Method and system for navigation of movable platform

• US 8,688,308 B2
• Filed: 11/20/2012
• Issued: 04/01/2014
• Est. Priority Date: 12/29/2011
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Wu, Tsung-Liang, Wang, Chun-Chieh, Chung, Yu-Liang, Wu, Chien-Feng, Liu, Yan-Chen
• Primary Examiner(s): Cheung, Mary
• Assistant Examiner(s): WONG, YUEN H
• Application Number:
  US13/682,638
• Publication Number:
  US 20130158775A1
• Time in Patent Office: 497 Days
• Field of Search: 701/28, 701/412
• US Class Current: 701/28
• CPC Class Codes: G05D 1/0236 in combination with a laser lasers per se H01S

Abstract

A method for navigation of a movable platform is provided. The method includes the steps. First, a plurality of reflection devices is placed to mark a range. A coordinate location and a direction of the movable platform are received by a positioning system, At least one laser to measure relative positions and distances between the reflection devices and the movable platform are emitted by a laser range finder, respectively. Absolute locations of the reflection devices and the range are calculated by a processor according to the coordinate location and the direction of the movable platform, the relative positions and the distances between the reflection devices and the movable platform. The reflection devices are scanned and tracked by the processor, and the coordinate location and the direction of the movable platform and the absolute locations are calibrated by the processor to control the movable platform to move in the range.

Claims

1. A method for navigation of a movable platform, used in a system;

the system includes a plurality of reflection devices and a movable platform, wherein the movable platform further includes a positioning system, a laser range finder and a processor, the method comprising;

placing the plurality of reflection devices to mark a range;

receiving, by the positioning system, a coordinate location and a direction of the movable platform;

emitting, by the laser range finder, at least one laser to measure relative positions and distances respectively between the plurality of reflection devices and the movable platform;

calculating, by the processor, absolute locations of the plurality of reflection devices and the range according to the coordinate location and the direction of the movable platform, and the relative positions and the distances between the plurality of reflection devices and the movable platform; and

scanning and tracking, by the laser range finder, the plurality of reflection devices, and calibrating, by the processor, the coordinate location and the direction of the movable platform and the absolute locations of the plurality of reflection devices to control the movable platform to move in the range;

wherein when the processor calibrates the coordinate location and the direction of the movable platform and the absolute locations of the plurality of reflection devices, the method further comprising;

locking, by using the laser, a first reflection device which is closest to the movable platform to calibrate the coordinate location of the mobile platform;

finding a second reflection device which is closest to the movable platform except the first reflection device when the mobile platform is close to a boundary of the range;

obtaining an angle between a line from the mobile platform to the first reflection device and a line from the mobile platform to the second reflection device; and

controlling the mobile platform to move in another direction in the range when the angle reaches 180 degrees.

2. The method for navigation of a movable platform as claimed in claim 1, wherein the distance between any two of the plurality of reflection devices is greater than a positioning error of the positioning system.

3. The method for navigation of a movable platform as claimed in claim 1, wherein the positioning system is a global positioning system (GPS), a GLObal NAvigation Satellite System (GLONASS), a Galileo or a satellite based augmentation system (SBAS).

4. The method for navigation of a movable platform as claimed in claim 1, further comprising using a specific reflective material configured for attachment to the surface of the reflection devices, wherein the laser range finder can recognize the laser reflected from the specific reflecting material.

5. The method for navigation of a movable platform as claimed in claim 4, wherein a reflection rate of the specific reflective material is greater than 60%, and the specific reflective material can scatter the incident light.

6. The method for navigation of a movable platform as claimed in claim 5, wherein a receiving hole diameter of the laser range finder is between 0.5 mm and 15 mm.

7. A system for navigation of a movable platform, comprising:

a plurality of reflection devices, configured to mark a range; and

a movable platform, configured to move in the range, comprising;

a positioning system, configured to position a coordinate location and a direction of the movable platform;

a laser range finder, configured to emit at least one laser to measure relative positions and distances respectively between the plurality of reflection devices and the movable platform; and

a processor, coupled to the positioning system and the laser range finder, configured to calculate absolute locations of the plurality of reflection devices and the range according to the coordinate location and the direction of the movable platform, and the relative position and the distances between the plurality of reflection devices and the movable platform;

wherein the movable platform scans and tracks the plurality of reflection devices by using the laser range finder, and calibrates the coordinate location and the direction of the movable platform and the absolute locations of the plurality of reflection devices to control the movable platform to move in the range; and

wherein when the processor calibrates the coordinate location and the direction of the movable platform and the absolute locations of the plurality of reflection devices, the laser range finder uses the laser to lock a first reflection device which is closest to the movable platform to calibrate the coordinate location of the mobile platform; and

when the mobile platform is close to a boundary of the range, the laser range finder finds a second reflection device which is closest to the movable platform except the first reflection device;

the processor obtains an angle between a line from the mobile platform to the first reflection device and a line from the mobile platform to the second reflection device, and when the angle reaches 180 degrees, the processor controls the mobile platform to move in another direction in the range.

8. The system for navigation of a movable platform as claimed in claim 7, wherein the distance between any two of the plurality of reflection devices is greater than a positioning error of the positioning system.

9. The system for navigation of a movable platform as claimed in claim 7, wherein the positioning system is a global positioning system (GPS), a GLObal NAvigation Satellite System (GLONASS), a Galileo or a satellite based augmentation system (SBAS).

10. The system for navigation of a movable platform as claimed in claim 7, wherein a specific reflective material is used for attachment to the surface of the reflection devices, so that the laser range finder can recognize the laser reflected by the specific reflecting material.

11. The system for navigation of a movable platform as claimed in claim 10, wherein a reflection rate of the specific reflective material is greater than 60%, and the specific reflective material can scatter the incident light.

12. The system for navigation of a movable platform as claimed in claim 11, wherein a receiving hole diameter of the laser range finder is between 0.5 mm and 15 mm.