sử dụng @ để tạo ra một chức năng ẩn danh, sử dụng nội tuyến (xem Chương 2 cho các), hoặc sử dụng một M-file (xem Chương 3). Các chức năng ẩn danh hoặc nội tuyến hữu ích nhất để xác định các chức năng đơn giản có thể được thể hiện trong một dòng và quay đầu ra của một lệnh biểu tượng vào một chức năng. Chức năng M-file | A Simple Differential Equation 113 Q -to tt eltwrcd ft Cormrtr uwd Bods ara i Cortovwn ft CMMMiraAK ft Ca ơH ft HUM anim iwiua ft lodio T Nm ft MathOcOTatm ft Modal VfrfMUon 1 SlattỈMM Z7 bond Fen ft ModdMMalMto ft Pwt k VAcyatMM ft SipMlMttfcutM ft R T an o tM Vauito Tunpot ft Mt ft twin ft UOM-Oafradfwwtim it ft todtml Maw Cwo 1 1 Figure . The Continuous Library. yet connect to another block so Simulink marks them with dotted lines to remind you that they are not fully operative. The idea so far is that u is obtained by integration from u and u is obtained by integration from u . Your model window should now look like Figure . Integrator Integrator Figure . The First Stage of the Simulink Model. Now we want to make use of the differential equation which can be rewritten in the form u 5u 2u . So we want to add other blocks to relate u the input to the first Integrator block to u and u according to this equation. For this purpose we add two Gain blocks which implement multiplication by a constant and one Sum block used for addition. These are all chosen from the Math Operations library seventh from the top in Figure or first in the second row in Figure . Hooking them up the same way we did with the Integrator blocks gives a model window that looks something like Figure . Gainl Figure . The Second Stage of the Simulink Model. We need to go back and edit the properties of the Gain blocks to change the 114 Chapter 8. Simulink constants by which they multiply from the default of 1 to 5 in Gain and 2 in Gainl . To do this double-click on each Gain block in turn. A Block Parameters box will open in which you can change the Gain parameter to whatever you need. Next we need to send u the output of the first Integrator block to the input port of block Gain1 . This presents a problem since an Integrator block has only one output port and it s already connected to the next Integrator block. So we need to introduce a branch line. Position the mouse
