1. Dynamical system
    systems where the effect of a certain action only becomes visable, or reaches a steady state, after some time
  2. Model
    Simplified dicription of a system, just complex enough to describe or study the phenomena that are relevant for our problem contect
  3. Control system
    System with a feedback loop to keep certain quantities constant (e.g. temperature of thermostat in house)
  4. Elementary system
    System>subsystem>sub(sub)system>sub(subsub)system>…>elementary system
  5. Bileteral interaction
    System where the action of one subsystem leads to a reaction of the other subsystem
  6. a-causal model
    Same relations as causal relation diagram but without choosing what we consider as cause and effect
  7. Positive feedback
    Leads to exponential growth
  8. Discrete systems
    Systems that are described at fixed, discrete, time intervals
  9. Continuous-time 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.
  10. Transient responses or transients
    Graphs which show how a system goes from equilibrium state to another
  11. Capacitor
    • Can be seen as battery, stores electrical energy
    • q = it
    • q = charge of battery, i = constant
    • If i is not constant:
    • Image Upload 1
  12. Inductor
    Coil of wire, stores energy in the form of a magnetic field
  13. Inductance
    Property that belongs to a coil.
  14. Magnetic flux
    the magnetic flux through a surface is the component of the magnetic field passing through that surface
  15. Flux linkage
    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.
  16. Transfer function
    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.
  17. Water hammer
    Can be observed when water is flowing through a pipe and the flow at the end of the pipe is cut off.
  18. Elementary physical models
    Elementary subsystem of a component
  19. Ideal Physical Model (IPM)
    Model solely built of elementary physical models (basically a 20-sim model)
  20. Lumped paramaeter
    model Dominant physical behavior of a model represented by a limited number of interconnected ideal physical elements
  21. Static equilibrium
    Gravity firce will be compensated by the force of a spring
  22. Moment of inertia
    = mass moment of inertia = angular mass
  23. Transfer function
    Function with delay operator
  24. Gyrator
    Used as a transducer between different physical domains.
  25. Ideal voltage source
    • Element that delivers constant voltage
    • Must have an internal resistance of zero
  26. Power
    P = ui
  27. Modulated voltage source
    Modulated by sinusoidal signal.
  28. Ideal current source
    • Element that delivers constant current
    • Must have a large internal resistance
  29. Node
    Point where two or more elements are connected
  30. Path
    Formed by a number of interconnected circuit elements
  31. Transducer
    Element that couples multiple domains (a.g. electrical en mechanical e.g. electric engine)
  32. Sensor
    • Transducer that is able to convert physical quantities
    • extract information from the system in the form of a digital signal
  33. Actuator
    Converts signals into physical quantities (modulated volatage source)
  34. Power conjugated variables
    Variables with the dimension of power in watts
  35. One-port element
    Elements for which there is a single variable which determines the flow of energy to and from this element
  36. Two-port element
    Elements that change the ratio between u and I of F and v, but the product P remains constant
  37. Bonds
    Half arrows, presents energy flow
  38. 1-junction
    • Neutral symbol “1” which replaces the domain-dependent variables I and v
    • Represents heat flows
  39. 0-junction
    Represents temperatures
  40. Bilateral signal flow
    Represented by a bond that combines two signals
  41. Actuator
    Element that converts signals to power (e.g. modulated voltage source)
  42. Commutation
    The process of inverting the direction of the current
  43. Counter electromotive force
    Voltage that is proportional to the angular velocity
  44. Tachogenerator
    Sensor to measure angular velocity
  45. Component
    Consists of physical elements, which under certain circumstances may be left out of the model
  46. Rectification
    The process of converting elements from AC to DC
  47. Diode
    Suppresses the negative parts of the sine wave
  48. Diode bridge
    Converts the negative parts of the sine waves to positive ones
  49. Double-sides rectification or full-wave rectification
    Extra diodes that ensure that both parts of the sinusoidal signal contribute to charging the capacitor
  50. Ramp signal
  51. Feed-forward control
    Real condition at the end of a process has no influence on the actual duration of the process
  52. Fuzzy controller
    Observation with no real values (a bit longer, much shorter, …)
  53. Proportional gain
    Depends on another variable (like approaching a red traffic light, the distance varies)
  54. Overshoot
    Proportional gain doesn’t work (driver brakes too late and crosses the stopping line)
  55. Derivative control
    Another variable is needed because there was an overshoot. This will be velocity. Velocity is derived from the position
  56. Control engineering
    The art of tuning the parameters of a controller
  57. Unstable system
    oscillations increase or exponential growth
  58. Op-amp
    Operational amplifier
  59. Active component
    Component with external power supply
  60. Non-inverting input
    Positive input of an amplifier
  61. Inverting input
    Negative input of an amplifier
  62. Adder circuit
    Circuit which can make the weighted sum of two or more input signals
  63. Passive circuit
    Circuit with only resistor, capacitors and inductances
  64. Low-pass filter
    Filter that passes low frequencies
  65. Pneumatic controllers
    Controller which uses compressed air to carry a signal
  66. Hydraulic systems
    Used when high forces are needed
  67. Soft real time performance
    Performance is fast enough
  68. Hard real time performance
    Performance is fast enough and at fixed time intervals
  69. Embedded computer
    Computers you don’t see (implemented in microwaves etc), fitted with embedded control systems
  70. Digital control systems
    Embedded control systems
  71. Ad-converter
    Analog to digital converter
  72. Hold circuit
    Equipped in DA-converter. Circuit that holds the voltage until a new conversion is performed
  73. Zero-order hold
    Hold circuit where the voltage is kept at a constant value
  74. Sampling rate
    T,sample = t,dominant/10
  75. Aliasing
    Happens when sampled with a too low sampling frequency. The frequency of the sine wave will change
  76. Nyquist rate
    2* the highest frequency
  77. ρ
  78. ζ
    Damping ratio
  79. Φ
    Magnetic flux
  80. λ
    Flux linkage
  81. L
  82. q
  83. ω
    Angular velocity
  84. Se
    Voltage source
  85. Hooke’s 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
  86. Newton’s law
    • F = ma
    • a = (1/m)* F
    • F = ma = m(d(v)/dt)
  87. Ohm`s law
    u = Ri
  88. Kirchoff’s law
    • Sum of all currents = 0
    • Sum of all voltages = 0
  89. d’Alembert’s 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.
Card Set