JPH11175149A - Autonomous traveling vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an autonomous traveling vehicle which can travel straight even in the presence of a recessed part in the side wall surface in the traveling direction. SOLUTION: This autonomous traveling vehicle has three ultrasonic distance measuring sensors each to measure the distance to a side wall surface at a specified time interval in a traveling direction and autonomously travels parallel to the wall surface according to the distances to the wall surfaces measured by the three ultrasonic distance measuring sensors. A measured value d1 is set corresponding to the smallest difference among differences Δdl-a to Δdl-c between measured distances dl-a to dl-c obtained at a certain point of time and previous measurements dl-a-old to dl-c-old obtained at a specified time before the above point of time (S203 to S206) and the above value dl is used to perform profiling travel control (S208 to S214).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an autonomous vehicle that autonomously travels parallel to a wall surface, and more particularly to waxing,
The present invention relates to an autonomous vehicle that autonomously runs parallel to a wall while performing operations such as cleaning and lawn mowing.

[0002]

2. Description of the Related Art Autonomous traveling vehicles have been known that can travel autonomously along an object such as a wall while performing work such as waxing. As a technology related to such an autonomous vehicle, the autonomous vehicle travels straight along a wall almost parallel to the traveling direction, and is not affected by a steep step (dent in the wall) of the wall. There is a technology to go straight.

[0003] In order to enable the autonomous vehicle to go straight as described above, such an autonomous vehicle detects a sudden change in the distance to the wall surface when traveling along a wall including a dent. Judging that the sudden change is due to the dent of the wall, it is controlled so that it goes straight without giving feedback to the control of traveling, and when the distance to the wall is stabilized again, the control for traveling parallel to the wall (hereinafter, referred to as Copying control may be performed).

[0004] Referring to FIGS. 13 to 19, the following traveling by a conventional autonomous vehicle will be described.

FIG. 13 is a diagram showing a conventional autonomous vehicle having one ultrasonic ranging sensor on each side, and FIG. 14 is a diagram showing the directional angle of the ultrasonic ranging sensor. Fifteen
FIG. 4 is a diagram for explaining a distance measurement value by an ultrasonic distance measurement sensor when facing an object.

As shown in FIG. 13, a conventional autonomous vehicle includes ultrasonic ranging sensors 1_a and 1_b, and the ultrasonic ranging sensor 1_a moves leftward with respect to the traveling direction (direction of arrow A). The distance to the wall is measured, and the ultrasonic ranging sensor 1_b measures the distance to the wall to the right in the traveling direction. In addition,
The ultrasonic distance measuring sensor has a wide range of directional angles as shown in FIG. 14, and in the distance measurement by such an ultrasonic distance measuring sensor, as shown in FIG. As long as the sound wave is radiated, the shortest distance from the wall surface is determined regardless of the relative angle between the wall surface to be measured and the autonomous vehicle.

In this autonomous vehicle, the distance to the wall surface is repeatedly measured by one of the ultrasonic ranging sensors 1_a and 1_b at predetermined time intervals. Copying travel control is performed. This contour running control is described in more detail in FIG.
6 is performed according to the flowchart shown in FIG.

FIG. 16 is a flow chart for explaining the conventional copying control of an autonomous vehicle. Here, it is assumed that the distance measurement is performed on the wall on the left side with respect to the traveling direction.
_A (see FIG. 13) measures the distance to the left wall as the reference distance D.

In the contour running control, first, in step 101,
(Hereinafter, step is abbreviated as S), the ultrasonic ranging sensor 1
_A is used to measure the distance dl to the left wall, and S1
In 02, a deviation Δdl between the reference distance D obtained at the time of starting the contour running and the distance dl calculated in S101 is obtained. Subsequently, in S103, it is determined whether the absolute value | Δdl | of the deviation Δdl obtained in S102 is larger than a predetermined set value d1 set for changing the reference distance D.

When the absolute value | Δdl | of the deviation is smaller than the set value d1, the reference distance D is not changed, and S104
Then, the deviation Δdl is compared with a set value d2 (> 0) for switching the driving control of traveling. If Δdl is smaller than −d2, the drive system is controlled such that the autonomous vehicle body curves left in S105. If Δdl is between −d2 and d2, the drive system is controlled in S106 so that the autonomous vehicle body goes straight. Is controlled, and if Δdl is larger than d2, S107
The drive system is controlled so that the autonomous traveling vehicle body curves right, and this routine ends.

The absolute value of the deviation | Δdl | is equal to the set value d.
If it is larger than 1, the reference distance D is set to dl in S108.
And the drive system is controlled so that the autonomous vehicle body goes straight in S109, and this routine ends.

A series of operations described with reference to FIG. 16 are performed at predetermined time intervals while the autonomous vehicle is following the vehicle.

Next, referring to FIGS. 17 to 19, a description will be given of traveling by the above-described contour traveling control when such a conventional autonomous traveling vehicle travels parallel to a left wall having a recess. . 17 to 19, the length in the horizontal direction is emphasized in order to make it easy to understand the locus of the change in the distance measurement value.

FIG. 17 shows an ultrasonic distance measuring sensor 1_a when the left wall is measured at equal intervals by using an ultrasonic distance measuring sensor when the autonomous vehicle travels straight at a reference distance from the wall surface.
It is a figure for demonstrating the shape of the wall which (refer FIG. 13) detects.

As shown in FIG. 17, when the autonomous vehicle is traveling straight through the area 1, the distance to the left wall is accurately measured. When an autonomous vehicle is traveling straight through area 2,
The left wall detected in area 1 has an effect, and a sudden change in distance due to the depression in the left wall is not immediately detected. As the autonomous vehicle goes straight in area 2, the distance measurement value to the left wall gradually increases. Approaching the distance to the concave surface of the left wall. Further, when the autonomous vehicle reaches the area 3, the distance to the left wall detected in the area 1 is not affected, and the distance to the concave surface of the left wall is accurately measured.

As described above, in the conventional autonomous vehicle, it is difficult to accurately recognize the position of the edge of the dent of the left wall (a sudden change in the wall surface at the boundary between the area 1 and the area 2). is there. Further, using FIGS. 18 and 19, the autonomous traveling control shown in FIG. 16 is performed while detecting the edge of the dent of the left wall by the ultrasonic ranging sensor. The following describes the copying of a traveling vehicle.

FIG. 18 and FIG. 19 are diagrams for explaining the following traveling of a conventional autonomous vehicle on a wall surface having a concave portion. L <b> 1 to L <b> 10 indicate the positions of the ultrasonic ranging sensors 1 </ b> _a accompanying the travel of the autonomous vehicle.

As shown in FIG. 18, the autonomous vehicle moves to position L
When the value is 1, the autonomous mobile vehicle measures the distance to the left wall to determine the reference distance D1. Even at the position L2, the distance to the left wall is accurately measured, and the autonomous vehicle travels by following the straight traveling control until reaching the position L2.

When the autonomous traveling vehicle reaches the position L3 beyond the position L2, the distance measured by the ultrasonic distance sensor 1_a affected by the depression in the left wall becomes larger than the reference distance D1 (D1 + α1). . When the distance measurement value measured by the ultrasonic distance measurement sensor 1_a gradually becomes larger than the reference distance D1, the distance from the left wall of the autonomous vehicle is maintained at the reference distance D1 in order to cancel this. The left curve control is performed (based on the control in S103 to S105 in FIG. 16).

Further, when the autonomous vehicle reaches the position L6, the distance to the concave surface of the left wall is correctly measured, and the distance measurement value sharply increases. Accordingly, the distance measurement value and the reference distance D1 are increased. The absolute value of the deviation from the value exceeds the set value (d1 in FIG. 16), and the reference distance D1 is changed to D2 in FIG. 18 (based on the control in S103 and S108 in FIG. 16).
After that, from the position L7 to the position L10 beyond the position L6, the autonomous vehicle travels while following the concave surface of the left wall and keeping the reference distance D2.

As described above, the conventional autonomous vehicle is controlled so as to approach the wall while the detection of the dent in the left wall is delayed, and the conventional autonomous vehicle cannot travel straight. .

Since the distance measurement is performed discretely at predetermined time intervals, when the reference distance is changed (S108 in FIG. 16), the distance is measured before the distance close to the concave surface is measured. The absolute value of the deviation between the distance value and the reference distance becomes larger than the set value, and the reference distance may be changed. FIG. 19 shown below shows such a case.

In the case shown in FIG. 18, at the position L6, the concave surface is accurately measured by the ultrasonic distance measuring sensor, and the vehicle travels autonomously while maintaining the reference distance D2 from the concave surface of the left wall. .

On the other hand, in the case shown in FIG. 19, the distance measured by the ultrasonic distance measuring sensor greatly changes at the position L6, and the reference distance D3 set at the start of traveling is changed to the reference distance D4. After this change, the distance to the concave surface at the position L7 is measured almost exactly. In this case, the distance measurement value at the position L6 is larger than the reference distance D4, and it is determined that the autonomous vehicle itself is traveling on the right side of the reference distance D4 in the autonomous vehicle, and The left curve control is performed, and the autonomous traveling vehicle travels so that the distance measurement value becomes the reference distance D4. After that, from the position L8 to the position L10 beyond the position L7, the autonomous vehicle travels while following the concave surface of the left wall and keeping the reference distance D4.

As described above, the conventional autonomous vehicle is shown in FIG.
In the case where the control is performed as shown in FIG. 9, the conventional autonomous vehicle is further deviated from the target straight traveling route as compared with the case where the control is performed as shown in FIG.

[0026]

As described above, in a conventional autonomous vehicle using an ultrasonic ranging sensor, the ultrasonic ranging sensor has a wide range of directional angles, so that the vehicle travels along a wall. It is difficult to recognize the edge of the dent that exists on the wall with high resolution when it is running, and the ultrasonic ranging sensor is controlled to continue following the running until it detects a sudden change in the distance exceeding a predetermined value. . As a result, the conventional autonomous traveling vehicle runs slightly meandering due to the influence of the dent on the wall surface, and cannot travel along the wall with high accuracy. For this reason, when the autonomous traveling vehicle performs a work such as waxing, the work cannot be completely performed in the work area, and a gap may be formed in the wax application.

The present invention has been made to solve these problems, and an object of the present invention is to provide an autonomous vehicle capable of traveling straight irrespective of the presence of a concave portion on a side wall in the traveling direction. It is to provide a traveling vehicle.

Another object of the present invention is to be able to easily and accurately detect the inclination with respect to the side wall with respect to the traveling direction while traveling straight regardless of the presence of the concave portion on the side wall. It is to provide autonomous vehicles.

[0029]

According to a first aspect of the present invention, there is provided a distance measuring apparatus which measures a distance from a wall surface to a side in a traveling direction at a predetermined time interval and has a wide range of directional angles. An autonomous vehicle that includes a plurality of means on the side and autonomously travels in parallel to the wall based on the distance to the wall measured by the plurality of distance measuring means.

The autonomous vehicle moves from the first distance to the wall surface measured at each first time point by each of the plurality of distance measuring means and the second time point separated by the time interval from the first time point. The difference between the measured wall surface and the second distance is calculated, and the wall surface is calculated using the second distance corresponding to the smallest one of the calculated plurality of differences corresponding to each of the plurality of distance measuring means. It is characterized by running autonomously in parallel with.

According to the first aspect of the present invention, the first distance to the wall surface measured at each first time point by each of the plurality of distance measuring means and the second distance time interval from the first time point. The difference from the second distance to the wall surface measured at the time is calculated, and the second distance corresponding to the smallest one of the calculated plurality of differences corresponding to each of the plurality of distance measuring means is used. Then, autonomous traveling parallel to the wall surface is performed. Thereby, even if the distance measuring means having a wide range of directivity angles is used, the shape of the recess on the side wall in the traveling direction is not erroneously detected, and regardless of the presence of the recess on the side wall. It is possible to provide an autonomous vehicle that travels straight.

According to a second aspect of the present invention, there is provided the autonomous vehicle according to the first aspect, wherein the plurality of distance measuring means transmits ultrasonic waves in directions different from each other with respect to the wall surface. The distance is measured based on receiving the reflected wave from.

According to the second aspect of the present invention, the distance is measured based on transmitting ultrasonic waves to the wall surface in different directions and receiving ultrasonic waves reflected from the wall surface.
Each of the plurality of distance measurement means measures a second distance between the first distance measured at the first time and the wall measured at a second time separated by a time interval from the first time. The difference from the distance is calculated, and the second distance corresponding to the smallest one of the plurality of differences corresponding to each of the plurality of calculated distance measuring means is used, and the autonomous traveling parallel to the wall surface is performed. Done. Thereby, even if the distance measuring means having a wide range of directional angles using ultrasonic waves is used, the shape of the concave portion on the side wall in the traveling direction is not erroneously detected, and the concave portion on the side wall is not detected. Irrespective of the presence of the vehicle, it is possible to provide an autonomous vehicle that travels straight.

By arranging a plurality of distance measuring means at a sufficient distance in the traveling direction, it is possible to detect a dent on the wall surface while keeping the distance measuring means oriented in a direction perpendicular to the wall surface. . However, the length of an autonomous vehicle cannot be lengthened due to other restrictions. Therefore, a wide range of distance information is obtained by turning the distance measuring means in different directions. This makes it possible to accurately detect the dent on the wall surface while keeping the distance between the distance measuring means short.

According to a third aspect of the present invention, there is provided an autonomous traveling system in which the vehicle travels autonomously in parallel to the wall surface based on measuring a distance from the wall surface to the side in the traveling direction at a predetermined time interval. It is a car.

The autonomous traveling vehicle transmits a wave transmitting means for transmitting an ultrasonic wave to a wall surface lateral to the traveling direction, and receives an ultrasonic wave transmitted by the wave transmitting means and reflected from the wall surface. A plurality of wave receiving means provided laterally with respect to the traveling direction, the transmission of ultrasonic waves by the wave transmitting means, and the reflection of ultrasonic waves from the wall surface by each of the plurality of wave receiving means. A first distance to a wall measured at a first time based on the received wave;
Calculating means for calculating a difference between the first time point and a second distance from the wall surface measured at a second time point separated by the time interval, and a plurality of wave receiving means calculated by the calculating means; And control means for controlling the vehicle to travel autonomously in parallel to the wall surface using the second distance corresponding to the smallest difference among the plurality of differences corresponding to the distance.

According to the third aspect of the present invention, the ultrasonic wave transmitted to the wall surface lateral to the traveling direction by the wave transmitting means is transmitted by the plurality of wave receiving means provided on the side. A first distance from the wall surface measured at the first time point and a second time interval from the first time point, based on the received ultrasonic waves and the reception of the reflected ultrasonic waves; The difference between the second distance and the wall surface measured at the time point is calculated, and the wall surface is calculated using the second distance corresponding to the smallest one of the plurality of differences corresponding to each of the plurality of receiving units. The autonomous traveling is performed in parallel with. Thereby, even if the distance measuring means having a wide range of directional angles using ultrasonic waves is used, the shape of the concave portion on the side wall in the traveling direction is not erroneously detected, and the concave portion on the side wall is not detected. Irrespective of the presence of the vehicle, it is possible to provide an autonomous vehicle that travels straight.

According to a fourth aspect of the present invention, there is provided the autonomous vehicle according to the first aspect, wherein the autonomous vehicle is configured to autonomously travel in parallel to a wall using a second distance corresponding to the smallest of the plurality of differences. While traveling, the inclination with respect to the wall surface is detected based on the distance from the plurality of wall surfaces measured by each of the plurality of distance measuring means.

According to the fourth aspect of the present invention, the vehicle travels autonomously in parallel to the wall using the second distance corresponding to the smallest of the plurality of differences.
The inclination with respect to the wall surface is detected based on the distance from the plurality of wall surfaces measured by each of the plurality of distance measurement means. This makes it possible to provide an autonomous vehicle that can easily and accurately detect the inclination with respect to the side wall with respect to the traveling direction while traveling straight regardless of the presence of the concave portion of the side wall.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an autonomous vehicle as an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 3 are views for explaining an autonomous traveling vehicle according to a first embodiment of the present invention, and FIG. 2 is a diagram showing a signal transmitted from an ultrasonic ranging sensor mounted on the autonomous traveling vehicle. It is a figure for explaining radiation intensity of an ultrasonic wave.

As shown in FIG. 1, the present autonomous vehicle includes six ultrasonic ranging sensors 2_a to 2_f, and the ultrasonic ranging sensors 2_a to 2_c move in the traveling direction (the direction of arrow A). And the distance to the wall to the left is measured, and the ultrasonic ranging sensors 2_d to 2_f measure the distance to the wall to the right in the traveling direction. The ultrasonic ranging sensors 2_a to 2_f usually have a directional angle characteristic as shown in FIG. 14 similarly to the ultrasonic ranging sensor used for the conventional autonomous vehicle, and have a directivity characteristic with respect to a wall surface as shown in FIG. Although the shortest distance is measured, in this autonomous vehicle, as shown in FIG.
cylinder parts 3_a to 3_f are provided for each of a to 2_f,
The accuracy of shape recognition of an object to be measured for distance measurement is improved by reducing the radiation of ultrasonic waves. The transmitting / receiving surface of the ultrasonic ranging sensor was approximately a square of about 28 × 28 mm, and the length of the cylindrical portion was 90 mm.

Further, as shown in FIG. 3, these ultrasonic distance measuring sensors 2_a to 2_f have their angles relative to the wall surface parallel to the traveling direction so that the directivity angle of the transmitted ultrasonic wave is shifted. It is installed differently. Here, the ultrasonic ranging sensor 2_b provided at the center with respect to the front and rear,
The angle formed between the ultrasonic distance measuring sensor 2_e and the ultrasonic distance measuring sensors 2_a, 2_c, 2_d, 2_f respectively provided at the front and rear is 5 degrees, and the ultrasonic distance measuring sensor 2 provided at the center with respect to the front and rear.
_B, 2_e, and the distance between the centers of the ultrasonic ranging sensors 2_a, 2_c, 2_d, 2_f provided before and after, respectively, are 75 mm.

In the present autonomous vehicle, the ultrasonic ranging sensors 2_a to 2_c or the ultrasonic ranging sensors 2_a to 2_c
The distance from the wall surface is repeatedly measured by any of the three ultrasonic ranging sensors _d to 2_f. For each of the three ultrasonic ranging sensors for the wall surface, the ranging value obtained at the measurement at a certain point in time and the previous measurement obtained at the previous measurement at a point in time a predetermined time before this point in time. The difference from the distance value is calculated, and the contour running control on the wall surface is performed using the distance measurement value at a certain point in time corresponding to the smallest of these three differences. More specifically, the following running control is performed according to a flowchart shown in FIG.

FIG. 4 is a flow chart for explaining the following control of the autonomous vehicle according to the first embodiment. Here, it is assumed that the distance measurement is performed on the wall on the left side with respect to the traveling direction, and the distance to the left wall is determined by the ultrasonic distance measurement sensor 2_b (see FIG. 1) at the time of starting the follow-up traveling. It is measured as a reference distance D.

In the copying traveling control of the autonomous traveling vehicle, first,
In S201, the distances dl_a to dl_c to the left wall are measured using the ultrasonic ranging sensors 2_a to 2_c, respectively. Subsequently, in S202, the distances dl_a to
dl_c and the distance measured in S201 one routine before, and S21
5. The previous distance values dl_a_old to dl_ stored at 5
Deviations Δdl_a to Δdl_c from c_old are obtained, respectively. In S203, the absolute value of the deviation | Δdl_a
| 〜 | Δdl_c | are compared. Of the absolute values of these deviations | Δdl_a | to | Δdl_c |, | Δdl_a
If | is the minimum, the distance value dl to be used later is the value of dl_a in S204. If | Δdl_b | is the minimum, the distance value dl is the value of dl_b in S205.
If | Δdl_c | is the minimum, the distance measurement value d is determined in S206.
l is the value of dl_c.

Next, in step S207, a deviation Δdl between the reference distance D obtained when starting the contour running and the distance measurement value dl obtained in steps S203 to S206 is obtained.
8, the absolute value | Δ of the deviation Δdl obtained in S207
It is determined whether or not dl | is greater than a predetermined set value d3 set for determining whether or not to change reference distance D.

When the absolute value | Δdl | of the deviation is smaller than the set value d3, the reference distance D is not changed, and S209
Then, the deviation Δdl is compared with a set value d4 (> 0) for switching the driving control of traveling. If Δdl is smaller than −d4, the drive system is controlled so that the autonomous vehicle body curves to the left in S210. If Δdl is between −d4 and d4, the drive system is controlled so that the autonomous vehicle body goes straight in S211. Is controlled, and if Δdl is greater than d4, S212
The drive system is controlled so that the main body of the autonomous vehicle curves right.

The absolute value | Δdl | of the deviation is equal to the set value d.
If it is larger than 3, the reference distance D is dl in S213.
And the drive system is controlled such that the autonomous traveling vehicle body goes straight in S214.

Further, after these processes, in S215, the distance measurement values of the ultrasonic distance sensors 2_a to 2_c are stored as dl_a_old to dl_c_old in a predetermined distance value memory.

The series of operations described with reference to FIG. 4 are performed at predetermined time intervals while the autonomous vehicle is following the vehicle.

Next, with reference to FIGS. 5 and 6, a description will be given of traveling by the above-described contour traveling control when the autonomous traveling vehicle travels in parallel with the left wall having the concave portion. 5 and 6, the length in the horizontal direction is emphasized in order to make it easy to understand the locus of the change in the distance measurement value.

FIG. 5 shows the ultrasonic ranging sensors 2_a to 2_ when the autonomous vehicle travels straight ahead at a reference distance from the wall surface.
FIG. 4 is a diagram for explaining the shape of a wall detected by each of the ultrasonic ranging sensors 2_a to 2_c when the left wall is measured at equal intervals using c (see FIG. 3).

As shown in FIG. 5, the autonomous vehicle
When traveling straight ahead, the ultrasonic ranging sensors 2_a to 2_
The distance to the left wall is accurately measured by each of c.
When an autonomous vehicle is traveling straight through Area 2,
The sudden change in distance due to the depression in the left wall is not immediately detected. In area 2,
With the straight traveling of the autonomous vehicle, the distance measurement value of the ultrasonic ranging sensor 2_a to the left wall starts to gradually change to the distance to the concave surface of the left wall, and in the area 2, the ultrasonic ranging sensor 2_b ,
2_c keeps measuring the distance to the left wall of the area 1, and these measured values remain the distance to the left wall of the area 1.

When the autonomous vehicle is traveling straight through the area 3, the ultrasonic distance measuring sensor 2_a
The distance measured value approaches the distance to the concave surface of the left wall,
The distance measurement value of the ultrasonic ranging sensor 2_b to the left wall begins to gradually change to the distance to the concave surface of the left wall, and the ultrasonic ranging sensor 2_c measures the distance to the left wall of the area 1. to continue.

When the autonomous vehicle is traveling straight through the area 4, the ultrasonic ranging sensor 2_a correctly measures the distance to the concave surface of the left wall, and the ultrasonic distance measurement sensor 2_a measures the ultrasonic distance as the autonomous vehicle travels straight. The distance measurement value of the distance sensor 2_b approaches the distance to the concave surface of the left wall, and the distance measurement value of the ultrasonic distance sensor 2_c to the left wall gradually increases to the distance to the concave surface of the left wall. And begin to change.

In the area 5, the ultrasonic ranging sensor 2_a,
2_b correctly measures the distance to the concave surface of the left wall, and the distance measured by the ultrasonic distance measuring sensor 2_c approaches the distance to the concave surface of the left wall as the vehicle travels straight. Further, in the area 6, each of the ultrasonic ranging sensors 2_a to 2_c correctly measures the distance to the concave surface of the left wall.

As described above, according to FIG. 5, from the ultrasonic distance measuring sensor 2_a provided in front of the autonomous vehicle to the ultrasonic distance measuring sensor 2_b and ultrasonic distance measuring sensor 2_c in the rear, in order. It can be seen that the recognition of the concave portion of the wall is shifted.

Further, the autonomous traveling vehicle in the case where the contour traveling control shown in FIG. 4 is performed while detecting the concave portion of the left wall by such an ultrasonic distance measuring sensor with reference to FIG. Will be described.

FIG. 6 is a diagram for explaining the following traveling of the autonomous traveling vehicle on a wall surface having a concave portion.

When the autonomous vehicle starts to follow the vehicle, the ultrasonic distance measuring sensor 2_b detects the reference distance D1 to the left wall.
Is required. As shown in FIG. 6, in area 1,
Immediately after the start of the contour running, the ultrasonic ranging sensors 2_a to 2_c measure almost the same distance, and the three ultrasonic ranging sensors 2_a
To 2_c based on the distance measurement value of the ultrasonic distance measurement sensor having the smallest change amount (dl = dl_ in S204 of FIG. 4).
a, dl = dl_b in S205, or d in S206
l = dl_c), and the copying traveling control is performed.

When the autonomous traveling vehicle enters the area 2, the ultrasonic ranging sensor 2_a is affected by the depression of the left wall, and the variation of the ranging value accompanying the traveling increases, and the deviation from the previous ranging value. Δdl
Although _a increases, the ultrasonic ranging sensors 2_b and 2_c continue to measure the distance of the left wall in the area 1. In the area 2, based on the distance measurement value dl_b or dl_c of the ultrasonic ranging sensor corresponding to the smaller variation Δdl_b or Δdl_c of the variation Δdl_b or Δdl_c of the variation due to the ultrasonic ranging sensors 2_b and 2_c. Then, the copying traveling control is performed.

In the area 3, the ultrasonic ranging sensor 2_a,
2_b is affected by the depression of the left wall, and the change of the distance measurement value accompanying the traveling increases, and the deviation Δdl_ from the previous distance measurement value.
a, Δdl_b increases, but the ultrasonic ranging sensor 2_c
Keeps measuring the left wall in area 1. Therefore, in the area 3, the ultrasonic ranging sensor 2 corresponding to the deviation Δdl_c
_C based on the distance measurement value dl_c (S205 in FIG. 4).
Is set to dl = dl_c), and the copying traveling control is performed.

When the autonomous traveling vehicle enters the area 4, the ultrasonic ranging sensors 2_b and 2_c are both affected by the left wall, and the variation of the ranging value accompanying the traveling increases, and the ultrasonic ranging sensors 2_b and 2_c increase the distance measurement value. Deviations Δdl_b and Δdl_c of the area 4
In this case, there is almost no change in the distance measurement value of the ultrasonic distance measurement sensor 2_a, and the deviation Δdl_a from the previous distance measurement value is the deviation Δdl_
b, Δdl_c. Therefore, when the autonomous traveling vehicle enters the area 4, the scanning traveling control is performed based on the distance measurement value dl_a of the ultrasonic distance measurement sensor 2_a corresponding to the deviation Δdl_a. This control is performed in step S204 of FIG.
Is set to dl = dl_a, the difference Δdl from the reference distance D1 is obtained in S207, and compared with the set value d3 in S208, and the distance measurement value dl (dl_a is larger than the set value d3) in S208. Is set to the reference distance D2, and S2
14 corresponds to the execution of straight-ahead control.

In the area 5, the ultrasonic ranging sensor 2_c is affected by the dent of the left wall and has a deviation Δdl from the previous ranging value.
Although _c is large, the ultrasonic ranging sensors 2_a and 2_b measure the dent of the left wall almost accurately. The autonomous traveling vehicle has a distance measurement value dl_ of the ultrasonic distance measuring sensor corresponding to the deviation that causes a smaller change amount among the ultrasonic distance measuring sensors 2_a and 2_b.
Based on a or dl_b, follow-up running control is performed.

Further, when the autonomous traveling vehicle enters the area 6, the ultrasonic ranging sensors 2_a to 2_c each measure the distance to the concave surface of the left wall (the ranging values are all D2) and travel. , The change of the distance measurement value decreases, and the deviations Δdl_a to Δdl_c from the previous distance measurement value are all small. In area 6, these deviations Δdl_a to Δdl_
Based on the distance measurement value dl_a, dl_b or dl_c of the ultrasonic distance measurement sensor corresponding to the minimum deviation of c, the scanning traveling control is performed.

FIGS. 7 to 10 show examples of numerical data of the distance measured by the ultrasonic distance measuring sensor.

FIG. 7 to FIG. 10 show that when the autonomous vehicle travels while following the distances to the walls of 0.5 m, 1 m, 1.5 m, and 2 m, respectively, 3 cm for the recess of 25 cm in depth.
It is a figure which shows the data of the ranging value in an ultrasonic ranging sensor.

Here, the traveling distance of the autonomous traveling vehicle is 90 cm.
Area 1 indicates a traveling area of the autonomous vehicle in which all the ultrasonic ranging sensors measure the wall in front of the dent, and area 2 indicates that the value of the ultrasonic ranging sensor 2_a starts to change. The sensors 2_b and 2_c indicate the traveling area of the autonomous vehicle in which the wall in front of the dent is measured, and the area 3 is where the value of the ultrasonic ranging sensor 2_b starts to change.
c indicates the traveling area of the autonomous vehicle that measures the wall surface just before the dent, and area 4 of the autonomous vehicle that measures the dent surface when the value of the ultrasonic ranging sensor 2_c starts to change. Area 5 indicates the traveling area of the autonomous vehicle in which the ultrasonic ranging sensors 2_a and 2_b measure the distance to the concave surface, and area 6 indicates the traveling area of all three ultrasonic ranging sensors to the concave surface. 3 shows a traveling area of the autonomous traveling vehicle for measuring the distance of the vehicle.

With reference to FIGS. 7 to 10, the distance measurement values of each ultrasonic distance measurement sensor with respect to the change in the distance to the wall are as follows. When the distance to the wall is 0.5 m (see FIG. 7):
Area 1 is 15 cm, area 2 is 10 cm, area 3 is 5 cm, area 4 is 5 cm, area 5 is 5 cm, and area 6 is 50 cm. When the distance to the wall is 1 m (Fig. 8
Reference): Area 1 is 15cm, Area 2 is 10cm, Area 3 is 10cm, Area 4 is 5cm, Area 5 is 10
cm and area 6 is 40 cm. The distance to the wall is 1.
At 5 m (see FIG. 9): area 1 is 15 cm, area 2 is 10 cm, area 3 is 10 cm, area 4 is 10 c
m, area 5 is 15 cm, and area 6 is 30 cm.
When the distance to the wall is 2.0 m (see FIG. 10): area 1 is 15 cm, area 2 is 15 cm, and area 3 is 10 c
m, area 4 is 15 cm, area 5 is 25 cm, and area 6 is 10 cm. From these results, as the distance between the autonomous vehicle and the wall increases, the directivity of each ultrasonic ranging sensor expands, making it more susceptible to the concave surface,
It can be seen that the range of areas 2 to 5 is widened.

As described above, the autonomous traveling vehicle is provided with a plurality of ultrasonic distance measuring sensors, and the distance measurement value changes due to the influence of the recessed portion of the wall accompanying the traveling, thereby causing a deviation. By performing control based on the change in the value, even if using an ultrasonic ranging sensor having a wide range of directional angles, the shape of the concave portion of the side wall in the traveling direction is not erroneously detected, It is possible to control the autonomous traveling vehicle body to move straight ahead regardless of the presence of the recess on the side wall. As a result, even when the autonomous vehicle performs an operation such as waxing, a gap is not formed after the wax is applied.

Next, an autonomous vehicle according to a second embodiment of the present invention will be described. FIG. 11 is a diagram for explaining an autonomous vehicle according to the second embodiment of the present invention. First
While the autonomous vehicle of the embodiment has three ultrasonic ranging sensors on each side, the autonomous traveling vehicle has two ultrasonic ranging sensors on the side.

The autonomous vehicle includes four ultrasonic ranging sensors 4_a to 4_d.
_B measures the distance to the wall to the left in the traveling direction (direction of arrow A), and the ultrasonic ranging sensors 4_c and 4_d measure the distance to the wall to the right in the traveling direction. . The directional angle characteristics of the ultrasonic ranging sensors 4_a to 4_d and the measurement of the distance to the wall are the same as those of the autonomous vehicle of the first embodiment.

In the autonomous vehicle shown in FIG. 11, the respective ultrasonic distance measuring sensors have their angles relative to the wall parallel to the traveling direction so that the transmitted ultrasonic waves have different directivity angles. It is installed differently, but if it can be installed with a sufficient distance between the two ultrasonic ranging sensors, the angle to the wall parallel to the direction of travel will be the same It can also be installed as follows.

In the present autonomous vehicle, the ultrasonic ranging sensors 4_a and 4_b or the ultrasonic ranging sensors 4
_C, 4_d, the distance to the wall surface is repeatedly measured by any two ultrasonic ranging sensors. For each of the two ultrasonic ranging sensors for the wall surface, the ranging value obtained at the measurement at a certain point in time and the previous measurement obtained at the previous measurement at a point in time a predetermined time before this point. The difference from the distance value is calculated, and the tracing control with the wall surface is performed using the distance measurement value at a certain point in time corresponding to the smaller of the two differences. More specifically, the contour running control is performed according to a flowchart shown in FIG.

FIG. 12 is a flow chart for explaining the following control of the autonomous vehicle according to the second embodiment. Here, it is assumed that the distance measurement is performed on the wall on the left side with respect to the traveling direction, and the distance to the left wall is measured as the reference distance D by the ultrasonic distance measurement sensor 4_a when starting the follow-up traveling. Have been.

In the copying traveling control of the autonomous traveling vehicle, first,
In S251, the distances dl_a and dl_b to the left wall are measured using the ultrasonic ranging sensors 4_a and 4_b, respectively. Subsequently, in S252, the distances dl_a, dl_b
And the previous distance values dl_a_old and dl_b_ol measured in S251 immediately before the routine and stored in S264.
The deviations Δdl_a and Δdl_b from d are obtained, respectively. In S253, the absolute value of the deviation | Δdl_a |, | Δ
dl_b | are compared. Absolute value of these deviations | Δd
If l_a | is smaller than | Δdl_b |, the distance value dl used later in S254 is the value of dl_a. If the absolute value | Δdl_b | of the deviation is smaller than | Δdl_a |, the distance value dl is increased in S255. dl_b.

Next, at S256, a deviation Δdl between the reference distance D obtained at the start of the contour running and the distance measurement value dl obtained at S253 to S255 is obtained.
7, the absolute value | Δ of the deviation Δdl obtained in S256
It is determined whether or not dl | is greater than a predetermined set value d5 set to determine whether to change reference distance D.

When the absolute value of the deviation | Δdl | is smaller than the set value d5, the reference distance D is not changed, and S258
Then, the deviation Δdl is compared with a set value d6 (> 0) for switching the driving control of traveling. If Δdl is smaller than −d6, the drive system is controlled so that the autonomous vehicle body curves to the left in S259. If Δdl is between −d6 and d6, the drive system is controlled so that the autonomous vehicle body goes straight in S260. Is controlled, and if Δdl is greater than d6, S261
The drive system is controlled so that the main body of the autonomous vehicle curves right.

The absolute value | Δdl | of the deviation is equal to the set value d.
If it is larger than 5, the reference distance D is dl in S262.
And the drive system is controlled so that the autonomous vehicle body goes straight in S263.

Further, after these processes, in S264, the distance measurement values of the ultrasonic distance measurement sensors 2a and 2b are stored in a predetermined distance value memory as dl_a_old and dl_b_old.

A series of operations described with reference to FIG. 12 are performed at predetermined time intervals while the autonomous vehicle is following.

In the autonomous traveling vehicle according to the second embodiment in which the control based on the distance measurement values of the two ultrasonic distance measurement sensors to the side as described above is performed, the wall located on the side with respect to the traveling direction If the width of the dent is sufficiently large, it has a wide range of directional angles as in the autonomous vehicle of the first embodiment in which control based on the distance measurement values of the three ultrasonic distance measurement sensors is performed in the lateral direction. Even if the ultrasonic ranging sensor is used, the shape of the concave portion on the side wall in the traveling direction is not erroneously detected, and the autonomous vehicle travels straight regardless of the presence of the concave portion on the side wall. Can be controlled as follows. Further, according to the autonomous traveling vehicle of the second embodiment, the production cost can be reduced as compared with the autonomous traveling vehicle of the first embodiment having three ultrasonic distance measuring sensors on each side.

Further, at the time of starting the follow-up traveling, the distance to the side wall is measured by using a plurality of lateral ultrasonic distance measuring sensors, and the autonomous traveling is measured from the values of these ultrasonic distance measuring sensors. A posture angle (inclination) of the vehicle body with respect to the wall is obtained, and drive control is performed such that the values of the plurality of ultrasonic ranging sensors are within a predetermined range so that the autonomous traveling vehicle body is parallel to the wall.
When the main body of the autonomous traveling vehicle is parallel to the wall, the traveling control is performed at predetermined time intervals thereafter using the distance measurement value of one of the plurality of ultrasonic distance measuring sensors as a reference distance. Can be performed.

In the above-described embodiment, a plurality of ultrasonic ranging sensors are provided in the autonomous traveling vehicle, and each ultrasonic ranging sensor transmits and receives ultrasonic waves, so that a lateral wall is detected. However, by providing one ultrasonic transmitting device and a plurality of ultrasonic receiving devices with a wide directivity angle to the side, the same effect as described above can be obtained. In addition, the drive control can be performed more quickly, and the production cost can be further reduced.

[Brief description of the drawings]

FIG. 1 is a first diagram illustrating an autonomous vehicle according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining the radiation intensity of ultrasonic waves from an ultrasonic ranging sensor mounted on the autonomous vehicle.

FIG. 3 is a second diagram for explaining the autonomous vehicle according to the first embodiment of the present invention.

FIG. 4 is a flowchart for explaining contouring control of the autonomous vehicle according to the first embodiment;

FIG. 5 is a graph showing an example of a case where the autonomous vehicle travels straight at a reference distance from a wall surface and measures the distance to the left wall at equal intervals using the ultrasonic ranging sensors 2_a to 2_c (see FIG. 3); It is a figure for explaining the shape of the wall which each of acoustic wave ranging sensors 2_a-2_c detects.

FIG. 6 is a diagram for explaining copying along a wall surface having a recess of the autonomous traveling vehicle.

FIG. 7 is a graph showing the relationship between the depth of a 25 cm depth dent and the distance between the autonomous vehicle and a wall when the distance to a wall is 0.5 m.
It is a figure which shows the data of the ranging value in an ultrasonic ranging sensor.

FIG. 8 is a diagram showing data of distance measurement values of three ultrasonic ranging sensors with respect to a dent having a depth of 25 cm when the autonomous traveling vehicle travels while following a distance to a wall of 1 m.

FIG. 9 is a graph showing the relationship between the autonomous traveling vehicle and a dent having a depth of 25 cm when the autonomous traveling vehicle travels while following a distance of 1.5 m to a wall.
It is a figure which shows the data of the ranging value in an ultrasonic ranging sensor.

FIG. 10 is a diagram showing data of distance measurement values of three ultrasonic ranging sensors with respect to a dent having a depth of 25 cm when the autonomous vehicle travels while following a distance of 2 m to a wall.

FIG. 11 is a diagram for explaining an autonomous vehicle according to a second embodiment of the present invention.

FIG. 12 is a flowchart for explaining contouring control in an autonomous vehicle according to the second embodiment.

FIG. 13 is a diagram showing a conventional autonomous vehicle having one ultrasonic distance measuring sensor on each side.

FIG. 14 is a diagram illustrating a directional angle of an ultrasonic ranging sensor.

FIG. 15 is a diagram for explaining a distance measurement value by an ultrasonic distance measurement sensor when facing an object.

And FIG. 16 is a flowchart for explaining the conventional copying control in an autonomous vehicle.

FIG. 17 shows an ultrasonic distance sensor 1_a when the left wall is measured at equal intervals using an ultrasonic distance sensor when the autonomous vehicle travels straight ahead at a reference distance from the wall surface (see FIG. 13). )
It is a figure for explaining the shape of the wall which detects.

FIG. 18 is a first diagram for explaining a contour traveling on a wall surface having a recess of a conventional autonomous traveling vehicle.

FIG. 19 is a second diagram for explaining the contour traveling on the wall surface having the recess of the conventional autonomous traveling vehicle.

[Explanation of symbols]

1_a, 1_b Conventional Ultrasonic Distance Sensor for Autonomous Vehicle 2_a to 2_f Ultrasonic Distance Sensor for Autonomous Vehicle in First Embodiment 3_a to 3_f Cylindrical Parts Provided Together with Ultrasonic Distance Sensors 2a to 2_f 4 — a to 4 — d Ultrasonic ranging sensor for autonomous vehicle according to second embodiment

Claims (4)

[Claims] 1. A method for measuring a distance from a wall surface to a lateral direction with respect to a traveling direction at a predetermined time interval, comprising a plurality of distance measuring means having a wide range of directional angles in a lateral direction, An autonomous vehicle that autonomously travels in parallel with the wall surface based on the distance to the wall surface measured by the distance measurement unit, and the autonomous traveling vehicle that runs at a first time by each of the plurality of distance measurement units. Calculating a difference between a first distance and a second distance between the first time and a wall surface measured at a second time separated by the time interval from the first time, each of the plurality of calculated distance measuring means; An autonomous traveling vehicle that runs autonomously in parallel to a wall surface using a second distance corresponding to a smallest one of a plurality of differences corresponding to (i). 2. The plurality of distance measuring means transmits an ultrasonic wave to a wall surface in directions different from each other, and measures a distance based on receiving a reflected wave of the ultrasonic wave from the wall surface. An autonomous vehicle according to claim 1. 3. An autonomous vehicle that autonomously travels in parallel to a wall based on measuring a distance from a wall to a side in a traveling direction at a predetermined time interval. A transmitting means for transmitting ultrasonic waves to a wall surface lateral to the direction, and for receiving ultrasonic waves transmitted by the transmitting means and reflected from the wall surface, with respect to the traveling direction A plurality of wave receiving means, provided on the side, based on the transmission of the ultrasonic wave by the wave transmitting means, and the reception of the reflected wave of the ultrasonic wave from the wall surface by each of the plurality of wave receiving means. A first distance to the wall surface measured at a first point in time;
Calculating means for calculating a difference between the first time point and a second distance measured from the wall surface at a second time point separated by the time interval; and a plurality of wave receiving means calculated by the calculating means. An autonomous vehicle including control means for controlling to run autonomously in parallel to a wall using a second distance corresponding to a smallest one of a plurality of differences corresponding to the respective autonomous vehicles. 4. A plurality of distances measured by each of the plurality of distance measuring means while autonomously traveling parallel to a wall using a second distance corresponding to the smallest of the plurality of differences. The autonomous vehicle according to claim 1, wherein an inclination with respect to the wall surface is detected based on a distance from the wall surface.