Abstract

  This design mainly for DC motor speed control system research and design. In the DC motor
operation  control,  usually  widely  used  pulse  width  modulation  (P  WM)  technology,  fast
response, high accuracy, stability is good. DC motor speed and the motor is proportional to
the voltage across, P WM modulation into the DC power supply has a frequency width (pulse
duty  cycle)  square  wave  pulses  with  adjustable  voltage,  added  to  the  DC  motor  armature,
through changes in accounting space than the average voltage across the motor to regulate the
duty  cycle  of  the  greater  increase  in  the  average  voltage  across  the  larger  motor,  the  motor
faster. DC motor drive based on the H bridge using a high voltage, high current motor drive
chip  L298,  LM3S1138  microcontroller-based  embedded  controller,  driven  by  PWM  to
achieve  in  the  L298  motor  speed  regulation.  For  the  error  rate,  using  simple,  practical  and
adjust  the  ratio  is  better  closed-loop  algorithm  to  adjust  motor  speed  precision.  Micro-
controller to detect the motor speed compared with the speed set by adjusting the proportion
of  closed-loop  pulse-width  modulated  square  wave,  thereby  changing  the  average  voltage
across the motor to realize the feedback control of motor speed.

Key word: Closed loop velocity modulation; Embedded; PWM; LM3S1138