corporations are some of the worst entities when it comes to actually paying taxes
The real problem is that corporations can easily move to countries where the tax burden is lighter. And if their entire operation: whether manufacturing, services or simply annoying people by phoning them up - is automated, it becomes even easier. These corporations are not "sticky": they are not bound to a specific geography, unlike people who tend to put down roots, dislike disrupting their kids' education by moving school, dislike moving to other countries where they don't speak the language and generally dislike change in general.
So for those companies, they can effectively play one tax-collecting country against another: getting deals, moving to the lowest tax-rate region, engaging in "creative" practices. There is already a question among economists of why corporation taxes are already non-zero (ans: probably because political stability, low corruption, "friendly" laws and lack of a nearby war are attributes worth paying for). It would seem reasonable that companies would seek to minimise any robo-tax they were subject to. Especially as it would be difficult for a single country to implement - they'd just see all roboticised industries leave.
I suppose the next thing would be for corporations to buy their own, independent, islands and set themselves up as sovereign states.