A unity feedback system has the following characteristic equation s^4 + 22s^3 + 10s^2 + 2s + K. List the characteristics of a stable system in terms of the output (in response to a bounded input) and also the location of the roots of the characteristic equation in the s-plane. [3 marks] (ii) Identify the range of K for the system to be stable using the Routh-Hurwitz criterion. [5 marks] If the value of K is chosen such that the system is marginally stable, determine the exact location of the roots on the imaginary axis in the s-plane. [2 marks]
A system with a forward transfer function G(s) = K and negative unity feedback is to be designed to have critical damping. Find the value of K to meet the specification and determine the steady-state error ess for a unit step input. [3 marks]
A negative feedback system has a loop transfer function given by K(s-3)(s+5) / (s+1)(s+3). Sketch the root locus of the system and hence determine the range of K for stability. [12 marks]