Tuesday, September 6, 2011

More intelligent, but not necessarily better?

Selecting sensors and designing algorithms that make autonomous robots perform their tasks is an interesting field of study. One could easily jump into the conclusion that better results can be obtained by adding more advanced sensors and programming intelligent control software that is able to use all the information collected.

The iRobot Roomba was the first domestic robot to achieve commercial success. It only uses simple sensors (I suspect it has IR proximity sensors, bumper switches, etc.) and a a cleaning pattern with a significant component of randomness. Lately competitors have emerged that attempt to differentiate their products by claiming that the addition of computer vision and mapping capabilities coupled with systematic cleaning patterns makes them produce better results.

The video below (from an independent source) clearly shows that the chaotic strategy of the Roomba is better. While the competitors' robots slowly ponder their paths, the Roomba has already cleaned the entire space, and covered most areas more than once, probably leading to a better cleaning result.

Saturday, September 3, 2011

Cyborgs: state of the art

(Via RobotShop blog.)

Okay, strictly speaking this has almost nothing to do with autonomous mobile robots, but I just wanted to share this rather cool documentary about real cyborgs, presented by a cyborg.

Not much progress to report on my robot project as I've been rather busy at work and Real LifeTM lately. Hopefully I'll have something to report in a few days.

Monday, August 29, 2011

A mad scientist's robot platform idea

I went sailing with my family in the weekend (one of those "other hobbies" that have served as an excuse to postpone building my robot), and suddenly I realized that our boat is an almost complete platform for a marine robot. It has the following array of sensors and actuators:

  • GPS
  • Radar
  • Sonar
  • Electronic compass
  • Wind instrument (speed and direction)
  • Speed instrument
  • Autopilot
Best of all, all of these are interconnected by an NMEA 0183 network, so e.g. the autopilot is able to receive route orders from the GPS chart plotter, and the radar image can be superimposed on top of the chart plotter's map. The only things missing are 

a) an NMEA-enabled central control unit that would contain the robot's control logic, and
b) actuators for speed control using the inboard diesel engine or the sails, or preferably both.
Imagine how fantastic it would be to be able to just enter (or even better, speak) the destination and let the boat calculate the route and take you there. The boat would use GPS to navigate, its radar, sonar, wind instrument, and compass to sense what's happening to it and in its environment, and steer using the autopilot. I suspect marine chart data would have to be directly available to the control unit, though, because it cannot be obtained from the chart plotter using NMEA.

I know that controlling the sails would be somewhat tricky. I would definitely have to get a self-tacking headsail and install electric winches for controlling the jib sheets and the mainsheet. I'm not sure if I'd be able to loosen as well as tighten the sheets using a winch, so possibly some custom mechanics and motors would be required. Even so, I wouldn't have proper feedback available to my control algorithm, only the readings of the wind and speed instruments and compass (and GPS). It would be preferable also to know the positions of the sheets and the angle of heel. Come to think of it, also the rudder angle would be nice to know, as well well as some sensor readings that would correspond to the tell-tales on the sails. But these are all optional and I could add them later. Even the entire speed control capability could be omitted. Initially it would be cool just to be able to automatically navigate from A to B while controlling speed manually.

No! Wait! Based on how they behave on the sea, I think some of the bigger motor yachts in this part of the world already are robots. Oh, well.

(Of course, I wasn't the first to think of a robotic sailboat.)

Friday, August 26, 2011

Yikes, a swarm of robots!

(Via Let's Make Robots!)

I think calling this relatively small group of robots called Swarmanoid a "swarm" may be a little exaggerated (although they are planning to extend the swarm size to about 60 'bots total), but this is nevertheless one of the coolest robot projects I've seen lately:

The Swarmanoid has been developed in a Future and Emerging Technologies project funded by the European Comission and coordinated by prof. Marco Dorigo.

I too should perhaps someday look into co-operation of two or more robots. The climbing capability of the handbot is also cool, and the robots seem to use navigational aids embedded in the environment in a clever way. Notice the red color on some of the surfaces of the bookshelf used by the handbot for guidance when climbing. Members of the swarm also act as temporary navigational landmarks for each other.

Thursday, August 25, 2011

What every recreational roboticist should know about computer vision

As I wrote before, I intend to apply some computer vision (CV) algorithms to make SHORT-E more aware of its surroundings. I guess that CV is still not routinely used by recreational roboticists. Hobbyists tend to use simpler sensory information such as that obtained from ultrasonic rangefinders or infrared proximity sensors to make their robots able to navigate in their operation environment.

This is understandable, as computer vision is quite a complicated discipline, the programming tools are not easy to use (or even compile in some cases), and most hobbyists' robots' computational hardware is just not up to the task of executing processor and memory intensive algorithms. However, while I'm not experienced in CV, I happen to have a PhD in computer science and will use Chumby One as my robot's brain, so I'd be a wussy if I didn't at least try to do some rudimentary CV.

For my fellow recreational roboticists that have not yet decided to take the leap: I recommend starting with this nice and popularized introduction to computer vision. If you're impatient, you can safely skip the first part about vision in biology and dive straight into chapters 2...4.

Wednesday, August 24, 2011

Household tags to aid robots

I'm back at work this week, so progress on the robot project will probably slow down a bit. Meanwhile, I'll at least try to post some general robotics-related stuff.

Automaton has a rather interesting article about making our homes more robot-friendly. As progress in computer vision is slow, why wouldn't we embed tags in our homes that assist household robots in their tasks? Using these tags robots could keep track of their location and recognize objects they are supposed to manipulate.

The idea isn't new and it has actually been applied before. I too have thought of someday using RFID or NFC tags to help my robots recognize objects and locations. There are also commercial robot indoor navigation sensor systems like the Hagisonic Stargazer that are based on fixing landmarks to the ceiling. Nevertheless, the concept is interesting and could help make genuinely useful household robots reality.

Tuesday, August 23, 2011

Robot platform videos

I found video reviews of the Traxster II and Lynxmotion 4WD1 robot platforms I mentioned in my earlier post:

The Lynxmotion 4WD1 looks awesome, but the lack of support for shaft encoders keeps bothering me, as I don't think that my optical encoders would work with these wheels. The chassis is available without motors or wheels, so I could purchase motors that have rear shafts for connecting encoders separately, but the total price would be higher, especially as I couldn't get everything I need from a single source inside the European Union. Ordering directly from Lynxmotion is out of the question, because they don't accept international credit cards.

The Traxster II is a bit smaller than I imagined and it does not have a bottom plate. But it does have built-in encoders and is therefore significantly cheaper than the 4WD1 when considering total price with all the parts I need.