- 4 Question 4 25 Marks The Block Diagram Of The Minor Loop Of A Servo Valve Actuator Is Shown In Figure Q4 The Discre 1 (83.66 KiB) Viewed 44 times
4. Question 4 (25 marks] The block diagram of the minor loop of a servo valve actuator is shown in Figure Q4. The discrete-time dynamics Ga(z) of the actuator is described by the difference equation yk = 0.9yk-1+2u+1.84–1. UK ук C(z) G (2) Figure Q4 (a) Derive the expression of Ga(z) [4 marks) (b) Use pole placement to design C(z) with the following specifications • inclusion of a fixed integral action • cancellation of the plant zero • placement of all other closed-loop poles at 0 (10 marks] (c) Electromechanical constraints require that, when the reference y, is a unit step, the first non-zero sample of the control signal (uk) does not exceed 0.5. Does the design satisfy this requirement? [5 marks] (d) Following an electrical fault, the discrete-time dynamics of the actuator is described by the new difference equation yk = 0.9yx-1 +ux +0.9uk-1. The controller remains the same. Describe the difference in the performance of the control system before and after the fault. [6 marks)