Manglemender
Member
the print cylinder is 1000 mm diameter, 4 m long, there is a total reduction of (1/60) between motor en cylinder axis. The final gear is on the print cylinder and has 60 teeth on a diameter of approx. 25 cm, so very coarse.
The symptoms you have sound far more like an external disturbance but...
How much backlash is there in the drive train? If there is any amount of backlash then the load will float backwards and forward on the mechanics. If there is any compliance in the drive train then you have a "load on a spring" scenario.
How is your inertia match? As a servo application It should really be <= 5:1.
People often fail to appreciate the finer points of drive system design.
Nick