One word "gyro"

As you all know we all received those neat expensive gyro chips, but how would one go about using one of those, does anyone have any spec. about them if so please e-mail me the specs. @ [email protected] i am literally dieing to figure out what the heck they can do…

The gyro (Yaw Rate Sensor) connects to the controller as a digital input and the PBASIC code interprets the input and determines what to do. Check out the Technokats Auto-Balance Code from last year if you’re wondering how the PBASIC works for it. The code is in the White Papers or at the following link.

http://www.chiefdelphi.com/forums/papers.php?action=downloadpaper&paperid=10

*Originally posted by Ydnar *
**As you all know we all received those neat expensive gyro chips, but how would one go about using one of those, does anyone have any spec. **

On the official homepage of FIRST, there is a 25 MB Acrobat Reader document called “Kit of Parts: Appendixes B-G” which contains in Appendix G all kinds of data sheets. To get there, click on “FIRST ROBOTICS” > “DOCUMENTS & UPDATES” > “Competition Documents” > “Kit of Parts: Appendixes B-G”. More specifically, on pages G-14 through G-20 you will find everything on the gyro sensor, from technical specifications to an article that explains you how to use the sensor.

Jan Olligs

*Originally posted by thedillybar *
**The gyro (Yaw Rate Sensor) connects to the controller as a digital input and the PBASIC code interprets the input and determines what to do. Check out the Technokats Auto-Balance Code from last year if you’re wondering how the PBASIC works for it. The code is in the White Papers or at the following link.

http://www.chiefdelphi.com/forums/papers.php?action=downloadpaper&paperid=10 **

I think you meant to say analog input, not digital. :slight_smile:

It made a lot of sense to use the gyro last year to help do the bridge balance, but are there good uses for it this year? Have any teams used the gyro as a “stabilizer” to help make their machine track a better line? E.g. in a tank style drive with variations in motors and transmissions perhaps 50% power equates to 50% in the left and 48% in the right. Would the gyro be useful for “fixing” that? We’ve messed with scaling in the code but it seems that one day its left, the next day its right.

I believe at this point, my team is still planning on a somewhat complex steering system. I won’t go into details, because it’s our teams “secret”. In any case, (since I’m the programmer) I was thinking I’d use the gyro to “kick in” the advanced steering system. Basically, if the robot’s not turning, and it should be, apply the steering mechanism. I think that would be easier on the driver than having to manually apply it. Just an idea that others may also be able to use.

*Originally posted by Morgan Jones *
**I believe at this point, my team is still planning on a somewhat complex steering system. I won’t go into details, because it’s our teams “secret”. In any case, (since I’m the programmer) I was thinking I’d use the gyro to “kick in” the advanced steering system. Basically, if the robot’s not turning, and it should be, apply the steering mechanism. I think that would be easier on the driver than having to manually apply it. Just an idea that others may also be able to use. **

I have no experience with the Gyro, but I wonder how sensitive it is to some of the bumping and bouncing that goes on during the game.

I suppose the code and sort of “average” all that out of the data.

Since many teams probably used the Gyro last year, there must be some that have a sense of how useful it is.

(I know that many had remarked that if you use it to calculate position, you can have alot of long-term error because of the missed sample time between iterations of the program loop…integration error)

-Quentin

Quentin,

You are correct that the gyro is very sensitive to noise. When using the gyro last year the Technokats used both mechanical and software filtering. We mounted the gyro on a foam pad that reduced some of the noise, and also used a simple filtering algorithm in the code. Details for both of these are provided in the white paper listed above. Obviously the sensitivity is only in the direction (or plane) you’re measuring.

If you’re concerned about responses to impacts, I suspect it will max out (i.e. read 0 or 255) with even a fairly slight bump. This can be a good thing since it’s not too hard to filter out spikes. If I remember right the gyro maxes out at an angle rate that’s equivelant to about 1 robot revolution in 5 seconds, so if you’re trying to use it to track your robot’s heading you better not turn too fast. :slight_smile:

Also, how sensitive is it? Not to bumps really, but to your position?