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Midland Helicopters . HeliProz . ZoomsHobbies

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Main Discussion > SERVOS: An in depth look - Part 1
 
 
GimbalFan
Elite Veteran
Location: Copter County, Nv

Excellent work, Dave. Good onya.

op-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-thwõp-t
04-15-2008 08:54 PM
 
 
playfair
Key Veteran
Location: Rochester, NY

Added HiTec HS-6975 servos to the speed/accuracy graphs.

Though they have impressive speeds, under even moderate loads they will not position to the original locations.


The sky is our canvas
05-08-2008 07:09 PM
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JKos
Elite Veteran
Location: City of California in the state of Maryland

playfair,
I don't think I understand/believe the results being shown on your "Servo Torque vs. Accuracy" graph. A digital servo is not going to stop 16 degrees from its intended position (such as the HS-5975 at 60 in*oz). If it can move the load at all, it will continue to move.

The position sensing within the servo is not affected by the load, so why would these servos possibly be stopping so short of the target? I just did some quick testing with a 9252, and it always goes back to the target within visual perception. I loaded it up until it was really straining, but it still gets there.

So, what are you really showing in this graph? Surely you can't be telling us that the HS-5975 gives up 16 degrees off of where it should be. I'm thinking something is up with your test rig.

Thanks,
John

MSH Protos
05-08-2008 08:34 PM
 
 
playfair
Key Veteran
Location: Rochester, NY

I thought the same thing, Jkos, and have discovered maybe 5deg of "twist and turn" of the setup at heavier loads, comprising the ball links, arms, and servo mounting.

The break I'm using is pretty unique to other servo tests I've seen. Perhaps it is an "unrealistic" way to stress a servo.
Even as a relative comparison, all the servos tested were under identical conditions yet the results differed significantly. The Hitec servos do "give up" more than the others. All of them are trying hard to reach the target, but perhaps some internal limiting that prevents them from overshooting hinders the finer precision.

Next time I run the rig I'll take video and post it.


The sky is our canvas
05-08-2008 09:16 PM
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MMike
Elite Veteran
Location: Holland,Mi-USA

Book mark.

Good stuff.
06-03-2008 03:10 PM
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2 pages [ <<    <     1     ( 2 )    >    >> ]1584 viewsPOST REPLY
HeliHobby . Ron’s HeliProz South . Century Helicopter

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Main Discussion > SERVOS: An in depth look - Part 1
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