2011/5/12 yann jautard <[email protected]>: > very nice work ! > > steppers or servos ? > > what will be the purpose of this arm ? >
Those are steppers and title of video says - arm for a welding robot, so I suspect, that it will hold the welding gun. 2011/5/12 doug metzler <[email protected]>: > I'll be very interested to know if there is any chatter at the end of the > arm during the welding process. Now the arm moves very smoothly, but the offset from tip of welding gun to wrist joints will be 400 mm, so it is hard for me to tell, how smooth the movement is going to be at the tip of the welding gun. I think that there is only one way to find that out :)) Put it all together and test. I think that I will share some more vids, when some progress on arm will be made. 2011/5/12 andy pugh <[email protected]>: > > Did you get genserkins working with sliding joints? > No. I was able to get genserkins to compile with my changes and move linear joints, but I was not able to overcome 2 things: 1) I found it impossible to allign the coordinate frame of arm with coordinate frame of the base - when I moved the arm along X, it _always_ had the X in the direction that was not the X of base frame 2) there were differences in scale between joint and teleop modes - there was very large difference in the travel distance of linear joint, when compared if I jogged some number of units in joint mode or in teleop mode. I really would like to get it right, but I need some help on this one - I have no idea, where to look. The kinematics for this arm are derived from scarakins. X and Y of scarakins are Y and Z for this arm, so there was little to add - linear joint <--> X axis is trivial and then the wrist joints, which also were pretty simple. The thing that I do not like about the design of this arm is that there is no joint, which woud rotate the wrist around the centerline of the lower arm. The reason, why I did not put it in there, is that I did not see a way to get it right in kinematics. And I do not see, how can I do it in a simple way. I was experimenting with pumakins recently, I wanted to try out, if I could get pumakins working for arm, where X would be handled by a linear joint, but I was getting following errors - something was not correct. Basically, what I tried, was: 1) give a fixed value of joint[0] angle, which would turn the arm to move in YZ plane 2) add trivial joint[0] <--> world.tran.x equations But I ran in difficulties understanding those matrices. Is there some source of reading, where I could find out more, what exactly are hom.rot.m.n and hom.tran.n hiding in them? What is their exact purpose? 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
