Running control system of robot and method thereof

• US 5,687,294 A
• Filed: 06/07/1995
• Issued: 11/11/1997
• Est. Priority Date: 06/07/1994
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jeong, Joon-Young
• Primary Examiner(s): Davis, George B.
• Application Number:
  US08/478,374
• Time in Patent Office: 888 Days
• Field of Search: 395/3, 395/90, 395/93, 901/23, 901/1, 318/568.16, 318/568.12, 318/587, 364/461
• US Class Current: 700/258
• CPC Class Codes: G05D 1/0221 involving a learning process
• CPC Class Codes: G05D 1/0255 using acoustic signals, e.g. ultra-sonic singals sonar systems designed for anti-collision purposes G01S15/93
• 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 706/90 Fuzzy logic

Abstract

A running control system of a mobil robot performs a fuzzy inference according to a position error, directional error and instantaneous directional angle detected in the travel of the robot, so that the robot can travel accurately to a target point and perform operations such as cleaning and monitoring. An obstacle detecting unit detects whether or not there is an obstacle within a prescribed area to be traveled by the robot and for detecting a distance to the obstacle.

Claims

1. A running control system for guiding a robot comprising:

a controller for controlling an overall running operation of the robot in accordance with input signals supplied thereto;

a drive unit including left and right running motors connected to the controller for moving and guiding the robot in a running direction in accordance with an output signal from the controller;

a running distance detector connected to the controller for detecting a running distance of the robot moved by the drive unit and outputting a running distance signal proportionate thereto to the controller as one of the input signals;

a directional angle detector connected to the controller for detecting a running direction varied by the drive unit and outputting a directional angle signal proportionate thereto to the controller as one of the input signals; and

an obstacle detector connected to the controller for detecting an obstacle within a prescribed area to be traversed by the robot and a distance to the obstacle and outputting an obstacle distance signal proportionate thereto to the controller as one of the input signals.

2. The system according to claim 1 wherein the controller includes:

a directional angle operating unit for receiving the directional angle signal and calculating an instantaneous directional angle, and an overall directional angle representative of a difference between a target running direction and a current direction of travel of the robot;

a position operating unit for receiving the overall directional angle from the directional angle operating unit, and the running distance signal, for calculating therefrom a position error of the robot;

a path control fuzzy inference unit for receiving the instantaneous directional angle from the directional angle operating unit and the position error from the position operating unit, for calculating therefrom path output variation magnitudes of the left and right running motors;

a speed error operator for comparing the running distance signal with a reference speed for calculating therefrom a speed error of the robot; and

a speed control fuzzy inference unit for receiving the speed error from the speed error operator, and the obstacle distance signal, for calculating therefrom speed control output variation magnitudes for the left and right running motors.

3. The system according to claim 2 wherein the controller includes an operator for receiving the path control output variation magnitudes from the path control fuzzy inference unit, and the speed control output variation magnitudes from the speed control fuzzy inference unit for modifying the left and right running motor output magnitudes in accordance therewith.

4. A method of controlling the running of a robot having left and right drive motors, comprising the steps of:

A) detecting a running distance of the robot;

B) detecting a directional angle of travel of the robot;

C) determining from the detected running distance and detected directional angle a path error, a position error, a directional angle error, and an instantaneous directional angle of the robot;

D) performing a path control fuzzy inference using the path error to calculate path control output variation magnitudes of the left and right running motors;

E) calculating a speed error by comparing the running distance with a reference speed;

F) performing a speed control fuzzy interference using the speed error to calculate speed control output variation magnitudes of the left and right drive motors; and

G) calculating from the path control output variation magnitudes and the speed control output magnitudes, final output magnitudes of the left and right drive motors.

5. The method according to claim 4 wherein the performing a path control fuzzy inference comprises calculating the path control output variation magnitudes as a function of a size of the instantaneous directional angle.

6. The method according to claim 4 further including the step of detecting an obstacle in a path of the robot, and determining from the speed error a distance to the detected obstacle.