Initial Power Spike
 

Posted by Gautham Arumilli at 2/11/2001 11:04 PM EST


Student on team #115, MVRT, from Monta Vista High School.



Hey everybody...We've been having this really weird problem when our robot starts up the past few days...Some sort of power spike on the PWM signal causes the drill motors to automatically move for a couple of seconds and then stop when the robot is started up, and we have no idea why...We've been wondering if anybody else has had this problem, and if it's a hardware problem or some sort of software problem on our part (we seem to have exhausted all possible causes, though)...Any help is appreciated. Thanks.

Gautham Arumilli
MVRT, Team #115

Re: Initial Power Spike
 

Posted by Joe Ross at 2/11/2001 11:36 PM EST


Engineer on team #330, Beach Bot, from Hope Chapel Academy and NASA/JPL , J&F Machine, and Raytheon.


In Reply to: Initial Power Spike
Posted by Gautham Arumilli on 2/11/2001 11:04 PM EST:



: Hey everybody...We've been having this really weird problem when our robot starts up the past few days...Some sort of power spike on the PWM signal causes the drill motors to automatically move for a couple of seconds and then stop when the robot is started up, and we have no idea why...We've been wondering if anybody else has had this problem, and if it's a hardware problem or some sort of software problem on our part (we seem to have exhausted all possible causes, though)...Any help is appreciated.

One thing that our team has noticed is that the first packet of data from the radio modem is often all 0's. Since 0 is full reverse then it causes the motors to move (most often the drill motors). This doesn't always seem to happen but it happens enough that we compensated for it in software.

We wrote a few lines of code that checked for several of the values coming in being 0. If they are zero then we initialize everything to neutral.

I can't really explain why it happens (and why it only happens sometimes for us), but this fixes it for us.

code changed this year
 

Posted by Joe Ross at 2/12/2001 4:06 AM EST


Engineer on team #330, Beach Bot, from Hope Chapel Academy and NASA/JPL , J&F Machine, and Raytheon.


In Reply to: Re: Initial Power Spike
Posted by Joe Ross on 2/11/2001 11:36 PM EST:



: We wrote a few lines of code that checked for several of the values coming in being 0. If they are zero then we initialize everything to neutral.

I just checked the code and we are doing something different this year. We are automatically skipping the first packet, not worrying about whether it contains bad data.

We are using a byte in the scratchpad ram to let us keep track of whether it is the first packet. We check that byte and if it is zero, then we set it to a 1, set both wheels output to neutral (not sure if that is necessary) and goto the beginning of the loop (before the serin command) otherwise we continue with the main program.

Re: Initial Power Spike
 

Posted by Jay Lundy at 2/11/2001 11:38 PM EST


Student on team #254, The Cheesy Poofs, from Bellarmine College Preparatory.


In Reply to: Initial Power Spike
Posted by Gautham Arumilli on 2/11/2001 11:04 PM EST:



The only two things I can think of are that your joysticks are messed up somehow, maybe calibration but i don't know why it goes back to off, or its programming. Make sure that nothing other than the joystick y-axes are controlling the pwms.

Oh, it could be wiring too.