3-AXIS Accelerometer ADXL345 Gyroscope Gyro L3G4200D for Arduino Balance Self-balancing Robot

3-AXIS Accelerometer ADXL345 Gyroscope Gyro L3G4200D Used for Arduino Balance Self-balancing Robot

[blip]

I ran out of characters. I hope this makes some sense as I have a banging headache from last nights imbibition.
You are right 2/3 of the gyro seem to be used but 3/3 of the accelerometer in the form of feedback to control the motors precisely.
Perhaps japanboxz can enlighten us more.
All the best Jack
blip

[Waffles]

Hmm, well now we are on the same terms about gyro.
But for accelerometer: because this device has two wheels on a single axle, it must always move in a direction perpendicular to that axle, and as the position of the accelerometer is fixed relative to said axle, the accelerometer will always be experiencing an acceleration in only a single direction: the one that is perpendicular to the axle.

I'm just a student, so I could be quite wrong about this.

Good discussion though.

Jack

[blip]

Hi Jack, there is no axle, but the motors/wheels do share a common axis. If the motors can only act in unison (as though axle mounted) then you most likely are correct and I am wrong.
I was assuming that they could act independently and opposite to each other enabling turning or spinning on the spot, rather than just forward motion. What effect would this have on the accelerometer along with its relative position changing to the motion applied to it and its physical location on the contraption?

[blip]

I see 3 motions:-
1 Forwards and backwards (pos and neg.) roll
2 Axial rotation (pos and neg) - pitch
3 Perpendicular axial rotation (pos and neg) - yaw

2 independent stepper motors are controlling these 3 motions. To achieve balance, a 0 value is required at motion 2. Motion 1 controls this figure; the greater this figure deviates from 0 the greater the acceleration needed for recovery deccelerating as it approaches the 0 value, Feedback is required from these 3 motions to control the motors.

[BogdanSorlea]

I'm curious about 2 things:
1. what motors and what motor driver do you use?
2. what accelerometer/gyro module do you use and how are they connected? (regarding the connection, I'm having problems connecting these two sensors [ADXL345 and L3G4200D] via SPI to the single SPI channel of Arduino Uno. What you have there might help so please at least link me to the module board of the two sensors)

[Chrnalis]

Try putting some finer rubbers on those wheels.  Those spokes aren't doing much to help the balancing

[Waffles]

That's basically what I said in my last comment, so because we have agreement on what is needed, let's break it down to see whats used and what isn't:
Gyroscope:
Balance Recovery-Measure Pitch
Turning Accuracy- Measure Yaw
No Need For Roll.

Accelerometer:
Measure Forward Motion- X axis
No Measurement of Side to Side (Y axis) Movement
No Measurement of Vertical (Z axis) Movement

So that's only 2/3 of the gyro measurements being used, and only 1/3 of the accelerometer measurements being used.

[JarlHolta]

Impressive! Arduino contineues to amaze me! :)

[Waffles]

Hmm, there's a 3 axis gyro, I see how needing to know how much it has tilted about the axle is necessary. And if you're turning, I see the need of the second axis, but then whats the point of the third? And for the accelerometer, I see how knowing your forward acceleration would be needed, but its not going to be moving perpendicular to its wheels, so unless there are some hidden helicopter blades on it (I wish...) why the other two? Am I missing something(s)?

[ehdwn]

Hey, I was wondering whether I could ask you about how this works and about the code that you used for this!

[Waffles]

Huh, you're probably right, there is no axle. Yet even without an axle, the accelerometer will always have its axes in the same position, relative to the contraption. And I suppose it could, but really, the gyro would be better for an inclinometer, wouldn't it?

I guess the only way to settle this will be to see the code, but based on these other comments, I'm not so sure japanboxz is too keen to sharing it. =P

[dorotaglazar]

Hi. I'm sorry for bothering you but i have a question concerning your robot. I am working on a similar project for my thesis and i have a bit of a problem with those little engines. Could you possibly tell me what kind of engines you have used? My robot is not working properly and its falling down. I would really apppreciate your help. Looking forward to your answer.

[daffyduck]

I also am stuck with the gyro data... esp with the filtering... did you guys get through this hurdle?

[blip]

Accelleration/decelleration - balance recovery?
Forwards/ backwards; turn left/right &Tilt?
Does it need blades to have the same motion characteristics as a helicopter??

[skperth]

Very well done. Are you willing to share technical detail?

[alextepal]

y que tipo de motores usas yo lo quería intentar con unos reductores, crees que funcione.

[PerryCodes]

Balancing... okay. Now let's see it actually move and turn ;)

[TheRooster]

Awesomem project thanks for sharing. Irritating music; I wish you would instead provide narration of how you built it and what is happening as the unit moves. Thanks!

[nawaryoussef]

Great job! Do you think I can use a Bluetooth connection between the Gyro and my computer?

[abmecha]

do you use an accelerometer and a gyro separately?