Mar 13, 2007

Gyro working... UPDATED

Check out this video of the HiTechnic gyro... very very very cool.




Some additional information:

The basic difference between a gyro and acceleration sensor is what they measure. The Acceleration sensor can be used to measure tilt by coupling the “g” vector into the result and thus measuring tilt based on the fraction of “g” detected. This however only works in static situations.

If a robot is being moved around by motors, there will be acceleration caused by the motors which cannot be distinguished from the acceleration caused by gravity so the measured tilt value is no longer a valid measurement of the angle with respect to the “g” vector. Because of this you cannot easily use accelerometers to create a balance feedback loop necessary to make a robot balance.

A gyro measures the rate of rotation change or angular acceleration. So in a balancing robot it would measure the acceleration caused by the robot rotating on the horizontal axis perpendicular to the rotation of the wheels. This measurement is not affected by the accelerations caused by the motor movements.

5 comments:

peter hoh said...

I am very impressed. Wow. Doesn't Dean Kamen hold some sort of patent on this, or would his patent only apply to wheelchairs and people movers?

Maniac... said...

Wow...Very impressive. I only wish the video had included driving and inclines, but the recovering from a push was just as good. A very good demo.

Now I'm lost. I know what a gyro sensor does, and what an acceleration sensor does. But looking at it from the standpoint of robotics. They seem to do the same thing. Tell the robot what angle it is at. The gyro sensor does it directly and the acceleration sensor...still does it.

For a robotics application, what are the differences between the two?

Maniac... said...

About the white wires. Are those from HiTechnic, or homemade. Do the HiTechnic sensors come with wires?

Philo said...

The white wires are probably Mindsensors' flexicables

About other demos, have a look to NXTway-G on Ryo's website. These were not done with Hitechnic sensor, but show what is possible with a gyro!

Miek said...

Thanks soooo much for the 'additional information'.
Really useful, I'm definitely gonna buy a gyro instead of an accelerometer now.
Can't believe they're so expensive though..

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