A project log for YARRM - 7-DOF Low-Cost Robot Arm

Yet Another Robot aRM - where I develop a low-cost compliant robot arm with a 1meter reach, 1KG payload.

Jonathan LussierJonathan Lussier 03/21/2016 at 00:390 Comments

Laser cutting definately have advantages. One is that steel makes an excellent spring material.

Why not kill two birds with one stone?

I've now integrated adjustable leaf springs into my laser cut tube directly.

The springs are the three "lines' present, which are not directly mirrored but are set 180degrees from each other on each side. By changing the thickness of the printed "counter-balance", I can "engage" one, two or three of the springs. In addition, I can change the preload by redesining the printed part, or by adding a u-bolt around the entire tube (similar to truck suspension).

This is one of the possible designs I have been considering for the stackable "pusher". As you can see it is bolted to the 8mm axle pivot (which is now a solid aluminium bar instead of a printed part with bearings).

In the first picture you also see some modifications to the old tube design (which was squared off and which was snagging on the rotator/pivot). The end is now all curved to allow the pivot to go around. In addition I added holes for IGUS igubal self-aligning bearing installation.

On the base I have added a very large (huge) counter-weight to balance the arm. See next post for more details on that and the rest of the substantial redesign, all of which originated from building the original arm.