Automatic guided vehicle and method for drive control of the same

• US 9,176,502 B2
• Filed: 09/01/2011
• Issued: 11/03/2015
• Est. Priority Date: 09/03/2010
• Status: Active Grant

• Current Assignee: Hitachi Industrial Products, Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Furuno, Hideaki, Tomioka, Yoshiharu, Yoshida, Yutaka
• Primary Examiner(s): Nguyen, John Q
• Assistant Examiner(s): SMITH, AARON C
• Application Number:
  US13/223,544
• Publication Number:
  US 20120059545A1
• Time in Patent Office: 1,524 Days
• Field of Search: 701/23, 701/24, 701/300, 701/301, 701/408, 701/533, 700/259
• US Class Current: 1/1
• CPC Class Codes: G05D 1/0225 involving docking at a fixed facility, e.g. base station or loading bay parking aids B62D15/027
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0244 using reflecting strips
• CPC Class Codes: G05D 1/0282 generated in a local control room
• CPC Class Codes: G05D 2201/0216 Vehicle for transporting goods in a warehouse, factory or similar

Abstract

An automatic guided vehicle and a method for drive control enable setting the vehicle alongside a conveyor with high accuracy in stopping at a task address. An automatic guided vehicle includes photoelectric sensors which detect the presence of an article by projecting light to a reflecting plate arranged on a conveyor and receiving signal light reflected from the reflecting plate and are arranged in one at each of the front and rear portions of the automatic guided vehicle, and a unit for detecting the distance between the vehicle and the conveyor. When both the photoelectric sensors arranged at the front and read portions of the side surface of the vehicle, a steering vehicle is steered toward the conveyor, and the automatic guided vehicle is driven toward the conveyor until the distance between the vehicle and the conveyor becomes within a predetermined distance.

Claims

1. An automatic guided vehicle that approaches an object by performing route data driving when the vehicle is distant from the object, the route data driving being driving on a preset route based on preset route data, and then switches to sensor driving, the sensor driving being based on a sensor thereof, the vehicle comprising:

a control section that includes a creep drive control section to perform creep driving, which is route data driving at a creep velocity, and a sensor drive control section to perform the sensor driving,

wherein the creep drive control section;

decelerates the automatic guided vehicle to the creep velocity when the vehicle approaches a predetermined target address of creep drive control,

determines whether points of a pair of predetermined points on the vehicle have approached predetermined start points of sensor drive control or not, and

switches the route data driving over to the sensor driving by using the sensor drive control section when the creep drive control section determines that the pair of predetermined points on the vehicle have matched the pair of predetermined start points of sensor drive control, and

wherein the sensor drive control section;

makes the automatic guided vehicle further approach the object by using a photoelectric sensor pair after switching the route data driving over to the sensor driving, and

makes the automatic guided vehicle further approach the object by using a distance measure sensor pair after determining a light from the object by the photoelectric sensor pair.

2. The automatic guided vehicle according to claim 1, comprising:

a laser distance sensor for measuring distances to surroundings by scanning with laser light, wherein the control section performs the route data driving with the laser distance sensor,

wherein the photoelectric sensor pair includes;

a photo-detection sensor that projects a signal light to a reflecting plate arranged on the object, receives a reflected light from the reflecting plate, and thereby detects a presence of the object; and

wherein the distance measure sensor pair includes;

a distance measuring sensor capable of measuring a distance to the object,

and wherein the control section performs the sensor driving with the photo-detection sensor and the distance measuring sensor.

3. The automatic guided vehicle according to claim 2,

wherein distance measuring sensors are arranged at each of a front portion and a rear portion of a side surface of the automatic guided vehicle,

and wherein when the distance to the object measured by one of the distance measuring sensors is within a predetermined distance and the distance to the object measured by the other one of the distance measuring sensors is out of the predetermined distance, the control section controls the automatic guided vehicle such that the distance measuring sensor whose distance to the object is out of the predetermined distance approaches the object.

4. The automatic guided vehicle according to claim 1, comprising:

a laser distance sensor for measuring distances to surroundings by scanning with laser light,

wherein the control section performs the route data driving with the laser distance sensor, and performs the sensor driving with the laser distance sensor as the sensor for the sensor driving.

5. The automatic guided vehicle according to claim 1, wherein the control section creates a start position to start approaching the object during sensor driving, at a position that is closer to the object than any position on a route by the route data.

6. The automatic guided vehicle according to claim 2, wherein the control section creates a start position to start approaching the object during sensor driving, at a position that is closer to the object than any position on a route set by the route data.

7. The automatic guided vehicle according to claim 3, wherein the control section creates a start position to start approaching the object during sensor driving, at a position that is closer to the object than any position on a route set by the route data.

8. The automatic guided vehicle according to claim 4, wherein the control section creates a start position to start approaching the object during sensor driving, at a position that is closer to the object than any position on a route set by the route data.

9. The automatic guided vehicle according to claim 5, wherein the control section includes a first sensor pair having sensors spaced apart at a distance which is less than a width of the object, and a second sensor pair having second sensors spaced apart at a distance which is less than a width of a reference indicator provided on the object, where the first sensor pair is used to determine whether or not first predetermined multiple positions have been concurrently obtained by the vehicle with respect to the object, and where the second sensor pair is used to determine whether or not second predetermined multiple positions have been concurrently obtained by the vehicle with respect to the reference indicator provided on the object, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start the sensor driving, where the first sensor pair and the second sensor pair are differing types of sensors from each other, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start approaching the object, and wherein the first and/or second predetermined multiple positions are more particularly a predetermined first position having been obtained by a first portion of the vehicle, and a second predetermined second position having been obtained by a second portion of the vehicle.

10. The automatic guided vehicle according to claim 6, wherein the control section includes a first sensor pair having sensors spaced apart at a distance which is less than a width of the object, and a second sensor pair having second sensors spaced apart at a distance which is less than a width of a reference indicator provided on the object, where the first sensor pair is used to determine whether or not first predetermined multiple positions have been concurrently obtained by the vehicle with respect to the object, and where the second sensor pair is used to determine whether or not second predetermined multiple positions have been concurrently obtained by the vehicle with respect to the reference indicator provided on the object, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start the sensor driving, where the first sensor pair and the second sensor pair are differing types of sensors from each other, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start approaching the object, and wherein the first and/or second predetermined multiple positions are more particularly a predetermined first position having been obtained by a first portion of the vehicle, and a second predetermined second position having been obtained by a second portion of the vehicle.

11. The automatic guided vehicle according to claim 7, wherein the control section includes a first sensor pair having sensors spaced apart at a distance which is less than a width of the object, and a second sensor pair having second sensors spaced apart at a distance which is less than a width of a reference indicator provided on the object, where the first sensor pair is used to determine whether or not first predetermined multiple positions have been concurrently obtained by the vehicle with respect to the object, and where the second sensor pair is used to determine whether or not second predetermined multiple positions have been concurrently obtained by the vehicle with resect to the reference indicator provided on the object, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start the sensor driving, where the first sensor pair and the second sensor pair are differing types of sensors from each other, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start approaching the object, and wherein the first and/or second predetermined multiple positions are more particularly a predetermined first position having been obtained by a first portion of the vehicle, and a second predetermined second position having been obtained by a second portion of the vehicle.

12. The automatic guided vehicle according to claim 8, wherein the control section includes a first sensor pair having sensors spaced apart at a distance which is less than a width of the object, and a second sensor pair having second sensors spaced apart at a distance which is less than a width of a reference indicator provided on the object, where the first sensor pair is used to determine whether or not first predetermined multiple positions have been concurrently obtained by the vehicle with respect to the object, and where the second sensor pair is used to determine whether or not second predetermined multiple positions have been concurrently obtained by the vehicle with respect to the reference indicator provided on the object, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start the sensor driving, where the first sensor pair and the second sensor pair are differing types of sensors from each other, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start approaching the object, and wherein the first and/or second predetermined multiple positions are more particularly a predetermined first position having been obtained by a first portion of the vehicle, and a second predetermined second position having been obtained by a second portion of the vehicle.

13. A method for drive control of an automatic guided vehicle that has a distance measure sensor pair and a photoelectric sensor pair, the method comprising:

when the vehicle is distant from an object, performing route data driving that is driving on a preset route based on preset route data; and

when the vehicle approaches the object, starting sensor driving that is based on a sensor thereof, to make the vehicle further approach the object,

wherein the automatic guided vehicle;

decelerates the automatic guided vehicle to a creep velocity when the vehicle approaches a predetermined target address of creep drive control,

determines whether or not

a pair of predetermined points on the vehicle have matched a pair of predetermined start points of sensor driving, and

switches the route data driving over to the sensor driving when the pair of predetermined points on the vehicle have matched the pair of predetermined start points of sensor driving,

further approach the object by using the photoelectric sensor pair after switching the route data driving over to the sensor driving, and

further approach the object by using the distance measure sensor pair after detecting a light from the object by the photoelectric sensor pair.

14. The method for drive control according to claim 13,

wherein the automatic guided vehicle comprises:

a laser distance sensor for measuring distances to surroundings by scanning with laser light,

wherein the photoelectric sensor pair includes;

a photo-detection sensor that projects a signal light to a reflecting plate arranged on the object, receives a reflected light from the reflecting plate, and thereby detects a presence of the object; and

wherein the distance measure sensor pair includes;

a distance measuring sensor capable of measuring a distance to the object,

and wherein the automatic guided vehicle;

performs the route data driving with the laser distance sensor up to a start position to start the sensor driving; and

performs the sensor driving with the photo-detection sensor and the distance measuring sensor from the start position.

15. The method for drive control according to claim 13,

wherein the automatic guided vehicle comprises:

a laser distance sensor for measuring distances to surroundings by scanning with laser light,

and wherein the automatic guided vehicle;

performs the route data driving with the laser distance sensor up to a start position to start the sensor driving; and

performs the sensor driving with the laser distance sensor after the start position.

16. The method for drive control according to claim 13,

wherein the automatic guided vehicle creates the start position to start the sensor driving, at a position that is closer to the object than any position on a route set by the route data.

17. The method for drive control according to claim 14,

wherein the automatic guided vehicle creates the start position to start the sensor driving, at a position that is closer to the object than any position on a route set by the route data.

18. The method for drive control according to claim 15,

wherein the automatic guided vehicle creates the start position to start the sensor driving, at a position that is closer to the object than any position on a route set by the route data.

19. The method for drive control according to claim 13, wherein the photoelectric sensor pair include a first sensor pair having sensors spaced apart at a distance which is less than a width of the object, and the distance measure sensor pair includes a second sensor pair having second sensors spaced apart at a distance which is less than a width of a reference indicator provided on the object, where the first sensor pair is used to determine whether or not first predetermined multiple position have been concurrently obtained by the vehicle with respect to the object, and where the second sensor pair is used to determine whether or not second redetermined multiple positions have been concurrently obtained by the vehicle with respect to the reference indicator provided on the object, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start the sensor driving, where the first sensor pair and the second sensor pair are differing types of sensors from each other, one set of the first predetermined multiple positions and the second predetermined multiple positions jointly representing a start position to start approaching the object, and wherein the first predetermined multiple positions and/or the second predetermined multiple positions are more particularly a predetermined first position having been obtained by a first portion of the vehicle, and a second predetermined second position having been obtained by a second portion of the vehicle.