bla2.txt

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

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

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

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

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

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

Leads to exponential growth

Systems that are described at fixed, discrete, time intervals

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.

Graphs which show how a system goes from equilibrium state to another

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

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

Property that belongs to a coil.

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

When the coil has n windings the so-called 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.

A mathematical representation of the relation between the input and output of a linear time-invariant system with zero initial conditions and zero-point equilibrium.

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

Elementary subsystem of a component

Model solely built of elementary physical models (basically a 20-sim model)

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

Gravity firce will be compensated by the force of a spring

= mass moment of inertia = angular mass

Function with delay operator

Used as a transducer between different physical domains.

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

P = ui

Modulated by sinusoidal signal.

• Element that delivers constant current
• Must have a large internal resistance

Point where two or more elements are connected

Formed by a number of interconnected circuit elements

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

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

Converts signals into physical quantities (modulated volatage source)

Variables with the dimension of power in watts

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

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

Half arrows, presents energy flow

• Neutral symbol “1” which replaces the domain-dependent variables I and v
• Represents heat flows

Represents temperatures

Represented by a bond that combines two signals

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

The process of inverting the direction of the current

Voltage that is proportional to the angular velocity

Sensor to measure angular velocity

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

The process of converting elements from AC to DC

Suppresses the negative parts of the sine wave

Converts the negative parts of the sine waves to positive ones

Extra diodes that ensure that both parts of the sinusoidal signal contribute to charging the capacitor

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

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

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

Proportional gain doesn’t work (driver brakes too late and crosses the stopping line)

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

The art of tuning the parameters of a controller

oscillations increase or exponential growth

Operational amplifier

Component with external power supply

Positive input of an amplifier

Negative input of an amplifier

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

Circuit with only resistor, capacitors and inductances

Filter that passes low frequencies

Controller which uses compressed air to carry a signal

Used when high forces are needed

Performance is fast enough

Performance is fast enough and at fixed time intervals

Computers you don’t see (implemented in microwaves etc), fitted with embedded control systems

Embedded control systems

Analog to digital converter

Equipped in DA-converter. Circuit that holds the voltage until a new conversion is performed

Hold circuit where the voltage is kept at a constant value

T,sample = t,dominant/10

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

2* the highest frequency

flow

Damping ratio

Magnetic flux

Flux linkage

Self-inductance

Charge

Angular velocity

Voltage source

• 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

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

u = Ri

• Sum of all currents = 0
• Sum of all voltages = 0

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.