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Dynamical system
systems where the effect of a certain action only becomes visable, or reaches a steady state, after some time

Model
Simplified dicription of a system, just complex enough to describe or study the phenomena that are relevant for our problem contect

Control system
System with a feedback loop to keep certain quantities constant (e.g. temperature of thermostat in house)

Elementary system
System>subsystem>sub(sub)system>sub(subsub)system>
>elementary system

Bileteral interaction
System where the action of one subsystem leads to a reaction of the other subsystem

acausal model
Same relations as causal relation diagram but without choosing what we consider as cause and effect

Positive feedback
Leads to exponential growth

Discrete systems
Systems that are described at fixed, discrete, time intervals

Continuoustime systems (question 3 on practice exam)
System with an input signal and feedback. A typical property is the memory function. This memory determines the state of the system (the amount of something at a certain moment, e.g. water in a tank) In a continuous time system the memory in an integrator. The output value of an integrator can be used as a state variable.

Transient responses or transients
Graphs which show how a system goes from equilibrium state to another

Capacitor
 Can be seen as battery, stores electrical energy
 q = it
 q = charge of battery, i = constant
 If i is not constant:

Inductor
Coil of wire, stores energy in the form of a magnetic field

Inductance
Property that belongs to a coil.

Magnetic flux
the magnetic flux through a surface is the component of the magnetic field passing through that surface

Flux linkage
When the coil has n windings the socalled flux linkage is equal to the product of the number of windings and the magnetic flux. Capacitor stores electrical energy in the form of electrical charge, an inductor, in the form of coil, in the form of flux linkage.

Transfer function
A mathematical representation of the relation between the input and output of a linear timeinvariant system with zero initial conditions and zeropoint equilibrium.

Water hammer
Can be observed when water is flowing through a pipe and the flow at the end of the pipe is cut off.

Elementary physical models
Elementary subsystem of a component

Ideal Physical Model (IPM)
Model solely built of elementary physical models (basically a 20sim model)

Lumped paramaeter
model Dominant physical behavior of a model represented by a limited number of interconnected ideal physical elements

Static equilibrium
Gravity firce will be compensated by the force of a spring

Moment of inertia
= mass moment of inertia = angular mass

Transfer function
Function with delay operator

Gyrator
Used as a transducer between different physical domains.

Ideal voltage source
 Element that delivers constant voltage
 Must have an internal resistance of zero


Modulated voltage source
Modulated by sinusoidal signal.

Ideal current source
 Element that delivers constant current
 Must have a large internal resistance

Node
Point where two or more elements are connected

Path
Formed by a number of interconnected circuit elements

Transducer
Element that couples multiple domains (a.g. electrical en mechanical e.g. electric engine)

Sensor
 Transducer that is able to convert physical quantities
 extract information from the system in the form of a digital signal

Actuator
Converts signals into physical quantities (modulated volatage source)

Power conjugated variables
Variables with the dimension of power in watts

Oneport element
Elements for which there is a single variable which determines the flow of energy to and from this element

Twoport element
Elements that change the ratio between u and I of F and v, but the product P remains constant

Bonds
Half arrows, presents energy flow

1junction
 Neutral symbol 1 which replaces the domaindependent variables I and v
 Represents heat flows

0junction
Represents temperatures

Bilateral signal flow
Represented by a bond that combines two signals

Actuator
Element that converts signals to power (e.g. modulated voltage source)

Commutation
The process of inverting the direction of the current

Counter electromotive force
Voltage that is proportional to the angular velocity

Tachogenerator
Sensor to measure angular velocity

Component
Consists of physical elements, which under certain circumstances may be left out of the model

Rectification
The process of converting elements from AC to DC

Diode
Suppresses the negative parts of the sine wave

Diode bridge
Converts the negative parts of the sine waves to positive ones

Doublesides rectification or fullwave rectification
Extra diodes that ensure that both parts of the sinusoidal signal contribute to charging the capacitor


Feedforward control
Real condition at the end of a process has no influence on the actual duration of the process

Fuzzy controller
Observation with no real values (a bit longer, much shorter,
)

Proportional gain
Depends on another variable (like approaching a red traffic light, the distance varies)

Overshoot
Proportional gain doesnt work (driver brakes too late and crosses the stopping line)

Derivative control
Another variable is needed because there was an overshoot. This will be velocity. Velocity is derived from the position

Control engineering
The art of tuning the parameters of a controller

Unstable system
oscillations increase or exponential growth

Opamp
Operational amplifier

Active component
Component with external power supply

Noninverting input
Positive input of an amplifier

Inverting input
Negative input of an amplifier

Adder circuit
Circuit which can make the weighted sum of two or more input signals

Passive circuit
Circuit with only resistor, capacitors and inductances

Lowpass filter
Filter that passes low frequencies

Pneumatic controllers
Controller which uses compressed air to carry a signal

Hydraulic systems
Used when high forces are needed

Soft real time performance
Performance is fast enough

Hard real time performance
Performance is fast enough and at fixed time intervals

Embedded computer
Computers you dont see (implemented in microwaves etc), fitted with embedded control systems

Digital control systems
Embedded control systems

Adconverter
Analog to digital converter

Hold circuit
Equipped in DAconverter. Circuit that holds the voltage until a new conversion is performed

Zeroorder hold
Hold circuit where the voltage is kept at a constant value

Sampling rate
T,sample = t,dominant/10

Aliasing
Happens when sampled with a too low sampling frequency. The frequency of the sine wave will change

Nyquist rate
2* the highest frequency









Hookes law
 Relation between the force F acting on a spring and the deformation of the spring, the change in length x:
 F = kx
 k = the spring constant
 also correct:
 x=1/k*F or x=cF
 c = 1/k = the compliance

Newtons law
 F = ma
 a = (1/m)* F
 F = ma = m(d(v)/dt)


Kirchoffs law
 Sum of all currents = 0
 Sum of all voltages = 0

dAlemberts law
The algebraic sum of all forces acting on an object in a mechanical system and the time derivative of the impulse of the object equals zero.

