Sync_Write timing question

Bioloid robot kit from Korean company Robotis; CM5 controller block, AX12 servos..
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3 postsPage 1 of 1

Sync_Write timing question

Post by FriedV » Fri Nov 09, 2012 3:18 pm

Post by FriedV
Fri Nov 09, 2012 3:18 pm

I have written a VB prgram to run a crustcrawler with 6 legs @ 3 AX18 servos using usb2dynamixel. For testing, the crawler is wire connected to the pc and sits on a bench with all legs running free in the air.
Experimenting with sync-write I see that I can move all 18 servos at once to i.e. a fixed start or reset position, but only if I set the servo speed to a quite small figure, around 250 of 873 possibel with AX18s. If I set the speed to 0 or max, the sync-write instruction stops somewhere in the middle of execution. I don't understand this, the faster the servos run the more commands should they be able to execute? Anything I'm overlooking?
Thx, Friedrich
I have written a VB prgram to run a crustcrawler with 6 legs @ 3 AX18 servos using usb2dynamixel. For testing, the crawler is wire connected to the pc and sits on a bench with all legs running free in the air.
Experimenting with sync-write I see that I can move all 18 servos at once to i.e. a fixed start or reset position, but only if I set the servo speed to a quite small figure, around 250 of 873 possibel with AX18s. If I set the speed to 0 or max, the sync-write instruction stops somewhere in the middle of execution. I don't understand this, the faster the servos run the more commands should they be able to execute? Anything I'm overlooking?
Thx, Friedrich
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Post by i-Bot » Fri Nov 09, 2012 4:33 pm

Post by i-Bot
Fri Nov 09, 2012 4:33 pm

I have not had a problem with sync write. How often are you sending the sync writes ? Is it just one time or repeated ?

Are you sure it is not a power supply problem ? moving all the servos together ? How is it powered/wired ?

When you say servo speed, you mean moving speed ?
I have not had a problem with sync write. How often are you sending the sync writes ? Is it just one time or repeated ?

Are you sure it is not a power supply problem ? moving all the servos together ? How is it powered/wired ?

When you say servo speed, you mean moving speed ?
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Post by FriedV » Sat Nov 10, 2012 11:43 am

Post by FriedV
Sat Nov 10, 2012 11:43 am

Thanks,
you were right, it was a current peak problem. The power supply from the land of the many people& the rising sun was not quite up to their specs. Now I use a Turnigy 11,1V 4000mA 30C LiPo, no problems. But operating the servo at full spped and long trajectories stresses the mechanics quite a bit,
so at least while testing my software I will reduce the moving speed.
Friedrich
Thanks,
you were right, it was a current peak problem. The power supply from the land of the many people& the rising sun was not quite up to their specs. Now I use a Turnigy 11,1V 4000mA 30C LiPo, no problems. But operating the servo at full spped and long trajectories stresses the mechanics quite a bit,
so at least while testing my software I will reduce the moving speed.
Friedrich
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