Anyone who is serious about professional servos should check out Dynamixels. I say professional because they are way overpriced. But, They now sell a $49 version that fits the form factor of the other X models. I have one which I will post the results here.
Here is the reason I sing their praises. I have three dynamixel MX64AT's inside Alan, two which control his up and down on his head. I have been doing endurance testing on them. They have been holding Alans dead weight head which is about 6 pounds (aluminum version) for 17 days non stop. To be clear they are on and in their 0 position so they are holding that weight, no sound, no heat for 17 days/24 hours a day. Its amazing.
I am very curious about the X brand I have now. They are much smaller than the 64's. About 1.5 times the size of a standard servo, with all the resolution and PID feedback etc.
Asked
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Or is the torque of the HDD servo a lot less?
I must admit I replaced some of the Servos in my InMoov and Hexapod robots and I’m very impressed with there performance, no buzzing under load and impressive torque!
Chris.
But the for professional projects, I will be using the big dynamixels. I don't think I have ever seen a hobby servo hold dead weight for more than a few hours without burning out. These are holding for weeks! The stress test I'm doing on the Alan robots are just unbelievable. There is no worm gear or braking system, just efficient gearing and power management.
Which ever servos you choose, just remember to use ezrobot controllers and ARC for your robot application