% control.m4
.PS 5i
circlerad = 0.2i
boxwid = boxwid*3/2
boxht = boxht*3/2

R: box "reference" "$R$"
   arrow right_ linewid*4/3 "${y_c}_{\hbox{\scriptsize ref}}$" above
Gh: box "```inverse'''" "$\hat G$"
   arrow from Gh.s down_ "${y_m}_{\hbox{\scriptsize ref}}$" ljust
E: circle
   arrow from E.e right_ "$e$" above
   box "stabilizer" "$K$"
   arrow "$\delta u$" above
D: circle
   line from Gh.e to (D,Gh.e) "$u_{\hbox{\scriptsize ref}}$" above
   arrow to D.n
   arrow from D.e right_ "$u$" above
G: box "plant" "$G$"
   arrow <- from G.n up_ boxht/2 
   "disturbance $z$" above
   arrow right_ from G.e + (0,boxht/4)
   "$y_c$" ljust
   arrow right_ from G.e + (0,-boxht/4)
   "$y_m$" ljust
   move to last arrow.c
   arrow down_ Here.y-G.s.y+boxht*2/3 then left_ Here.x-E.x then to E.s
   "$-$" at Here + (-0.15,-0.1)
   arrow <- down_ from R.s
   "$W$ control input" at Here - (0,0.1)

UL:R.nw +(-boxht/2,boxht/2)
UR:(D.e,UL) + (0.1,0)
   line dashed from UL to UR then to (UR,G.s+(0,-boxht*3/2))
   line dashed to (Gh.w,Here) "Controller" above
   line dashed to (Here,Gh.s+(0,-boxht/2))
   line dashed to (UL,Here) then to UL
.PE