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Author Topic: Servos/wheels rotate automatically  (Read 2203 times)

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Offline 1qaz2wsxTopic starter

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Servos/wheels rotate automatically
« on: March 10, 2009, 07:37:28 PM »
We are trying to bulid a robot for our project. We got 4 servos mount to the wheels, and the servos have been modify already. We also write a simple coding to test on the controlling of the servos. However, 2 of the wheels are just rotating automatically no matter what. With our coding, we can still change the speed of it, but we just can't make it stop. So we reset the board to erase all the code, which the servos/wheels should be stop, but those 2 wheels are just keep rotating. Does anyone know why?? We are thinking maybe there is some coding already set in the servo, but we are not sure.

Offline ArcMan

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Re: Servos/wheels rotate automatically
« Reply #1 on: March 11, 2009, 03:03:40 PM »
Assuming that you are properly sending 1500 uS pulses to the servo, the servo position feedback potentiometers are not "centered" properly.  When servos are modified for continuous rotation, the feedback pot is de-coupled from the output shaft.  The pot must be set to the center position so that the output shaft doesn't rotate when given 1500 uS pulses.  You can fix this by opening up the servo body and adjusting the pot.

Offline 1qaz2wsxTopic starter

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Re: Servos/wheels rotate automatically
« Reply #2 on: March 12, 2009, 01:22:56 PM »
We been "centered" the servos already. The model of the servos is HS 5625MG and connected to the mini dragon board. Someone told me, maybe the current between two are not compatible, so which may damage the servo.

Offline offy

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Re: Servos/wheels rotate automatically
« Reply #3 on: March 13, 2009, 08:12:42 PM »
You missed up modifying those 2 servos. I did the same thing. And since I could not fix them with super glue, I hooked up a resistor. http://www.societyofrobots.com/member_tutorials/node/82

Offline pomprocker

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Re: Servos/wheels rotate automatically
« Reply #4 on: March 13, 2009, 08:41:22 PM »
Use a multimeter to see of the servos are being brought high with voltage, and test if the mcu pin is putting out voltage when the servos are disconnected

 


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