ExamQuestions

Set of questions; answers should be submitted to: andrej.skraba@gmail.com on Friday 27.12.2019.

1. Define Cyber-physical Systems and describe the relation to the Internet of Things.

2. What are main technologies that were used in class?

3. Draw the structure of the control system (block diagram) that was realized (controlling the position of pointer). Relate abstract elements to the components used.

Use 3rd figure from example 13 ("Example of the element positions in the realised system") and enumerate block diagram appropriately. No. 6 represents the PC with Linux Ubuntu, that was used in the class, here ARM MK802V5 LE is pictured (6).

4. Write down the equation for PID control and provide the software implementation of the algorithm.

5. What are main differences between Proportional (P) control and PID control?

6. Is it possible to control the system only with the integral part of the PID regulator? Explain and relate to analytical equation.

7. Is it possible to control the system only with the differential part of the PID regulator? Explain and relate to analytical equation.

8. If the plant is described as the first order integral element with initial value 1. Within the system, PID controller is used. What would be the response of the P, I and D part, if the input to the system (desired value) is similar to the function on the following figure:

The desired value therefore goes from initial 1 (which is equal do initial state of integral element) to new desired value 2. Provide the response of the plant (integral element). Provide your definition for the s-shaped curve, which should be as simple as possible starting at 1 and ending at 2. Consider the response if Kp=2, Ki=0.025 and Kd=0.9. The tasks are:

• a) Provide the expression for the function shown in above figure which should start at 1 and end at 2 having an s-shaped form. This expression should be as simple as possible
• b) Plot the proportional term in PID controller
• c) Plot the integral term in PID controller
• d) Plot the differential term in PID controller
• e) Plot the actual value (value of the plant i.e. first order integral element)

9. State typical values of the Kp, Ki and Kd that were used in our setup. How could you explain their ratio?

10. What is integral windup and how can you eliminate it?

11. Print your address of github repository with code (if you haven't done it already).

12. Develop the code (html file with javascript code) where the user interface includes the slider which values goes from 0 to 1023 and the canvas on which the pointer is shown moving from left (slider value 0) to the right (slider value 1023). Take into account, that the full potentiometer spin is 300 degrees.

Please fill out the survey (if you haven't already done it): https://forms.gle/qMcYcVXdFc9iKUo49

In the eMail with the solutions, provide also your name and eMail address.