I am planning to get an AL5D for my first robotics project. Speed and lifting capacity are not important, but positioning accuracy is. I probably need accuracy similar to that of the checkers-playing arms, which I’m guessing use the kit analog servers.
I would like to know if I could expect a noticeable improvement in positioning accuracy by using digital, rather than analog, servos for the elbow, shoulder and base rotation. (I wouldn’t expect it to matter for the wrist or grip.) Being new to the game, I don’t know whether that would help or whether other factors have a much greater bearing on accuracy.
The AL5D kit includes:
HS-645MG for the elbow (133 oz-in)
HS-755HB for the shoulder (183 oz-in)
HS-805BB for base rotation (343 oz-in)
It appears that the digital replacements for these are, respectively, the HS-5645MG, HS-5755MG and HS-5805MG. Is that correct?
I also have a general question. Descriptions of some brackets specify particular servos (the ASB-203 for example). On the other hand, there are many “standard” brackets that are intended to be used with “standard servos”. Does that mean, for example, that any of ServoCity’s “standard” servos (including “High Torque Standard”, “High Speed Standard” and “Digital Standard”) should fit every standard Lynxmotion bracket? If not, how do I tell if a particular standard servo fits a particular standard bracket?
Yes but… The 5755 uses a different case and spline that we do not currently have brackets for. The 805BB, 805MG and 5805 all share the same case so should all work with the brackets we sell.
The Hitec 311, 322, 422, 425, 475, 485, 5485, 645, 5645, 5685, 5980, 5990 all have been verified to fit. Comparing the case specs to the 422 should let you know which of the 7 series will fit. I have not had them in house to test the fit. I do not know which other brand servos will fit the brackets.
Thanks, Jim. I’d appreciate any remarks re my initial question:
I would like to know if I could expect a noticeable improvement in positioning accuracy by using digital, rather than analog, servos for the elbow, shoulder and base rotation.
The null band (probably better known as a dead band) of a servo is that area around it’s center point (1500 mS) where it doesn’t attempt to drive. The servo won’t respond forward or reverse until a few counts (mS) are moved away from the 1500 mS center. The smaller this dead band is, the quicker the servo will respond. However the servo must be very stable (Analog servos are less so), in order to use this smaller response time, otherwise the servo ends up “hunting” (small moves back and forth) when it could be at rest.
