the substep includes re obtaining the first leg ZMP position and the second leg ZMP position which satisfy the ZMP equation under {HEAD ~ the first leg ZMP restraint condition} if {TAIL ~ the obtained first leg ZMP position} is located out of a first leg ZMP permissible area defined within a ground contact area of the first leg, and 
the substep includes re obtaining the first leg ZMP position and the second leg ZMP position which satisfy the ZMP equation under { HEAD ~ the first leg ZMP restraint condition } if { TAIL ~ the obtained first leg ZMP position } is located out of a first leg ZMP permissible area defined within a ground contact area of the first leg , and
OTH OTH OTH 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 HEAD HEAD HEAD OTH TAIL TAIL TAIL 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