JP2006301716A - Autonomous traveling vehicle and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform a accurate traveling control, while facilitating setting of a detection object in an autonomous traveling vehicle which reads a reference direction and sets the reference direction of a gyro sensor, by detecting the detecting object fixed at a site. <P>SOLUTION: Detection objects (reflectors R1-R4) fixed to two or more positions specified as points on XY coordinates, arranged virtually in the site are detected by a laser scanner 44, and the direction α of own vehicle on the XY coordinates is calculated, based on the resulting information. This is performed at a start point 5 of a traveling route or the like, and the reference direction of the gyro sensor is set, based on the direction α of the own vehicle. The traveling along the traveling route 4 is controlled, based on the detection signal of the gyro sensor, and the setting number of reflectors is minimized. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an autonomous traveling vehicle that autonomously travels based on a detection signal of a direction sensor that detects a traveling direction with respect to a preset reference direction, and a control method thereof.

  Autonomous traveling control using a gyro sensor is used to cause a traveling vehicle to travel along a route with high accuracy. This gyro sensor detects a traveling direction with respect to a preset reference direction and outputs it to a control device. The control device that has received the detection signal of the gyro sensor calculates the deviation from the route, controls the drive wheels, and corrects the traveling direction, thereby allowing the traveling vehicle to travel along the route with high accuracy.

However, when the gyro sensor is used, the error included in the detected value of the gyro sensor increases with the passage of travel time due to the drift of the gyro sensor itself and the drift of the integrator included in the signal processing circuit. There is a problem. Thereby, the reference azimuth | direction recognized from the detection signal of a gyro sensor will shift | deviate from the reference azimuth | direction at the time of initial setting.
In order to solve such a problem, in the invention described in Patent Document 1, a detection object such as a magnetic tape, a light reflecting tape, or a light reflecting paint along a reference direction is laid on a part of a running surface such as a floor surface. By detecting this with a sensor, the reference orientation is read and the reference orientation of the gyro is set (Patent Document 1, paragraphs 0030, 0031, etc.).

In addition, there is a problem that it is difficult to place the traveling vehicle in the correct position and in the correct direction at the start point of the traveling route.
In order to solve such a problem, in the invention described in Patent Document 2, a tape-shaped signal transmitter such as a magnetic tape is installed along the reference direction at the start point of the travel route, and this is detected by a sensor. To read the reference direction and set the reference direction of the gyro at the start of running.
JP-A-9-167014 Japanese Patent Laid-Open No. 9-282036

However, the above-described conventional technology has the following problems.
In the inventions described in Patent Documents 1 and 2, since the detection target object indicating the reference orientation is installed on the traveling surface, the installation may be difficult.
That is, the installation of the detection object on the surface of a floor, a paved road, or the like may impair the landscape and order, and it may be difficult to obtain permission for installation.
When there is a carpet or other easy-to-removable rug on the floor, the magnetic tape can be easily installed under the rug, but a hard pavement surface such as asphalt or concrete, a hard floor such as board, stone, or tile. It is not easy to install the magnetic tape on the surface without exposing the surface.

  The present invention has been made in view of the above-described problems in the prior art, and is based on a direction sensor that detects a traveling direction with respect to a preset reference direction, travels by controlling traveling means, and is fixed on the site. In an autonomous vehicle that reads a reference azimuth by detecting an object and sets the reference azimuth of the azimuth sensor, it is an object to facilitate installation of the detection object and perform accurate traveling control.

The invention according to claim 1 for solving the above-described problems includes a traveling means, a direction sensor that detects a traveling direction of the traveling means with respect to a preset reference direction,
Control means for controlling the traveling means based on a detection signal of the direction sensor;
A scanner that scans the surroundings of the vehicle and detects a detection object;
Based on the information obtained by detecting the detection objects fixed at two or more positions specified as points on the coordinates virtually arranged on the site by the scanner, the vehicle on the coordinates Direction calculating means for calculating the direction;
An autonomous traveling vehicle comprising reference azimuth setting means for setting a reference azimuth of the azimuth sensor based on the direction of the own vehicle calculated by the direction calculation means.

The invention described in claim 2 is a control method for controlling the autonomous vehicle according to claim 1,
A first step of disposing the detection object at a position detectable by the scanner from within a predetermined traveling area;
A second step of arranging the autonomous traveling vehicle according to claim 1 in the traveling area;
A third step of detecting the detection object by the scanner;
A fourth step of calculating the direction of the vehicle by the direction calculating means;
A fifth step of setting a reference orientation of the orientation sensor by the reference orientation setting means;
And a sixth step of traveling on a predetermined travel route in the travel area based on the detection signal of the direction sensor by the control means.

  According to a third aspect of the present invention, the detection object is arranged so that an area that can be detected by the scanner mounted on the autonomous vehicle arranged in the traveling area and an area that cannot be detected are generated, and the detection is performed. The autonomous traveling vehicle according to claim 2, wherein the third step is executed in a possible area, and the sixth step is executed in the undetectable area or the detectable area and the undetectable area. This is a control method.

  The invention according to claim 4 is the method for controlling an autonomous traveling vehicle according to claim 2 or 3, wherein in the first step, the detection object is arranged outside the traveling area.

  The invention according to claim 5 is characterized in that, in the second step, the autonomous traveling vehicle is arranged in the detectable region. It is a control method.

  According to the present invention, the detection object is detected by scanning the surroundings of the own vehicle with the scanner mounted on the autonomous vehicle, and therefore the detection object may be arranged at any position around the autonomous vehicle. . It does not need to be arranged on the running surface, and can be arranged inside or outside the running area. Therefore, there is an effect that the degree of freedom of installation of the detection object is increased, and the installation of the detection object becomes easy.

Since the reference direction of the direction sensor is set using the detection information of the detection object by the scanner and the traveling control is performed based on the detection signal of the direction sensor, the detection information of the detection object by the scanner is directly driven without using the direction sensor. Compared to the case of using for control, there is an effect that accurate traveling can be performed even if the number of scans is reduced.
In addition, it may be better to stop traveling because of the accuracy of control based on detection and detection information at the time of scanning. The effect is that it can be performed smoothly and quickly.

As long as there is an area in the travel area where the required number of detection objects can be detected by the scanner, there is an effect that accurate traveling according to the number of detection objects can be performed even if the number of detection objects is small.
In fact, when the detection target is arranged so that a region that can be detected by the scanner and a region that cannot be detected are generated in the travel area, a necessary number of detection targets can be detected from all positions in the travel area. Therefore, the number of objects to be detected can be reduced, and the object can be easily installed.

Since the reference direction of the azimuth sensor is set using the detection information of the detection object by the scanner, the initial setting can be accurately performed, and the error of the azimuth sensor with the passage of travel time can be corrected. There is.
In particular, when an autonomous vehicle is placed at a position where a detection object can be detected by a scanner and the vehicle starts to travel, there is an effect that an arrangement direction error of the autonomous vehicle at the start of traveling can be corrected.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention. FIG. 1A is a plan view of the autonomous traveling vehicle of the present embodiment, and FIG. 1B is an upper side view of the autonomous traveling vehicle of the present embodiment. Fig. 1 (a) shows the general layout of the equipment configuration.

  As shown in FIG. 1 (a), a right wheel 12a and a left wheel 12b are arranged on a traveling vehicle 10 that is self-propelled in the direction of arrow A, and are rotated by a right drive motor 11a and a left drive motor 11b, respectively. The right drive motor 11a and the left drive motor 11b are driven by the right driver 15a and the left driver 15b. The control device 16 includes a gyro sensor 18, front obstacle sensors 17a, 17b and 17c, a positioning system including a laser scanner 44, a right driver 15a and a right driver 15a according to detection results of the right distance sensor 14a and the left distance sensor 14b. The left driver 15b is controlled.

  FIG. 2 shows the device configuration including the internal configuration of the control device 16. The control device 16 includes interfaces 19a to 19e, a main controller 20, and a counter 21. As shown in FIG. 1A, the front obstacle sensors 17a, 17b and 17c are provided at the front center and both sides of the traveling vehicle 10, and when an obstacle is detected, the detection signal is sent to the interface 19a. input.

  The gyro sensor 18 detects the traveling direction of the traveling vehicle 10 with respect to the reference direction and inputs an orientation detection signal to the interface 19b. The operation panel 23 inputs information input by the operator to the interface 19b.

As shown in FIG. 1B, the laser scanner 44 is attached to the uppermost portion of the traveling vehicle 10 so that other portions of the host vehicle do not interfere with scanning. The laser scanner 44 is an optical / rotary reading / scanning device having a rotating optical head that rotates a laser light projecting unit and a light receiving unit 360 ° by a rotating mechanism, and rotates around the traveling vehicle 10. The two-dimensional scanning is performed to detect the rotation angle at which the detection target is detected based on a specific position (for example, the traveling direction) and the distance to the detection target. The positioning system 40 includes a laser scanner 44. Based on the detection information of the detection target detected by the laser scanner 44, the position coordinate (X, Y) and direction (α) of the traveling vehicle 10 on the coordinates are determined. The system includes an arithmetic processing unit to calculate, communicates with the main controller 20 via the interface 19e, and outputs (X, Y, α) to the main controller 20 in response to a request from the main controller 20.
The detection target of the laser scanner 44 is a reflector. This reflector is an optical component (reflector) that reflects incident light in the incident direction. Information necessary for calculation in the positioning system 40 such as the coordinate information of the reflector is given from the main controller 20 to the positioning system 40 via the interface 19e.
As the positioning system 40 and the reflector as described above, several types of products can be generally used. For example, a NAV 200 positioning system manufactured by ZIC Corporation can be applied.

  The interface 19a receives signals output from the front obstacle sensors 17a to 17c, performs necessary processing such as amplification, and supplies the processed signals to the main controller 20. The interface 19 b receives signals from the gyro sensor 18 and the operation panel 23, amplifies the signal, and supplies the amplified signal to the main controller 20.

  In this embodiment, the traveling vehicle 10 is applied to an unmanned cleaning vehicle. The main controller 20 gives a control signal related to cleaning to the cleaning unit controller 33 via the interface 19d. The cleaning unit controller 33 controls a cleaning unit such as a cleaning brush (not shown) according to a control signal from the main controller 20.

  Next, autonomous traveling control of a traveling vehicle using the above system will be described. FIG. 3 shows a layout diagram of the traveling site. This is because the road 1 is divided into several blocks, a rectangular traveling route 4 is preset for each block, and if there is an obstacle, the traveling vehicle 10 travels along the traveling route 4 while avoiding it, This is an example in which the traveling vehicle 10 performs a cleaning operation during traveling. In the layout diagram of FIG. 3, layers composed of XY coordinates, travel route 4, reset position 6, and reflectors R1 to R4 set for travel control are displayed in an overlapping manner. For convenience of explanation, the travel area 2, the travel route start point 5, the travel route end point 7, and the reflector undetectable area 3 are shown.

First, appropriate XY coordinates are set on the layout of the travel site, and the fixed positions of the reflectors R1 to R4 are determined based on the XY coordinates. The fixed position coordinates of the four reflectors R1 to R4 are (X1, Y1) to (X4, Y4) as shown in FIG. One of (X1, Y1) to (X4, Y4) may be the origin O of the XY coordinates. The XY coordinates are determined so that they can be specified on site. The absolute value of each coordinate is the actual length from the origin O.
In this embodiment, as shown in FIG. 3, two reflectors are arranged on both outer sides of the road 1 at the end where the travel route start point 5 and the end point 7 of the travel area 2 corresponding to one block exist. Although it depends on the positioning system used, the position coordinates (X, Y) and direction (α) of the traveling vehicle 10 on the XY coordinates can be calculated if at least two reflectors can be detected.
For example, when the laser scanner 44 can detect the distance to the reflector, if two reflectors can be detected, its own position can be specified. If the laser scanner 44 can detect the angle between two reflectors as seen by the laser scanner 44, it can detect its position if it can detect the angle between two different pairs of reflectors (and therefore detect at least three reflectors). Can be identified. When the laser scanner 44 can detect the distance to the reflector and the angle between the two reflectors as viewed from the laser scanner 44, the position of the laser scanner 44 can be identified if the two reflectors can be detected. For the direction (α), for example, an object that reflects light from the laser scanner 44 to the laser scanner 44 when the laser scanner 44 scans the front direction of the traveling vehicle 10 is fixed to the traveling vehicle 10. Can be identified by detecting. Detection information exceeding the necessary minimum is also used for calculation, and the position coordinates (X, Y) and the direction (α) are specified accurately.
Therefore, the minimum system configuration is two reflectors. If the number of reflectors decreases, the area of the reflector non-detectable region 3 increases, but the reflector can be easily installed. The reflector undetectable area 3 is an area in which a necessary number of reflectors cannot be detected.

The travel route 4 is designed as a line on the XY coordinates.
A reset position 6 is set on the travel route 4 as necessary. In this embodiment, one reset position 6 is set. The reset position 6 may not be set, or may be set to two or more.
Thereafter, before starting the route travel, layer information including the XY coordinates, the travel route 4, the reset position 6, and the reflectors R1 to R4 is input to the main controller 20.

  Next, the reflectors R1 to R4 are arranged on the actual site so as to be arranged at the coordinates determined by the above layers. The reflector may be fixed to an existing object such as a curb, a handrail, a fence, or an outer wall of a building, or a support for fixing the reflector such as a pole or a tripod may be specially prepared. If it is installed at a low position such as a curbstone, there is a high possibility that an object that blocks the laser beam will be placed or passed through. If it is indoors, it is safe to fix it to a wall or pillar, but at that time, it is arranged at a height that can be detected as reliably as possible. The reflector may be disposed in the traveling area 2 as long as it can be detected by the laser scanner 44. Since the reflector can be removed after the necessary scanning is completed, the reflector may be removed before it interferes with the reflector after the scanning when it is arranged in the traveling area. This is effective when the reflector cannot be arranged outside the traveling area at the site. Since it can be arranged both inside and outside the traveling area, the degree of freedom of installation is high and the installation is easy. In the present embodiment, the reflectors R <b> 1 to R <b> 4 are arranged outside the traveling area 2.

  Next, the traveling vehicle 10 is arranged in the traveling area 2. The traveling vehicle 10 is arranged in a reflector detectable region (outside the reflector undetectable region 3) in the traveling area 2.

Hereinafter, an example in which the traveling vehicle 10 is arranged at the traveling route start point 5 and (X, Y) information is not used for traveling control will be described. First, the traveling vehicle 10 is arranged at the traveling route starting point 5.
(a1) Thereafter, the operator inputs a cleaning start command to the main controller 20 via the operation panel 23. The main controller 20 performs the following process (a2). As shown in FIG. 3, the coordinates of the rotation axis of the laser scanner 44 are set to the position coordinates (X, Y) of the traveling vehicle 10, and the rotation axis of the laser scanner 44 and the yaw axis of the traveling vehicle 10 are matched. It was.
(a2) The main controller 20 requests the position and direction (X, Y, α) of the host vehicle.
(a3) The positioning system 40 having received the request (X, Y, α) causes the laser scanner 44 to detect the reflectors R1 to R4.
(a4) When the required number of reflectors can be detected, the positioning system 40 calculates (X, Y, α) based on the information obtained by the detection and the layer information, and outputs it to the main controller 20.
(a5) Upon receiving (X, Y, α), the main controller 20 sets the reference orientation of the gyro sensor 18 based on the direction (α) of the host vehicle. This setting is performed as follows. In the case where the positioning system 40 can handle only the direction (α) of the host vehicle, (X, Y, α) may be (α) in the processes (a2) to (a5).
When there is a difference between the direction α received from the positioning system 40 and the direction along the travel route 4 at the travel route start point 5, the main controller 20 sets the right driver 15a and the left driver 15b so that the difference is zero. And the traveling vehicle 10 is turned around on the spot. By repeating the processes (a2) to (a4), the main controller 20 receives the direction α after the rotation drive from the positioning system 40 and continues until the difference becomes zero.
When the difference becomes zero, the main controller 20 maintains the current direction α, advances the traveling vehicle 10 to start the route travel, and associates the detection signal output from the gyro sensor 18 with the retained direction α.
As described above, the reference orientation of the gyro sensor 18 is set.

(a6) The main controller 20 controls the right driver 15a and the left driver 15b based on the detection signals of the gyro sensor 18, the right distance sensor 14a, and the left distance sensor 14b to travel on the travel route 4 until the travel route end point 7 is reached. Let it run. However, the main controller 20 makes detours necessary for obstacle avoidance based on the detection signals of the front obstacle sensors 17a, 17b, and 17c. When the traveling vehicle 10 reaches the reset position 6, the reference direction of the gyro sensor 18 is reset as follows.
The main controller 20 makes the request (a2) while stopping the vehicle 10 or moving straight, and causes the positioning system 40 to perform the processes (a3) and (a4) to obtain the direction α.
When there is a difference between the direction α received from the positioning system 40 and the direction of the straight route passing through the resetting position 6, the main controller 20 controls the right driver 15a and the left driver 15b so that the difference becomes zero. Then the direction of the traveling vehicle 10 is changed. By repeating the processes (a2) to (a4), the main controller 20 receives the direction α after the direction change drive from the positioning system 40 and continues until the difference becomes zero.
When the above difference becomes zero, the main controller 20 holds the current direction α, and advances the traveling vehicle 10 to associate the detection signal output from the gyro sensor 18 with the held direction α.
As described above, the reference orientation of the gyro sensor 18 is reset.

(a7) When the main controller 20 causes the traveling vehicle 10 to reach the traveling route end point 7, the cleaning of this block (traveling area 2) is terminated.
(a8) The traveling vehicle 10 is moved to the next block and the same processing is performed. For the movement of the traveling vehicle 10 to the next block, it is preferable to set the inter-block movement route as layer information and allow the traveling vehicle 10 to autonomously travel. The reset position 6 may also be set on the inter-block movement route.

According to the above traveling control, the reference direction of the gyro sensor 18 is set using the detection information of the reflector by the laser scanner 44, and the traveling control is performed based on the detection signal of the gyro sensor 18. Therefore, the gyro sensor 18 is used. Compared to the case where the information detected by the reflector by the laser scanner 44 is directly used for travel control, accurate travel can be performed even if the number of scans is reduced.
An error in the arrangement of the traveling vehicle 10 at the traveling route start point 5 and an error in the gyro sensor 18 that increases with the passage of time cause a deviation of the traveling locus from the traveling route 4, but it is possible to travel within an allowable error. it can.
However, by using the position information (X, Y) of the own vehicle obtained from the positioning system 40, it is possible to realize more accurate traveling and improved ease of arrangement of the traveling vehicle 10. The control example is shown below.

First, it is not necessary to arrange the traveling vehicle 10 accurately, and the traveling vehicle 10 is disposed at an arbitrary position within the reflector detectable region (outside the reflector undetectable region 3) in the traveling area 2.
Next, the above processing (a1) to (a4) is performed to output (X, Y, α) from the positioning system 40 to the main controller 20, and the following processing (b1) to (b3) is performed.

(b1) Upon receiving (X, Y, α), the main controller 20 compares (X, Y) received from the positioning system 40 with the layer information, and (X, Y) = (X5, Y5). Judge whether there is.
(b2) When not (X, Y) = (X5, Y5), the traveling vehicle 10 is moved by a distance of (X5-X) in the X-axis direction and (Y5-Y) in the Y-axis direction. That is, the main controller 20 controls the right driver 15a and the left driver 15b on the basis of the current position (X, Y) and direction (α), and the detection signals of the right distance sensor 14a and the left distance sensor 14b, and moves them. The above steps (a2) to (a4) and the determination of (b1) are performed again, and the movement is continued until (X, Y) = (X5, Y5). The reference direction of the gyro sensor 18 is set based on the direction (α) obtained during traveling for this movement, and thereafter, this movement is performed based on detection signals of the gyro sensor 18, the right distance sensor 14a, and the left distance sensor 14b. Preferably it is done.

(b3) When (X, Y) = (X5, Y5), the processes (a2) to (a6) are performed. However, even when the reference orientation of the gyro sensor 18 is reset in (a6), the return control to the travel route 4 can be performed using the position information (X, Y). For example, the return control is performed as follows (c).

(c) The processes (a2) to (a4) are performed, and the main controller 20 obtains (X, Y, α) and determines whether (X, Y) is on the travel route 4 or not. When (X, Y) is not on the travel route 4, the return route that joins from the own vehicle position (X, Y, α) to the travel route 4 (this is a route that converges α in the direction of the travel route 4). Is calculated from (X, Y, α) and the layer information, and travels along this return route. The processes (a2) to (a4) are performed again, the main controller 20 obtains (X, Y, α), and whether (X, Y) is on the travel route 4 and the direction (α) and the travel The difference from the direction of the route 4 is determined, and this movement is continued until (X, Y) is on the travel route 4. The reference direction of the gyro sensor 18 is set based on the direction (α) obtained during traveling for this movement, and thereafter, this movement is performed based on detection signals of the gyro sensor 18, the right distance sensor 14a, and the left distance sensor 14b. Preferably it is done.
If (X, Y) is on the route 4 and the difference between the direction (α) and the direction of the travel route 4 is not zero, the traveling vehicle 10 is stopped and the reference orientation of the gyro sensor 18 in the above (a6) is set. Perform reconfiguration.

  In the above embodiment, laser light is used as a detection medium. However, electromagnetic waves other than laser light and other natural phenomena may be used.

It is a top view (a) and an upper side view (b) of an autonomous vehicle according to an embodiment of the present invention. It is a block diagram of the equipment composition concerning the autonomous running vehicle of one embodiment of the present invention. It is a layout figure of the driving field in one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Road 2 Traveling area 3 Reflector undetectable area 4 Traveling route 5 Traveling route start point 6 Reset position 7 Traveling route end point 10 Traveling vehicle 11a Right drive motor 11b Left drive motor 12a Right wheel 12b Left wheel 14a Right distance sensor 14b Left distance sensor 15a Right driver 15b Left drivers 17a to 17c Front obstacle sensor 18 Gyro sensors 19a to 19e Interface 20 Main controller 21 Counter 23 Operation panel 33 Cleaning unit controller 40 Positioning system 44 Laser scanner R1 to R4 Reflector

Claims (5)

Traveling means;
An azimuth sensor for detecting a traveling azimuth of the traveling means with respect to a preset reference azimuth;
Control means for controlling the traveling means based on a detection signal of the direction sensor;
A scanner that scans the surroundings of the vehicle and detects a detection object;
Based on the information obtained by detecting the detection objects fixed at two or more positions specified as points on the coordinates virtually arranged on the site by the scanner, the vehicle on the coordinates Direction calculating means for calculating the direction;
An autonomous traveling vehicle comprising reference azimuth setting means for setting a reference azimuth of the azimuth sensor based on the direction of the own vehicle calculated by the direction calculation means. A control method for controlling an autonomous vehicle according to claim 1,
A first step of disposing the detection object at a position detectable by the scanner from within a predetermined traveling area;
A second step of arranging the autonomous traveling vehicle according to claim 1 in the traveling area;
A third step of detecting the detection object by the scanner;
A fourth step of calculating the direction of the vehicle by the direction calculating means;
A fifth step of setting a reference orientation of the orientation sensor by the reference orientation setting means;
And a sixth step of causing the control means to travel on a predetermined travel route in the travel area based on a detection signal of the direction sensor. The detection object is arranged such that an area that can be detected by the scanner mounted on the autonomous vehicle arranged in the traveling area and an area that cannot be detected are generated, and the third step is performed in the detectable area. 3. The autonomous vehicle control method according to claim 2, wherein the sixth step is executed in the undetectable region or the detectable region and the undetectable region. 4. The autonomous traveling vehicle control method according to claim 2, wherein, in the first step, the detection object is disposed outside the traveling area. 5. 5. The autonomous traveling vehicle control method according to claim 2, wherein the autonomous traveling vehicle is arranged in the detectable region in the second step.

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