Is this a reliable balancing robot design?

[airman00]

I saw this balancing robot:
http://robo3.com/robot_1.htm?PHPSESSID=0884f8f3737d78e1545f33cdeccc90b3

It says that it only uses :      

Encoder x 2 / UltraSonic Sensor(3m) x 4

Now I don't know if the Ultrasonic sensors were used for balancing or only for obstacle avoidance. But I do know that the encoders were used for balancing.

No complex accelerometers, no gyros , none of that difficult stuff. Can you really get reliable balancing using only encoders?

[airman00]

nevermind....
 if you look closely there is a tiny caster in the back of the robot.

[pomprocker]

There is a caster, but its only used when the robot is at rest

[airman00]

There is a caster, but its only used when the robot is at rest

you're right!

So you can balance reliably using only encoders?

[MaltiK]

It makes sense, because if you think about it, the MCU could read the sonars value, to insure that on both ends its the same as when it was first calibrated (0), and as it increases on either the front or back one, the motors could accelerate in the opposite direction, to insure that it stays afloat, and the encoders would insure the velocity is proportional to the distance needed to travel to stay upright. Many balancing bots have been made using only encoders, sonar, or IR detectors, it really is all in the code.

Side Note: how the hell can that cost $25,000 to make?!?!? Is that yen or some Korean currency??

[airman00]

the question is does it use only encoders for balancing , or does it also use ranging sensors for the balancing?

[paulstreats]

Quote from the website

Product Features :
- ROBIN is Korea's first two-wheel balancing robot using original gyro technology.
- Upon order, it can be used for PLC program education, surveillance, service, event, curator etc.
- Robin is Korea's first humanoid robot based on PLC, which is used in automatizing factories.
- This all-weather robot uses three wheels when indoors and two wheels when outdoors.
- It can be used during robot education based on PLC.
- Humanoid robot controlled by PLC(Comfile.co.kr)
- Suitable for line video cognition, PLC, motor control, sensor input, and GUI education

The first feature mentions gyro technology

[dunk]

it can be done without gyros using some sort of ranging sensor (such as IR or sonar) as long as you are on a level surface.

search for LegWay for a examples.

eg.
[youtube]ol9qdjFCO5E[/youtube]


dunk.

[pomprocker]

I personally don't see the point of balance bots, yeah its a cool trick, but it cant help a robot maneuver around a human's world. If I were to make a robot that were to interact with human's it would be able to traverse just as well as us.

[cosminprund]

Apparently it does help the bot maneuver better in our world because it's more stable (because it stabilizes itself). Take a look at the videos of the nBot, there are some nice videos showing the bot going uphill and downhill on grass!

There's also an wheelchair I've seen on Discovery channel that balances on two wheels and apparently has very beneficial effects on it's occupant.
Here's a Wikipedia page: http://en.wikipedia.org/wiki/IBOT
And you might want to search for videos of this "iBOT  Wheelchair", it looks grate!

[pomprocker]

A wheeled humanoid bot, whether balancing or not, would not have much purpose in my home, seeing almost every room on the 1st floor is separated by a step, and there is also stairs leading to the second floor.

[SmAsH]

lol thats why we have bipeds?

[dunk]

A wheeled humanoid bot, whether balancing or not, would not have much purpose in my home, seeing almost every room on the 1st floor is separated by a step, and there is also stairs leading to the second floor.

i used to be able to get a segway up small steps at work. takes a bit of practice but doable. they are surprisingly stable and able to traverse far rougher ground than you would think.
that segway broke though... probably coincidence...


dunk.