Cork Institute of Technology
Bachelor of Engineering (Honours) in Mechanical Engineering -
Stage 3
(NFQ – Level 8)
Autumn 2006
Control Systems Engineering
(Time: 3 Hours)
Answer any FOUR Questions Examiners: Prof. M. Gilchrist
ALL questions carry equal marks. Mr. J. E. Hegarty
Dr. M. J. O’Mahony
1. Determine the transfer function relating the output displacement X1(s) to the input
force F(s) for the mechanical system shown in Fig. Q.1 where:
M1, M2 = Masses [kg]
K1, K2 = Spring stiffness [N/m]
C1, C2, C12 = Coefficients of viscous damping [N per m/s]
(20 marks)
What is the order of the system and which elements of the system determine it?
(5 marks)
2. A control system is found to have the following open loop transfer function:
GsHs K
ss s
() () ()( )( )
=++ +123
Plot the root locus as K varies from 0 to ∞.
(15 marks)
Determine the values of K that will result in:
(a) Marginal Stability
(b) Underdamped Response with damping ratio: ξ = 0.7
(10 marks)
