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Servo gun problem




I have a problem with my servo gun. There are two joints: first revolute (for output link), second prismatic (for fixed link)  and two poses: HOME (j1:0, j2:0) and CLOSE (j1:-1, j2:10). I defined tool as servo gun and mounted in on the robot. 


At any weldpoint gun is moving its joints as I set in "Set external Axes Values" then it moves slightly fixed link and then output link jumps from current position to its CLOSE pose and jumps back. After that output and fixed link moves slightly to its position via "Set external Axes Values". 


What i want to do is to move output link slightly so I could check if it has no collision at weldpoints. 


Any ideas what i need to do?


Re: Servo gun problem

Siemens Phenom Siemens Phenom
Siemens Phenom

Which servo gun joints did you connect to the robot external? For a servo gun, you should connect only the prismatic joint (main joint). This is the only joint controlled by the (real) robot.

The other joint is the balancing joint. It is not controller by the robot.

Simulation will do as follow (to mimic as much as possible the behavior of the real robot):

- move to the weld location with servo gun value stored on the location (set external axes values)

- move the main joint to close position

- jump the balancing joint to close positon

- wait welding time

- jump back the balancing joint to original position

- move the main joint to servo gun value stored on the location


If you want another behaviour of the balancing joint, you need to model the balancing joint as a dependent joint that follows the main joint (with some mathematical formulae). The servo gun will have only one joint as seen from the outside (the balancing joint will be an internal joint). The simulation will only drive the main joint, the internal balancing joint will move according to the position of the main joint with the formulae you have defined.

Re: Servo gun problem


Can you give an example formula that would be used for a pinch style servo gun? Mine has a revolute motion for the tips but I cant figure out how to set the joints properly to each other and the robot.



Re: Servo gun problem


It is not that easy, because you have to define the gun correctly in modeling.

Don't you have guidelines from your end customer?