A floor cleaning machine includes a cleaning system, a front wheel, two rear wheels, and a drive mechanism. This technique uses the microprocessor within the personal computer to pre-compute the time critical PHY waveforms required to respond to received packets. The drive control device switches either a state of the first or the second plurality of switching elements. The electric power steering device further includes a diameter enlargement member which is arranged in the first tubular portion and which enlarges a part of the first tubular portion in an axial direction thereof to press the internal teeth portion toward the external teeth portion.