On Mon, 22 May 2023 at 11:26, Les Newell <les.new...@fastmail.co.uk> wrote: > > I think the OP is referring to a function on some robot arms where the > drives apply enough torque to counterbalance the weight of the arm while > not trying to hold position. This allows you to grab hold of it and > manually move it around. I think this would require some interesting > kinematics to apply just the correct amount of torque on each joint > depending on the arm's position.
I would imagine that part of the system would involve a PID loop to hold position, but one that both holds the current output and updates the commanded position to match the actual if the required output torque exceeds a threshold. It is possible that the need for clever kinematics could be avoided with clever filtering of the torque window limits based on the current torque. I would imagine that this would be very difficult for a heavy robot where the component weights exceed human strength, and very easy for a lightweight system where a human can easily overpower even a fully-driven motor. -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
