☰

缩短tikz中箭头的长度

tag-icon • tag-icon tikz-pgf tikz-arrows
缩短tikz中箭头的长度

我正在尝试绘制一幅代表控制理论图的图。

我基本上已经做到了，但是有两个问题：

  1. 我需要在大框中第一个方程的 x(t) 上方加一个点。当我将其置于数学模式时，它会绘制四条线而不是两条，或者，根据我如何拆分数学模式，它会将所有点都放在一条线上。有没有办法在不改变框布局的情况下将那个该死的点放在 x 上方？

  2. 带有 y(.) 的 RHS 箭头太长了。我想将其缩短到接近带有 v(.) 的 LHS 箭头的长度，这样看起来会更美观！

这是我的代码：

\documentclass{article}

\usepackage[utf8]{inputenc}

\usepackage{tikz}

\usetikzlibrary{shapes,arrows}

\usetikzlibrary{positioning, quotes}

\begin{document}

\tikzstyle{block} = [draw, fill=white, rectangle, 
    minimum height=6em, minimum width=12em]

\tikzstyle{sum} = [draw, fill=white, circle, node distance=2cm]

\tikzstyle{input} = [coordinate]

\tikzstyle{output} = [coordinate]

\begin{center}

\begin{tikzpicture}[auto, node distance=4cm,>=latex']
    \node [input, name=input] {};

    \node [sum, right of=input] (sum) {B};

    \node [block, right of=sum] (controller) {\begin{array} \dot{x}(t)=&Ax(t)+Bu(t)\\ x(0)=&x_0 \end{array}};

    !\node [sum, right of=controller, node distance=3.651cm] (mat) {C};
    \node [sum, below of=controller] (K) {K};
    \node [output, right of=controller] (output) {C};
    \node [input, name=end, right of=output, node distance=5cm] {};
    \coordinate [below of=sum] (measurements) {};
    \coordinate [right of=output](fin) {};
    \coordinate[left of =output, xshift=2.7cm] (nodek) {};
    \draw [draw,->] (input) -- node {$v(\bullet)$} (sum);
    \draw [->] (sum) -- node {$u(\bullet)$} (controller);
    \draw [->] (controller) -- node[name=(x)] {$x(\bullet)$} (mat) {};
    \draw [->] (output) -- node {$y(\bullet)$} (fin);
    \draw [-] (nodek) |- (K);
    \draw [->] (K) -| (sum);
\end{tikzpicture}

\end{center}

\end{document}

在此处输入图片描述

答案1

如同jak123 的回答很好但略有不同：

  • \mywidth我利用的是密钥，而不是引入新的长度node distance=2cm。
  • 我也切换到\tikzset语法而不是\tikzstyle。
  • 我删除了代码中多余的元素。

这是您的代码中出现的问题

  • 您忘记在数组中添加列说明符，这就是它不起作用的原因。
  • 您正在加载但未使用定位库。
  • 几个坐标是多余的。

结果如下：

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{tikz}
\usetikzlibrary{arrows,positioning}

\begin{document}

\tikzset{block/.style={draw, fill=white, rectangle, 
    minimum height=6em, minimum width=12em},
sum/.style={draw, fill=white, circle, node distance=2cm},
input/.style={coordinate},
output/.style={coordinate}}

\begin{center}

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

    \node [sum, right= of input] (sum) {B};

    \node [block, right=of sum,align=left] (controller) 
    {$\begin{array}{r@{\,}l} \dot{x}(t)=&Ax(t)+Bu(t)\\ x(0)=&x_0 \end{array}$};

    \node [sum, right=of controller] (mat) {C};
    \node [sum, below=1cm of controller] (K) {K};
    \coordinate [below=of sum] (measurements) {};
    \coordinate [right=1.5cm of mat](fin) {};
    \draw [draw,->] (input) -- node {$v(\bullet)$} (sum);
    \draw [->] (sum) -- node {$u(\bullet)$} (controller);
    \draw [->] (controller) -- node[name=x,above,midway] {$x(\bullet)$} 
    coordinate[midway] (x) (mat);
    \draw [->] (mat) -- node[midway,above] {$y(\bullet)$} (fin);
    \draw [-] (x) |- (K);
    \draw [->] (K) -| (sum);
\end{tikzpicture}
\end{center}

在此处输入图片描述

答案2

像这样？

\documentclass{minimal}
\usepackage[utf8]{inputenc}
\usepackage{tikz}
\usetikzlibrary{shapes,arrows}
\usetikzlibrary{positioning, quotes}
\newlength{\mywidth}
\setlength{\mywidth}{2cm}

\begin{document}

\tikzstyle{block} = [draw, fill=white, rectangle, 
    minimum height=6em, minimum width=12em]
\tikzstyle{sum} = [draw, fill=white, circle, node distance=2cm]
\tikzstyle{input} = [coordinate]
\tikzstyle{output} = [coordinate]

\begin{center}
\begin{tikzpicture}[auto, node distance=4cm,>=latex']
    \node [input, name=input] {};
    \node [sum, right=\mywidth of input] (sum) {B};
    \node [block, right=\mywidth of sum] (controller) {$\begin{array}{ccc} \dot{x}(t)&=&Ax(t)+Bu(t)\\ x(0)&=&x_0 \end{array}$};
    \node [sum, right=\mywidth of controller] (mat) {C};
    \node [sum, below=1cm of controller] (K) {K};
    \node [output, right=\mywidth of controller] (output) {C};
    \node [input, name=end, right=\mywidth of output] {};
    \coordinate [below=\mywidth of sum] (measurements) {};
    \coordinate [right=\mywidth of output] (fin) {};
    \coordinate[left = \mywidth/2 of output] (nodek) {};
    \draw [draw,->] (input) -- node {$v(\bullet)$} (sum);
    \draw [->] (sum) -- node {$u(\bullet)$} (controller);
    \draw [->] (controller) -- node[name=(x)] {$x(\bullet)$} (mat) {};
    \draw [->] (mat) -- node {$y(\bullet)$} (fin);
    \draw [-] (nodek) |- (K);
    \draw [->] (K) -| (sum);
\end{tikzpicture}

\end{center}

\end{document}

是

相关内容