Active Z Height Adjustment

rakshithb174

Can the robot be programmed to actively adjust its Z distance when it is in certain regions of the workobject? For example, consider a 100 mm by 100 mm plate as workobject and the origin is at lower left corner. When robot TCP is in the region A (see image attached), it should lift up Z axis by a small compensation factor. Similiarly, when TCP is in region B, it should lower Z axis by small compensation factor. These small adjustments are always less than 1 mm and to account for small deformations in the plate. 

How would one program this? Do I need to create some sort of a parallel routine continusously running in background checking robot TCP to make adjustment?  

lemster68

Two questions:  1. What is the robot doing?  2. why not just have a very small tilt if the workobject to account for the difference?

rakshithb174

lemster68 said:

Two questions:  1. What is the robot doing?  2. why not just have a very small tilt if the workobject to account for the difference?

Robot is depositing a fine bead of ceramic paste on the plate. The workobject (plate) is fixtured so that it can't be tilted. The height of the paste deposited is important for the next steps. Since the workobject isn't entirely flat, the height of paste deposited won't be same either. Can some sort of multi-tasking routine be written to check robot TCP and adjust the Z height? 

lemster68

You are referring to the actual work piece as the workobject.  The workobject is the data representation of the work piece in the robot.  What I suggested is that you manipulate the data to correct the deposition on the work piece.

rakshithb174

lemster68 said:

You are referring to the actual work piece as the workobject.  The workobject is the data representation of the work piece in the robot.  What I suggested is that you manipulate the data to correct the deposition on the work piece.

I can modify the workobject data (datum), but this doesn't fully take into account local deviations in workpiece surface. 

I was thinking to create a background task that checks robot position and adjusts Z value by some fixed amount depending on where the robot is w.r.t. workpiece. Can this be done or is there a simple alternative?

lemster68

Why not teach the points higher or lower as necessary?