statefeed4
\documentclass{standalone} \usepackage{tikz} \usepackage{amsmath} \usetikzlibrary{shapes,positioning,calc} \usetikzlibrary{narrow} \usetikzlibrary{arrows,decorations.markings} % The double arrow comes from % http://www.texample.net/tikz/examples/double-arrows/ % with modification in % http://tex.stackexchange.com/questions/169061/tikz-increase-arrow-head-size \tikzset{blockMinus/.style={draw,minimum width=2em, minimum height=2em,line width=1.5pt, label=center:{$-1$} }} \tikzset{every picture/.style={auto, line width=1pt, >=narrow,font=\small}} \tikzset{block/.style={draw, rectangle, line width=1.5pt, minimum height=3em, minimum width=3em, outer sep=0pt}} \tikzset{sumcircle/.style={draw, circle, outer sep=0pt, label=center:{{$\sum$}}, minimum width=2em}} \tikzset{vecArrow/.style={ line width=1pt, decoration={ markings,mark=at position 1 with { \arrow[scale=2.5,line width=0.4pt] {open triangle 60} } }, double distance=4pt, shorten >= 13pt, preaction = {decorate}, postaction = {draw,line width=4pt, white,shorten >= 10pt} }} \begin{document} \begin{tikzpicture} \node[sumcircle](sum){}; \node[block, right=25mm of sum](g_p){$G_P$}; \node[block, below=13mm of sum.center, xshift=15mm](l){$-L$}; \node[block, left=30mm of sum](l_r){$l_r$}; \node[blockMinus, below=26mm of sum](minus_e){}; \node[block, left=32mm of l](l_i){$-l_i$}; \node[block, left=10mm of l_i](integrator){$\dfrac{1}{s}$}; \node[sumcircle, left=10mm of integrator](sum_e){}; \coordinate[above=15mm of sum_e](input); \draw[->](l_r.west)++(-3.3,0)--node[xshift=-10mm]{$R$}(l_r); \draw[->](l_r)--(sum); \draw[->](sum)--node{$U$}(g_p); \draw[->](g_p.east)--node(output){$Y$}+(2,0); \draw[vecArrow](g_p)|-node[xshift=4mm, yshift=8mm]{$X$}(l); \draw[->](l)-|(sum); \draw[->](input)--(sum_e); \draw[->](output)|-(minus_e); \draw[->](minus_e)-|(sum_e); \coordinate[right=5mm of l_i](l_i1); \draw[-](l_i)--(l_i1); \draw[->](l_i1)--(sum); \draw[->](sum_e)--node{$E$}(integrator); \draw[->](integrator)--node{$x_i$}(l_i); \end{tikzpicture} \end{document}