[Tex/LaTex] Block Diagrams using Tikz


I am trying to implement this Block Diagram:
enter image description here

Forget about the math, I can do it. I just want to implement the diagram. I used the example here; it is nice, but whenever I remove the "measurement" block, the feedback path cannot be obtained unless directly (-180 deg). Also, I am still unable to get more than one box on top of each other.

enter image description here




\tikzstyle{block} = [draw, fill=white, rectangle, 
    minimum height=3em, minimum width=6em]
\tikzstyle{sum} = [draw, fill=white, circle, node distance=1cm]
\tikzstyle{input} = [coordinate]
\tikzstyle{output} = [coordinate]
\tikzstyle{pinstyle} = [pin edge={to-,thin,black}]

\begin{tikzpicture}[auto, node distance=2cm,>=latex']

    \node [input, name=input] {};
    \node [sum, right of=input] (sum) {};
    \node [block, right of=sum] (controller) {Controller};
    \node [block, right of=controller, pin={[pinstyle]above:D},
            node distance=3cm] (system) {System};

    \draw [->] (controller) -- node[name=u] {$u$} (system);
    \node [output, right of=system] (output) {};
    \node [block, below of=u] (measurements) {Measurements};

    \draw [draw,->] (input) -- node {$r$} (sum);
    \draw [->] (sum) -- node {$e$} (controller);
    \draw [->] (system) -- node [name=y] {$y$}(output);
    \draw [->] (y) |- (measurements);
    \draw [->] (measurements) -| node[pos=0.99] {$-$} 
        node [near end] {$y_m$} (sum);

Best Answer

Would this be it?

To draw a block diagram,

(1) First define a style definition for each repeated blocks, input/output, summations, or pins; so that different property of each node is attributed. Use them properly in each node definition mentioned below.

(2) Use node command to place each node, it is convenient to allocate each node based on relative position (above, below, right, left =xx cm of < a node >) where positioning tikzlibrary is instrumental. For each node it is convenient to assigned an <internal name> for later reference, for example, when drawing lines.

(3) Use draw to complete the line connections, assigning labels along the line via node[<location>](<internal name>){<external name>} syntax.

enter image description here




block/.style = {draw, fill=white, rectangle, minimum height=3em, minimum width=3em},
tmp/.style  = {coordinate}, 
sum/.style= {draw, fill=white, circle, node distance=1cm},
input/.style = {coordinate},
output/.style= {coordinate},
pinstyle/.style = {pin edge={to-,thin,black}

\begin{tikzpicture}[auto, node distance=2cm,>=latex']
    \node [input, name=rinput] (rinput) {};
    \node [sum, right of=rinput] (sum1) {};
    \node [block, right of=sum1] (controller) {$k_{p\beta}$};
    \node [block, above of=controller,node distance=1.3cm] (up){$\frac{k_{i\beta}}{s}$};
    \node [block, below of=controller,node distance=1.3cm] (rate) {$sk_{d\beta}$};
    \node [sum, right of=controller,node distance=2cm] (sum2) {};
    \node [block, above = 2cm of sum2](extra){$\frac{1}{\alpha_{\beta2}}$};  %
    \node [block, right of=sum2,node distance=2cm] (system) 
{$\frac{a_{\beta 2}}{s+a_{\beta 1}}$};
    \node [output, right of=system, node distance=2cm] (output) {};
    \node [tmp, below of=controller] (tmp1){$H(s)$};
    \draw [->] (rinput) -- node{$R(s)$} (sum1);
    \draw [->] (sum1) --node[name=z,anchor=north]{$E(s)$} (controller);
    \draw [->] (controller) -- (sum2);
    \draw [->] (sum2) -- node{$U(s)$} (system);
    \draw [->] (system) -- node [name=y] {$Y(s)$}(output);
    \draw [->] (z) |- (rate);
    \draw [->] (rate) -| (sum2);
    \draw [->] (z) |- (up);
    \draw [->] (up) -| (sum2);
    \draw [->] (y) |- (tmp1)-| node[pos=0.99] {$-$} (sum1);
    \draw [->] (extra)--(sum2);
    \draw [->] ($(0,1.5cm)+(extra)$)node[above]{$d_{\beta 2}$} -- (extra);
%\caption{A PID Control System} \label{fig6_10}