My robot vacuum cleaner repeatedly got stuck on my laundry rack - the reason for this was the cross bar that runs along the floor. The cross bar can be pulled out of the plastic corner connectors with a little force. I designed T-Joints that make it possible to attach the cross strut higher up so that the robot can drive underneath it. I also designed feet that can be attached to the legs as end caps (best printed in TPU).

You acceive the best fit if you wrap the metal tube with some scotch tape until it fits snuggly ;-)
Tubes have 18.1 mm diameter - maybe it fits some other cloths hanger/drying rack as well…

Edit: Shout out to derhein who obviously had the same problem but solved it differently: https://makerworld.com/models/40392