Robot Lerching at 45 % power

Rob7

·Hi all,

I just completed hooking my HB 25's to my robot and with expermenting with foward and reverse motions, the foward motion seems to lerch. Slow speed then fast speed ?
In reverse the motion is constant and no abnormal speed is seen. The motors are 7.5 constant rotation motors.
Has anybody had this problem ?
·Thanks,
·Rob7

Mike Green

This sounds like a power supply issue. The HB-25s shouldn't cause lurching. Make sure the logic supply is well filtered and that you have no ground loops involving the motor current. The logic (servo) ground should attach to the motor power source at one point, preferably the battery.

Chris Savage

What does the 7.5 indicate for this motor? Also, how often are you sending pulses to the HB-25? It does not require refresh, however if you over-drive it you might get some unpredictable behavior.

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Chris Savage
Parallax Tech Support

Rob7

Sorry, Chris

I have not been home, I live near Rainbow, and have been volunteering at the Red Cross station near my home.
Several thousand displaced families here.
The 7.5 is the Battery voltage.
I repleyed on this post http://forums.parallax.com/showthread.php?p=685933

·Rob7

Rob7

Thanks Mike,
I looked over the power distribution pcb I created and everthing looks good.
Chris,
"I failed to overlook one small item !"
I know what you are thinking ?, "Reading the manual"!
Yup,
Well in my code, I had entered two pause lines witch caused my motors to "Run, Stop, Run, Stop".
"Sometime the answer is right in front of your face !"
Well I missed it the first time.
I learned that the timeing of the HB-25 is very important.
Rob7