Actor Rising(Y-Axis)

Hi guys,
does somebody know how to make your actor (VR VIVE SETUP with PS4 CONROLLER) go higher over time and limiting it to go lower then requested. Kind of like if you were rising higher and higher(y), while still being able to roam around.(on x and z)
I tried working with blocking volumes/Level bounds decreasing. Until now nothing worked.
Any suggestions?

Kind Regards,
Vito Boeckx