Autonomous Robot

• US 20080183349A1
• Filed: 12/04/2007
• Published: 07/31/2008
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: Mtd Products Incorporated (Stanley Black & Decker, Inc.)
• Original Assignee: F Robotics Acquisitions Ltd. (Stanley Black & Decker, Inc.)
• Inventors: Ikar, Ido, Abramson, Shai
• Granted Patent: US 8,306,659 B2
• Time in Patent Office: Days
• US Class Current: 701/23
• CPC Class Codes: A01D 34/008 for automated or remotely controlled operation
• CPC Class Codes: A01G 25/00 Watering gardens, fields, sports grounds or the like special apparatus or adaptations for fertilising-liquids A01C23/00; nozzles or outlets, spraying apparatus B05B
• CPC Class Codes: A47L 2201/00 Robotic cleaning machines, i.e. with automatic control of the travelling movement or the cleaning operation
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: B25J 9/0003 Home robots, i.e. small robots for domestic use
• 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 1/0265 using buried wires
• CPC Class Codes: H04B 2203/5458 Monitor sensor; Alarm systems
• CPC Class Codes: H04B 3/54 Systems for transmission via power distribution lines
• CPC Class Codes: H04B 3/548 the power on the line being DC arrangements for feeding power H04L12/10; extracting feeding power from signals H04L25/02
• CPC Class Codes: Y10S 901/01 Mobile robot

Abstract

A method for communication between a charging station and a robot, via a pair of power lines coupled between a power supply in the charging station and a battery in the robot. In operation, the power supply is sequentially switched between a first voltage level and a second voltage level in accordance with a predetermined signal pattern. The voltage level on the power lines in the robot is monitored and correlated with a specific command to be executed by the robot.

Claims

1. A method for communication between a charging station and a robot, via at least one pair of power lines coupled between a power supply in the charging station and a battery in the robot, the method comprising:

sequentially switching the power supply between a first voltage level and a second voltage level in accordance with a predetermined signal pattern; and

monitoring the voltage level on the power lines in the robot;

wherein the signal pattern monitored by the robot is correlated with a specific command to be executed by the robot.

2. The method of claim 1, wherein the command executed by the robot is selected from the group consisting of commands for activating a specific perimeter loop controlling the robot, commands for controlling a signal level on the perimeter loop, commands for indicating a battery type in the robot, commands for indicating the voltage of the battery in the robot, and commands for controlling an electronic irrigation system.

3. The method of claim 1, wherein the power supply is switched in an ON and OFF sequence by a switch in the charging station to establish the signal pattern, and wherein the robot determines the signal pattern by monitoring the ON and OFF sequence.

4. The method of claim 1, wherein the signal pattern is established by the robot by

switching the power received on the power lines by the robot in an ON and OFF sequence by a switch in the robot, and wherein the charging station determines the signal pattern by monitoring the ON and OFF sequence via detection of respective voltage levels on the power lines, and wherein the signal pattern is correlated with the specific command to be executed by the charging station.

5. The method of claim 1, wherein bidirectional communication is effected between the robot and the charging station by performing additional steps comprising:

establishing a second signal pattern by switching the power received on the power lines by the robot in an ON and OFF sequence by a switch in the robot, wherein the charging station determines the second signal pattern by monitoring the ON and OFF sequence via detection of respective voltage levels on the power lines, and

correlating the sequence with the specific command to be executed by the charging station.

6. The method of claim 5, wherein the electrical current level, in lieu of the voltage level, on the power lines, is monitored to determine the signal pattern in the robot and the second signal pattern in the charging station.

7. A method for determining a lawn mowing schedule for a robot comprising:

traversing the lawn during a scanning session to determine a total lawn area to be mowed;

calculating the number of mowing sessions required to mow the total lawn area in accordance with the size of an area that can be mowed by the robot per a single mowing session and the total lawn area to be mowed;

distributing, over a specific time interval, the number of mowing sessions required; and

optimizing a length of a specific mowing session by utilizing information obtained during the specific mowing session.

8. The method of claim 7, wherein the total lawn area to be mowed is determined by following the lawn perimeter to determine a polygonal area.

9. The method of claim 7, wherein the total lawn area to be mowed is determined by:

performing an autonomous scanning operation to determine the length of an average leg traversed by the robot after multiple traverses across the lawn; and

determining the total lawn area to be mowed by calculating a value equal to two times the square of the length of an average leg.

10. The method of claim 7, wherein said mowing sessions are scheduled in response to information determined during a mowing operation.

11. The method of claim 7, wherein, during one of the mowing sessions, the robot monitors electric current drawn by a motor that rotates a mowing blade to determine lawn height from resistance on the blade as a function of the electric current, and causes the mowing schedule to be modified to accommodate the lawn height.

12. The method of claim 7, wherein the length of the specific mowing session is optimized by utilizing information obtained from a charging station prior to the mowing session.

13. The method of claim 7, wherein the mowing schedule is adapted in accordance with calendar information, such that the number of mowing sessions in a given period of time is increased or decreased in accordance with the present date.

14. The method of claim 7, wherein input from an environmental sensor is used to determine the rate of the growing period and adapt the robot mowing schedule.

15. The method of claim 7, wherein the environmental sensor is selected from the group consisting of a wet grass sensor, a temperature sensor, a rain sensor, and a humidity sensor.

16. A method for scanning, by a robot, a work area to be covered by the robot, wherein the robot travels inside the work area in successive paths, each initiated when the robot changes direction, the method comprising:

scanning the work area using a first scanning pattern;

monitoring the length of each of the paths traveled by the robot;

switching from the first scanning mode to a second scanning pattern when an obstacle is encountered on a minimum number of consecutive said paths each having a length between a first threshold distance and a longer, second threshold distance; and

switching back to the first scanning pattern when the length of one of the paths has increased to more than the second threshold distance.

17. The method of claim 16, wherein the first scanning pattern comprises the robot traveling in a random walk pattern, and wherein the second scanning pattern comprises the robot traveling in a pattern comprising alternating pairs of essentially parallel paths, wherein a first one of the paths in each of the alternating pairs is oriented at an angle between approximately 120 and 240 degrees from the angle of the immediately previous one of the paths.

18. The method of claim 16, wherein, if a predetermined number of consecutive paths traveled by the robot are each shorter than the first threshold distance, determining that the robot has reached a corner, in response to which the robot performs a maneuver to exit from the corner.

19. The method of claim 16, wherein the robot changes direction in the first scanning mode and in the second scanning mode when a work area boundary is encountered and when an obstacle is encountered.

20. The method of claim 16, wherein the minimum number of consecutive paths is at least two.

21. A method for maneuvering a robot to extricate a robot from a problem area comprising:

saving the heading of the robot as heading H1, when the robot encounters a first obstacle;

performing an in-place turn in a first direction;

saving the heading of the robot as heading H2, when the robot encounters a second obstacle;

performing a turn in the reverse direction of the first turn substantially toward the bisector of the sector bounded by headings H1 and H2; and

continuing operation with a forward leg to move between the first obstacle and the second obstacle, in a heading whose angular direction is substantially equal to the bisected angle H1-H2.

22. The method of claim 21, wherein the first obstacle and the second obstacle are selected from a combination of obstacles consisting of two solid obstacles, and one solid obstacle and a perimeter boundary wire.

25. The method of claim 22, wherein the step of determining whether the robot is still inside the problem area is performed by observing that a straight leg traversed by the robot is longer than a predetermined value.

23. A method for maneuvering a robot to extricate a robot from within a problem area bounded partially by an obstacle comprising:

(a) traversing a straight leg until an obstacle is encountered;

(b) performing a turn in a first direction;

(c) continuing a straight leg traverse;

(d) determining whether the robot is still inside the problem area; and

(e) repeating steps (a) and (b) until the robot is no longer inside the problem area.

24. The method of claim 23, wherein the turn has an angular value of between approximately 10 and 30 degrees.