Comments on: Jegway Rev2 http://www.engscope.com Engineering, Kayaking, Guitar and More Wed, 01 Sep 2010 00:29:56 +0000 hourly 1 http://wordpress.org/?v=3.0.1 By: jliu83 http://www.engscope.com/jegway/jegway-rev2/comment-page-1/#comment-6538 jliu83 Sun, 24 Jan 2010 01:19:16 +0000 http://www.engscope.com/jegway-rev2/#comment-6538 Something like that. I wrote the thing 2 years ago, so I don't remember most of it. If you read the write up for the Jegway I think I might mention something about how I use them. -J Something like that. I wrote the thing 2 years ago, so I don’t remember most of it. If you read the write up for the Jegway I think I might mention something about how I use them.

-J

]]> By: Dylan Vester http://www.engscope.com/jegway/jegway-rev2/comment-page-1/#comment-6511 Dylan Vester Fri, 22 Jan 2010 23:04:56 +0000 http://www.engscope.com/jegway-rev2/#comment-6511 J, Man, ok, so I think I figured out why I'm having so much trouble tuning the PID coefficients. I'm using a complementary filter to combine my accelerometer and gyroscope data. I think the response time on this type of integration is too slow. I was reviewing your code, and it appears that you barely even utilize the accelerometers signal, accept for minor adjustments to the angle depending on the direction of the error. I can only assume that this is to correct the gyroscope drift (as well as get a reference angle at the beginning of the program). Have I made a correct observation? Dylan J,

Man, ok, so I think I figured out why I’m having so much trouble tuning the PID coefficients. I’m using a complementary filter to combine my accelerometer and gyroscope data. I think the response time on this type of integration is too slow. I was reviewing your code, and it appears that you barely even utilize the accelerometers signal, accept for minor adjustments to the angle depending on the direction of the error. I can only assume that this is to correct the gyroscope drift (as well as get a reference angle at the beginning of the program).

Have I made a correct observation?

Dylan

]]> By: jliu83 http://www.engscope.com/jegway/jegway-rev2/comment-page-1/#comment-6349 jliu83 Sun, 17 Jan 2010 04:59:29 +0000 http://www.engscope.com/jegway-rev2/#comment-6349 I've only had problems when the batteries were extremely low. The control system will compensate for any changes in motor drive. The placement of the acceleromenter is critical. If you think about it from a physics perspective, the position at which you will get the most precise reading from the acceleromenter is if it is placed at the axis of rotation (of the system, NOT the wheels! Ie. When the system is trying to balance, it is the spot that receives the least amount of movement). If it is placed far from the axis of rotation, then things such as centripital force and/or readings from falling will make the readings inaccurate. The gyroscope however, since it is a mems device, should be fine placed anywhere. Tell me how it goes. -J I’ve only had problems when the batteries were extremely low. The control system will compensate for any changes in motor drive. The placement of the acceleromenter is critical. If you think about it from a physics perspective, the position at which you will get the most precise reading from the acceleromenter is if it is placed at the axis of rotation (of the system, NOT the wheels! Ie. When the system is trying to balance, it is the spot that receives the least amount of movement). If it is placed far from the axis of rotation, then things such as centripital force and/or readings from falling will make the readings inaccurate. The gyroscope however, since it is a mems device, should be fine placed anywhere.

Tell me how it goes.

-J

]]> By: Dylan Vester http://www.engscope.com/jegway/jegway-rev2/comment-page-1/#comment-6346 Dylan Vester Sun, 17 Jan 2010 00:45:52 +0000 http://www.engscope.com/jegway-rev2/#comment-6346 Also, I've actually rebuilt my little segway to more closely resemble what you show in your videos. It's by no means exact, but I've now supported the axle on each motor on both sides so that there is less unintentional toe on the wheels and things are generally more rigid. Dylan Also, I’ve actually rebuilt my little segway to more closely resemble what you show in your videos. It’s by no means exact, but I’ve now supported the axle on each motor on both sides so that there is less unintentional toe on the wheels and things are generally more rigid.

Dylan

]]> By: Dylan Vester http://www.engscope.com/jegway/jegway-rev2/comment-page-1/#comment-6345 Dylan Vester Sun, 17 Jan 2010 00:43:16 +0000 http://www.engscope.com/jegway-rev2/#comment-6345 J, I've still yet to get my little segway to balance. Your tips did help a lot and I have a much better understanding of P.I.D. control. However, I think where my problem lies now, is that as I'm tuning the constants, my batteries are getting lower and changing the actual speed of the motors. Did you face this issue at all? If so, how did you correct for battery drain? I don't remember seeing anything in your code that combats it. Any comments on this? Dylan J,

I’ve still yet to get my little segway to balance. Your tips did help a lot and I have a much better understanding of P.I.D. control. However, I think where my problem lies now, is that as I’m tuning the constants, my batteries are getting lower and changing the actual speed of the motors. Did you face this issue at all? If so, how did you correct for battery drain? I don’t remember seeing anything in your code that combats it.

Any comments on this?

Dylan

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