Level Winding

[Garyhlucas]

We are automating an existing oscillating level winding application operated by hydraulic motors, using our go to BRX36.  The hydraulic valves are being operated by servo motors.  There are quadrature encoders on the level winder screw and the winding spindle.  The level winding head must oscillate back and forth synchronized with the winding spindle rotation. So we control the speed of the spindle by positioning the hydraulic valve 0 to 100% and then operate the other hydraulic valve plus or minus 100% to move one pitch per revolution in both directions.

Suggestion on the appropriate way to handle this?  In my mind I am picturing this as an AXCAM operation. The cam (spindle) has one lobe that goes 180 degrees around.  So when the follower is on the lobe the level winder is running forwards. When it ramps down to the lower level it it runs in reverse.

PID loop controlling 0 to 100% position of servo operating the valve to control spindle speed from quadrature encoder?  Second PID loop controlling +- servo position of hydraulic valve for level winder position?

Interesting little job, customer wants to do about 10 machines if this works!

Thanks.

[jackmarvia689]

Use electronic gearing instead of dual PID loops slave the level winder to the spindle encoder with a position ratio (pitch/rev) and reverse direction at limits. Cleaner, more precise, and easier to tune.

[Controls Guy]

Use electronic gearing instead of dual PID loops slave the level winder to the spindle encoder with a position ratio (pitch/rev) and reverse direction at limits. Cleaner, more precise, and easier to tune.

Does the shaft for the winding guide not look like the guts out of a Stanley push-push screwdriver and auto-reverse at the ends?

[Garyhlucas]

No this is just a straight screw and the reels are different sizes. So we are doing a scan with a distance laser to locate the flanges then reading two encoders to get the size of of one or more wires and calculating the appropriate pitch and range of motion, with NO input from the operator!