Method and device for sensing of obstacles for an autonomous device

• US 5,867,800 A
• Filed: 09/30/1996
• Issued: 02/02/1999
• Est. Priority Date: 03/29/1994
• Status: Expired due to Term

• Current Assignee: Aktiebolaget Electrolux
• Original Assignee: Aktiebolaget Electrolux
• Inventors: Leif, Edlund
• Primary Examiner(s): Mojica, V. Lissi
• Application Number:
  US08/718,399
• Time in Patent Office: 855 Days
• Field of Search: 701/23, 701/24, 701/26, 701/301, 180/167, 180/169, 340/435, 340/436, 342/132
• US Class Current: 701/23
• CPC Class Codes: A47L 11/4011 Regulation of the cleaning machine by electric means; Control systems and remote control systems therefor
• CPC Class Codes: A47L 11/4061 Steering means; Means for avoiding obstacles; Details related to the place where the driver is accommodated
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: G01S 15/06 Systems determining the position data of a target
• CPC Class Codes: G01S 15/104 wherein the transmitted pulses use a frequency- or phase-modulated carrier wave
• CPC Class Codes: G01S 15/74 Systems using reradiation of acoustic waves, e.g. IFF, i.e. identification of friend or foe
• CPC Class Codes: G01S 15/86 Combinations of sonar systems with lidar systems; Combinations of sonar systems with systems not using wave reflection
• CPC Class Codes: G01S 15/874 Combination of several spaced transponders or reflectors of known location for determining the position of a receiver G01S15/872 takes precedence
• CPC Class Codes: G01S 15/89 for mapping or imaging
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 2015/938 in the bumper area radar in bumper area G01S2013/93275; bumper with obstacle sensor of electric or electronic type B60R19/483
• CPC Class Codes: G01S 7/54 with receivers spaced apart
• CPC Class Codes: G05D 1/0221 involving a learning process
• CPC Class Codes: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/0246 using a video camera in combination with image processing means
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

The present invention provides a method and a system for proximate field orientation of an autonomous device and utilizes a transmitted wave having a first frequency of slow propagation, whereby reflections from obstacles within a proximate area are detected. According to the present invention receivers are arranged in a slanted plane or preferably along a curved base-line to, in a simple way, obtain a three-dimensional direction to an obstacle reflecting the frequency of slow propagation. Additionally, an absorber or a screen or a combination thereof is arranged above at least one receiver to act as an "eyebrow" attenuating undesired reflections which at the receiver come from overhead. Additionally, at least one of the receivers along the generally curved base-line is arranged differently in height in relation to the remaining receivers, and preferably the most outer receiver on each side in the line of receivers along the generally curved base-line is arranged differently in height in relation to the remaining receivers for an improvement of the three-dimensional resolution.

Claims

1. A method for sensing proximity for an autonomous device, said autonomous device including wheels, a motor, and a microprocessor and proximity sensing system for orientation and guidance of said autonomous device, said proximity sensing system including a transmitter and receivers, said receivers having signal interfaces for transmitting digital signals to said microprocessor and being arranged in one of a slanted plane and along a curved baseline, comprising the steps of:

transmitting a wave from said transmitter, said wave having a slow propagation and being transmitted within a continuous sector of a normal travelling direction of said autonomous device;

detecting reflections of said wave by a number of said receivers during a predetermined time slot, corresponding to a proximate area, thereby obtaining a three-dimensional direction to an obstacle;

a transmitting digital signals from said number of said receivers to said microprocessor in response to said detecting;

processing said digital signals by said microprocessor and creating an orientation data base within said proximate area;

utilizing said data base continuously for orientation and guidance of said autonomous device with respect to detected obstacles during continued automatic motion of said autonomous device, and obtaining further proximity data for use by said microprocessor in combination with said data base for orientation and guidance of said autonomous device during said continued automatic motion by processing further digital signals transmitted from a number of said receivers to said microprocessor in response to further of said transmitting and detecting on the same wave frequency within said predetermined time slot during said continued automatic motion.

2. The method according to claim 1 including the further step of arranging at least some of said receivers differently in height in relation to the remaining receivers for improving three-dimensional resolution.

3. The method according to claim 1 including the further step of providing said autonomous device with an absorber above at least one receiver in the line of said receiver to attenuate undesired reflections from above and/or from the side, said absorber acting as an eyebrow above the receiver.

4. The method according to claim 1 further including the step of providing said autonomous device with a screen above at least one receiver in the line of said receiver to attenuate undesired reflections from above and/or from the side, said screen acting as an eyebrow above said receiver.

5. The method according to claim 1 wherein said wave comprises a longitudinal acoustic wave.

6. The method according to claim 1 wherein said wave comprises an acoustic wave having a frequency within the ultrasonic range.

7. The method according to claim 1 wherein said wave comprises one of a short, regularly repeated pulse and a repeated swept pulse (chirp signal).

8. The method according to claim 1 including the further step of arranging the most outer receiver on each side of a line of said receivers differently in height in relation to the remaining receivers.

9. The method according to claim 1 wherein said receivers comprise microphone elements adopted to the frequency of said wave.

19. The method according to claim 2, wherein said autonomous device is provided with an absorber above at least one receiver in the line of said receiver to attenuate undesired reflections from above and/or from the side, said absorber acting as an eyebrow above the receiver.

10. A system for sensing proximity for an autonomous device, said autonomous device including wheels, a motor, and a microprocessor and proximity sensing system for orientation and guidance of said autonomous device, said proximity sensing system including at least a transmitter and a plurality of receivers, said receivers having signal interfaces for transmitting digital signals to said microprocessor and being arranged in one of a slanted plane and along a curved baseline for obtaining direction resolution to obstacles having reflected a wave of slow propagation, said transmitter being structured and arranged to transmit said wave, said wave having a slow propagation and being transmittable within a continuous sector of a normal travelling direction of said autonomous device;

said receivers being structured and arranged to detect reflections of said wave during a predetermined time slot, corresponding to a proximate area, thereby obtaining a three-dimensional direction to an obstacle;

said receivers further being structured and arranged to transmit digital signals from said receivers to said microprocessor in response to said reflections;

said microprocessor being structured and arranged to process said digital signals and create an orientation data base within said proximate area which is utilized continuously for orientation and guidance of said autonomous device with respect to detected obstacles during continued automatic motion of said autonomous device, and which is used in combination with further proximity data for orientation and guidance of said autonomous device during said continued automatic motion by processing further digital signals transmitted from a number of said receivers to said microprocessor in response to further transmission and detection on the same wave frequency within said predetermined time slot during said continued automatic motion.

11. The system according to claim 10 wherein at least some of said receivers are arranged differently in height in relation to the remaining receivers for improving the three-dimensional resolution.

12. The system according to claim 10 wherein said autonomous device is provided with an absorber above at least one receiver in the line of said receivers, said absorber attenuating undesired reflections from above and/or from the side and then acts in the same manner as an eyebrow above said receivers.

13. The system according to claim 10 wherein said autonomous device is provided with a screen above at least one receiver in the line of said receivers, said screen attenuating undesired reflections from above and/or from the side and then acts in the same manner as an eyebrow above the receivers.

14. The system according to claim 10 wherein the most outer receivers on each side of the line of said receivers are arranged differently in height in relation to the remaining receivers.

15. The system according to claim 10 wherein said wave comprises a longitudinal acoustic wave.

16. The system according to claim 10 wherein said wave comprises an acoustic wave having a frequency within the ultrasonic range.

17. The system according to claim 10 wherein said wave comprises one of a short, regularly repeated pulse and a repeated swept pulse (chirp signal).

18. The system according to claim 10 wherein said receivers comprise microphone elements adopted to the frequency of said wave.

20. The system according to claim 11 wherein said autonomous device is provided with an absorber above at least one receiver in the line of receiver, said absorber attenuating undesired reflections from above and/or from the side and then acts in the same manner as an eyebrow above the receiver.