I am using a 5 axis Robot arm (Robolink robot from Igus) to perform some 3D printing routines. By now I am trying to use them and have him have some good position (and speed) control. The robot is atuated by stepper motors (encoders included), but, generally, it lacks stiffnnes. When I tech him some consecutive reference positions its movement is not very soft. I believe I can improve its behaviour by tunning speed references (maximum speed, minimum speed, reference speed) of each joint. Can anybody give me some hint on how to set good speed references?
I think the softness you describe has to do with stepper motor step sizes, try micro stepping to increase smoothness. And devise a motion profile with 3rd order spline to have acceleration equal to zero at turning points.