JP2010262461A - Mobile object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile object and a mobile object system for much more precisely performing autonomous movement even when a slide is generated between the mobile object and a ground surface. <P>SOLUTION: This mobile object includes: a vehicle body 2; a traveling device 4 for making the vehicle body travel; an actuator 32 for driving the traveling device 4; an encoder 33 for detecting the driving amounts of the actuator 32; a speed sensor 34 for detecting a relative speed between the vehicle body 2 and a road surface on which the vehicle body 2 travels; and a controller 3 for controlling the operation of the actuator 32 so that the vehicle body may travel along a predetermined traveling path. In this case, the controller 3 includes a correction means 22 for correcting an operation command to the actuator 32 on the basis of the detection value of the encoder 33 and the detection value of the speed sensor 34. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a moving body that can move autonomously and be used for various purposes in factories, offices, hospitals, commercial facilities, and the like, and a moving body teaching method.

In production factories and the like, mobile bodies that can autonomously travel to transport products and components are used for labor saving. The mainstream of such moving bodies is a vehicle that autonomously moves by controlling its traveling so that it travels along a guide rail such as a reflective tape or a magnetic tape installed on the floor.
However, this method can reliably guide the moving body along the guide rail, but the work of installing the guide rail is complicated, and it is not easy to change the travel route, and the guide rail is damaged or dirty. There are also technical problems such that the guidance accuracy of the mobile object is easily reduced, or the degree of freedom of travel of the mobile object is limited.
Therefore, recently, a moving body that can autonomously travel without installing a guide rail or the like on the floor has been proposed and put into practical use.

  For example, Patent Document 1 includes a laser distance sensor (laser range finder) for performing a traveling operation of a moving body, measuring the number of rotations of the left and right drive wheels with an encoder, and calculating the accumulated movement distance from the count accumulated value of the encoder. In addition, it is disclosed that the information on the moving direction is grasped from the difference between the rotational speeds of the left and right drive wheels or a gyro sensor provided separately.

JP 2009-080804 A

  However, as described above, since the conventional moving body obtains the accumulated movement distance or the like from the measurement value of the encoder built in the motor or the like of the driving wheel, it slips between the driving wheel and the road surface (idle driving wheel). When this occurs, there is a problem that the detection value such as the accumulated movement distance and the actual position of the moving body are shifted, and the accuracy of the traveling position of the moving body is lowered.

  In order to solve such a problem, it is conceivable to add a visual sensor such as a camera to correct the decrease in accuracy of the traveling position based on the surrounding captured image. In this case, however, software for advanced image processing It is necessary to separately develop an image sensor, and the additional cost of the sensor is required, and there is a problem that control becomes impossible if an obstacle such as a person or an object enters between the camera and the teaching image.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a moving body that can perform autonomous movement more accurately even when slippage occurs with the ground. To do.

  In order to solve the above problems, the present invention (Claim 1) includes a vehicle body, a travel device that travels the vehicle body, an actuator that drives the travel device, an encoder that detects a drive amount of the actuator, and the vehicle body A speed sensor that detects a relative speed between the vehicle body and the road surface on which the vehicle body travels, and a controller that controls the operation of the actuator so as to follow a preset travel route. The movable body includes a correcting unit that corrects an operation command to the actuator based on a detection value and a detection value of the speed sensor.

A laser distance sensor attached to the vehicle body for detecting the distance and direction between the moving body and an object existing in the search range by scanning a detection laser in the search range; It is preferable that the operation command is calculated based on the map information thus obtained and the detection result of the laser sensor.
The speed sensor is preferably a laser Doppler velocimeter attached to the vehicle body toward the road surface.
Further, it is preferable that the traveling device has a pair of left and right drive wheels attached to the vehicle body, and the speed sensor is attached to each of the pair of drive wheels.

It is also preferable that the speed sensor is attached to the outside of each driving wheel.
It is also preferable that the speed sensor is attached to the inside of each drive wheel.

  The invention of the present application (Claim 7) is a land having a characteristic shape discretely arranged on a road surface on which the mobile body according to any one of Claims 2 to 6 and the vehicle body of the mobile body travel. And a mark.

According to the present invention (Claims 1 and 7), the operation command to the actuator is taken into account the slip (idle) generated between the traveling device and the road surface that can be calculated from the detected value of the encoder and the detected value of the speed sensor. Therefore, even if slippage occurs between the drive wheels and the ground, which cannot be detected only by the detection result of the encoder, errors due to slippage between the traveling device and the road surface can be reduced, and the moving body can be made more accurate. It can be autonomously run.
In addition, since the speed sensor directly measures the road surface, there is an advantage that it is difficult to receive disturbance such as external light.

According to the present invention (Claim 2), the difference between the actual traveling position and the pre-stored map information is corrected based on the pre-stored map information and the detection result of the laser sensor, and the mobile body is accurately detected. It can be autonomously run.
According to the present invention (Claim 3), the road speed during traveling can be directly measured in a non-contact manner, so that measurement errors can be reduced.

  Further, according to the present invention (Claim 4), since the operation command is corrected in consideration of the slip amount between the left and right drive wheels and the road surface, only one of the left and right drive wheels causes the slip. Even when the sliding amount of one drive wheel is larger than that of the other, it is possible to prevent the moving body from changing its posture (traveling direction) and to autonomously travel more accurately. it can.

Further, according to the present invention (Claim 5), the speed sensor detects the relative speed with the road surface at a position closer to the contact point between the driving wheel and the road surface, so that the relative speed can be detected with higher accuracy.
Further, according to the present invention (Claim 6), since the disturbance factor such as external light is shielded by the driving wheel and the vehicle body, the relative speed can be detected with higher accuracy.

Both schematically show the moving body according to the first embodiment of the present invention, wherein (a) is a plan view thereof and (b) is a side view thereof. It is a schematic diagram for demonstrating the whole structure of the mobile body system concerning 1st Example of this invention. (A)-(d) is a figure for demonstrating the operation | movement aspect of the moving body concerning 1st Example of this invention. Both schematically show a moving body according to a second embodiment of the present invention, wherein (a) is a plan view thereof and (b) is a side view thereof. Both schematically show a moving body according to a third embodiment of the present invention, wherein (a) is a plan view thereof and (b) is a side view thereof. Both schematically show a moving body according to a fourth embodiment of the present invention, wherein (a) is a plan view thereof and (b) is a side view thereof.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First embodiment]
(overall structure)
As shown in FIG. 2, in the mobile system 100 according to the present embodiment, a travel route R that patrols the floor 101 is set in advance on a floor 101 that is a road surface on which the mobile body 1 travels. The vehicle is configured to autonomously travel along the travel route R. A plurality of flat landmarks 102 having a light receiving plane are discretely installed in the vicinity of the travel route R. Note that the route of the travel route R can be changed as appropriate.
Here, the landmark 102 is arranged so as to be positioned in front of the traveling direction of the mobile body 1 on the travel route R, and the mobile body 1 travels toward the landmark 102 positioned in front. ing.
Although the travel route R is illustrated in FIG. 2 for ease of explanation, there is no line or the like indicating the travel route R on the actual floor 101 or the like.

(Configuration of mobile body)
As shown in FIGS. 1A and 1B, the moving body 1 includes a vehicle body 2 with a control device (controller) 3 including an electronic calculator, a storage device, and an input device.
The vehicle body 2 has a traveling device 4, and the traveling device 4 is arranged in parallel on the both sides of the vehicle body 2 with two drive wheels (a pair of drive wheels) 30 and 30 on both the left and right sides so as to be steerable in all directions. The driven wheels 31 and 31 and the actuators 32 and 32 (for example, servo motors) that individually drive the driving wheels 30 and 30 are respectively moved forward and backward by driving the driving wheels 30. The moving body 1 can be steered (changed direction) by the difference in rotational speed of the wheels 30.

Each actuator 32 is provided with an encoder 33 for detecting the drive amount of the actuator (here, the rotation amount of the drive wheel), and the detection result D of the encoder 33 is input to the control device 3. Yes.
A laser Doppler sensor (speed sensor) 34 is attached to the rear side of each drive wheel 30 and 30 toward the floor 101 (that is, downward).

  That is, the laser Doppler sensor 34 detects the relative speeds VdL and VdR between the vehicle body 1 and the floor 101 by irradiating the laser beam for measurement toward the floor 101 and detecting the reflected light from the floor 101, respectively. (VdL is a detection value of the left sensor 34, and VdR is a detection value of the right sensor 34). The speed sensor is preferably a laser Doppler sensor, but can be selected as appropriate. However, a non-contact type speed sensor that measures the speed without directly contacting the floor 101 or the traveling device is preferable.

  A laser distance sensor 35 is attached to the front side of the vehicle body 2. The laser distance sensor 35 is a laser distance sensor (distance direction detecting device) having a laser transmitting device such as a semiconductor laser, for example, and is at a predetermined angle within a predetermined search range in the horizontal direction (in the direction of the vehicle body 2) from the laser distance sensor 35. A laser beam (detection light) for detection is transmitted every time (for example, every 0.5 °), and the distance from the time until the detection light is reflected back to the object and returned to the object within the search range The angle of the measurement point is detected. That is, the effective search range of the laser distance sensor 35 (the range in which the detection of the distance and the angle is effective) has a fan shape parallel to the floor 101 surface (horizontal) with the search angle as the central angle. The distance data L measured by the laser distance sensor 35 is input to the control device 3.

The control device 3 includes a travel control unit 21 and a correction unit (correction unit) 22 as its functions. The control device 3 stores in advance obstacles (not shown) on the floor 101, the positions (coordinates) of the landmarks 102, and the travel route R as map information.
As will be described in detail below, the travel control unit 21 determines the end point position (FIG. 2) from the start position (point Ps in FIG. 2) input in advance based on the stored map information and the input information from the laser distance sensor 35. Then, a speed command (operation command) V ₀ is calculated so that the mobile body 1 travels along the travel route R up to the point Pe), and is transmitted to each actuator 32.

The correction unit 22 performs differential processing on the detection results D from the encoders 33 to calculate the speed calculation values (angular speeds) VeL and VeR of the drive wheels 30. Note that VeL corresponds to the left drive wheel 30 and VeR corresponds to the right drive wheel 30.
Then, the correction unit 22 determines the difference between the detection results VdL, VdR from the left and right laser Doppler sensors 34 and the calculated speed calculation values VeL, VeR, respectively, and the slip amount between the corresponding drive wheel 30 and the floor 101 ( Calculated as the idling amount).

That is, when the detection result from the laser Doppler sensor 34 is V [m / s], the angular velocity of the drive wheel 30 is ω [rad / s], and the radius of the drive wheel 30 is r [m], the unit time t [s] ] Is the following equation (1).
S [m] = (rω−V) t [m] (1)
Then, the correction unit 22 adds and corrects only the slip amount S calculated for each drive wheel 30 to the speed command V0 from the travel control unit 21, and transmits the corrected speed command to the actuator 32.

The mobile body system according to the first embodiment of the present invention is configured as described above, and the operation mode of the mobile body 1 will be described below.
Here, a case where the vehicle travels autonomously on the travel route R from the start point position Ps to the end point position Pe via the waypoint Pt in FIG. 2 will be described. In addition, the movement of the mobile body 1 is not limited to this example, and can be appropriately changed along with the setting of the travel route R.

As described above, the coordinates of the start point position Ps (JX1, JY1, Jθ1), the waypoint Pt (JX2, JY2, Jθ2), and the end point position Pe (JX3, JY3, Jθ3) are previously stored in the control device 3 as map information. Is remembered as As shown in FIGS. 3A to 3D, the coordinates of each point include a secondary plane component along the floor 101 surface and a rotation component at each position.
As shown in FIG. 3A, the control device 3 transmits a speed command V ₀ to the traveling device, and moves the moving body 1 from the starting point position Ps (JX1, JY1) to the coordinates (JX2, JY2) of the waypoint Pt. Let it run. The speed command V0 at this time is calculated based on the direction vector from the starting point position Ps (JX1, JY1, Jθ1) to the waypoint Pt (JX2, JY2, Jθ2) and the characteristics of the actuator 32.
When the moving body 1 starts traveling, the correction unit 22 calculates the slip amount S of each drive wheel 30 and corrects the speed command V0 for each calculation cycle of the control device 3.

As shown in FIG. 3B, the traveling control unit 21 stops the temporary traveling when it is determined from the detected value D and the slip amount S of the encoder that the moving body 1 has reached the waypoint Pt.
Then, in order to go to the end point position Pe, the vehicle turns at the waypoint Pt to the end point position Pe and starts running again.

Next, an operation when the landmark 102 is detected will be described. As shown in FIG. 3C, a landmark 102 is provided on the side of the travel route R in the section from the transit point Pt to the end point position Pe.
When the moving body 1 starts traveling from the waypoint Pt toward the end point Pe, the landmark 102 is included in the search range E of the laser distance sensor 35, and the landmark 102 is detected by the laser distance sensor 35. Input to the control device 3.
When the detected position and orientation (direction) of the landmark 102 are different from the position and orientation (RX1, RY1, Rθ1) in the map information stored in advance, the traveling control unit 21 detects the detected landmark 102. The map information stored is corrected by assuming that the position of is correct. By doing so, the error between the actual course of the moving body 1 and the travel route R is corrected.

  Similarly, when the traveling control unit 21 moving body 1 approaches the end point position Pe, the landmark 102 arranged in the vicinity of the end point position Pe is detected by the laser distance sensor 35 as shown in FIG. Thus, the travel control unit 21 corrects the map information based on the detected position of the landmark 102 and then travels the mobile body 1 to the coordinates of the waypoint Pt in the latest map information. To stop.

As described above, according to the mobile system according to the present embodiment, the control device 3 uses the detection results of the two laser Doppler sensors 34 attached to the left and right of the vehicle body 2 to connect the driving wheels 30 to the floor 101. The slip amount S is calculated, and this slip amount S is added and corrected to the speed command to each actuator 32, so that errors due to slip between the drive wheels 30 and the floor 101 that cannot be detected only by the detection result of the encoder 33 are reduced. Thus, the moving body 1 can travel more accurately and accurately with respect to the travel route R.
Further, since the correction unit 22 measures and corrects the slip amount S for each of the left and right drive wheels 30, when only one of the left and right drive wheels 30 slips (or the slip amount of one drive wheel). It is possible to autonomously travel more accurately along the travel route R by successively correcting that the direction (traveling direction) of the moving body 1 changes when the distance is larger / smaller than the other.
[Second Embodiment]

Next, a second embodiment of the present invention will be described. This embodiment is configured in the same manner as the above-described first embodiment except for the mounting position of the laser Doppler sensor, and the same points as in the first embodiment are omitted and the same reference numerals are used. explain.
As shown in FIGS. 4A and 4B, in this embodiment, one laser Doppler sensor 34 is attached to the front side surface of the vehicle body 2 and oriented toward the floor 101.
The detection result Vd of the laser Doppler sensor 34 is input to the control device 3, and the control device 3 performs the traveling control similarly with the relative speeds VdL and VdR in the first embodiment set to Vd.
Since the mobile system according to the second embodiment of the present invention is configured as described above, the slip amount S between the left and right drive wheels 30 and the floor 101 is calculated, and the slip amount S is applied to each actuator 32 as a speed. Since the correction is added to the command, the moving body 1 can autonomously travel with higher accuracy.
Further, since only one laser Doppler sensor 34 is used, there is an advantage that it can be configured at a lower cost than that of the first embodiment.
[Third embodiment]

Next, a third embodiment of the present invention will be described. This embodiment is configured in the same manner as the above-described first embodiment except for the mounting position of the laser Doppler sensor, and the same points as in the first embodiment are omitted and the same reference numerals are used. explain.
As shown in FIG. 5, a laser Doppler sensor 34 is attached to the outside of each drive wheel 30, 30 in the moving body 1 according to the present embodiment.
By configuring as in the present embodiment, the laser Doppler sensor 34 can detect the relative speed with the floor 101 at a position closer to the grounding point between each drive wheel 30 and 30 and the road surface, and therefore slips with higher accuracy. The quantity S can be detected.
[Fourth embodiment]

Next, a fourth embodiment of the present invention will be described. This embodiment is configured in the same manner as the above-described first embodiment except for the mounting position of the laser Doppler sensor, and the same points as in the first embodiment are omitted and the same reference numerals are used. explain.
As shown in FIG. 6, a laser Doppler sensor 34 is attached to the inside of each drive wheel 30, 30 in the moving body 1 according to the present embodiment.
By configuring as in the present embodiment, the laser Doppler sensor 34 can detect the relative speed with the floor 101 at a position closer to the contact point between each drive wheel 30, 30 and the road surface. In addition, since the external light and the like are shielded by the driving wheels 30 and the vehicle body 2 and the disturbance factor is reduced, the slip amount S can be detected with higher accuracy.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, a laser Doppler sensor is used as the speed sensor. However, the speed sensor is not limited to this, and various types of speed sensors may be used as long as the speed sensor does not depend on the encoder value. it can.
Moreover, the mobile body system according to the present invention can be appropriately applied by being modified to a use for moving the mobile body autonomously, such as an article conveying use or a service robot.

DESCRIPTION OF SYMBOLS 1 Mobile body 2 Car body 3 Control apparatus (controller)
4 travel device 21 travel control unit 22 correction unit (correction means)
30 Drive Wheel 31 Driven Wheel 32 Actuator 33 Encoder 34 Laser Doppler Sensor (Speed Sensor)
35 Laser distance sensor 100 Mobile system 101 Floor (road surface)
102 landmark

Claims (7)

The car body,
A traveling device for traveling the vehicle body;
An actuator for driving the traveling device;
An encoder for detecting the drive amount of the actuator;
A speed sensor for detecting a relative speed between the vehicle body and a road surface on which the vehicle body travels;
A controller for controlling the operation of the actuator so as to follow a preset travel route,
The moving body according to claim 1, wherein the controller includes correction means for correcting an operation command to the actuator based on a detection value of the encoder and a detection value of the speed sensor. A laser distance sensor that is attached to the vehicle body and that detects a distance and direction between a moving object and an object existing in the search range by scanning a detection laser in the search range;
The moving body according to claim 1, wherein the controller calculates the operation command based on map information stored in advance and a detection result of the laser sensor. The moving body according to claim 1, wherein the speed sensor is a laser Doppler speedometer attached to the vehicle body toward the road surface. The traveling device has a pair of left and right drive wheels attached to the vehicle body,
The moving body according to any one of claims 1 to 3, wherein the speed sensor is attached to each of the pair of driving wheels. The moving body according to claim 4, wherein the speed sensor is attached to the outside of each driving wheel. The moving body according to claim 4, wherein the speed sensor is attached inside each of the driving wheels. The moving body according to any one of claims 2 to 6,
And a landmark having a characteristic shape discretely arranged on a road surface on which the vehicle body of the movable body travels.

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