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<div id="pf1" class="pf w0 h0" data-page-no="1"><div class="pc pc1 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62509f4874bc5c01056cd70f/bg1.jpg"><div class="t m0 x1 h2 y1 ff1 fs0 fc0 sc0 ls0 ws0">第<span class="ff2">5</span>章<span class="_ _0"> </span><span class="ls1">数字控制技术</span></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
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<div id="pf2" class="pf w0 h0" data-page-no="2"><div class="pc pc2 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62509f4874bc5c01056cd70f/bg2.jpg"><div class="t m0 x2 h3 y2 ff2 fs1 fc1 sc0 ls0 ws0">5.1<span class="_ _1"></span> <span class="_ _2"></span> <span class="ff1 ls2">数字控制基础</span></div><div class="t m0 x3 h4 y3 ff1 fs2 fc1 sc0 ls1 ws0">数字控制主要用于数控机<span class="_ _3"></span>床、线<span class="_ _3"></span>切割机<span class="_ _3"></span>、焊接<span class="_ _3"></span>机、气<span class="_ _3"></span>割机</div><div class="t m0 x3 h4 y4 ff1 fs2 fc1 sc0 ls1 ws0">以及低速小型数字绘图仪<span class="_ _3"></span>等。数<span class="_ _3"></span>控机床<span class="_ _3"></span>可以加<span class="_ _3"></span>工形状<span class="_ _3"></span>复杂</div><div class="t m0 x3 h4 y5 ff1 fs2 fc1 sc0 ls1 ws0">的零件，具有加工精度高<span class="_ _3"></span>、生产<span class="_ _3"></span>效率高<span class="_ _3"></span>、便于<span class="_ _3"></span>改变加<span class="_ _3"></span>工零</div><div class="t m0 x3 h5 y6 ff1 fs3 fc1 sc0 ls0 ws0">件品种等众多优点，是机<span class="_ _3"></span>床实现<span class="_ _3"></span>自动化<span class="_ _3"></span>的发展<span class="_ _3"></span>方向。<span class="_ _3"></span>对于</div><div class="t m0 x3 h5 y7 ff1 fs3 fc1 sc0 ls0 ws0">不同的设备，其控制系统<span class="_ _3"></span>有所不<span class="_ _3"></span>同，但<span class="_ _3"></span>基本的<span class="_ _3"></span>数字控<span class="_ _3"></span>制原</div><div class="t m0 x3 h4 y8 ff1 fs2 fc1 sc0 ls1 ws0">理是相同的。</div><div class="t m0 x2 h6 y9 ff2 fs4 fc1 sc0 ls0 ws0">5.1<span class="_ _3"></span>.1 <span class="_ _3"></span> <span class="ff1">数字控制的基本原理</span></div><div class="t m0 x2 h7 ya ff3 fs5 fc2 sc0 ls0 ws0"><span class="_ _4"> </span><span class="ff1 fs2 fc1 ls1">平面曲线图形如图<span class="ff2 ls0">5-1<span class="ff1">所示，下<span class="_ _3"></span>面<span class="_ _3"></span>分析如<span class="_ _2"></span>何利用计算机<span class="_ _2"></span>在</span></span></span></div><div class="t m0 x3 h4 yb ff1 fs2 fc1 sc0 ls1 ws0">绘图仪或加工装置上重现<span class="_ _3"></span>，下面<span class="_ _3"></span>分四步<span class="_ _3"></span>。</div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
<div id="pf3" class="pf w0 h0" data-page-no="3"><div class="pc pc3 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62509f4874bc5c01056cd70f/bg3.jpg"><div class="t m0 x4 h8 yc ff4 fs6 fc1 sc0 ls0 ws0">b</div><div class="t m0 x5 h9 yd ff4 fs7 fc1 sc0 ls0 ws0">y</div><div class="t m0 x6 h9 ye ff4 fs7 fc1 sc0 ls0 ws0">x</div><div class="t m0 x7 h9 yf ff4 fs7 fc1 sc0 ls0 ws0">a</div><div class="t m0 x8 h8 y10 ff4 fs6 fc1 sc0 ls0 ws0">c</div><div class="t m0 x9 h9 y11 ff4 fs7 fc1 sc0 ls0 ws0">d</div><div class="t m0 x5 h8 y12 ff4 fs6 fc1 sc0 ls0 ws0">O</div><div class="t m0 xa ha y13 ff1 fs7 fc1 sc0 ls0 ws0">图<span class="ff5">5-1 </span>曲线分段</div><div class="t m0 x2 hb y14 ff3 fs8 fc2 sc0 ls0 ws0"><span class="_ _4"> </span><span class="ff2 fs3 fc1">1<span class="ff1">）将此曲线分割成若干线<span class="_ _2"></span>段，可以是直<span class="_ _2"></span>线段，也可是<span class="_ _2"></span>曲线</span></span></div><div class="t m0 x3 hc y15 ff1 fs2 fc1 sc0 ls1 ws0">段，把该图分割成<span class="ff2 ls0">3</span>段，即<span class="_ _5"> </span><span class="ls0">，<span class="_ _6"> </span></span>和弧线<span class="_ _7"> </span>，然后把<span class="ff4 ls0">a,b<span class="_ _1"></span>,c,d</span></div><div class="t m0 x3 h4 y16 ff1 fs2 fc1 sc0 ls1 ws0">四点坐标记下来并送给计<span class="_ _3"></span>算机。</div><div class="t m0 x2 hc y17 ff3 fs8 fc2 sc0 ls0 ws0"><span class="_ _4"> </span><span class="ff2 fs2 fc1">2<span class="ff1 ls1">）当给定</span><span class="ff4">a,b<span class="_ _1"></span>,c,d<span class="ff1">各点坐<span class="_ _2"></span>标和<span class="ff4">x,y<span class="_ _2"></span><span class="ff1">值之后，如何<span class="_ _2"></span>确定各<span class="_ _2"></span>坐标值</span></span></span></span></span></div><div class="t m0 x3 h5 y18 ff1 fs3 fc1 sc0 ls0 ws0">之间的中间值？求得这些<span class="_ _3"></span>中间值<span class="_ _3"></span>的数值<span class="_ _3"></span>计算方<span class="_ _3"></span>法称为<span class="_ _3"></span>插值</div><div class="t m0 x3 h5 y19 ff1 fs3 fc1 sc0 ls0 ws0">或插补。插补计算的宗旨<span class="_ _3"></span>是通过<span class="_ _3"></span>给定的<span class="_ _3"></span>基点，<span class="_ _3"></span>以一定<span class="_ _3"></span>的速</div><div class="t m0 x3 h4 y1a ff1 fs2 fc1 sc0 ls1 ws0">度连续定出一系列中间点<span class="_ _3"></span>，而这<span class="_ _3"></span>些中间<span class="_ _3"></span>点的坐<span class="_ _3"></span>标值是<span class="_ _3"></span>以一</div><div class="t m0 x3 h4 y1b ff1 fs2 fc1 sc0 ls1 ws0">定的精度逼近给定的线段<span class="_ _3"></span>的。</div><div class="c xb y1c w2 hd"><div class="t m1 xc he y1d ff5 fs9 fc1 sc0 ls3 ws0">ab</div></div><div class="c xd y1e w3 hf"><div class="t m2 xc h10 y1f ff5 fsa fc1 sc0 ls4 ws0">bc</div></div><div class="c xe y20 w4 h11"><div class="t m3 xc h12 y21 ff4 fsb fc1 sc0 ls5 ws0">cd</div></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
<div id="pf4" class="pf w0 h0" data-page-no="4"><div class="pc pc4 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62509f4874bc5c01056cd70f/bg4.jpg"><div class="t m0 x2 h7 y22 ff3 fs5 fc2 sc0 ls0 ws0"><span class="_ _4"> </span><span class="ff2 fs2 fc1">3<span class="ff1 ls1">）把插补运算过程中定出<span class="_ _2"></span>的各中间点，<span class="_ _2"></span>以脉冲<span class="_ _3"></span>信号形<span class="_ _3"></span>式去</span></span></div><div class="t m0 x3 hc y23 ff1 fs2 fc1 sc0 ls1 ws0">控制<span class="ff4 ls0">x,y<span class="ff1">方<span class="_ _2"></span>向上的<span class="_ _3"></span>步进电<span class="_ _3"></span>机，带<span class="_ _2"></span>动画笔、刀具<span class="_ _2"></span>或线电<span class="_ _2"></span>机运动，</span></span></div><div class="t m0 x3 h5 y24 ff1 fs3 fc1 sc0 ls0 ws0">从而绘出图形或加工出符<span class="_ _3"></span>合要求<span class="_ _3"></span>的轮廓<span class="_ _3"></span>。这里<span class="_ _3"></span>的每一<span class="_ _3"></span>个脉</div><div class="t m0 x3 h13 y25 ff1 fs3 fc1 sc0 ls0 ws0">冲信号代表步进电机走一<span class="_ _3"></span>步，即<span class="_ _3"></span>画笔或<span class="_ _3"></span>刀具在<span class="ff4">x</span>方向<span class="_ _3"></span>或<span class="ff4">y</span>方向</div><div class="t m0 x3 h4 y26 ff1 fs2 fc1 sc0 ls1 ws0">移动一个位置。我们把对<span class="_ _3"></span>应于每<span class="_ _3"></span>个脉冲<span class="_ _3"></span>移动的<span class="_ _3"></span>相对位<span class="_ _3"></span>置称</div><div class="t m0 x3 h4 y27 ff1 fs2 fc1 sc0 ls1 ws0">为脉冲当量，又称为步长<span class="_ _3"></span>，常用<span class="_ _5"> </span><span class="ls0">和<span class="_ _8"> </span></span>来表示，并且总是</div><div class="t m0 x3 h14 y28 ff1 fs2 fc1 sc0 ls0 ws0">取<span class="_ _9"> </span><span class="ff5">=<span class="_ _8"> </span></span>。</div><div class="t m0 x2 hb y29 ff3 fs8 fc2 sc0 ls0 ws0"><span class="_ _4"> </span><span class="ff1 fs3 fc1">图<span class="ff2">5-2<span class="_ _3"></span><span class="ff1">是一段用折线逼近直线的直<span class="_ _3"></span>线插补<span class="_ _3"></span>线段，<span class="_ _3"></span>其中</span></span></span></div><div class="t m0 x3 h13 y2a ff1 fs3 fc1 sc0 ls0 ws0">代表该线段的起点坐标值<span class="_ _3"></span>，<span class="_ _a"> </span>代表终点坐标值，则<span class="ff4">x</span>方</div><div class="t m0 x3 h13 y2b ff1 fs3 fc1 sc0 ls0 ws0">向和<span class="ff4">y</span>方向应移动的总步数<span class="_ _5"> </span>和<span class="_ _b"> </span>分别为</div><div class="c xf y2c w5 h15"><div class="t m4 x10 h16 y2d ff5 fsc fc1 sc0 ls0 ws0">x<span class="_ _c"></span><span class="ff6"></span></div></div><div class="c x11 y2e w6 h17"><div class="t m5 x12 h18 y2f ff5 fsd fc1 sc0 ls0 ws0">y<span class="_ _d"></span><span class="ff6"></span></div></div><div class="c x13 y30 w5 h15"><div class="t m4 x10 h16 y2d ff5 fsc fc1 sc0 ls0 ws0">x<span class="_ _c"></span><span class="ff6"></span></div></div><div class="c x14 y31 w7 h19"><div class="t m6 x10 h1a y32 ff5 fse fc1 sc0 ls0 ws0">y<span class="_ _e"></span><span class="ff6"></span></div></div><div class="c x15 y33 w8 h1b"><div class="t m7 x16 h1c y34 ff1 fsf fc1 sc0 ls0 ws0">）<span class="_ _f"></span>（</div><div class="t m7 x17 h1d y35 ff5 fs10 fc1 sc0 ls0 ws0">0<span class="_ _10"></span>0</div><div class="t m7 x18 h1e y34 ff4 fsf fc1 sc0 ls0 ws0">y<span class="_ _11"></span>x<span class="_ _12"> </span><span class="ff7">,</span></div></div><div class="c x19 y36 w9 h1b"><div class="t m8 x1a h1f y37 ff1 fs11 fc1 sc0 ls0 ws0">）<span class="_ _13"></span>（</div><div class="t m8 x17 h20 y38 ff4 fs12 fc1 sc0 ls0 ws0">e</div><div class="t m8 x18 h21 y37 ff4 fs11 fc1 sc0 ls0 ws0">y<span class="_ _14"></span>x<span class="_ _15"> </span><span class="ff7">,</span></div><div class="t m8 x1b h22 y38 ff5 fs12 fc1 sc0 ls0 ws0">e</div></div><div class="c x1c y39 wa h23"><div class="t m9 x1d h24 y3a ff4 fs13 fc1 sc0 ls0 ws0">x</div><div class="t m9 xc h25 y3b ff5 fs14 fc1 sc0 ls0 ws0">N</div></div><div class="c x1e y3c wa h26"><div class="t ma x1d h27 y3d ff5 fs15 fc1 sc0 ls0 ws0">y</div><div class="t ma xc h28 y3e ff5 fs16 fc1 sc0 ls0 ws0">N</div></div><div class="c x1f y3f wb h29"><div class="t mb x20 h2a y40 ff5 fs17 fc1 sc0 ls6 ws0">e0</div><div class="t mb x21 h2a y41 ff5 fs17 fc1 sc0 ls0 ws0">x</div><div class="t mb x22 h2b y42 ff4 fs18 fc1 sc0 ls7 ws0">xx</div><div class="t mb x23 h2b y43 ff4 fs18 fc1 sc0 ls0 ws0">N</div><div class="t mb x24 h2b y44 ff4 fs18 fc1 sc0 ls0 ws0">x</div><div class="t mb x25 h2c y42 ff6 fs18 fc1 sc0 ls0 ws0"></div><div class="t mb x26 h2c y43 ff6 fs18 fc1 sc0 ls0 ws0"></div><div class="t mb x27 h2c y44 ff6 fs18 fc1 sc0 ls0 ws0"></div></div><div class="c x1f y45 wc h2d"><div class="t mc x28 h2e y46 ff5 fs19 fc1 sc0 ls8 ws0">e0</div><div class="t mc x29 h2e y47 ff5 fs19 fc1 sc0 ls0 ws0">y</div><div class="t mc x2a h2f y48 ff4 fs1a fc1 sc0 ls9 ws0">yy</div><div class="t mc x2b h2f y49 ff4 fs1a fc1 sc0 ls0 ws0">N</div><div class="t mc x25 h2f y4a ff4 fs1a fc1 sc0 ls0 ws0">y</div><div class="t mc x2c h30 y48 ff6 fs1a fc1 sc0 ls0 ws0"></div><div class="t mc x2d h30 y49 ff6 fs1a fc1 sc0 ls0 ws0"></div><div class="t mc x2e h30 y4a ff6 fs1a fc1 sc0 ls0 ws0"></div></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
<div id="pf5" class="pf w0 h0" data-page-no="5"><div class="pc pc5 w0 h0"><img class="bi x0 y0 w1 h1" alt="" src="https://static.pudn.com/prod/directory_preview_static/62509f4874bc5c01056cd70f/bg5.jpg"><div class="t m0 x2 h5 y4b ff3 fs8 fc2 sc0 ls0 ws0"><span class="_ _4"> </span><span class="ff1 fs3 fc1">如果把<span class="_ _16"> </span>和<span class="_ _17"> </span>约定为坐标增量值，即<span class="_ _18"> </span>均是以</span></div><div class="t m0 x3 h4 y4c ff1 fs2 fc1 sc0 ls1 ws0">脉冲当量定义的坐标值，<span class="_ _3"></span>则</div><div class="t m0 x2f h9 y4d ff4 fs7 fc1 sc0 ls0 ws0">y</div><div class="t m0 x30 h9 y4e ff4 fs7 fc1 sc0 ls0 ws0">x</div><div class="t m0 x31 h9 y4f ff4 fs7 fc1 sc0 ls0 ws0">O</div><div class="t m0 x32 ha y50 ff5 fs7 fc1 sc0 ls0 ws0">(<span class="ff4">x</span></div><div class="t m0 x33 h31 y51 ff5 fs1b fc1 sc0 ls0 ws0">e</div><div class="t m0 x34 ha y50 ff5 fs7 fc1 sc0 ls0 ws0">,<span class="_ _19"> </span><span class="ff4">y</span></div><div class="t m0 x35 h31 y51 ff5 fs1b fc1 sc0 ls0 ws0">e</div><div class="t m0 x36 ha y50 ff5 fs7 fc1 sc0 ls0 ws0">)</div><div class="t m0 x5 ha y52 ff5 fs7 fc1 sc0 ls0 ws0">(<span class="ff4">x</span></div><div class="t m0 x37 h31 y53 ff5 fs1b fc1 sc0 ls0 ws0">0</div><div class="t m0 x38 ha y52 ff5 fs7 fc1 sc0 ls0 ws0">,<span class="_ _19"> </span><span class="ff4">y</span></div><div class="t m0 x39 h31 y53 ff5 fs1b fc1 sc0 ls0 ws0">0</div><div class="t m0 x3a ha y52 ff5 fs7 fc1 sc0 ls0 ws0">)</div><div class="t m0 x3b ha y54 ff1 fs7 fc1 sc0 ls0 ws0">图<span class="ff5">5-2 </span>用折线逼近直线段</div><div class="c x3c y55 wd h32"><div class="t md x3d h33 y56 ff5 fs1c fc1 sc0 ls0 ws0">x<span class="_ _1a"></span><span class="ff6"></span></div></div><div class="c x3e y57 we h34"><div class="t me x3d h35 y58 ff5 fs1d fc1 sc0 ls0 ws0">y<span class="_ _1b"></span><span class="ff6"></span></div></div><div class="c x3f y59 wf h36"><div class="t mf x40 h37 y5a ff4 fs1e fc1 sc0 ls0 ws0">e<span class="_ _1c"></span>e</div><div class="t mf x41 h38 y5b ff4 fs1f fc1 sc0 ls0 ws0">Y<span class="_ _1d"></span>X<span class="_ _1d"></span>Y<span class="_ _1e"></span>X<span class="_ _1f"> </span><span class="ff7">,<span class="_ _20"></span>,<span class="_ _21"></span>,</span></div><div class="t mf x42 h39 y5a ff5 fs1e fc1 sc0 ls0 ws0">0<span class="_ _22"></span>0</div></div><div class="c x43 y5c w10 h3a"><div class="t m10 x44 h3b y5d ff5 fs20 fc1 sc0 ls0 ws0">x<span class="_ _23"> </span>e<span class="_ _24"> </span>0</div><div class="t m10 x44 h3b y5e ff5 fs20 fc1 sc0 ls0 ws0">y<span class="_ _25"> </span>e<span class="_ _26"> </span>0</div><div class="t m10 x45 h3c y5f ff4 fs21 fc1 sc0 ls0 ws0">N<span class="_ _27"> </span>X<span class="_ _26"> </span>X</div><div class="t m10 x45 h3c y60 ff4 fs21 fc1 sc0 ls0 ws0">N<span class="_ _28"> </span>Y<span class="_ _29"> </span>Y</div><div class="t m10 x46 h3d y5f ff6 fs21 fc1 sc0 lsa ws0"></div><div class="t m10 x46 h3d y60 ff6 fs21 fc1 sc0 lsb ws0"></div></div></div><div class="pi" data-data='{"ctm":[1.333333,0.000000,0.000000,1.333333,0.000000,0.000000]}'></div></div>
