RoboSavvy Forum

roboBuilder:robot balance control

2012-07-31T16:31:42+01:00

I'm not sure if I understand your question.

I don't have information about the center of gravity of the Robot or where the sensor is located in relation to it.

What the sensor returns are the acceleration readings on each axis.

If it's standing still it will be reading only the Acceleration of Gravity (you'll get a value on the Y axis when the Robot is standing up).

If the Robot falls down you will have readings on other axis as gravity is always perpendicular to the floor; depending on the reading you can know in which position the Robot is.

Please refer to the product page of the ACC sensor for more information http://robosavvy.com/store/product_info ... cts_id/456

I just want to leave one final note regarding hacking the Robot and the advance in previous posts: I can never stress enough that all procedures should be done at your own risk; modifying the Robot's hardware will void it's warranty.
The information provided is what it is: a "hack"; not an official procedure.

Regards
Pedro.

Statistics: Posted by PedroR — Tue Jul 31, 2012 4:31 pm

roboBuilder:robot balance control

2012-07-31T15:32:49+01:00

I'm really thankful for your answer!

I think I'll try your method

Just one more question to ask

Is the x,y,z coordinates get by the accelerometer means the center of gravity(COG) of the robot?

thanks a lot!

Statistics: Posted by chickenkai — Tue Jul 31, 2012 3:32 pm

roboBuilder:robot balance control

2012-07-31T14:47:42+01:00

Hi Chienkai

Robobuilder does not supply a Gyro for the 57xx Robots.

There is a way to "hack" the robot to add a gyro using the I2C bus of the Accelerometer.
However, to do this, you need to program the micro controller in WinAVR (C).

If you're familiar with doing this, you may want o reffer to the following posts:
- Sample C code to get you started: http://robosavvy.com/forum/viewtopic.php?t=3379
- You will need to design your board (or prototype) and add any I2C Gyro and eventually the Accelerometer.

You will then need to write the code to read the sensors and also to make use of them.

When using custom C programs written in WinAVR, the Robobuilder Graphical tools (MotionBuilder, ActionBuilder) and RBC Protocol will not work though.

There are also some alternative firmwares for Robobuilder that _might_ let you access the I2C bus without having to get down to WinAVR (maybe the BASIC firmware by l3v3rz but I'm not sure).

If you're familiar with these topics, the explanation above should be good enough; if you're not familiar with I2C and WinAVR, I would sincerely recommend sticking to the default configuration and firmware.

Regards
Pedro.

Statistics: Posted by PedroR — Tue Jul 31, 2012 2:47 pm

roboBuilder:robot balance control

2012-07-31T03:53:03+01:00

thank for your answer, Pedro!

Now I understand the main function of the accelerometer.

What is Gyro you've mentioned? Can you give me more information?

thanks a lot!

Regards
Chickenkai

Statistics: Posted by chickenkai — Tue Jul 31, 2012 3:53 am

roboBuilder:robot balance control

2012-07-30T12:54:05+01:00

Hi Chikenkai

The main purpose of the accelerometer is to detect when the Robot has fallen.

It can be used to provide some basic form of balance, but for Balancing the Robot while it's walking you'll need a Gyro.

The Robobuilder 57xx does not include one by default but there are possible hacks to add one.
This will greatly depend on your skill level. (if you want to know more about this, please post back).

Regards
Pedro.

Statistics: Posted by PedroR — Mon Jul 30, 2012 12:54 pm

roboBuilder:robot balance control

2012-07-30T08:45:02+01:00

hi everybody,

do anyone knows how to achieve robot balance control by using Acceleration Sensor built in robobuilder?

thanks all!

Statistics: Posted by chickenkai — Mon Jul 30, 2012 8:45 am