need help for my 6dof robotic arm with position/force control strategy

[douyouzhe]

Hi all, I m working on a school project which is to build a 6 DoF robotic arm that is capable of writing and drawing. I plan to add compliance force control to it and I am a lit bit confused with the concept like position/force control, compliance force control and (someone add PID to the position force control strategy).... can someone help me distinguish all this and maybe provide me something to read? appreciate your help. cheers.

[cyberjeff]

It seems like you should be Googling this, not me.

http://ocw.mit.edu/courses/mechanical-engineering/2-12-introduction-to-robotics-fall-2005/lecture-notes/chapter9.pdf

As you can see,  for the task at hand (literally) you can use either. You can choose to have a feedback loop to adjust the force. To do that, you need to be able to measure the force of the pen against the paper. Not an easy task, I would imagine.

Otherwise you can build some compliance into the system in a mechanical way, that can be as simple as a spring.

As far as PID, you can either  Google that or search for my post on that here. With servos in particular there is overshoot, if you can predict what the actual position is compared to what it was programmed for you can error correct, hence predictive.

[douyouzhe]

i found this articles also. I understand the theories behind, just not very sure how to implement them.