurement wheels 25, 25
_cL, v from _cr, obtained by _{v s = (v cL + v} cr) / 2.

Therefore, the speed at the control start position in the X and Y directions
v _xs and v _ys can be obtained by v _xs = v _s · cos θ _s v _ys = v _s · sin θ _s .

Here, when the error due to the slippage of the drive wheel is small,
Measuring wheel speed v _cL, v instead of _cr, the left and right speed command value v _L to the drive wheels, v with _r obtained by the following equation.

v _xs = ((v _L + v _r ) · cos θ _s ) / 2 v _ys = ((v _L + v _r ) · sin θ _s ) / 2 On the other hand, the acceleration α _xs at the control start position in the X and Y directions, α _ys is obtained by the time differentiation of the speeds v _xs and v _ys , and when the azimuth angle error is small, command values α _x and α _y to the drive system can be used.

Next, a calculation procedure inside the travel control device 12 will be described.

The X-direction and direction-acceleration generators 21 and 22 calculate accelerations required for the automatic guided vehicle to reach the target stop position in the X and Y directions, respectively. That is, the X-direction acceleration generation device 21 calculates the acceleration in the X direction, which is the target azimuth at stop, and the Y-direction acceleration generation device 22 calculates the acceleration in the Y direction, which is a direction orthogonal to the target azimuth at stop. Calculate.

 Next, a calculation procedure in the X-direction acceleration generation device 21 will be described.

First, the position and orientation information of the target stop position 47 obtained by the position measurement computer 15, the current position and direction information of the automatic guided vehicle, and the drive units 10 and 11 are currently output to the drive wheels 2 and 3. In order to generate an acceleration pattern in the X-direction acceleration pattern generator 32, the position and speed information in the X-direction 44 on the XY orthogonal coordinate system must be obtained from the current vehicle speed. Therefore, the travel information storage unit 24, the current X-direction position coordinate value x _s and X-direction velocity v _xs AGV in the X direction 44, the X-direction target position coordinate value x _d and the X-direction target AGV The speed v _xd is calculated. At this time, target stop position 4
Since 7 is set as the origin, the X-direction target position coordinate value x _d = 0 of the automatic guided vehicle is set, and the X-direction target speed v _xd = 0 for performing positioning at the time of stopping is set.

Next, the X-direction acceleration pattern generator 32 calculates a continuous acceleration pattern required to reach the target position from the traveling direction storage speed information from the traveling information storage device 24 obtained as described above in the third order. Generate by time function. The calculation is performed as follows. FIG. 6A shows the calculation process.

The X-direction acceleration pattern AGV generated by cubic function f _x of following time t (t).

f _x (t) = a _x · t ³ + b _x · t ² + c _x · t + d _x Therefore, the speed pattern F _x (t) of the automatic guided vehicle in the X direction
Integrated the X-direction acceleration pattern f _x (t) Becomes In addition, the automatic guided vehicle has the X-direction acceleration pattern.
When controlled based on f _x (t) and the X direction speed pattern F _x (t), the X direction component of the target trajectory of the AGV is obtained by integrating the speed pattern F _x (t). Becomes Here, C ₁ and C ₂ are integration constants.

The automatic guided vehicle must continuously and smoothly travel from the current position azimuth speed to the stop target position azimuth speed. Therefore, the pattern functions of acceleration, velocity, and position
_{f x (t), F x} (t), G x (t) must continuously combine to control end time t _xe from the control start time t _xs. Therefore, the current X-direction position coordinate value _xs and X-direction speed v of the automatic guided vehicle output from the travel information storage device 24 are output.
_xs , X-direction acceleration α _xs , X-direction target position coordinate value x _{d of} the automatic guided vehicle, X-direction target speed v _xd, and X-direction acceleration α _xd, as boundary conditions, and a pattern function f of acceleration, speed, and position.
_{x (t), F x (} t), solving the G _x (t). In this embodiment,
At the control end time t = t _xs = t _ye , the automatic guided vehicle reaches the target stop position (x _d , y _d ) = (0,0). Also in this case, the control start time t in acceleration alpha _xs to _xs, in the acceleration alpha _xs to the control end time t _xe, to provide continuity in the acceleration pattern f _x (t), is set to 0. Other boundary conditions of the pattern functions f _x (t), F _x (t), and G _x (t) for acceleration, velocity, and position are as follows.

f _x (t _xs ) = α _xs = 0 f _x (t _xe ) = α _xe = 0 F _x (t _xs ) = v _xs F _x (t _xe ) = v _xe = 0 G _x (t _xs ) = x _s G _x (t _xe ) = x _d = 0 At this time, the control end time t _xe is stored in the travel information storage device 24.
The X-direction acceleration pattern generator 32
Supplied to From the above conditions, the coefficients a _x , b _x , c _x , and d _x of f _x (t) are calculated as the solution of the six-way simultaneous equation. At the same time, each coefficient of F _x (t) and G _x (t) is obtained.

On the other hand, in the Y-direction acceleration pattern generator 33, Y
Third order time function f _x (t) =
^{_{a y t 3 + b y t}} 2 + c y t + d coefficient _{y a y, b y, c} y, as a boundary condition travel information about Y-direction of d _y from the travel information storage unit 24, in FIG. 6 (b) As shown, the determination is made in the same manner as the generation of the X-direction acceleration pattern.

As described above, all the accelerations, velocities, and positions at all times in the X direction 44 and the Y direction 45 required to reach the target stop position are determined.

Then, in the X direction and Y direction acceleration calculator 37, the current time t = t _1, which is instructed by the clock 38, to a time t obtained respectively in the X direction and Y direction acceleration pattern generator 32, 33 X Direction and Y direction acceleration pattern f _x
By substituting (t) and f _y (t), the accelerations α _x and α _y in the X direction and the Y direction at the current time t ₁ required to reach the target position are sequentially controlled in the control cycle. The calculation is performed as follows for each case.

_{α x = f x (t 1} ); t xs <t 1 <t xe = 0; t 1 ≧ t xe α y = f y (t 1); t ys <t 1 <t ye = 0; t 1 ≧ t _ye Next, the control command value calculation device 23 converts the acceleration command values α _x , α _y calculated by the X-direction and Y-direction acceleration generation devices 21, 22 for each control cycle into control commands to the drive devices 10, 11. Convert sequentially to values. The calculation procedure will be described below.

First, the vector integrator 39, in the time t ₁ which is input by the X-direction and Y-direction acceleration calculator 36, 37 X-direction and Y-direction acceleration command value alpha _x, from alpha _y, vehicle speed at time t ₁ vector value specified (v _x, v _y) sequentially calculates for each control cycle. That is, the operation is as follows.

At this time, instead of performing the integration, when the acceleration pattern functions f _x (t) and f _y (t) are obtained by the X-direction and Y-direction acceleration pattern generators 32 and 33, the integrated speeds are simultaneously obtained. The pattern functions F _x (t) and F _x (t) can be obtained in advance. In this case, by substituting the time t = t ₁ into the speed pattern functions F _x (t) and F _y (t), the vector command value (v _x , v _y ) of the vehicle body speed is directly obtained as follows. be able to.

v _x = F _x (t ₁ ) v _y = F _y (t ₁ ) In the vector calculator 40, the X direction and the Y direction sequentially input from the X and Y direction acceleration pattern generation devices 21 and 22 for each control cycle From the acceleration command values α _x , α _y of the vehicle and the vehicle speed command values v _x , v _y in the X direction and the Y direction sequentially input from the vector calculator 40 for each control cycle. calculated vehicle speed v _sd and radius of curvature of the command value r _d of the AGV t _1, sequentially outputs to the driving wheel speed calculator 41 for each control cycle. These calculation procedures will be described with reference to the vector diagram of FIG.

First, the vehicle acceleration vector ▲ ▼ commanded to the automatic guided vehicle at time t ₁ is calculated by the following equation using the acceleration command values α _x , α _y and the vehicle speed command values v _x , v _y . Define.

This vehicle acceleration vector ▲ ▼, vehicle speed vector ▲
▼ by using the vehicle speed of the magnitude of the time t ₁ | ▲ ▼
|, The vehicle lateral velocity vector ▲ ▼, and the radius of curvature r _d are calculated as follows.

In the driving wheel speed calculator 41, the size of the vehicle speed at time t ₁ sequentially calculating in each control cycle in vector calculator 40 | ▲
▼ | and the radius of curvature r _d, the speed command value for the left and right drive wheels v _L, the v _r calculated, and outputs to the drive devices 10 and 11. Since the automatic guided vehicle is a two-wheel independent drive type, the radius of curvature r _d , the drive wheel tread w, and the traveling track 71 have a geometric relationship shown in FIG. Therefore, it is possible to calculate the left and right driven wheel speed command value v _L, the v _r as follows.

However, the upper side of the sign indicates the case where the AGV turns clockwise, and the lower side indicates the case where the AGV turns counterclockwise.

As described above, in order to realize the calculated speed command value v _L, the v _r as the travel speed of the automatic guided vehicle, the driving devices 10 and 11
The motors 8 and 9 are feedback controlled. Although not shown in the figure, this feedback signal includes a tachogenerator (hereinafter referred to as T.
G.), the driving devices 10 and 11 configured with servo circuits using a voltage proportional to the output speed of the TG
The output voltage, by controlling the speed of the motor 8 and 9, to match the left and right driven wheel speed v _L, the v _r. This motor 8, 9
Output torque by the reduction gears 6, 7 and its output shaft 4,
5 to the drive wheels 2, 3. As described above speed command value v _L, v and sequentially outputs _r for each control cycle, the control end time t _xe, continues until t _ye.

FIG. 9 shows an example of a traveling locus by the traveling control device of the present embodiment. This is a case where the vehicle travels on the track 67 from the control start position 66 to the control end position 63 by the control means. At this time, as described above, the X-axis 62 and the Y-axis 63 are set with reference to the target azimuth 64 at the time of stopping, and the control of the vehicle body 68 in the Y-axis direction is completed. As shown in the figure, the present embodiment makes it possible to generate in real time a trajectory pattern, a velocity pattern, and an acceleration pattern that smoothly and continuously couple to a target stop position, which was difficult in the past. Further, it is possible to realize a smooth running by generating a drive command value from the speed and the acceleration pattern. As described above, accurate stop positioning of the automatic guided vehicle is enabled.

Second Embodiment FIG. 10 is a system block diagram of a second embodiment.
The second embodiment is obtained by adding a target trajectory calculator 69 and a comparator 70 to the first embodiment, and belongs to the third invention described above. That is, the target trajectory calculator 69 receives the speed commands V _x and V _y in the X direction and the Y direction at the time t ₁ from the vector integrator 40, and outputs the current time on the target trajectory based on the drive pattern already generated. position should be present AGV at _{t = t 1 (x t,} y t) for calculating a and orientation theta _t.

This operation is the starting point of the control (x _s, y _s) and time t _xs, t _ys and the vehicle speed command value v _x, by a v _y is calculated as follows.

θ _t = tan ⁻¹ (v _y / v _x ); V _x ≠ 0 = π / 2 · sgnV _y ; v _x = 0 At this time, the position (x _t , y
Instead of calculating _t ), the X- and Y-direction acceleration pattern generators 32, 33 use acceleration pattern functions f _x (t), f _y
By substituting G _x (t) and time t ₁ into the trajectory pattern function G _x (t) determined simultaneously when obtaining each coefficient of (t), the position (x _t , y _t ) is directly obtained. It is also possible to get The comparator 70 calculates the position (x, y) and the azimuth θ where the automatic guided vehicle actually exists at the time t ₁ calculated by the position measurement computer 15 and the position (x _t , y _t ) and azimuth θ _t are input, and the distance between the two positions or the azimuth difference between the two is determined by the respective thresholds A,
If it is larger than B, a regeneration command is output to the X-direction and Y-direction acceleration pattern generators 32, 33.

That is, when (x−x _t ) ² + (y−y _t ) ² > A ² or | θ−θ _t |> B, a regeneration command is output. The X-direction and Y-direction acceleration pattern generators 32, 33 determine the times at which the regeneration commands are input as new control start times t _xs , t
_{As ys} , in the X direction and Y by the same operation as in the first embodiment.
Direction acceleration pattern f _x (t), to regenerate the f _x (t).
Then, based on the regenerated acceleration pattern, the automatic guided vehicle travels on a new track to the target position by the driving devices 10 and 11.

FIGS. 11 (a) and 11 (b) show flowcharts of the traveling control by generating and regenerating the driving pattern described above.

As described above, by accurately regenerating the target trajectory in accordance with the position and orientation error of the automatic guided vehicle from the target trajectory, accurate stopping to the target stop position can be realized. This will be described with reference to FIG. Stop target position 82
Are generated by the X-direction and Y-direction acceleration generation devices 21 and 22. Then, a drive command value is calculated by the control command value calculation device 23 so as to travel on the target track, and is sent to the drive devices 10 and 11. By the way, when there are various error factors such as unevenness of the traveling floor surface, slip between the driving wheel and the traveling floor surface, delay due to various calculation times, fluctuation of dynamic characteristics of the automatic guided vehicle due to load weight and the like, The actual running track 83 deviates from the target track 84, causing an error. Therefore, at the time when all the drive command values for traveling on the target track 84 have been output, it is impossible to reach the stop target position. To prevent that,
Comparator 70 compares the position and orientation of the automatic guided vehicle on the target track with the actual position and orientation of the automatic guided vehicle, and when the difference between them exceeds a set threshold value 81, generates an acceleration pattern in the X and Y directions. The target trajectory 85 is newly generated by the devices 32 and 33. Thereby, the error near the stop target position 82 that may have occurred on the past target trajectory 84 is deleted,
It is possible to accurately control the stop target 82.

Third Embodiment In a third embodiment, the traveling information storage device 24 has a control time adjusting function and performs more precise traveling control, and belongs to the above-described fourth invention. The X direction will be described below with reference to the drawings.

FIG. 13 is a system block diagram of the travel control device 12 of the third embodiment.

The running information storage device 24 stores the X-direction and Y-directions already generated by the X-direction and Y-direction acceleration pattern generators 32 and 33.
The direction acceleration pattern functions f _x (t) and f _y (t) are input, and the control end times t _xe and t _ye are newly corrected, and X is calculated again.
Output to the direction and Y direction acceleration pattern generators 32 and 33. At this time, the traveling information storage device 24 generates control end times t _xe and t _ye so as to suppress the maximum value and the minimum value of the acceleration pattern within the acceleration limit of the driving ability of the driving means,
Not only does it prevent track deviation due to the inability of the dynamic characteristics of the drive means to follow the drive command value, but also causes slippage between the traveling floor surface and the drive wheels due to excessive acceleration and deceleration and centrifugal force applied to the automatic guided vehicle To prevent orbital misalignment.

As described above, the X-direction acceleration pattern is obtained by the X-direction acceleration pattern generator 32 from the position, velocity, and acceleration at the start and end of the control in the X-direction and the time of the following in the following manner. The coefficients a _x , b _x , of the cubic function f _x (t)
Generated as c _x , d _x .

f _x (t) = a _x · t ³ + b _x · t ² + c _x · t + d _x At this time, the cubic function of time f _x (t) is the control start time t
_Since the acceleration is generated so as to satisfy the boundary conditions of f _x (t _xs ) = 0 and f _x (t _xe ) = 0 so that the acceleration is continuous from the control end time t _xe , the cubic function of time f
The maximum value and the minimum value of _x (t) are 0 or the extreme value f _mx of the cubic time function f _x (t) existing between the control start time t _xs and the control end time t _xe. . This extreme value f
_mx is calculated as follows.

f _mx = a _x · t _m ³ + b _x · t _m ² + c _x · t _m + d _{x where tm} is the equation 3a _x · t _m ² + 2b _x · t _m + c _x = 0
Sought as a solution of, t _m = - a ^{_{{b x ± (b x 2}} -3 · a x · c x) 1/2} / (3 · a x). Therefore, the control end time t _xe is determined such that the extreme value f _mx and the preset acceleration limit value α _max of the driving ability of the driving means satisfy the following expression.

| f _mx | ≦ α _max The control end time t _xe in the X direction obtained in this way is output to the X direction acceleration pattern generator 32, and the cubic function f _{x of} time is output.
The coefficients a _x , b _x , c _x , and d _x of (t) are generated by the calculation method.

FIG. 14 is a graph showing an example of an acceleration pattern in a fixed direction in which time is taken on the horizontal axis and acceleration is taken on the vertical axis. The acceleration pattern 74 is generated by the X-direction or Y-direction acceleration pattern generators 32 and 33 so as to be continuous from the control start time 78 to the control end time 79. At this time, the maximum value 75 and the minimum value 76 of the acceleration pattern are determined by the control end time 79. For example, when the control end time 79 is advanced, it is necessary to perform more rapid acceleration and deceleration in a short time, and the maximum value 75 and the minimum value 76 of the acceleration pattern tend to increase. Further, if the control end time 79 is delayed, since it is necessary to perform slow acceleration and deceleration for a long time, the maximum value 75 and the minimum value 76 of the acceleration pattern tend to decrease more. Therefore, the maximum value 75 and the minimum value 76 of the acceleration pattern
, The control end time 79 can be determined. In the third embodiment, the maximum value 75 and the minimum value
The control end time 79 is generated so as to suppress 76.

Similarly, the Y-direction control end time t _ye is also the
4 and output to the Y-direction acceleration pattern generator 33,
Coefficients a _y time cubic function _{f y (t), b y} , c y, to produce d _y.

Next, in the control command value calculating device 23, the X direction and the Y direction
The signals calculated by the directional acceleration calculators 36 and 37 for each control cycle are sequentially converted into control command values for the driving devices 10 and 11.

As described above, if the drive commands are continuously output until the control end times t _xe and t _{ye in} each control cycle, the vehicle travels on a smooth and continuous trajectory, and positioning at the time of stop can be performed. Also,
Since the maximum and minimum of the acceleration pattern are suppressed within the acceleration limit due to the driving capability of the driving means, it is possible to suppress the trajectory deviation due to the inability of the dynamic characteristics of the driving means to follow the driving command value, and furthermore, it is not possible to add an unreasonable load. It is possible to prevent slippage between the traveling floor surface and the drive wheels due to deceleration and a track deviation due to centrifugal force applied to the automatic guided vehicle.

Fourth Embodiment The fourth embodiment belongs to the fourth invention, and the control end times t _xe and t _ye are set in the X direction and the Y direction by the control time adjustment function of the traveling information storage means 24 of the third embodiment. It is set differently. Hereinafter, the calculation procedure will be described.

For simplicity, the X and Y direction control start times are set to t _xs = t
_ys = 0.

As in the first embodiment, the vehicle travels in an XY orthogonal coordinate system in which the target stop position 47 is set as the origin, the target azimuth at stop 44 is set as the reference X axis, and the direction 45 is set as the Y axis. Take on plane 41. In order to set the automatic guided vehicle in the target stop direction at the target stop position 47, first, before reaching the target stop position, the error in the Y direction is first converged, and then the vehicle is driven on the X-axis. It is desirable to make. For this purpose, it is necessary to set the Y-direction control start time t _ye so as to be later than the X-direction control start time t _xe , that is, t _xe > t _ye . This is performed in the following procedure.

If, if t _xe · const <t _ye, replace the value of t _xe, so as to t _xe = t _ye / const. Here, const is a constant that determines the shape of the trajectory, and is set so as to satisfy const <1. As a result, the Y direction control start time t _ye can be set to be later than the X direction control start time t _xe .

As described above, by adjusting the X and Y direction control end times t _xe and t _ye , it is possible to perform positioning at the time of stopping such that the automatic guided vehicle is aligned with the target stop direction.

Next, in the control command value calculator 23, the X direction and Y
The directional acceleration calculators 36 and 37 sequentially convert the acceleration commands α _x and α _y calculated for each control cycle into control command values for the driving devices 10 and 11.

As described above, the speed command values v _x and v _y are sequentially set for each control cycle,
If the output is continued until the control end times t _xe and t _ye , the vehicle travels on a smooth and continuous track, and positioning at the time of stop can be performed.

The shape of the target trajectory is adjusted as described above, and the speed command value v _L ,
v _r a control cycle every turn, the control end time t _xe, if continues to output up to t _ye, traveling on a smooth, continuous orbit and vehicle direction stop target AGV At a time of stopping Positioning at the time of a stop that matches the traverse can be performed.

The above is described with reference to FIG. FIG. 15 shows examples 89, 90, and 91 of target trajectories when the automatic guided vehicle is controlled from a control start position 86 to a target stop position 87 and a stop orientation 88. The target trajectory 89 is defined by the X-direction control start time t _xe and Y
This shows a case where the direction control start time t _ye is set to a substantially equal time. The corrected target trajectory 90 shows a case in which the X-direction control end time t _xe is set to be later than the Y-direction control end time t _ye by setting the constant const <1 in the traveling information storage device 24. . Comparing the target trajectories 89 and 90, the target trajectory 90 with the adjusted time parameter
In this case, the body direction of the automatic guided vehicle is closer to the stop target direction before the stop target position, and the automatic guided vehicle is more smoothly connected to the stop target position direction. As shown in the figure, the azimuth accuracy at the target stop position of the automatic guided vehicle can be improved by the travel control device.

Modified Example Next, a modified example in which a tricycle is used as the driving means of the automatic guided vehicle is shown in FIG. AGV 92 Miwa switches the steering angle theta _st about its central axis 94 the Misaohebiwa 93, commanded radius of curvature r, the center 99
Is controlled so that the center 98 of the automatic guided vehicle passes on the circular arc of.
At the same time, the left driving wheel 95 and the right driving wheel 96 achieve the commanded vehicle speed. Reference numeral 97 denotes a middle point of a line connecting the left driving wheel 95 and the right driving wheel 96.

Therefore, in the first embodiment, by controlling the calculation of the travel control device as follows, it becomes possible to control the three-wheeled automatic guided vehicle.

In this modification, the calculation in the drive wheel speed calculator 41 is changed as follows. The size of the vehicle speed in vector calculator 40 by a time t ₁ which is sequentially calculating in each control cycle | ▲
▼ | by the radius of curvature r _d, velocity strength value v _L of the steering angle command value theta _st and the drive wheels 95, 96 of Misaohebiwa 93, the v _r is calculated by the following procedures, and outputs to the drive unit .

Miwa type automatic guided vehicles, around the arc of the center 99, the center 93 of Misaohebiwa 94 moves arc on a radius r _1, the vehicle body center
98 moves on an arc of radius r, the midpoint 97 of the drive wheels 95 and 96 are moving the arc over the radius r _2. Therefore, when the radius of curvature r _d calculated by the vector calculator 40 is given at the center 98 of the vehicle body, the steering angle θ _st of the automatic guided vehicle can be determined by the following formula.

θ _st = tan ^-1 {L ₁ / (r _d ² −L ₂ ² ) ^1/2 } The magnitude of the vehicle speed calculated by the vector calculator 40 |
▲ ▼ | is, as it is the command speed V _s of the drive wheels 95, 96
It is good.

As described above, sequentially a speed command value V _s of the steering angle command value of the computed Misaohebiwa 93 theta _st to the drive wheels 95, 96 in each control cycle, the control end time t _xe, outputs until t _ye .

According to the above procedure, even in a three-wheeled automatic guided vehicle, a track pattern, a speed pattern, and an acceleration pattern that are smoothly and continuously connected to a target stop position can be generated in real time, so that smooth traveling can be realized and accurate stopping can be achieved. Positioning is possible.

In addition, many design changes and additional changes can be made to the above-described invention without departing from the spirit of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a basic configuration of the first invention. FIG. 2 is a block diagram showing a basic configuration of the third invention. FIG. 3 is a schematic configuration diagram of an automatic guided vehicle according to an embodiment of the present invention. FIG. 4 is a system block diagram of the travel control device in the first embodiment. FIG. 5 is a diagram showing the relationship between the control start and control end positions and the XY coordinate system. FIG. 6 is a diagram showing the generated drive pattern. FIG. 7 is a vector diagram of the acceleration and speed of the vehicle body. FIG. 8 is a diagram showing a relationship between a radius of curvature and a drive wheel tread. FIG. 9 is a view showing a running locus by the running control in the first embodiment. FIG. 10 is a system block diagram of the travel control device in the second embodiment. FIG. 11 is a flowchart of a traveling control operation by generating and reconfiguring a driving pattern. FIG.
FIG. 9 is a diagram illustrating a relationship between a target trajectory and a regenerated trajectory in the example. FIG. 13 is a system block diagram of the travel control device in the third embodiment. FIG. 14 is a diagram showing acceleration limitation by control time setting. FIG.
It is a figure showing a run track in an example. FIG. 16 is a diagram showing a relationship between a radius of curvature and a control wheel in a modification. I: travel information storage means, II _1: X direction drive pattern generation means, II _2: Y direction drive pattern generation means, III: drive command value calculation means, IV: drive means, V: position measurement Means, VI ₁ ... Comparison means, VI ₂ ... Target trajectory calculation means, 1... Automatic guided vehicle, 10, 11... Drive device, 12... Travel information storage device, 15. 22 ... X-direction and Y-direction acceleration pattern generation device, 23 ... drive command value calculation device, 24 ... travel information storage device, 26 ... encoder, 38 ... clock, 69 ... target trajectory calculation device, 70 ... … Comparator

Claims (4)

(57) [Claims] 1. The position, speed and acceleration information at the control start position of the automatic guided vehicle in the X direction on the plane on which the automatic guided vehicle travels, and the position and speed in the X direction to be taken by the automatic guided vehicle at the control end position And acceleration information, the position and speed and acceleration information at the control start position of the automatic guided vehicle in the Y direction different from the X direction, and the position and speed in the Y direction to be taken by the automatic guided vehicle at the control end position Driving information storage means for storing and outputting the control start and control end times at the two positions, and acceleration information, and output from the driving information storage means based on a predetermined continuous time function in the X direction. Using the traveling information on the X direction of the automatic guided vehicle at the two positions, An X-direction drive pattern generating means for generating a drive pattern in the X-direction between: an automatic guided vehicle at the two positions output by the travel information storage means based on a predetermined continuous time function in the Y-direction; Y-direction drive pattern generation means for generating a drive pattern in the Y direction between the two positions using the travel information on the Y direction, drive means for driving the wheels of the automatic guided vehicle, Based on the drive patterns in the X and Y directions generated by the direction drive pattern generation means,
A drive command value calculation means for calculating a drive command value for the drive means, and for different X and Y directions on a travel plane, a time function independently determined and travel information at two positions, By generating a continuous drive pattern in each of the X and Y directions, the automatic guided vehicle can travel smoothly to a target control end position, and can be accurately guided to the target position. Control device. 2. The X-direction drive pattern includes a coefficient of a predetermined continuous time function in the X-direction and travel information in the X-direction, that is, position, velocity and acceleration information in the two positions in the X-direction. , A time pattern of the acceleration in the X direction generated by determining the time at the two positions as a boundary condition, and the Y direction driving pattern is obtained by calculating a predetermined continuous time function in the Y direction by each coefficient. Is a time pattern of the acceleration in the Y direction generated by determining the traveling information in the Y direction, that is, the position, velocity, and acceleration at the two positions in the Y direction and the time at the two positions as boundary conditions. And the unmanned conveyance in which the drive command value is determined from acceleration and speed values in the X direction and the Y direction. Claim (1) AGV running control apparatus, wherein it is a vehicle speed and trajectory curvature. 3. The target trajectory calculation device according to claim 1, wherein the travel control device for the automatic guided vehicle calculates a position on the target trajectory where the automatic guided vehicle should exist based on the drive patterns in the X and Y directions. Means, a position measuring means for measuring a current position where the automatic guided vehicle actually exists, and a current position of the automatic guided vehicle from the position measuring means and a target track of the automatic guided vehicle from the target track calculating means. Calculating means for calculating a deviation from the position, and when the deviation exceeds a predetermined threshold value, comparing means for outputting a regeneration command to the X-direction and Y-direction drive pattern generating means, respectively. A travel control device for an automatic guided vehicle, wherein the X-direction and Y-direction drive pattern generation means regenerates the X-direction and Y-direction drive patterns, respectively, in response to a regeneration command input from the comparison means. 4. The automatic guided vehicle according to claim 2, wherein said travel information storage means includes a time parameter adjusting means for determining a time at said two positions in accordance with said two positional relationships. Travel control device.