Wherein, the control unit 1 is mainly to provide {HEAD ~ the driving device} 5 with {TAIL ~ the function} to move forward and change direction 
Wherein , the control unit 1 is mainly to provide { HEAD ~ the driving device } 5 with { TAIL ~ the function } to move forward and change direction
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH