Needing assistance with accelerometer

Hitec robotics including ROBONOVA humanoid, HSR-8498HB servos, MR C-3024 Controllers and RoboBasic
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Needing assistance with accelerometer

Post by serithseraki » Tue Oct 25, 2011 4:10 am

Post by serithseraki
Tue Oct 25, 2011 4:10 am

I got the 2Axis-accelerometer from active robots shown here.
http://www.active-robots.com/special-offers/robonova-accessories/robonova-2-axis-accelometer.html

Now I understand how to get the signal from the AD ports and I have set my Robonova to stand up after falling. But recently I read on this website that the accelerometer can allow individual servos to correct their placement when deviating from the set axis.
http://ornella.iwr.uni-heidelberg.de/ROBOTICSLAB/ROBPROJECTS/COMPLETED/robonova_stab1/software.php

Now my question is how does one write the proper code for this? Can someone demonstrate how this would be done?
I got the 2Axis-accelerometer from active robots shown here.
http://www.active-robots.com/special-offers/robonova-accessories/robonova-2-axis-accelometer.html

Now I understand how to get the signal from the AD ports and I have set my Robonova to stand up after falling. But recently I read on this website that the accelerometer can allow individual servos to correct their placement when deviating from the set axis.
http://ornella.iwr.uni-heidelberg.de/ROBOTICSLAB/ROBPROJECTS/COMPLETED/robonova_stab1/software.php

Now my question is how does one write the proper code for this? Can someone demonstrate how this would be done?
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Post by limor » Tue Oct 25, 2011 10:26 am

Post by limor
Tue Oct 25, 2011 10:26 am

Usually a gyro is used to identify and correct involuntary rolling motion of the robot that is usually early signs of falling.
Have you checked out the accelerometer references on the Robonova Wiki
http://robosavvy.com/site/index.php?opt ... nova-i_faq
Usually a gyro is used to identify and correct involuntary rolling motion of the robot that is usually early signs of falling.
Have you checked out the accelerometer references on the Robonova Wiki
http://robosavvy.com/site/index.php?opt ... nova-i_faq
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Post by serithseraki » Tue Oct 25, 2011 5:26 pm

Post by serithseraki
Tue Oct 25, 2011 5:26 pm

I have read what I could find on the forum and wiki and I am aware that gyros would be the better alternative for this. I would use them if I had the funds and available space on my robonova for them. But sadly I have to use what I got available and the accelerometer is it. Now I assume I would have to use the servo command to adjust the servos individually according to tilt, but I do not know how to write code for this. But to give you all an idea on my plans I want to use the accelerometer to compensate for slight tilt, and then use the arms and legs to brace for impact at a large tilt.
I have read what I could find on the forum and wiki and I am aware that gyros would be the better alternative for this. I would use them if I had the funds and available space on my robonova for them. But sadly I have to use what I got available and the accelerometer is it. Now I assume I would have to use the servo command to adjust the servos individually according to tilt, but I do not know how to write code for this. But to give you all an idea on my plans I want to use the accelerometer to compensate for slight tilt, and then use the arms and legs to brace for impact at a large tilt.
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Post by limor » Wed Oct 26, 2011 7:44 am

Post by limor
Wed Oct 26, 2011 7:44 am

Reading on the above wiki and this blog looks like the gyro signal is used by the gait generator eeprom motion player through GYROSET GYROSENSE GYRODIR
the gyro signal is of rate vs the accelerometer signal which is absolute directional. So plugging the accelerometer to the gyro port won't work.
some people here hacked the rn1 firmware and maybe can help you take take the difference between consecutive samples as input to the gyro port.

Haven't looked at how to directly control servos from code in case that's what you are interested. That should be in the rn1 programming manua and some examples pointed at in the wiki.
Reading on the above wiki and this blog looks like the gyro signal is used by the gait generator eeprom motion player through GYROSET GYROSENSE GYRODIR
the gyro signal is of rate vs the accelerometer signal which is absolute directional. So plugging the accelerometer to the gyro port won't work.
some people here hacked the rn1 firmware and maybe can help you take take the difference between consecutive samples as input to the gyro port.

Haven't looked at how to directly control servos from code in case that's what you are interested. That should be in the rn1 programming manua and some examples pointed at in the wiki.
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