\definecolor{cocoabrown}{rgb}{0.82, 0.41, 0.12}
\begin{tikzpicture}

\tikzstyle{system} = [rectangle,very thick,minimum width=1.5cm,font=\scriptsize];
\tikzstyle{output} = [rectangle,very thick,rounded corners=3pt,minimum width=1.5cm,align=center,font=\scriptsize];

\begin{scope}[local bounding box=MULTIPLE]
    \node [system,draw=orange!70,text=orange] (engine3) at (0,0) {系统 $n$};
    \node [system,draw=ugreen!70,text=ugreen,anchor=south] (engine2) at ([yshift=0.6cm]engine3.north) {系统 $2$};
    \node [system,draw=red!70,text=red,anchor=south] (engine1) at ([yshift=0.3cm]engine2.north) {系统 $1$};

    \node [output,draw=orange!70,text=orange,anchor=west] (output3) at ([xshift=0.5cm]engine3.east) {输出 $n$};
    \node [output,draw=ugreen!70,text=ugreen,anchor=west] (output2) at ([xshift=0.5cm]engine2.east) {输出 $2$};
    \node [output,draw=red!70,text=red,anchor=west] (output1) at ([xshift=0.5cm]engine1.east) {输出 $1$};

    \draw [very thick,decorate,decoration={brace}] ([xshift=3pt]output1.north east) to node [midway,name=final] {} ([xshift=3pt]output3.south east);

    \node [output,draw=cocoabrown!70,text=cocoabrown,minimum width=1cm,right=0pt of final,minimum height=2.5em] () {最终\\输出};

    \draw [->,very thick] (engine1) to (output1);
    \draw [->,very thick] (engine2) to (output2);
    \draw [->,very thick] (engine3) to (output3);

    \node [] () at ([yshift=0.4cm]output3.north) {$\vdots$};
\end{scope}

\begin{scope}[local bounding box=SINGLE]
    \node [output,draw=ugreen!70,text=ugreen,anchor=west] (output3) at ([xshift=4cm]output3.east) {输出 $n$};
    \node [output,draw=ugreen!70,text=ugreen,anchor=west] (output2) at ([xshift=4cm]output2.east) {输出 $2$};
    \node [output,draw=ugreen!70,text=ugreen,anchor=west] (output1) at ([xshift=4cm]output1.east) {输出 $1$};

    \node [system,draw=ugreen!70,text=ugreen,anchor=east,align=center,inner sep=1.9pt] (engine) at ([xshift=-0.5cm]output2.west) {单系统};

    \draw [very thick,decorate,decoration={brace}] ([xshift=3pt]output1.north east) to node [midway,name=final] {} ([xshift=3pt]output3.south east);

    \node [output,draw=cocoabrown!70,text=cocoabrown,minimum width=1cm,right=0pt of final,minimum height=2.5em] () {最终\\输出};

    \draw [->,very thick] (engine.east) to (output1.west);
    \draw [->,very thick] (engine.east) to (output2.west);
    \draw [->,very thick] (engine.east) to (output3.west);

    \node [] () at ([yshift=0.4cm]output3.north) {$\vdots$};
\end{scope}

\node [align=center,anchor=north,font=\small] () at ([yshift=-0.3cm]MULTIPLE.south) {\footnotesize{(a) 多系统输出结果融合}};
\node [align=center,anchor=north,font=\small] () at ([yshift=-0.3cm]SINGLE.south) {\footnotesize{(b) 单系统多输出结果融合}};

\end{tikzpicture}