Posted by Chris, Coach on team #308, Walled Lake Monster, from Walled Lake Schools and TRW Automotive Electronics.
Posted on 4/1/99 1:15 PM MST
In Reply to: Future Control System posted by John Cunningham on 4/1/99 11:19 AM MST:
I’ve posted something about this a long time ago. I’ll try and remember everything I said and state it again here.
First and foremost, a more powerful microcontroller is needed. Maybe not as a standard feature, but maybe as an option. The terribly slow loop time (not to mention variable loop time) really limits a team from doing any good automatic control through the feedback sensors. Sure, some control can be done, but not much that would be considered good in the real world. Adding four filters is just about enough to slow the thing to an unusable loop time.
I would like to see some teams given the option of using something that you can program in Assembly or C. Perhaps not all teams will have the people with the software know how to do this, which is why it should be an option. Also, to me, that would help level the playing field some. I work at an Automotive Electronics place, and we have very few mechanincal engineers. We end up having somewhat of a disadvantage in the mechanical department compared to a lot of teams. However, we have great strenghts in control theory and software, but we can’t use this to our advantage because of the microcontroller. If we had this option, we could have an advantage in the control of the robot that would help neutralize the advantage that Beatty has in building machines.
I’m not asking for pentiums to be put on the control board, but maybe a Motorola HC11, HC16, or something in that class.
To go along with that, if a team wants to use control, you have to use PWM outputs, so more PWM outputs would be nice.
One last thing: more (and more useful) sensors would be nice. The yaw sensors this year were a great adition, but the maximum yaw rate that they would sense was terrible for many of the applications. We wanted to use the yaw sensors to aid the drive train, but our robot turns at about 5 times the yaw rate that the sensor could measure, rendering the sensor virtually useless. We tried doing some things in software to make up for it, but the resolution of the sensor data became so bad that it was, once again, useless. Not to mention that the slow microcontroller really limited our control algorithm. Perhaps an accelerometer might be useful. But definitely yaw sensors with larger sensing ranges. Acutally, about three yaw sensors each having different ranges would be nice. That way we could make the resolution / range tradeoff ourselves.
: Hello All,
: Because of the power of this forum, I would like to pose this question here.
: In the future, FIRST will upgrade it’s control system. Some things will stay the same and others will change. What I would like to know is what you think is good about the robot controllers, what needs work, or what you think should be done away with completely.
: Some things to keep in mind are to keep answers practical, and remember that FIRST is on a limited budget because it is a non-profit organization.
: I thank you in advance for your thoughts, and am looking forward to reading your ideas.
: John Cunnigham