SYSTEM AND METHOD FOR ESTIMATING STATE OF CARRIER

• US 20100164807A1
• Filed: 03/05/2009
• Published: 07/01/2010
• Est. Priority Date: 12/30/2008
• Status: Abandoned Application

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Tang, Chih-Wei, Yang, An-Tao, Lee, Chin-Lung, Tseng, Kuo-Shih, Kuo, Chia-Lin
• Application Number:
  US12/398,187
• Publication Number:
  US 20100164807A1
• Time in Patent Office: Days
• US Class Current: 342/386
• CPC Class Codes: G01C 21/1656 with passive imaging devices, e.g. cameras
• CPC Class Codes: G01S 5/0247 Determining attitude
• CPC Class Codes: G01S 5/0284 Relative positioning

Abstract

A system and a method for estimating a state of a carrier are provided. The system includes the carrier, an electromagnetic wave sensing device, a motion sensing device, and a controller. The electromagnetic wave sensing device detects an electromagnetic wave emitted by at least one feature object in an environment around the carrier. The motion sensing device detects motion information of the carrier moving in the environment. The controller estimates state information of the carrier in the environment through a probabilistic algorithm according to the electromagnetic wave and motion information detected by aforementioned sensing devices. Thereby, in the present invention, the location and posture of the carrier in the environment can be precisely estimated according to the motion information of the carrier and existing information of the environment around the same.

Claims

1. A carrier state estimation method, suitable for estimating state information of a carrier, the carrier state estimation method comprising:

detecting an electromagnetic wave emitted by at least one feature object in an environment around the carrier, so as to calculate a relative position between the carrier and each of the feature objects;

detecting motion information of the carrier moving in the environment; and

estimating the state information of the carrier in the environment through a probabilistic algorithm according to the relative position and the motion information.

2. The carrier state estimation method according to claim 1, wherein before the step of detecting the electromagnetic wave emitted by the feature object in the environment, the carrier state estimation method further comprises:

obtaining a map of the environment, wherein the map comprises location information of the feature object in the environment.

3. The carrier state estimation method according to claim 2, wherein the step of obtaining the map of the environment comprises:

detecting the electromagnetic wave before and after a time interval to obtain two image information of the environment; and

calculating location information of the feature object in the environment by using the image information, so as to establish the map of the environment.

4. The carrier state estimation method according to claim 3, wherein after the step of obtaining the image information of the environment, the method further comprises:

performing one or a combination of noise removal, illumination correction, image rectification, feature extraction, image description, and eye comparison to the image information.

5. The carrier state estimation method according to claim 1, wherein the step of calculating the relative position between the carrier and each of the feature objects comprises:

estimating a distance between the carrier and the feature object according to a power or a geometric distance of the detected electromagnetic wave; and

calculating the relative position between the carrier and the feature object according to two of the distances estimated consecutively and an angle of the electromagnetic wave.

6. The carrier state estimation method according to claim 1, wherein the step of detecting the motion information of the carrier moving in the environment comprises:

detecting posture angles of the carrier corresponding to three coordinate axes.

7. The carrier state estimation method according to claim 6, wherein the step of estimating the state information of the carrier in the environment through the probabilistic algorithm according to the relative position and the motion information comprises:

integrating the posture angles to calculate a displacement and a speed of the carrier corresponding to each of the coordinate axes; and

determining a location and a posture of the carrier in the environment according to the posture angle, the displacement, and the speed of the carrier on each of the coordinate axes and serving the location and the posture of the carrier as the state information of the carrier in the environment.

8. The carrier state estimation method according to claim 7, wherein the step of estimating the state information of the carrier in the environment through the probabilistic algorithm according to the relative position and the motion information further comprises:

correcting the location of the carrier in the environment through the probabilistic algorithm according to the relative position between the carrier and the feature object.

9. The carrier state estimation method according to claim 1, wherein the motion information comprises a speed, an acceleration, an angular speed, or an angular acceleration.

10. The carrier state estimation method according to claim 1 further comprising:

emitting a mechanical wave from the carrier to the environment, and receiving the mechanical wave reflected by the feature object in the environment, so as to calculate the relative position between the carrier and the feature object.

11. The carrier state estimation method according to claim 10, wherein the step of calculating the relative position between the carrier and the feature object comprises:

estimating a distance between the carrier and the feature object according to a power or a geometric distance of the mechanical wave reflected by the feature object in the environment; and

calculating the relative position between the carrier and the feature object by using two of the distances estimated consecutively and an angle of the mechanical wave.

12. A carrier state estimation system, comprising:

a carrier;

an electromagnetic wave sensing device, disposed in the carrier, for detecting an electromagnetic wave emitted by at least one feature object in an environment around the carrier;

a motion sensing device, disposed in the carrier, for detecting motion information of the carrier moving in the environment; and

a controller, disposed in the carrier and coupled to the electromagnetic wave sensing device and the motion sensing device, for estimating state information of the carrier in the environment through a probabilistic algorithm according to the electromagnetic wave and the motion information.

13. The carrier state estimation system according to claim 12 further comprising:

a storage unit, disposed in the carrier, for recording a map of the environment and providing the map to the controller for estimating the state information, wherein the map comprises location information of the feature object in the environment.

14. The carrier state estimation system according to claim 13, wherein the electromagnetic wave sensing device detects the electromagnetic wave before and after a time interval to obtain two image information of the environment, and the controller calculates the location information of the feature object in the environment by using the image information so as to establish the map of the environment.

15. The carrier state estimation system according to claim 12, wherein the controller comprises:

a quaternion calculation unit, for receiving angular displacements of the carrier corresponding to three coordinate axes of the carrier detected by the motion sensing device and converting the angular displacements into a plurality of operators;

a direction cosine calculation unit, for performing a direction cosine calculation on the operators to obtain a posture angle of the carrier corresponding to each of the coordinate axes;

a gravity component extraction unit, for calculating an acceleration of the carrier corresponding to each of the coordinate axes according to the posture angle of the carrier corresponding to the coordinate axis;

an acceleration integration unit, for calculating a speed of the carrier on each of the coordinate axes according to the acceleration of the carrier corresponding to the coordinate axis and the angular displacements of the carrier corresponding to the three coordinate axes of the carrier detected by the motion sensing device;

a speed integration unit, for calculating a displacement of the carrier on each of the coordinate axes according to the speed of the carrier on the coordinate axis;

a coordinate conversion unit, for converting the coordinate axes of the displacement of the carrier into the coordinate axes of the environment;

a data association unit, for calculating a plurality of environment features on the coordinate axes corresponding to features currently detected by the carrier according to the displacement of the carrier on each of the converted coordinate axes through data association; and

a digital filter, for calculating a posture angle, a speed, and a displacement of the carrier on each of the coordinate axes according to the environment features of the carrier on the coordinate axis, and generating a plurality of operators and sending the operators back to the quaternion calculation unit.

16. The carrier state estimation system according to claim 15, wherein the controller further comprises:

an environment feature calculation unit, for estimating a distance between the carrier and the feature object according to a power or a geometric distance of the electromagnetic wave detected by the electromagnetic wave sensing device, and calculating the relative position between the carrier and the feature object by using two of the distances estimated consecutively and an angle of the electromagnetic wave, so as to calculate a location and a posture of the carrier in the environment.

17. The carrier state estimation system according to claim 16, wherein the digital filter further corrects the displacement of the carrier on each of the coordinate axes through a probabilistic algorithm according to the location and the posture of the carrier in the environment calculated by the environment feature calculation unit.

18. The carrier state estimation system according to claim 15, wherein the digital filter further sends the speed and the displacement of the carrier on each of the coordinate axes back to the acceleration integration unit and the speed integration unit.

19. The carrier state estimation system according to claim 15, wherein the digital filter comprises a Kalman filter, a particle filter, or a Bayesian filter.

20. The carrier state estimation system according to claim 12 further comprising:

a mechanical wave transceiver device, disposed in the carrier, for emitting a mechanical wave from the carrier to the environment and receiving the mechanical wave reflected by the feature object in the environment.

21. The carrier state estimation system according to claim 20, wherein the controller calculates the state information of the carrier in the environment according to the mechanical wave received by the mechanical wave transceiver device.

22. The carrier state estimation system according to claim 21, wherein the mechanical wave transceiver device comprises an ultrasound, an ultrasound array, or a sonar.

23. The carrier state estimation system according to claim 12, wherein the electromagnetic wave sensing device comprises a visible light vision sensor, an invisible light vision sensor, an electromagnetic wave sensor, or an infrared sensor.

24. The carrier state estimation system according to claim 12, wherein the motion sensing device comprises an accelerometer, a gyroscope, or a rotational speed sensor.

25. The carrier state estimation system according to claim 12, wherein the carrier comprises an automobile, a motorcycle, a bicycle, or a robot.