Lack Servo Control

Christj

I am trying to build line following boe-bot. When BS2 read sensor value and instruct the motor to stop, motor not stop immediately. So, when motors stop, the sensor position has changed. How to control this precisely (when sensor read, motor stop immediately)? I want to stop the boe-bot when sensor found intersection or T.

Btw, any references or hints how to make line follower boe-bot with intersection and T?

Thanks in advanced.

--chris

Mike Green

I don't think you can get that kind of precision with a servo motor. I suspect that you will need to get the sensor enough ahead of the BoeBot so it can stop in time given the limitations of the servo motors (control pulses about every 20ms). You can speed up the control cycle (to less than 20ms), but the servo itself will stop responding if it's sped up too much. You'll have to experiment with this.

Having two separate sensors at different distances from the BoeBot also gives you the opportunity to use the further sensor as a warning to slow down, then the closer sensor will tell you if you've gone too far and you can back up slightly to be in the position you want to be in.

kemprof

Hi Chris... still having trouble at intersections? What sensor are you using... photoresistor with the RCTIME command, or using something else like the QTI IR trans/rec? Put up a little of your code; you shouldn't have any trouble at all stopping at an intersection.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Kemprof ,· Santa Ana High School

www.sahsrobotics.org