Mobile robot guidance and navigation system

• US 5,165,064 A
• Filed: 03/22/1991
• Issued: 11/17/1992
• Est. Priority Date: 03/22/1991
• Status: Expired due to Fees

• Current Assignee: Cyberotics Incorporated
• Original Assignee: Cyberotics Incorporated
• Inventors: Mattaboni, Paul J.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US07/674,517
• Time in Patent Office: 606 Days
• Field of Search: 901/1, 901/46, 901/47, 356/1, 356/152, 364/424.01, 364/424.07
• US Class Current: 356/141.2
• CPC Class Codes: G05D 1/0234 using optical markers or beacons optical beacons per se G01S1/70
• CPC Class Codes: G05D 1/0242 using non-visible light signals, e.g. IR or UV signals
• 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 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

A mobile robot which has a guidance and navigation system (sometimes called a "vision" system) employing one or more arrays of ultrasonic transducers and, preferably, one or more infrared detectors, as well. Each of the ultrasonic transducers is arranged to monitor its own sector of the robot'"'"'s workspace. Sector monitoring is facilitated by providing for each such transducer a horn fronting the transducer; at least part of the horn'"'"'s surface is covered by ultrasonic energy absorptive material. According to a second aspect of the invention, the robot is used in conjunction with an infrared beacon system including one or more (preferably ceiling-mounted) beacons each of which emits a uniquely coded infrared signal. The robot is equipped with an infrared detection means affixed to the robot and arranged to allow light from the beacon to impinge on an infrared sensor only when the detector is in precise alignment with the beacon. Multiple sensors are preferably provided, each receiving light from the beacon only when that sensor is aligned with the beacon. The signal from the infrared beacon is decoded to ascertain the particular beacon the robot is near. The orientation of the robot relative to the beacon is signalled by which sensor is aligned with the beacon, which is determined by the processor examining all sensor outputs and picking the one with the largest output signal.

Claims

1. In a mobile robot of the type having

a. a vision system employing at least one array of ultrasonic transducers in which each transducer is arranged to monitor its own sector of the robot'"'"'s workspace;

b. means for simultaneously activating a plurality of the transducers in the array whereby each activated transducer transmits a pulse of ultrasonic energy, the improvement for reducing crosstalk comprising

i. a horn fronting each activated transducer, the horn flaring at an angle related to the extent of the sector monitored by the transducer; and

ii. ultrasonic energy absorptive material covering at least part of each horn'"'"'s surface.

2. In a mobile robot of the type having

a. a vision system employing at least one array of ultrasonic transducers in which each transducer is arranged to monitor its own sector of the robot'"'"'s workspace;

b. means carried on the robot for enabling the robot to utilize data provided by the ultrasonic vision system for autonomous navigation within the workspace, the improvement for enabling the robot to ascertain its precise location in the workspace, comprising,

i. at least one infrared beacon situated in a known location in the workspace; and

ii. at least one infrared detection means affixed to the robot, including an infrared sensor and means limiting the direction from which light can reach the sensor from a beacon; and

iii. a horn having an inner surface coated in part by ultrasonic energy absorptive materials fronts each of said transducers.

3. The robot of claim 2 wherein each beacon emits infrared light modulated by a code unique to the beacon'"'"'s location and the robot further includes means coupled to the sensors for decoding the modulation of the received infrared signal to determine the location of the robot.

4. The robot of claim 3 means for determining which of a plurality of sensors is receiving the light from the beacon, when a plurality of sensors are employed, for determining the orientation of the robot relative to the beacon.

5. The robot of claim 2 including a fixed array of infrared detection means.

6. A mobile robot comprising:

a. a vision system employing at least one array of ultrasonic transducers in which each transducer is arranged to monitor its own sector of the robot'"'"'s workspace;

b. means for simultaneously activating a plurality of the transducers in the array; and

c. a horn fronting each activated transducer, the horn flaring outwardly from the transducer at a rate related to the extent of the sector monitored by the transducer.

7. The mobile robot according to claim 6 further including an ultrasonic energy absorptive material covering at least part of each horn'"'"'s interior surface.

8. A mobile robot guidance system comprising:

a. a beacon system having at least one information-transmitting beacon providing information concerning the workspace; and

b. a robot having

1. a vision system employing at least one array of ultrasonic transducers in which each transducer is arranged to monitor an associated sector of the robot'"'"'s workspace,

2. means carried on the robot for enabling the robot to utilize data provided by the ultrasonic vision system for autonomous navigation within the workspace, and

3. means carried on the robot, for receiving the information from said beacon and making a decision based on the information.