mugen自带的低空受身是5200，其changestate是在5050里面，可以去看看。
其中最值得参考的一条trigger是canrecover，一个用于判断人物是否能恢复（也就是受身）的trigger

一般翻滚可以删掉留一个canrecover

前提：fall.recover = 0 禁止空中受身
[State -1] ;地面受身，CMD部分（需要有cns受身动作）
type = ChangeState
value = 777 ;对应cns
triggerall = command = "recovery"
triggerall = alive
triggerall = Canrecover
trigger1 = stateno = 5050
trigger1 = pos y >=-30
trigger1 = vel y > 0 && vel y <= 20
[State -1] ;地面受身，（需要有受身动作）
type = ChangeState
value = 777
triggerall = command = "x+a"
triggerall = alive
trigger1 = stateno = 5050
trigger1 = pos y >=-40
trigger1 = vel y > 0
trigger2 = stateno = 5071
trigger3 = stateno = 5090
trigger4 = stateno = 5080
trigger5 = stateno = 5100
trigger6 = stateno = 5051
trigger7 = stateno = 5061
trigger8 = stateno = 5160
trigger9 = stateno = 5161
trigger10 = stateno = 5081
trigger11 = stateno = 5170
trigger12 = stateno = 5091
trigger13 = stateno = 5171
trigger14 = stateno = 5070
trigger15 = stateno = 5101
trigger16 = stateno = 5062
trigger17 = stateno = 5082
trigger18 = stateno = 5092
trigger19 = stateno = 5102
trigger20 = stateno = 5162
trigger21 = stateno = 5151
trigger22 = stateno = 5152
;-----------------------------------------------------
[Statedef 777] ;受身CNS部分
type = S
movetype = I
physics = N
poweradd= 0
ctrl = 0
anim = 711;指定一个动作
velset = 0,0
sprpriority = 1
;-------------------
[State 700, 2];
type = NotHitBy
trigger1 = 1
value = SCA
[state a]
type = playerpush
trigger1 = 1
value = 0
[State 600, 1];音
type = PlaySnd
trigger1 = Time = 1
value = 200, 0
[state a] ;动作的距离
type = posset
trigger1 = time = 0
y = 0
[State 600, 1]
type = velset
trigger1 = Time = 0
x = -10
[State 600, 1]
type = velset
trigger1 = animelem = 7
x = 0
[State 600, 1]
type = velmul
trigger1 = 1
x = 0.9
[State 200, 7]
type = ChangeState
trigger1 = AnimTime = 0
value = 0
ctrl = 1
以上是我总结出来的，已经是完整的代码