PID control of DC motor

Under stand the PID control of DC motor
set Kp=0.1 and varies Kp
or ......
then simulate and read /sigama and Ts
make table and discuss it

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PID control materials:

 PID control on simulink
http://wenku.baidu.com/view/41350dbff121dd36a32d8217.html?from=rec&pos=2&weight=6&lastweight=5&count=4 

PID Design Method for the DC Motor Position
http://www.engin.umich.edu/group/ctm/examples/motor2/PID2.html


PID Design Method for DC Motor Speed Control
http://www.engin.umich.edu/group/ctm/examples/motor/PID2.html 

designing a pid controller for a dc-motor [video demo]
http://www.mathworks.co.uk/products/demos/slcontrol/designing-a-pid-controller-for-a-dc-motor-video-demo/ 

DC Motor Position PD & PID Controllers
http://www.psut.edu.jo/sites/alasali/Control%20Lab%20New/Experiment7%20New.pdf

On a Modification of the PID Controller
http://www.springerlink.com/content/r53v678v02522542/fulltext.pdf 

PID controller
http://www.ecircuitcenter.com/circuits/pid1/pid1.htm

What The Gains Do
http://www.hitex.com/fileadmin/img/download/Basic_DC_Motor_Speed_PID_Control_With_The_Infineon_C167_Family.pdf

 Integral Gain: Ensures that under steady state conditions that the motor speed (almost) exactly matches the setpoint speed. A low gain can make the controller slow to push the speed to the setpoint but excessive gain can cause hunting around the setpoint speed. In less extreme cases, it can cause overshoot whereby the speed passes through the setpoint and then approaches the required speed from the opposite direction. Unfortunately, sufficient gain to quickly achieve the setpoint speed can cause overshoot and even oscillation but the other terms can be used to damp this out.
Proportional Gain: Gives fast response to sudden load changes and can reduce instability caused by high integral gain. This gain is typically many times higher than the integral gain so that relatively small deviations in speed are corrected while the integral gain slowly moves the speed to the sepoint. Like integral gain, when set too high, proportional gain can cause a "hard" oscillation of a few Hertz in motor speed.
Derivative Gain: Can be used to give a very fast response to sudden changes in motor speed. Within simple PID controllers it can be difficult to generate a derivative term in the output that has any significant effect on motor speed. It can be deployed to reduce the rapid speed oscillation caused by high proportional gain. However, in many controllers, it is not used.