Navigational control system for a robotic device

• US 8,515,578 B2
• Filed: 12/13/2010
• Issued: 08/20/2013
• Est. Priority Date: 09/13/2002
• Status: Expired due to Term

• Current Assignee: iRobot Corporation
• Original Assignee: iRobot Corporation
• Inventors: Chiappetta, Mark J., Jones, Joseph L.
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): PATTON, SPENCER D
• Application Number:
  US12/966,509
• Publication Number:
  US 20110144805A1
• Time in Patent Office: 981 Days
• Field of Search: 700/245, 700/253, 700/254, 700/255, 700/258, 700/259, 701/23, 701/24, 701/200, 701/207, 701/208, 701/300, 318/568.12, 318/580, 180/167, 180/168, 901/1, 901/46, 901/47, 153/19, 342/385, 342/386
• US Class Current: 700/253
• 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: 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: G05D 1/0227 using mechanical sensing means, e.g. for sensing treated area
• CPC Class Codes: G05D 1/0231 using optical position detecting means position-fixing by using electromagnetic waves other than radio waves, e.g. optical position detecting means G01S5/16
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• CPC Class Codes: G05D 1/0272 comprising means for registering the travel distance, e.g. revolutions of wheels measuring distance traversed on the ground by vehicles, e.g. using odometers G01C22/00
• CPC Class Codes: Y10S 901/01 Mobile robot
• CPC Class Codes: Y10S 901/09 Closed loop, sensor feedback controls arm movement

Abstract

A navigational control system for altering movement activity of a robotic device operating in a defined working area, comprising a transmitting subsystem integrated in combination with the robotic device, the transmitting subsystem comprising means for emitting a number of directed beams, each directed beam having a predetermined emission pattern, and a receiving subsystem functioning as a base station that includes a navigation control algorithm that defines a predetermined triggering event for the navigational control system and a set of detection units positioned within the defined working area in a known spaced-apart relationship, the set of detection units being configured and operative to detect one or more of the directed beams emitted by the transmitting system; and wherein the receiving subsystem is configured and operative to process the one or more detected directed beams under the control of the navigational control algorithm to determine whether the predetermined triggering event has occurred, and, if the predetermined triggering event has occurred transmit a control signal to the robotic device, wherein reception of the control signal by the robotic device causes the robotic device to implement a prescribed conduct that alters the movement activity of the robotic device.

Claims

1. A robotic cleaner, comprising:

a chassis and an outer shell secured to the chassis;

left and right main drive wheel assemblies and respective independent electric motors, independently mounted in pivotally-biased combination with the chassis for pivotal motion with respect thereto at opposed ends of the transverse diameter of the chassis, and movable between a retracted position under the weight of the robotic cleaner during operation and an extended position wherein their axes of rotation are below the bottom plane of the chassis;

a navigational control system operative to monitor movement activity of the robotic cleaner within a defined working area, the monitored movement activity including at least one of a position history of the robotic cleaner and an instantaneous position of the robotic cleaner; and

a transmitting subsystem including a mechanical sweeping transmitter laser, wherein the mechanical sweeping transmitter laser;

is configured to sweep to redirect a transmitting element of the mechanical sweeping transmitter laser;

is configured to transmit in the infrared range from about 750 nm to about 1.4 ×

10^4 nm;

is configured to cover the defined working area by transmitting a beam substantially parallel to a surface of the defined working area;

is mounted in combination with the outer shell secured to the chassis to define an overall structural envelope of a height to enable movement of the robotic cleaner under furniture; and

is integrated in combination with a high point of a housing infrastructure of the robotic cleaner so that none of the structural features of the robotic cleaner interfere with sweeping of the transmitting element of the mechanical sweeping transmitter laser.

2. The robotic cleaner of claim 1, further comprising a receiver unit configured to receive control signals.

3. The robotic cleaner of claim 1, wherein the navigational control system is configured to create a tessellation of the defined working area by segmenting the defined working area into a set of individual cells.

4. The robotic cleaner of claim 3, wherein the navigational control system is configured to define a size of each individual cell based on a width of a cleaning head system of the robotic cleaner.

5. The robotic cleaner of claim 1, further comprising a rechargeable battery pack integrated in combination with the chassis.

6. The robotic cleaner of claim 1, further comprising a forward bumper integrated in movable combination with the chassis, wherein the forward bumper is configured so that when the chassis encounters an obstacle, the bumper is displaced towards the chassis and returns to an extended position when contact with the obstacle is terminated.

7. The robotic cleaner of claim 1, further comprising a wheel drop sensor integrated in combination with each of the main drive wheel assemblies and operative to generate a signal whenever any of the wheel assemblies is in an extended position in which the axes of rotation thereof is below the bottom plane of the chassis.

8. The robotic cleaner of claim 1, further comprising an obstacle-following unit comprising an IR emitter—

detector pair configured to transmit a signal to a control module if reflected radiation is not detected by the detector.

9. The robotic cleaner of claim 1, further comprising respective stall-sensor units integrated in combination with each respective independent electric motor and operative to transmit a signal to the control module when a change in current is detected in the respective independent electric motor.

10. The robotic cleaner of claim 1, further comprising at least one cliff detection unit comprising an IR emitter—

detector pair configured to transmit a signal to the control module when a drop-off is encountered.

11. The robotic cleaner of claim 1, wherein the mechanical sweeping transmitter laser is configured to cycle on/off sequentially.