Based on some designs that I developed
in 1976, I started Johnson Robotics in 1980. At the time is was barely
more than a workbench in a garage. Later I was able to put the earnings
from working models I built into funding a lab, complete with test equipment
and a decent inventory of parts and tools. My primary goal is R&D,
but it generates enough revenue to pay for expenses.
The idea of a personal robot as a sort of valet or companion is popular in fiction. If you like gadgets they can be interesting, and maybe useful. If you really want a companion though, get yourself a dog.