\documentclass{standalone}

\usepackage{blox}
\usepackage{tikz}
\usetikzlibrary{positioning}
\newcommand{\equal}{=}
\usepackage{tikz}
\usetikzlibrary{intersections}
\usepackage{tkz-euclide}
% Radius for arc over intersection
\def\radius{1.mm} 

\tikzset{
	connect/.style args={(#1) to (#2) over (#3) by #4}{
		insert path={
			let \p1=($(#1)-(#3)$), \n1={veclen(\x1,\y1)}, 
			\n2={atan2(\y1,\x1)}, \n3={abs(#4)}, \n4={#4>0 ?180:-180}  in 
			(#1) -- ($(#1)!\n1-\n3!(#3)$) 
			arc (\n2:\n2+\n4:\n3) -- (#2)
		}
	},
}

\begin{document}
\begin{tikzpicture}
\bXInput{input}				% Input
\bXComp{adder1}{input}			% First adder
\bXLink[$R(s)$]{input}{adder1}	% Input Label
\bXBloc[1.5]{Gc}{$G_c$}{adder1}			%BLock Gc
\bXComp{adder2}{Gc}		% second adder
\bXBloc[1.5]{G1}{$G_1$}{adder2}	% G1 Block
\bXSuma{adder3}{G1}			% third adder --suma variant
\bXBloc[1.5]{G2}{$G_2$}{adder3}	% G2 Block
\bXBranchy[-4.5]{adder3}{adder3up3} % adder3 up 3 units
\bXLink[$D(s)$]{adder3up3}{adder3}

\bXBranchx[3]{G2}{G2Right15}		% Right of G2 1.5 units	
\bXBloc[1.5]{G3}{$G_3$}{G2Right15}		% G3 Block
\bXBranchx[3.5]{G3}{G3Right15}		% Right of G3 1.5 units
\bXBranchy[4.5]{G2Right15}{G2Right15Down3}	% Right from G2 1.5 units right and 3 units down
\bXBloc[-9]{H1}{$H_1$}{G2Right15Down3}	% H1 Block
\bXBranchy[10]{G3Right15}{outputDown10}

\bXBloc[-15.5]{H2}{$H_2$}{outputDown10}
\bXOutput[3]{end}{G3Right15}

%%Drawing most of the connecters here
\draw[->] (adder1) -- (Gc);
\draw[->] (Gc) -- (adder2);
\draw[->] (adder2) -- (G1);
\draw[->] (G1)  -- (adder3);
\draw[->] (adder3) -- (G2);
\draw[-] (G3) -- (end);
\draw[-] (G2Right15.center) -- (G2Right15Down3.center);
\draw[-] (G3Right15.center) -- (outputDown10.center);
\draw[->] (outputDown10.center) -- (H2);
\draw[->] (G2) -- (G3); % Connect G2 and G3
\draw[->] (G2Right15Down3.center)  -- (H1);

\bXLinkxy{H2}{adder1}
\bXLink[$C(s)$]{G3Right15}{end}	% Output Label
\bXLinkxy{H1}{adder2}
\end{tikzpicture}
\end{document}