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