For example, tax the robot work equal to human work. But since the robots don't need money the salary paid to a robot is pooled to a "common bank account" and then distributed to humans according to some criteria by the goverment.
Robots won't replace humans on a one-for-one basis. One human could be replaced by a hundred tiny robots or a factory with a hundred workers might be replaced by a single big robot. We already have single robots that can do a task hundreds of times faster than a human so how do you tax them equally to human work?
