NAVIGATION MODULE

Abstract

A navigation module determines the position of an automated guided vehicle. The navigation module includes a light source for emitting light; a receiver for receiving light emitted from the light source; and a processor operatively connected to the light source and to the receiver. The navigation module also includes a first mode of operation in which light is emitted continuously from the light source and the processor processes light received by the receiver to identify a predetermined reflective target; and a second mode of operation in which light is pulsed from the light source and the processor processes light received by the receiver to determine a distance to the predetermined reflective target.

Claims

1. A navigation module for determining the position of an automated guided vehicle, the navigation module comprising: a light source for emitting light; a receiver for receiving light emitted from the light source; and a processor operatively connected to the light source and to the receiver; wherein the navigation module further comprises: a first mode of operation in which light is emitted substantially continuously from the light source and the processor processes light received by the receiver to identify a predetermined reflective target; and a second mode of operation in which light is pulsed from the light source and the processor processes light received by the receiver to determine a distance to the predetermined reflective target.

2. The navigation module according to claim 1, wherein the light source includes: a first emitter which is configured to operate in the first mode of operation; and a second emitter which is configured to operate in the second mode of operation.

3. The navigation module according to claim 2, wherein the receiver comprises: a first light sensor which is configured to receive light emitted, in use, by the first emitter; and a second light sensor which is configured to receive light emitted, in use, by the second emitter.

4. The navigation module according to claim 2, wherein the first emitter is configured to emit light having a first wavelength; and the second emitter is configured to emit light having a second wavelength.

5. The navigation module according to claim 2, wherein the first emitter is spaced apart from the second emitter, and/or wherein the receiver comprises a single light sensor which is configured to receive light emitted, in use, by the first emitter and light emitted, in use, by the second emitter.

6. An automated guided vehicle including the navigation module according to claim 1.

7. An automated guided vehicle navigation system for determining the position of an automated guided vehicle, the automated guided vehicle navigation system comprising: a navigation module comprising: a light source for emitting light; a receiver for receiving light emitted from the light source; and a processor operatively connected to the light source and to the receiver; wherein the navigation system further comprises a predetermined reflective target; and wherein the navigation module further comprises: a first mode of operation in which light is emitted substantially continuously from the light source and the processor processes light received by the receiver to identify the predetermined reflective target; and a second mode of operation in which light is pulsed from the light source and the processor processes light received by the receiver to determine a distance to the predetermined reflective target.

8. The automated guided vehicle navigation system according to claim 7, wherein the light source comprises: a first emitter which is configured to operate in the first mode of operation; and a second emitter which is configured to operate in the second mode of operation.

9. The automated guided vehicle navigation system according to claim 8, wherein the receiver comprises: a first light sensor which is configured to receive light emitted, in use, by the first emitter; and a second light sensor which is configured to receive light emitted, in use, by the second emitter.

10. The automated guided vehicle navigation system according to claim 8, wherein the first emitter is configured to emit light having a first wavelength; and the second emitter is configured to emit light having a second wavelength.

11. The automated guided vehicle navigation system according to claim 8, wherein the first emitter is spaced apart from the second emitter.

12. The automated guided vehicle navigation system according to claim 8, wherein the receiver comprises a single light sensor which is configured to receive light emitted, in use, by the first emitter and by the second emitter.

13. A method of determining the position of an automated guided vehicle, the method comprising: providing a navigation module comprising: a light source for emitting light; a receiver for receiving light emitted from the light source; and a processor operatively connected to the light source and to the receiver; operating the navigation module in a first mode of operation in which light is emitted substantially continuously from the light source, the receiver receives light emitted from the light source, and the processor processes light received by the receiver to identify a predetermined reflective target; and operating the navigation module in a second mode of operation in which light is pulsed from the light source, the receiver receives light emitted from the light source, and the processor processes light received by the receiver to determine a distance to the predetermined reflective target.

14. The method of determining the position of an automated guided vehicle according to claim 13, wherein the steps of operating the navigation module in the first mode of operation and operating the navigation module in the second mode of operation are performed substantially simultaneously.

15. The method of determining the position of an automated guided vehicle according to claim 13, wherein the step of operating the navigation module in the first mode of operation is performed before the step of operating the navigation module in the second mode of operation.

16. The method of determining the position of an automated guided vehicle according to claim 13, wherein the light source comprises: a first emitter; and a second emitter; wherein, in the first mode of operation, the first emitter is operated to emit light substantially continuously; and wherein, in the second mode of operation, the second emitter is operated to pulse light.

17. The method of determining the position of an automated guided vehicle according to claim 16, wherein the receiver comprises: a first light sensor which receives light emitted, in use, by the first emitter; and a second light sensor which receives light emitted, in use, by the second emitter.

18. The method of determining the position of an automated guided vehicle according to claim 16, wherein the first emitter is operated to emit light having a first wavelength; and the second emitter is operated to emit light having a second wavelength.

19. The method of determining the position of an automated guided vehicle according to claim 16, wherein the first emitter is spaced apart from the second emitter.

20. The method of determining the position of an automated guided vehicle according to claim 16, wherein the receiver includes a single light sensor which receives light emitted, in use, by the first emitter and light emitted, in use, by the second emitter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

[0099] FIG. 1 is a schematic representation of a navigation module according to an embodiment of the invention;

[0100] FIG. 2 is a schematic plan view of an automated guided vehicle including the navigation module of FIG. 1 in a transport area;

[0101] FIG. 3 is a flow diagram showing the steps in the operation of the navigation module of FIG. 1;

[0102] FIG. 4 is a schematic representation of a navigation module according to an alternative embodiment of the invention; and

[0103] FIG. 5 is a schematic representation of a navigation module according to a further embodiment of the invention.

DETAILED DESCRIPTION

[0104] Referring now to FIG. 1, there is shown a navigation module 10 according to an embodiment of the invention.

[0105] The navigation module 10 comprises a light source 12, a receiver 14 and a processor 16.

[0106] The light source 12 includes a first emitter 12a, for example a first, continuous wave, laser, and a second emitter 12b, for example a second, pulsed, laser. The first emitter 12a is configured to emit a first beam of light 18a over a search sector 20, for example within a warehouse. The first beam of light 18a has a first wavelength. The first beam of light 18a is a substantially continuous beam of light. The second emitter 12b is configured to emit a pulse of light 18b over the search sector 20. The pulse of light 18b has a second wavelength, which is different to the first wavelength. The pulse of light 18b may be a single pulse or may be multiple pulses of light. In embodiments of the invention where the pulse of light 18b is multiple pulses of light, the multiple pulses may be intermittent or the light may be pulsed regularly.

[0107] The receiver 14 is configured to receive or detect light 22 which is reflected by reflecting objects, such as a predetermined reflective target 24, in the search sector 20. The reflected light 22 includes a first beam of reflected light 22a and at least one pulse of reflected light 22b which are reflected by the predetermined reflective target 24. The first beam of reflected light 22a is a substantially continuous beam of light from the first emitter 12a which is reflected by the predetermined reflective target 24. The at least one pulse of reflected light 22b is pulsed from the second emitter 12b and reflected by the predetermined reflective target 24.

[0108] The processor 16 is operatively connected to the light source 12 and to the receiver 14.

[0109] The processor 16 is configured to control the light source 12 to operate in a first mode of operation and a second mode of operation, as will be described further below.

[0110] With reference to FIG. 2, an automated guided vehicle (AGV) 26 within a search area 20 is shown. The AGV 26 is equipped with a navigation module 10. The navigation module 10 includes a rotation stage (not shown) such that the navigation module 10 can move with the AGV 26 and can also revolve, spin or rotate relative to the AGV 26.

[0111] The search area 20 includes a number of reflective targets 24a, 24b, 24c, 24d, 24e, 24f which are in known locations. A digital representation, for example a map, of the search area 20 is made available to the navigation module 10 so that a comparison between scanned reflective targets and the map can be made in order to accurately determine the position of the AGV 26. More accurate identification of objects or reflective targets, as well as more accurate determination of the distance to an object or reflective target from the AGV, reduces the uncertainty when matching scanned reflective object positions to the map, thereby reducing the computational requirements of the navigation module 10. Such maps can also be produced and/or improved using an AGV 26 having a navigation module 10 according to the invention.

[0112] Operation of the navigation module 10 will now be described with particular reference to FIG. 3.

[0113] The AGV 26 is positioned within the search area 20. In order to locate the reflective targets 24a, 24b, 24c, 24d, 24e, 24f, the navigation module 10 is operated in the first mode of operation (steps 30a, 32a, 34a).

[0114] The rotation stage (not shown) is rotated in order to spin the navigation module 10 relative to the AGV 26.

[0115] In step 30a, the processor 16 controls the first emitter 12a of the light source 12 to emit a substantially continuous beam of light 18a within the search sector 20. As the navigation module 10 is rotated around the search area 20, the beam of light 18a is scanned across the surface of the reflective targets 24a, 24b, 24c, 24d, 24e, 24f. Light which is reflected by the reflective targets 24a, 24b, 24c, 24d, 24e, 24f is reflected back as the beam of reflected light 22a.

[0116] The reflected signals 22a from the reflective targets 24a, 24b, 24c, 24d, 24e, 24f, or other reflecting objects within the search sector 20, are detected or received by the receiver 14 (step 32a). The processor 16 processes the received beam of reflected light 22a and is thereby able to identify one or more, for example two or more, edges of the reflective targets 24a, 24b, 24c, 24d, 24e, 24f. In this way, the periphery or outer perimeter of the reflective 24a, 24b, 24c, 24d, 24e, 24f can be determined.

[0117] The processor 16 then compares the reflected signals 22a with a map in order to accurately identify or determine the position of the predetermined reflective targets 24a, 24b, 24c, 24d, 24e, 24f (step 34a).

[0118] The processor 16 uses the reflected signals 22a to determine or measure a dimension of the reflective target, for example the width defined between two edges of the reflective target. By comparing the measured dimension of the reflective target with the expected dimension for a predetermined reflective target, the processor 16 is able to reject reflections from shiny, non-target, objects within the search sector 20.

[0119] Once the position of the predetermined reflective targets 24a, 24b, 24c, 24d, 24e, 24f is determined, the processor 16 switches the navigation module into the second mode of operation (steps 30b, 32b and 34b) in order to accurately determine the distance between the AGV 26 and the predetermined reflective targets 24a, 24b, 24c, 24d, 24e, 24f.

[0120] The rotation stage (not shown) is rotated in order to spin the navigation module 10 relative to the AGV 26.

[0121] In step 30b, the processor 16 controls the second emitter 12b of the light source 12 to emit pulses of light 18b within the search sector 20 as the navigation module 26 spins. As the navigation module 10 is rotated around the search area 20, the pulse of light 18b reaches the surface of the reflective targets 24a, 24b, 24c, 24d, 24e, 24f. Light which is reflected by the reflective targets 24a, 24b, 24c, 24d, 24e, 24f is reflected back as the pulse of reflected light 22b.

[0122] Reflected signals 22b from the reflective targets 24a, 24b, 24c, 24d, 24e, 24f, or other reflecting objects within the search sector 20, are detected or received by the receiver 14 (step 32b).

[0123] The processor 16 measures the time of flight of the or each pulse in order to determine the distance of the predetermined reflective targets 24a, 24b, 24c, 24d, 24e, 24f from the AGV 26 (step 34b).

[0124] A navigation module 110 according to an alternative embodiment of the invention will now be described with reference to FIG. 4.

[0125] The navigation module 110 comprises a light source 112, a receiver 114 and a processor 116.

[0126] The light source 112 includes a first emitter 112a, for example a first laser, and a second emitter 112b, for example a second laser. The first emitter 112a is configured to emit a first beam of light 118a over a search sector 120, for example within a warehouse. The first beam of light 118a has a first wavelength. The first beam of light 118a is substantially continuous. The second emitter 112b is configured to emit a pulse of light 118b over the search sector 120. The second beam of light 118b has a second wavelength, which is different to the first wavelength. The pulse of light 118b may be a single pulse of light or may be multiple pulses of light. In embodiments of the invention where the pulse of light 118b is multiple pulses of light, the multiple pulses may be intermittent or the light may be pulsed regularly.

[0127] The receiver 114 is configured to receive or detect light 122 which is reflected by reflecting objects, such as a predetermined reflective target 124, in the search sector 120. The receiver 114 includes a first light sensor 114a and a second light sensor 114b The reflected light 122 includes a first beam of reflected light 122a and at least one pulse of reflected light 122b which are reflected by the predetermined reflective target 124. The first light sensor 114a is configured to receive the first beam of reflected light 122a. Similarly, the second light sensor 114b is configured to receive the at least one pulse of reflected light 112b. The first beam of reflected light 122a is a substantially continuous beam of light from the first emitter 112a which is reflected by the predetermined reflective target 124. The at least one pulse of reflected light 122b is pulsed from the second emitter 112b and reflected by the predetermined reflective target 124.

[0128] The processor 116 is operatively connected to the light source 112 and to the receiver 114.

[0129] The processor 116 is configured to control the light source 112 to operate in a first mode of operation and a second mode of operation, as is described above in relation to the first embodiment of the present invention.

[0130] A navigation module 210 according to a further embodiment of the invention will now be described with reference to FIG. 5.

[0131] The navigation module 210 comprises a light source 212, a receiver 214 and a processor 216.

[0132] The light source 212 includes a single emitter, for example a single laser. The light source 212 is configured to emit a first beam of light 218a over a search sector 220, for example within a warehouse. The first beam of light 218a has a first wavelength. The first beam of light 218a is substantially continuous. The second emitter 212b is configured to emit a pulse of light 218b over the search sector 220. The second beam of light 218b has a second wavelength, which is different to the first wavelength. The pulse of light 218b may be a single pulse of light or may be multiple pulses of light. In embodiments of the invention where the pulse of light 218b is multiple pulses of light, the multiple pulses may be intermittent or the light may be pulsed regularly.

[0133] The receiver 214 is configured to receive or detect light 222 which is reflected by reflecting objects, such as a predetermined reflective target 224, in the search sector 220. The reflected light 222 includes a first beam of reflected light 222a and at least one pulse of reflected light 222b which are reflected by the predetermined reflective target 224. The first beam of reflected light 222a is a substantially continuous beam of light from the light source 212 which is reflected by the predetermined reflective target 224. The at least one pulse of reflected light 222b is pulsed from the light source 212 and reflected by the predetermined reflective target 224.

[0134] The processor 216 is operatively connected to the light source 212 and to the receiver 214.

[0135] The processor 216 is configured to control the light source 212 to operate in a first mode of operation and a second mode of operation, as is described above in relation to the first embodiment of the present invention.

[0136] The embodiment of FIG. 5 employs a single source (light source 212) to emit light in each of the modes of operation and a single detector (receiver 214) to receive reflected light in each of the modes of operation. The navigation module is operated in each mode of operation sequentially. The versatility of the invention is, therefore, provided by a less complex arrangement.

[0137] It will be appreciated by those skilled in the art that several variations to the aforementioned embodiments are envisaged without departing from the scope of the invention. For example, in the embodiments above, the first emitter 12a, 112a emits light 18a, 118a having a first wavelength and the second emitter 12b, 112b emits light 18b, 118b having a second wavelength which is different to the first wavelength. In alternative embodiments of the invention, the first and second emitters may be spaced apart, thereby removing the need for the first emitter and the second emitter to emit light having different wavelengths. The first emitter and the second emitter may, for example be physically offset relative to each other. The first emitter may be mounted at a non-zero angle, for example approximately 20 degrees, relative to the second emitter. By correlating the reflected light from each of the emitters in each of the modes of operation, light emitted from the first emitter and light emitted from the second emitter could have the same wavelength. Similarly, light emitted from the first emitter and light emitted from the second emitter could have the same colour.

[0138] In the embodiment described above, the light source 12 includes a first emitter 12a, which is configured to emit a first beam of light 18a which has a first wavelength. The light source 12 also includes a second emitter 12b, which is configured to emit a second beam of light 18b which has a second wavelength. The first and second wavelengths are different. In alternative embodiments of the invention, the first emitter may emit light having a first colour and the second emitter may emit light having a second colour. The first and second colours may be different.

[0139] In the embodiment described above, the light source 212 is configured to emit a first beam of light 218a which has a first wavelength. The light source is also configured to pulse a second beam of light 218b which has a second wavelength. The first and second wavelengths are different. In alternative embodiments of the invention, the light source may be configured to emit a first beam of light having a first colour and to pulse a second beam of light having a second colour, wherein the first and second colours may be different.

[0140] In the embodiment described above, steps 30a, 32a, 34a of the first mode of operation are carried out before steps 30b, 32b, 34b of the second mode of operation (i.e. the first mode of operation and the second mode of operation are performed sequentially). In alternative embodiments of the invention, steps 30a, 32a, 34a may be carried out at substantially the same time as steps 30b, 32b, 34b of the second mode of operation (i.e. the first and second modes of operation may be performed substantially simultaneously).

[0141] It will also be appreciated by those skilled in the art that any number of combinations of the aforementioned features and/or those shown in the appended drawings provide clear advantages over the prior art and are therefore within the scope of the invention described herein.