Autonomous lawn mower and a system for navigating thereof

Patent metadata

Field	Value
Publication number	US-11832552-B2
Application number	US-201716312236-A
Country	US
Kind code	B2
Filing date	Jun 30, 2017
Priority date	Jun 30, 2016
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

An autonomous lawn mower (100) comprises a mower body (102) having at least one motor (210) arranged to drive a cutting blade (212b) and to propel the mower body (102) on an operating surface via a wheel arrangement. The mower body (102) includes a navigation system (204) arranged to assist a controller (202) to control the operation of the mower body (102) within the predefined operating area (208). The navigation system includes an odometry module (106, 220), a rotatable optical surveying module (222), a sonic obstacle detection module (224), a heat absorbing unit set on the outer surface of the mower body (102) for directing the heat generated within the mower body towards the atmosphere, and a detachable docking module (816) arranged to receive the mower body (102).

First claim

What is claimed is:

1. An autonomous lawn mower comprising:
a mower body having at least one motor arranged to drive a cutting blade and to propel the mower body on an operating surface via a wheel arrangement, wherein the mower body includes a navigation system arranged to assist a controller to control the operation of the mower body within a predefined operating area;
wherein the navigation system includes an odometry module arranged to track movement of the mower body on the operating surface, wherein the odometry module includes one or more encoder sensors arranged to detect a rate of rotation of at least one wheel of the wheel arrangement,
wherein the rate of rotation of each wheel of the at least one wheel is applied to a transmission ratio to determine a respective rotation distance of each wheel,
wherein the one or more encoder sensors are disposed onto a driving motor arranged to drive the at least one wheel of the wheel arrangement,
wherein (i) a first wheel of the at least one wheel, (ii) the driving motor, (iii) a gearbox connected to the driving motor and the first wheel, and (iv) a first encoder sensor of the one or more encoder sensors are located on a motor axis of the driving motor,
wherein an amount of current drawn by the driving motor is measured and compared to the rate of rotation of the at least one wheel, and
wherein the controller is configured to detect spinning of the at least one wheel along the operating surface without movement of the mower body in response to determining that the current drawn by the driving motor is low relative to the rate of rotation of the at least one wheel.

2. The autonomous lawn mower of claim 1 , wherein the odometry module is arranged to communicate with the one or more encoder sensors disposed onto the driving motor to determine the rotation distance and a direction travelled by the at least one wheel.

3. The autonomous lawn mower of claim 2 , wherein the odometry module is arranged to transmit the rotation distance and the direction travelled of each wheel of the at least one wheel to the navigation system.

4. The autonomous lawn mower of claim 1 , wherein a magnetic member is disposed onto a shaft of the driving motor, and the one or more encoder sensors is disposed adjacent to the magnetic member to determine an angular movement of the magnetic member.

5. The autonomous lawn mower of claim 1 , wherein the one or more encoder sensors are located at a first end of the driving motor that is opposite a second end of the driving motor to which the gearbox is connected.

6. The autonomous lawn mower of claim 1 , wherein the one or more encoder sensors are disposed onto the driving motor by being included on a printed circuit board (PCB) that is connected to a first end of the driving motor that is opposite a second end of the driving motor to which the gearbox is connected.

7. An autonomous lawn mower comprising:
a mower body having at least one motor arranged to drive a cutting blade and to propel the mower body on an operating surface via a wheel arrangement, wherein the mower body includes a navigation system arranged to assist a controller to control the operation of the mower body within a predefined operating area;
wherein the navigation system includes a sonic obstacle detection module arranged to use sound waves to detect obstacles proximate to the lawn mower, wherein the sonic obstacle detection module includes at least two sonar sensors located at an elevated position on top of the mower body, wherein a first sonar sensor is disposed on a left side of the top of the mower body and a second sonar sensor is disposed on a right side of the top of the mower body,

wherein the mower body includes a perimeter cutter separate from the cutting blade and configured to trim an edge of the predefined operating area by moving along the edge of the predefined boundary, and
wherein a third sonar sensor is positioned on an elongated side of the mower body proximate to the perimeter cutter to measure a distance from the mower body to a side obtrusion to navigate close to the side obtrusion without bumping the side obtrusion during trimming of the edge of the predefined operating area.

8. The autonomous lawn mower of claim 7 , wherein the sonic obstacle detection module is a sonar unit.

9. The autonomous lawn mower of claim 7 , wherein the sonic obstacle detection module includes four sonar sensors.

10. The autonomous lawn mower of claim 7 , wherein the at least two sonar sensors are pointed in the forward direction of the mower body.

Assignees

• Tti Macao Commercial Offshore Ltd
• Techtronic Outdoor Products Tech Limited

Inventors

• Hahn Klaus
• Rickey Todd Brandon
• Montgomery Benjamin Edgar
• Ensslen Nikolai
• Yildirim Levent

Classifications

• A01D34/008 Primary

  for automated or remotely controlled operation · CPC title

• A01D34/54

  Cutting-height adjustment · CPC title

• A01D34/69

  with motor driven wheels · CPC title

• A01D34/84

  for edges of lawns or fields, e.g. for mowing close to trees or walls ({for embankments A01D34/86 takes precedence;} edge trimmers A01G3/00) · CPC title

• B60L50/66

  Arrangements of batteries · CPC title