Mobile robots and their control system

• US 20020120364A1
• Filed: 03/01/2002
• Published: 08/29/2002
• Est. Priority Date: 11/27/1997
• Status: Active Grant

• Current Assignee: Andre Colens
• Original Assignee: Andre Colens
• Inventors: Colens, Andre
• GRANTED PATENT: US 6,532,404 B2
• Time in patent office: 0 Days
• US Class Current: 700/262
• CPC Class Codes: A47L 11/4005 Arrangements of batteries or cells; Electric power supply arrangements
• 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 2201/022 Recharging of batteries
• CPC Class Codes: A47L 2201/024 Emptying dust or waste liquid containers
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: B25J 9/1694 characterised by use of sensors other than normal servo-feedback from position, speed or acceleration sensors, perception control, multi-sensor controlled systems, sensor fusion
• CPC Class Codes: G05B 2219/24136 Monitor load state of battery
• CPC Class Codes: G05B 2219/31004 Move vehicle to battery charge or maintenance area
• CPC Class Codes: G05B 2219/37266 Infrared
• CPC Class Codes: G05B 2219/40522 Display of workpiece, workspace, locus of robot tip in different planes, xy xz yz
• CPC Class Codes: G05B 2219/40621 Triangulation sensor
• 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 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 2201/0215 Vacuum cleaner
• CPC Class Codes: Y10S 706/905 Vehicle or aerospace

Abstract

System of guidance and positioning relative to a fixed station (1) for an autonomous mobile robot (7) utilizing at least a directional infra-red beam (2′) emitted by the fixed station, the mobile robot being provided with a directional system of detection (10a, 10b) of infra-red emission connected to a microcomputer incorporated in the said robot, the robot moving on a work surface in an essentially random manner, the microcomputer (44) including an algorithm able to control the return to fixed station (1) by displacement of the robot (7) towards the direction of emission of said infra-red beam (2′), characterized in that the infra-red beam (2′) is a narrow directional beam and in that the system of detection (10a, 10b) is located on a frame at the center of rotation of the robot (7), oriented in the direction of movement of the robot, precise positioning in the fixed station (1) being carried out by rotation of the machine around a vertical axis according to an algorithm based on the detection of the narrow beam (2′).

Claims

1. System of guidance and positioning relative to a fixed station (1) for an autonomous mobile robot (7) utilizing at least a directional infra-red beam (2′

) emitted by the fixed station, the mobile robot being provided with a directional system of detection (10a, 10b) of infra-red emission connected to a microcomputer incorporated in the said robot, the robot moving on a work surface in a essentially random manner , the microcomputer (44) including an algorithm able to control the return to fixed station (1) by displacement of the robot (7) towards the direction of emission of said infra-red beam (2′

), characterized in that the infra-red beam (2′

) is a narrow directional beam and in that the system of detection (10a, 10b) is located on the frame at the center of rotation of the robot (7), oriented in the direction of movement of the robot, precise positioning in the fixed station (1) being carried out by rotation of the machine around a vertical axis according to an algorithm based on the detection of the narrow beam (2′

).

2. System of guidance according to claim 1 in which the narrow directional beam (2′

) has an angle ranging between 2 and 10°

.

3. System according to any of claims 1 or 2 characterized in that it utilizes at least two beams (2′

, 3′

) of substantially different directionality emitted from or in the vicinity of the fixed station (1), the one or several least directional beams (3′

) being used for the approach towards the fixed station (1), while the one or several more directional beams (2′

) are used for the ultimate step of precise positioning of the robot relative to the fixed station (1).

4. System according to any of the preceding claims wherein the algorithm of the microcomputer initiates the return towards the fixed station of recharge after a minimum working time, independently of the state of charge of a battery, and when the mobile robot detects an infra-red radiation of an intensity higher than a certain threshold, the aforementioned threshold decreasing with the increase in the duration of the working time and/or when the state of charge of the battery is below a predetermined level.

5. System according to the claim 1 or 2 wherein the algorithm of the microcomputer initiates the return towards the fixed station of recharge when the state of load of the battery is under a predetermined level.

6. System according to the preceding claims characterized in that during the step of return of the robot towards the fixed station, and according to the state of charge of the battery and/or the intensity of the detected infra-red radiation, the brush roller and/or the suction turbine are inactivated.

7. System for direction finding and positioning according to any of claims 1 to 5 characterized in that the fixed station emits two modulated infra-red beams (2′

, 3′

), essentially in the plane of the rooms wherein the said robot (7) moves, one of the beams being appreciably more directional than the other, the transmitter of the least directional beam allowing the finding of the direction and the approach of the fixed station by the mobile robot carrying directional sensors (10a, 10b, 11a, 11b) sensitive to said beams, the signals of the sensors being treated by one microcomputer (44) controlling the advance of the mobile robot, the transmitter (3) of the least directional beam being located on the fixed station (1) such that it is directly above the mobile robot when the latter joins its desired position in the fixed station, the more directional beam (2) being then able to be more intensively detected by the said sensors, precise positioning being carried out by rotation of the machine around a vertical axis in accordance with an algorithm based on the detection of the narrow beam.

8. System for direction finding and positioning according to any of claims 1 to 6 characterized in that the fixed station emits at least three modulated infra-red beams (2′

, 3′

), one (2) of the beams being appreciably more directional than the two others, the transmitters (3b, 3c) of the least directional beams allowing the finding of the direction and the approach of the fixed station by the mobile robot carrying directional sensors sensitive to said beams, the signals of the sensors being treated by one microcomputer (44) controlling the advance of the mobile robot, the transmitter of high intensity being oriented and located in the fixed station at a location such that the beams cross (2′

, 3′

) each other in the immediate vicinity of the station, the more directional beam being then able to be more intensively detected by the aforementioned sensors, the precise positioning being carried out by rotation of the machine around a vertical axis in accordance with an algorithm based on the detection of the narrow beam.

9. System according to any of the preceding claims wherein the transmitter of the more directional infra-red beam (2) is less powerful than the transmitter (3) of the less directional infra-red beam.

10. Autonomous mobile robot incorporating a microcomputer (44) able to apply the system of claims 1 to 8.

11. Robot according to claim 10 comprising at least a rotary brush roller (24) and a microcomputer (44) controlling at least, via an algorithm, the speed and/or the path of robot characterized in that the microcomputer is associated with an algorithm which takes into account, in order to determine the aforementioned speed and/or the aforementioned path, the measurement of the rotation speed of the aforementioned rotary brush roller.

12. Robot for cleaning according to the preceding claim characterized in that it is a robotic vacuum-cleaner.

13. Robot according to the preceding claim characterized in that the microcomputer (44) takes at least in account, for determining the suction power, the measurement of number of revolutions of the aforementioned brush roller (24).

14. Robot according to the preceding claim incorporating a guiding technique for the cleaning of the ground characterized in that the path followed by the robot (7) depends on the quantity of particles present on the surface to clean, the said quantity being estimated by a particle analyzer (27,28) located near the suction inlet of the robotic vacuum cleaner, the aforementioned analyzer sending the signals to the microcomputer (44) carried by the mobile robot and controlling the displacement of the robot according to the said signals.

15. Robot according to the preceding claim wherein the microcomputer can control a deceleration and/or a linear back and forth movement and/or a back and forth movement in a fan shape of the mobile robot.

16. Robot according to claims 13 and 14 wherein the microcomputer keeps in memory a global average of dust level as detected by the sensor (27, 28) of dust on a long distance, the activation of one particular algorithm for cleaning taking account of the aforementioned average.

17. Robot according to any of the preceding claims characterized in that it comprises a linear sensor of collision surrounding entirely or partly the base of the careenage, the sensor including a linear metal (62) conductor and, in parallel, a linear element (61) made of conducting plastic, for example conducting rubber, whose ends are subjected to a potential difference, the linear element in plastic being able to come elastically into contact with the conducting linear element under the effect of a temporary pressure resulting from the impact of the robot with an obstacle (65), the measurement of the current measured at the level of the conducting element being a signal fed to the microcomputer to locate the point of impact at the basis of the careenage.