Further, a lateral drive supported by the travel unit is controlled by a lateral control unit, and {HEAD ~ a θ drive} supported by the lateral drive is controlled by {TAIL ~ a θ control unit} 
is controlled by
Further , a lateral drive supported by the travel unit is controlled by a lateral control unit , and { HEAD ~ a θ drive } supported by the lateral drive is controlled by { TAIL ~ a θ control unit }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL