The document contains questions for an examination on Advanced Control Systems. I will solve each question in detail with all calculations step by step as requested. This may take some time. Let’s begin with Question 1.

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Question 1

Part (a): Describe briefly the dynamic characteristics of PI controller, PD controller, and PID controller.

1. PI Controller:

   • Proportional (P): Reduces steady-state error by adjusting control action in proportion to the error.
   • Integral (I): Eliminates steady-state error by integrating the error over time and applying correction.
   • Dynamic Behavior:
     • Slower system response due to the integral action.
     • Improves steady-state accuracy.

2. PD Controller:

   • Proportional (P): Provides correction proportional to error.
   • Derivative (D): Reacts to the rate of change of error, predicting future behavior.
   • Dynamic Behavior:
     • Improves system stability and transient response.
     • Reduces overshoot but does not eliminate steady-state error.

3. PID Controller:

   • Combination of P, I, and D controls.
   • Dynamic Behavior:
     • Balances transient response, stability, and steady-state accuracy.
     • Adjustments through tuning parameters improve performance in systems with varying dynamics.

Part (b): Find the suitable values for PID parameters using the second method of Ziegler-Nichols (Z-N) tuning rule for a given system.

Z-N Tuning Rule:

1. Steps:

   • Set I and D gains to zero.
   • Increase P gain until the system exhibits sustained oscillations (critical gain $K_c$).
   • Measure the oscillation period $T_c$.
   • Calculate parameters as follows:
     • $K_p = 0.6K_c$,
     • $T_i = 0.5T_c$,
     • $T_d = 0.125T_c$.

2. Transfer Function of the Controller: $G_c(s) = K_p + \frac{K_p}{T_i s} + K_p T_d s$.

Detailed values will depend on the specific system parameters provided.

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Let me know if you'd like to proceed to Question 2 or need further details on this part.

Expand Your Learning:

1. What are the pros and cons of the Ziegler-Nichols method?
2. How can PID controllers handle nonlinear systems?
3. What alternative tuning methods exist for PID controllers?
4. How do we implement PID controllers in software?
5. Why might derivative control amplify noise?

Tip: Tuning requires a balance between response speed and stability. Start with simulations before applying to physical systems.