I have some height differences between the rooms in my apartment.
Therefore I needed some ramps for my vacuum robot to get from one room to the other.

One ramp segment has a height of 2 cm. You can also scale it in your slicer to fit your needs.
Each part is 15 cm wide. To cover a regular door you will most likely need 3-4 ramps and screw them together. For assembly you will need a M3 nut and screw.

You can get the print time down to approx. 2 hours if you activate "optimize wall printing order" in Cura and with a resolution of 0.3 mm.

You also might want to attach some velcro stripes to the front side so you can attach the ramp safely to your step and it does not move when the robot runs over it.