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