We feel like all the designs for the fuzzy compensator will be an improvement upon the PID controller and will have greater ability to deal with disturbances.
The final step in the development of our controllers was to design various forms Fuzzy logic compensators in order to improve the performance of the PID controller and to allow it to account for the disturbance.
We designed three types of Fuzzy logic Compensators
Fuzzy PI
Fuzzy PD
Fuzzy Precompensated
13.
Fuzzy logic Introduction Fuzzy logic is a problem-solving control system methodology that lends itself to implementation in systems ranging from simple, small, embedded micro-controllers to large, networked, multi-channel PC or workstation-based data acquisition and control systems. It can be implemented in hardware, software, or a combination of both. Inputs Rules Output
14.
Fuzzy Precompensated PID Membership Functions, and Fuzzy Rule Sets
The P is Low and I is Optimal then output is –(R+S)/2
The P is Low and I is High then output is -S
The P is Optimal and I is Low then output is (–R+S)/2
The P is Optimal and I is Optimal then output is 0
The P is Optimal and I is High then output is (R-S)/2
The P is High and I is Low then output is S
The P is High and I is optimal then output is (R+S)/2
The P is High and I is High then output is R
Where R=L 1 *K i +L 2 *K p S=L 2 *K p +L 1 *K i
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Linear Fuzzy PI Control Table Surface Viewer R (R+S)/2 S High ( P ) (R-S)/2 0 -(R-S)/2 Optimal ( P ) -S -(R+S)/2 -R Low ( P ) High ( D ) Optimal ( D ) Low ( D) Output
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