Engage offset filtering using a simple alpha filter (EWMA) and set the filter coefficient.

When applying an offset, it must have a smooth velocity profile in order for the robot to be able to follow the offset trajectory. This can potentially be cumbersome to obtain, not least as offset application starts, unless filtering is applied.

The alpha filter is a very simple 1st order IIR filter using a weighted sum of the commanded offset and the previously applied offset: filtered_offset= alpha*offset+ (1-alpha)*filtered_offset.

See more details and examples in the UR Support Site: Modify Robot Trajectory

Parameters

alpha: The filter coefficient to be used - must be between 0 and 1.
A value of 1 is equivalent to no filtering.

For welding; experiments have shown that a value around 0.1 is a good compromise between robustness and offsetting accuracy.

The necessary alpha value will depend on robot calibration, robot mounting, payload mass, payload center of gravity, TCP offset, robot position in workspace, path offset rate of change and underlying motion.