RC Servo not reaching target position

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sgeiger
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RC Servo not reaching target position

Post by sgeiger »

When setting high speed and acceleration, or when disabling speed ramping, the servo motor sometimes doesn't reach its target (when the target is far from current position). I guess the controller stops transmitting pulses when it "thinks" the motor reached its target.
Tested with RCC1000 and 1061_1.

BTW: the forums system doesn't allow to search the word "servo" (it says it's too common and ignores it). this makes finding similar topics very difficult (maybe the servo motors deserve their own category in the hardware section?).
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Patrick
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Re: RC Servo not reaching target position

Post by Patrick »

You mean the motor physically doesn't reach position? Are you keeping the channel open and engaged? Can you post relevant source code?

-Patrick
sgeiger
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Re: RC Servo not reaching target position

Post by sgeiger »

Yes - open and attached.
This happens in code, but also when testing the controller in the control panel, so I don't think the code is relevant.
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mparadis
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Re: RC Servo not reaching target position

Post by mparadis »

Do you have any other servo motors you can test with to confirm that it's a problem with the controller? It could be an issue with the servo's internal position controller. Alternatively, if you have a multimeter you may be able to scope the data line going to the servo to confirm that the controller stops the PWM signal early.
sgeiger
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Re: RC Servo not reaching target position

Post by sgeiger »

OK. Solved.
The problem was only with digital RC servos: when setting to a position outside the servo range, some digital servos stopped from moving and others disengaged. Analog servos rotated to the maximum travel possible and kept it (as expected).
To avoid this, it is very important to set pulse min and max for the specific servo used.

Thanks.
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