I'll be very interested to know if there is any chatter at the end of the arm during the welding process.
Great design! Thanks, DougM On Wed, May 11, 2011 at 12:12 PM, Viesturs Lācis <[email protected]>wrote: > Thanks, guys! I am glad, that You like it :)) > > 2011/5/11 gene heskett <[email protected]>: > > > > Looking great! Keep us posted. What heating method will be used? > > > > What do You mean with the method of heating? > If You mean - what kind of welding is that going to be, then - it will > be MIG welding machine. > Power source, cooling unit and wire feeder units already have arrived, > but the welding gun and cable will arrive after few weeks. That > welding gun will be something specifically for robots. Very similar to > those that can be seen on Youtube on Fanuc welding robots. The tip of > the gun will be 400 mm below the wrist, always at 45 degree angle. > > > 2011/5/11 Andrew <[email protected]>: > > Very nice Viesturs! > > > > Add more details please. Worm gears? What's the long stroke lenght, which > > actuator is there? > > I thought noone would ask :)) > Linear slide is 4000 long, it is a MOD1,5 rack and 48 teeth pinion, > driven by Nema42 motor through a 15:1 worm gear reducer. I was able to > achieve 15000 mm/min rapid speed, but will settle down to 10000 mm/min > - I find it safer. And that's what is told in tech specs in my > contract. > The arm dimensions - distance between centers of shoulder and elbow > joints is 600 mm, between elbow and wrist joints - 500 mm. > Shoulder and elbow joints are 80:1 worm gear reducers, driven by > Nema23 steppers through additional 8:1 planetary gearboxes, giving > total ratio of 640:1. And still the arm is very quick - after taking > that video I started tweaking acceleration and velocity and the arm is > capable to deliver 10000/min rapid speed of the "controlled point" > (which currently is at the end of the arm). > In the wrist there are 2 Nema23 steppers on a 64:1 planetary > gearboxes. One keeps the wrist straight, the other will turn the > welding gun around vertical axis. > At the beginning I thought that all those ratios might be too large, > because Harmonic Drives (manufacturer top-class zero-backlash > planetary reducers, used by ABB and others in high-end robots) has the > max ratio of 160:1. I wanted such ratios to get smooth positioning and > with servos it would work with a 160:1, but with steppers even now I > have ~ 0,07 mm travel distance on each full step of motor. So I think > that it is a success :) > But I think that I would like to use some small servos for the next arm. > > > 2011/5/11 Igor Chudov <[email protected]>: > > Very nice. Can this arm survive welding and its shielding/interference > > issues? > > I hope so :)) > Actually my task in this project was: > 1) design the arm itself; > 2) design and implement controls. > Actual production of parts and assembly is not my task. The boss of > the company, who contracted me, thinks that there should not be issues > with interference, so I do not worry about that yet. The motor wires > are not shielded - I just put them in some kind of cable sockets. Each > motor has a different color so that I do not spend half a day, trying > to figure out which one of six blue/yellow/black/red leads is going to > which motor and really helps keeping them away of becoming a huge mess > of wires. But inductive homing switches are about to be installed and > I think that their cables have shielding. > > Viesturs > > > ------------------------------------------------------------------------------ > Achieve unprecedented app performance and reliability > What every C/C++ and Fortran developer should know. > Learn how Intel has extended the reach of its next-generation tools > to help boost performance applications - inlcuding clusters. > http://p.sf.net/sfu/intel-dev2devmay > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Achieve unprecedented app performance and reliability What every C/C++ and Fortran developer should know. Learn how Intel has extended the reach of its next-generation tools to help boost performance applications - inlcuding clusters. http://p.sf.net/sfu/intel-dev2devmay _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
