Cleaning robot and control method thereof

• US 8,442,683 B2
• Filed: 05/17/2011
• Issued: 05/14/2013
• Est. Priority Date: 01/28/2011
• Status: Active Grant

• Current Assignee: iRobot Corporation
• Original Assignee: MSI Computer Company Limited (Micro-Star International Co., Ltd.)
• Inventors: Lee, Yung-Shen, Chen, Shui-Shih
• Primary Examiner(s): Tran, Khoi
• Assistant Examiner(s): NGUYEN, ROBERT T
• Application Number:
  US13/109,216
• Publication Number:
  US 20120197437A1
• Time in Patent Office: 728 Days
• Field of Search: 700/255, 700/258, 15/211, 153/19
• US Class Current: 700/258
• CPC Class Codes: A47L 2201/04 Automatic control of the travelling movement; Automatic obstacle detection
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93

Abstract

A cleaning robot including a roller unit, a sensing unit, a first control unit and a second control unit is disclosed. The roller unit includes a plurality of rollers. The sensing unit receives a reflection signal and generates a detection signal according to the reflection signal. When the detection signal is less than or equal to a reference signal, the first control unit controls the traveling direction of the rollers according to the detection signal such that a distance between the cleaning robot and a wall is equal to a first distance. When the detection signal is larger than the reference signal, the second control unit controls the traveling direction of the rollers according to the detection signal such that a distance between the cleaning robot and a wall is equal to a second distance larger then the first distance.

Claims

1. A cleaning robot, comprising:

a roller unit comprising a plurality of rollers;

a sensing unit receiving a reflection signal and generating a detection signal according to the reflection signal;

a first control unit, wherein when the detection signal is less than or equal to a reference signal, the first control unit controls the traveling direction of the rollers according to the detection signal such that a distance between the cleaning robot and a wall is equal to a first distance; and

a second control unit, wherein when the detection signal is larger than the reference signal, the second control unit controls the traveling direction of the rollers according to the detection signal such that a distance between the cleaning robot and a wall is equal to a second distance larger then the first distance.

2. The cleaning robot as claimed in claim 1, wherein the reflection signal is an ultrasonic wave.

3. The cleaning robot as claimed in claim 1, wherein the second control unit delays the detection signal and controls the rollers according to the delayed detection signal.

4. The cleaning robot as claimed in claim 1, wherein the first control unit comprises a phase-lead controller, and the second control unit comprises a phase-lag controller.

5. The cleaning robot as claimed in claim 4, wherein the second control unit comprises:

a filter filtering the detection signal when the detection signal is larger than the reference signal, wherein the phase-lag controller controls the traveling direction of the rollers according to the filtered detection signal.

6. The cleaning robot as claimed in claim 5, wherein a cut-off frequency of the filter relates to the width of the cleaning robot.

7. The cleaning robot as claimed in claim 5, wherein the filter is an infinite impulse response (IIR) filter, a finite impulse response (FIR) filter, a Kalman filter or a particle filter.

8. The cleaning robot as claimed in claim 1, wherein the second control unit comprises a proportional-integral-derivative (PID) controller, a fuzzy controller or a learning controller.

9. A control method for controlling a cleaning robot comprising a first control unit and a second control unit, wherein traveling route of the cleaning robot is controlled by the first and the second control units, comprising:

activating the cleaning robot to receive a reflection signal;

generating a detection signal according to the reflection signal;

when the detection signal is less than or equal to a reference signal, the first control unit is enabled such that the cleaning robot maintains a first distance with a wall; and

when the detection signal is larger than the reference signal, the second control unit is enabled such that the cleaning robot maintains a second distance with the wall, wherein the second distance is larger than the first distance.

10. The control method as claimed in claim 9, wherein when the second control unit is enabled, the second control unit delays the detection signal and controls the cleaning robot according to the delayed detection signal such that the cleaning robot maintains the second distance with the wall.

11. The control method as claimed in claim 9, wherein when the second control unit is enabled, the second control unit filters the detection signal.