I seem to have a little problem assembling my arm… it seem that i overestimated the servos strength… i build an arm similar to the one pictured… but i used the stye gripper in the other pic… the gripper is too heavy for the elbow servo. I have already spent quite a bit on this little project… and have already ended up with some left over parts… what would be the best solution to the problem? btw: i chose this style gripper for larger objects. Here are just a few things that i’ve thought of, however I am open to suggestions.
- use shorter tubing between the shoulder and wrist
- use 2 servos for the elbow via a dual servo bracket
- purchase a smaller gripper? what kind?
Also i have purchased the load ballancing springs, however the arm should beable to hold its own weight without them… it looks like i spent about $85 on the gripper setup alone… so i would prefer to keep it if possible… however… i am looking for the cheapest solition. the elbow servo is 144oz/in analog.
here are the pics… it wouldnt let me post the 1st time
This style arm:
lynxmotion.com/images/hi-res/aarm01.jpg
with this type of gripper:
lynxmotion.com/images/hi-res/sparky2.jpg
Please tell us what servos you are using in each position… 
well… the shoulder isnt together yet but will be 645mg’s the elbow and gripper are analog futaba style servo (ebay special) thats MG/BB with 144oz/in tq, and the wrist is a 5625mg.
If the gripper really is too heavy for a single 645MG in the elbow, then you should probably try to duplicate the two servo setup as in the shoulder (your option 2 in the original post). If the servo is stalling in that configuration, then you don’t really have a choice. Another option is to try a stronger single servo such as the digital 5645MG, but that might not work either.
Adding the Lynxmotion Little Grip Kit would also solve the problem. Since all the Lynxmotion SES arms are using it, you know it works with a 645MG in the elbow:
lynxmotion.com/Product.aspx? … egoryID=88
I’m going to be building a small arm using the SES with the Little Grip and a single 645MG in the shoulder and elbow. This one:
lynxmotion.com/images/jpg/asb043.jpg
I would be reluctant to compromise the design of the arm by shortening it if a full size arm is what you are building…
Lynxmotion is developing a solution to this problem using powerful gearhead motor servos, but it’s not available yet. See the threads in the Servo Erector Set forum:
lynxmotion.net/viewtopic.php?t=2211
Good luck, and please let us know how you work it out (post pictures too)!
