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### Topic: Self balancing waiter tray. (or almost it) (Read 19099 times)previous topic - next topic

#### Rivello

##### Aug 08, 2011, 05:37 amLast Edit: Aug 09, 2011, 09:25 am by Rivello Reason: 1
Ok, in truth it's not exactly that, but that's the nickname it got.

It's a self-stabilizing platform. It doesn't matter the angle you put the lower platform in, the upper platform will ever stay in the horizontal position.

I used the method from this post, by Lauzsus, and adapted to my needs, including the servo motors.

Check it here:
http://www.youtube.com/watch?v=T0SFAdPUUYs

#### frank26080115

#1
##### Aug 08, 2011, 05:38 am
It needs to go on a roller coaster for testing

#### retrolefty

#2
##### Aug 08, 2011, 06:23 am
That's pretty cool. Got any code you can share with us?

Lefty

#### Rivello

#3
##### Aug 08, 2011, 07:06 am
Sure, the principle is the following:

It reads the inclination angle data given by the accelerometer and gyro, applies Kalman Filter to best predict the real inclination and write to the servo motors the inverse angle to compensate the inclination.

For my luck, I found an already made Kalman Filter algorithm for arduino in this post: http://arduino.cc/forum/index.php/topic,58048.msg417140.html#msg417140

Then I basically used the same code, just adapting it to write the angles to the servos:

// added in the beginning:
#include <Servo.h>
Servo servo1;
Servo servo2;

// added in setup:
servo1.attach(6);
servo2.attach(9);

// added in the end of loop() function:
servo1.writeMicroseconds(1560-yAngle*9.55);
servo2.writeMicroseconds(1510+xAngle*9.55);

Where 1560 and 1510 are the values corresponding to the center position of my servos and yAngle and xAngle varies from -90 to +90 and are scaled to fit the observed servo limits.

Any question, please comment!

#### bld

#4
##### Aug 08, 2011, 08:32 pm

Sure, the principle is the following:

It reads the inclination angle data given by the accelerometer and gyro, applies Kalman Filter to best predict the real inclination and write to the servo motors the inverse angle to compensate the inclination.

For my luck, I found an already made Kalman Filter algorithm for arduino in this post: http://arduino.cc/forum/index.php/topic,58048.msg417140.html#msg417140

Then I basically used the same code, just adapting it to write the angles to the servos:

// added in the beginning:
#include <Servo.h>
Servo servo1;
Servo servo2;

// added in setup:
servo1.attach(6);
servo2.attach(9);

// added in the end of loop() function:
servo1.writeMicroseconds(1560-yAngle*9.55);
servo2.writeMicroseconds(1510+xAngle*9.55);

Where 1560 and 1510 are the values corresponding to the center position of my servos and yAngle and xAngle varies from -90 to +90 and are scaled to fit the observed servo limits.

Any question, please comment!

By sure, you mean "No, but I do what to show you how I use the servo lib"?
captain-slow.dk | non contagious!

#### Rivello

#5
##### Aug 08, 2011, 09:28 pm
Well, but it's exactly that,

why to complicate things? It's just an union of a kalman filter, an IMU and servo motors.   XD

#### retrolefty

#6
##### Aug 08, 2011, 11:05 pm
Well it is your sketch, and your free to show what parts of it you wish.

#### liuzengqiang

#7
##### Aug 09, 2011, 12:10 am
Very well done! Your machine passed bar exam

If I had this, I would walk with it mounted on my right shoulder and put my drink on top of it.
Serial LCD keypad panel,phi_prompt user interface library,SDI-12 USB Adapter

#### Rivello

#8
##### Aug 09, 2011, 09:20 am

Well it is your sketch, and your free to show what parts of it you wish.

I hope you didn't get me wrong. I didn't show the rest because it was not my creation. (I adapted from Lauszus post, which adapted from another project)

You can see the sketch I started from by downloading the file "IMU6DOFVer3.zip" which I got from this post Guide to gyro and accelerometer with Arduino including Kalman filtering by Lauszus.

The only modifications I did was the mentioned above.

Cheers,

#### dgxanadu

#9
##### Oct 12, 2012, 04:04 am
Hi Rivello,
I'm not an expert...but I will like to know how to connect  (wire) all the listed components.
Please help me. Thank you!
Dan

#### freak174

#10
##### Oct 13, 2012, 03:59 pm
What is the name of the sensor ur using?

Nice Project though.
cheers

#### raghavendrandme

#11
##### Oct 16, 2012, 05:49 pm
really thanks for info sharing buddy! i am confused with how to connect the 6dof to my my arduino uno!!! there is no pins declared in the program! it is done via i2c! i am sorry i am a beginner and can u exp about i2c connections?  my mail id is raghavendran.dme@gmail.com

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