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Australia
Asked
Resolved Resolved by DJ Sures!

Servo Positions On Power Up

I have a problem with the head servos moving into a damaging position when powering up.
I have looked at various comments on the problem but haven't found a solution.
My vertical head servo appears to move into about -10 on powering up.
My INIT script moves it back to 1 but -10 or so is going to break the robot's mouth.
An EZ servo can physically move beyond the limits of 0 to 180 but I don't expect this on powering up.
Do you know of any solution?


Related Hardware EZ-Robot EZ-B v4
Synthiam
#12  
I understand they are from the company ezrobot. While we’re not that company and we make the software for the robot, I’m curious about why the servos twitch. Do they read HDD on the servo? We did the software for the ezrobot servos and I can’t imagine how the HDD labeled servos can ever twitch. If they read HD, then they’d twitch because those old HD servos did 

the HDD servos can never ever twitch
Australia
#13  
They definitely say HDD on the servo. I can live with it now I have turned the servo around. I wonder if they do the same thing with the IOTiny. I do have one to use later for a similar project. But I'm using the EVBv-4 for this robot,.
Synthiam
#14   — Edited
It’s from applying power, not the controller. The controller doesn’t send a signal it has been instructed to. That was the experience with old ezrobot hd and other similar hobby servos. Which was the reason we programmed the HDD servos to not do that, and to not vibrate or make noise. so I’m confused of why the HDD servos you have are twitching. The ezrobot servos with the sticker hd would twitch, but not the HDD. 

wish there was something more I could help you with about this. It’s got me boggled lol

well hopefully the solution you have works for your application with the servos you got! Fingers crossed for ya
Australia
#15  
Seems you were correct. I went to swap the servo for another in case it was faulty.
Somehow this one is a HD servo whereas all the others are HDD. Can't imagine where this one came from as I thought they were all part of my latest purchase. I couldn't see it properly until I took it out of the container it was housed in, so I assumed it was like the others. Changing this servo has cured the jerking problem. Sorry about that. You can sleep easy now!
Synthiam
#16  
Wooo thanks for that! I was ready to chat with our engineer who originally designed the servos to find out how it could possibly twitch - that saved him a panic:D