MME 3350 System Modeling and Control – Question Bank, Study Guide, and
Exam Preparation Material
Name three major advantages of closed loop control when compared to open loop control -
ANS ✔✔1. Able to reduce system's sensitivity to external disturbances
2. changes in feedback signal can be reduced by the controller
3. good accuracy and high speed of response
Name two disadvantages of closed-loop control - ANS ✔✔1. Usually cost more than open loop
controller
2. Sensitivity to disturbances; can lead to instability if this sensitivity is too high
Use of Laplace Transforms is limited to _________Systems - ANS ✔✔Linear Time Invariant
Systems
Give one use of the Final Value theorem in control system analysis - ANS ✔✔rotational
applications
Give one use of Inverse Laplace Transforms in system dynamics - ANS ✔✔determines steady-
state value of a system
Define the term 'Transfer function' for describing the dynamics of a system - ANS ✔✔the ratio
of the laplace transform of the output variable to the laplace transform of the input variable
Transfer functions of a system are governed by __________ and __________ of the system. -
ANS ✔✔Input and Output
Force produced by a spring is proportional to its _______ - ANS ✔✔its displacement
, When a spring is compressed, it produces forces at its two ends in the _____________
direction. - ANS ✔✔opposite
Force produced by a viscous damper is proportional to its ______ - ANS ✔✔velocity
When studying vibration of mass spring systems along the vertical direction, why does the
gravity not taken into account? - ANS ✔✔because the displacements are measured form static
equilibrium configuration, gravity is cancelled out
If a resistor R is connected in parallel with a capacitor C, what is the total impedance of the
system? - ANS ✔✔(Rx1/cs)/(R+1/cs)
What is the name of the "special node" used in the modelling of OP-Amp based circuits? State
its significance. - ANS ✔✔Virtual ground. Acts as a zero potential, like a real ground, but unlike a
real ground it is not a current sink
Back e.m.f associated with an armature controlled DC motor opposes the ____________
voltage and is proportional to the armature ____________. - ANS ✔✔applied, velocity
Write down the typical transfer function of an armature controlled DC motor between the
applied voltage and the output angle, when the armature inductance is negligible. - ANS
✔✔Output angle/applied voltage
What is the order of a system that represents an armature controlled DC motor when armature
inductance is negligible. - ANS ✔✔Second Order
In the liquid level control system, what is the most important special feature that is used to
derive the system transfer function? - ANS ✔✔regulating control valve at the bottom of the
tank, (The Taylor Expansion is used to convert non-linear equation into linear form for solving
Exam Preparation Material
Name three major advantages of closed loop control when compared to open loop control -
ANS ✔✔1. Able to reduce system's sensitivity to external disturbances
2. changes in feedback signal can be reduced by the controller
3. good accuracy and high speed of response
Name two disadvantages of closed-loop control - ANS ✔✔1. Usually cost more than open loop
controller
2. Sensitivity to disturbances; can lead to instability if this sensitivity is too high
Use of Laplace Transforms is limited to _________Systems - ANS ✔✔Linear Time Invariant
Systems
Give one use of the Final Value theorem in control system analysis - ANS ✔✔rotational
applications
Give one use of Inverse Laplace Transforms in system dynamics - ANS ✔✔determines steady-
state value of a system
Define the term 'Transfer function' for describing the dynamics of a system - ANS ✔✔the ratio
of the laplace transform of the output variable to the laplace transform of the input variable
Transfer functions of a system are governed by __________ and __________ of the system. -
ANS ✔✔Input and Output
Force produced by a spring is proportional to its _______ - ANS ✔✔its displacement
, When a spring is compressed, it produces forces at its two ends in the _____________
direction. - ANS ✔✔opposite
Force produced by a viscous damper is proportional to its ______ - ANS ✔✔velocity
When studying vibration of mass spring systems along the vertical direction, why does the
gravity not taken into account? - ANS ✔✔because the displacements are measured form static
equilibrium configuration, gravity is cancelled out
If a resistor R is connected in parallel with a capacitor C, what is the total impedance of the
system? - ANS ✔✔(Rx1/cs)/(R+1/cs)
What is the name of the "special node" used in the modelling of OP-Amp based circuits? State
its significance. - ANS ✔✔Virtual ground. Acts as a zero potential, like a real ground, but unlike a
real ground it is not a current sink
Back e.m.f associated with an armature controlled DC motor opposes the ____________
voltage and is proportional to the armature ____________. - ANS ✔✔applied, velocity
Write down the typical transfer function of an armature controlled DC motor between the
applied voltage and the output angle, when the armature inductance is negligible. - ANS
✔✔Output angle/applied voltage
What is the order of a system that represents an armature controlled DC motor when armature
inductance is negligible. - ANS ✔✔Second Order
In the liquid level control system, what is the most important special feature that is used to
derive the system transfer function? - ANS ✔✔regulating control valve at the bottom of the
tank, (The Taylor Expansion is used to convert non-linear equation into linear form for solving
