【正文】 ology, motor speed control system in the industrial and agricultural production, transportation and daily life plays an increasingly important role in. DC motor is acplished by a two magic field interactions which occur rotation. The stator by permanent mags or stimulated the electromag produces a fixed magic field, the rotor is posed of a series of winding and the magic materials formed, the current through each winding will generate a magic field. The brush DC motor, rotor and stator of the mutator brush in the motor rotates for each winding supplies electrical energy. Energized rotor winding and the stator mags have opposite polarity, through attraction to produce torque rotating the rotor. The speed of the motor and the applied voltage is proportional to the torque is proportional to the current, and the. For the DC motor control is a challenge, because must be at work during changing the speed of DC motor. The DC motor is the efficient operation of most monly used method is applied to a PWM ( pulse width modulation ) square wave, the onoff ratio corresponding to the desired speed. The motor has a low pass filter function, it will PWM signal is converted to an effective level. The design of STC89C52 monolithic integrated circuits to control the PID the direct pulse （ PWM ） machinery velocity modulation system, and elaborated on the system of control methods, structure and design, the application design problems. the system simple and good performance machinery velocity modulation prices are high, really to direct the electrical machinery velocity modulation control system of highprecision. Key words： monolithic integrated circuits, a direct motor, machinery velocity modulation system . 引言 ................................................................................................................................................... 4 1 系統(tǒng)硬件介紹 ............................................................................................................................. 4 硬件主控芯片概述及功能介紹 ............................................................................ 4 STC89C52 單片機(jī)主控制電路圖 ........................................................................... 4 L298N 直流電機(jī)的專(zhuān)用驅(qū)動(dòng)器 ........................................................................... 6 硬件電路設(shè)計(jì) ................................................................................................................ 7 顯示電路的設(shè)計(jì) ..................................................................................................... 7 鍵盤(pán)電路的設(shè)計(jì) ..................................................................................................... 8 電機(jī)驅(qū)動(dòng)電路的設(shè)計(jì) .............................................................................................. 8 2 系統(tǒng)軟件設(shè)計(jì) ............................................................................................................................. 9 設(shè)計(jì)要求 ............................................................................................................................ 9 總體設(shè)計(jì)方案 .................................................................................................................... 9 設(shè)計(jì)思路 ................................................................................................................. 9 方案論證與設(shè)計(jì) ................................................................................................... 9 系統(tǒng)組成 ............................................................................................................. 10 3 硬件制作、調(diào)試與軟件 ........................................................................................................... 10 系統(tǒng) PCB 板的設(shè)計(jì) ....................................................................................................... 10 系統(tǒng)硬件調(diào)試 .................................................................................................................. 11 主控程序 .......................................................................................................................... 11 4 實(shí)訓(xùn)心得體會(huì) ........................................................................................................................... 13 謝 辭 ............................................................................................................................................. 14 參考文獻(xiàn) ......................................................................................................................................... 15 附錄 A： ......................................................................................................................................... 17 附錄 B： ......................................................................................................................................... 18 附錄 C： ......................................................................................................................................... 23 附錄 D： ......................................................................................................................................... 24 . 引言 隨著時(shí)代的進(jìn)步和科技的發(fā)展，電機(jī)調(diào)速系統(tǒng)在工農(nóng)業(yè)生產(chǎn)、交通運(yùn)輸以及日常生活中起著越來(lái)越重要的作用 .由于直流電動(dòng)機(jī)具有優(yōu)良的起 、制動(dòng)性能，宜與在廣泛范圍內(nèi)平滑調(diào)速。長(zhǎng)期以來(lái)，由于直流調(diào)速系統(tǒng)的性能指標(biāo)優(yōu)于交流調(diào)速系統(tǒng)。 PWM控制技術(shù)就是以該結(jié)論為理論基礎(chǔ)，使輸出