Digital_Controllers self tuning and cascade control

Digital_Controllers self tuning and cascade control

1. The maharaja Sayajirao University of Baroda Faculty of technology and engineering ME – Electrical 21-22 Part-2 Microprocessor system and application Subject : Embedded Application in Industrial Control Seminar Topic : Digital Controllers Algorithms, Self Tuning and Cascade Control Name : Rinkesh V Patel PNR : 8021066945

2. Topics Digital Controllers Digital Control System Advantages of Digital Controllers over Analog Controllers Digital control algorithms Self-Tuning Cascade Control

3. Digital Controller In control systems, a controller is a device that find and minimize the difference between the actual value of a system and the desired value of the system. In Digital Controller we use Micro-controller/ Micro-processor or PLC and other digital devices. Full Digital Control system made up with this types of Devices and some other peripherals like sensors , comparators, actuators, analog to digital and digital to analog converter.

4. Digital Control System ADC Microprocessor DAC Correction element Process CLOCK Measurement + -

5. Digital Control System Steps Take a sample of the signals at its Input. Calculate the error signal. Calculate the required controller output. Send the controller output to its DAC output port. Wait for the next sampling interval. Repeat the process.

6. Advantages of Digital Controllers over Analog Controllers With analog control, separate controllers are required foreach process being controlled. With a microprocessor many separate processes can be controlled by sampling processes with a multiplexer. Digital control gives better accuracy than analog control.

7. Digital Control Algorithm PID ( Proportional, Integral, Derivative ) PID control provides a continuous variation of output within a control loop feedback mechanism to accurately control the process, removing oscillation and increasing process efficiency. In our case we use Digital PID control

8. Self-Tuning A self-tuning controller includes a traditional PID control function as well as a self-tuning function that tries to maintain optimal closed-loop performance by continuously updating the controller’s P, I, and D tuning parameters. An auto-tuning controller is similar except that it performs its tuning operation just once, then initiates closed-loop control using the parameters it has computed. Many commercial PID controllers include both auto-tuning and self-tuning options, and many vendors use those two.

9. Self-Tuning Controller Process Parameter Estimation Adjustment Mechanism + - Self Tuning Regulator Set Point Normal Loop New Controller Parameters Parameter Adjustment Loop Manipulated Variable Controlled Output

10. Cascade Control In single-loop control, the controller’s set point is set by an operator, and its output drives a final control element. In a cascade control arrangement, there are two (or more) controllers of which one controller’s output drives the set point of another controller. The controller driving the set point (the level controller in the example above) is called the primary, outer, or master controller. The controller receiving the set point (flow controller in the example) is called the secondary, inner or slave controller.

11. Cascade Control + - Master PID controller + Slave PID controller Heater response Pellet response Inner control loop Outer control loop

12. Cascade Control Disadvantages I t requires an additional hardware And also require to tuned our additional hardware T he control strategy is more complex 

13. References https://www.youtube.com/watch?v=9CHZu81Iqhw https://www.electrical4u.com/types-of-controllers-proportional-integral-derivative-controllers/ https://robotics.sjtu.edu.cn/upload/course/1/files/Chapter51.pdf https://www.controleng.com/articles/fundamentals-of-self-tuning-control/ https://instrumentationtools.com/cascade-control-principle/ https://www.researchgate.net/publication/291376020_Heating_system_of_pellet_samples_integrated_with_terahertz_spectrometer#pf5