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The Five Senses - Lasers
LASERS
While it is not one of a human beings five senses, lasers are a integral part of machines sensing their environment. Early hopes were that machines would be able to navigate much like bats and dolphins do using sonar. It turns out that application of inexpensive sonar to machine navigation is more complex than engineers expected. Sonar beams refused to behave the way engineers wanted them to. When rugged, inexpensive laser diodes became available they did work the way engineers had hoped sonar would have. Laser diodes produce a nice crisp signal going out and a equally crisp return, from a single point, everything engineers had been hoping for.
LASER BUMPERS
Scanning laser range finders are becoming quite common now, so much so that laser manufacturers are offering complete laser bumper kits for AGV builders. The laser bumpers allow the vehicle to react to objects around it without coming in contact with them. Zones can be set up around the vehicle such as a warning zone and a stop zone. When something enters the vehicles warning zone it can product an audible or flashing warning to encourage the person, if it is a person, to get out of the way. If that does not clear its path and the object enters its stop zone, the vehicle can halt until the object moves out of its stop zone, resets itself, and resume motion. More sophisticated behaviors of newer AGVs sometimes include driving around obstacles in its path.
LASER TARGET NAVIGATION
A night sky like constellation of laser reflectors mounted throughout the AGV's operating area can act as stars for the vehicle to navigate by. Precise location of the AGV is possible when angle and range measurements to three or more laser reflector targets are made. With this and other navigation options now availble, wire imbedded in the floor is no longer the first choice.
POINT CLOUD
For obstacle detection and navigation by landmarks, laser scanners can be moved to scan in more than one plane. Moving the scanner creates a three dimensional array of data points or point cloud. Some machines created this movement by rocking the laser scanner and others by spinning it. Eventually I suspect that the laser manufacturers will add a 3D scanning feature at the factory.
FIRST THING IT SEES
The laser dot is reflected by the first thing it hits so it produces no knowledge about what is beyond that point. In most cases what is closest to the vehicle is of most urgent importance and what is beyond that is not of immediate interest. Fan shaped laser scanning beams, are used for profiling objects and the individual rays of light are not visible - except in the movies where red or green visible spectrum lasers are used on smoke filled sets so that the individual rays or fans of laser light are visible.
2007 DARPA URBAN CHALLENGE
Many of the electronics companies that produce industrial automation also have a separate automotive division. As time passes, the items they produce for each of these divisions are starting to look more and more alike. Scanning laser range finders were used by every vehicle in the most recent driverless vehicle race, the 2007 DARPA Urban Challenge. The race has helped speed up the development of AGV software and sensors.
Below is a picture AIM Team members Linda and Tom Graham took of a driverless truck as it passed the grand stand starting the 55 mile rally style race in urban traffic. Race officials said it was eerie at first to see vehicles moving around without drivers but within the first hour it became apparent that each of the vehicles was a capable driver and had a personality of it's own. Having a recognizable personality or driving style made people forget there wasn't person behind the wheel. The Oshkosh truck, which gave the impression of being a "gentle giant" by the curtious way it drove, was taken out of the race when nosed up to a post supporting a roof and couldn't make up its mind what to do next. Perhaps we shall see a driverless version of the Gumball Rally in the near future?
GO ROBOTS !
The Five Senses - Lasers
December 7, 2007
LASERSWhile it is not one of a human beings five senses, lasers are a integral part of machines sensing their environment. Early hopes were that machines would be able to navigate much like bats and dolphins do using sonar. It turns out that application of inexpensive sonar to machine navigation is more complex than engineers expected. Sonar beams refused to behave the way engineers wanted them to. When rugged, inexpensive laser diodes became available they did work the way engineers had hoped sonar would have. Laser diodes produce a nice crisp signal going out and a equally crisp return, from a single point, everything engineers had been hoping for.
LASER BUMPERS
Scanning laser range finders are becoming quite common now, so much so that laser manufacturers are offering complete laser bumper kits for AGV builders. The laser bumpers allow the vehicle to react to objects around it without coming in contact with them. Zones can be set up around the vehicle such as a warning zone and a stop zone. When something enters the vehicles warning zone it can product an audible or flashing warning to encourage the person, if it is a person, to get out of the way. If that does not clear its path and the object enters its stop zone, the vehicle can halt until the object moves out of its stop zone, resets itself, and resume motion. More sophisticated behaviors of newer AGVs sometimes include driving around obstacles in its path.
LASER TARGET NAVIGATION
A night sky like constellation of laser reflectors mounted throughout the AGV's operating area can act as stars for the vehicle to navigate by. Precise location of the AGV is possible when angle and range measurements to three or more laser reflector targets are made. With this and other navigation options now availble, wire imbedded in the floor is no longer the first choice.
POINT CLOUD
For obstacle detection and navigation by landmarks, laser scanners can be moved to scan in more than one plane. Moving the scanner creates a three dimensional array of data points or point cloud. Some machines created this movement by rocking the laser scanner and others by spinning it. Eventually I suspect that the laser manufacturers will add a 3D scanning feature at the factory.
FIRST THING IT SEES
The laser dot is reflected by the first thing it hits so it produces no knowledge about what is beyond that point. In most cases what is closest to the vehicle is of most urgent importance and what is beyond that is not of immediate interest. Fan shaped laser scanning beams, are used for profiling objects and the individual rays of light are not visible - except in the movies where red or green visible spectrum lasers are used on smoke filled sets so that the individual rays or fans of laser light are visible.
2007 DARPA URBAN CHALLENGE
Many of the electronics companies that produce industrial automation also have a separate automotive division. As time passes, the items they produce for each of these divisions are starting to look more and more alike. Scanning laser range finders were used by every vehicle in the most recent driverless vehicle race, the 2007 DARPA Urban Challenge. The race has helped speed up the development of AGV software and sensors.
Below is a picture AIM Team members Linda and Tom Graham took of a driverless truck as it passed the grand stand starting the 55 mile rally style race in urban traffic. Race officials said it was eerie at first to see vehicles moving around without drivers but within the first hour it became apparent that each of the vehicles was a capable driver and had a personality of it's own. Having a recognizable personality or driving style made people forget there wasn't person behind the wheel. The Oshkosh truck, which gave the impression of being a "gentle giant" by the curtious way it drove, was taken out of the race when nosed up to a post supporting a roof and couldn't make up its mind what to do next. Perhaps we shall see a driverless version of the Gumball Rally in the near future?
GO ROBOTS !
Paul F. Grayson - Chief Engineer
AMERICAN INDUSTRIAL MAGIC, LLC
Racing to build technology that saves soldier's lives.
390 4-Mile Rd. S.
Traverse City, MI 49686-8411
(231) 946-0187, (231) 883-4463 Cell
pgrayson@aimagic.org
http://aimagic.org
http://tech.groups.yahoo.com/group/robotcluboftraversecitymi/
http://www.controleng.com/index.asp?layout=blog&blog_id=1180000318
AMERICAN INDUSTRIAL MAGIC, LLC
Racing to build technology that saves soldier's lives.
390 4-Mile Rd. S.
Traverse City, MI 49686-8411
(231) 946-0187, (231) 883-4463 Cell
pgrayson@aimagic.org
http://aimagic.org
http://tech.groups.yahoo.com/group/robotcluboftraversecitymi/
http://www.controleng.com/index.asp?layout=blog&blog_id=1180000318
Posted by Paul Grayson on December 7, 2007 | Comments (0)
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