# bla2.txt

 .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } 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 a-causal 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 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. Transient responses or transients Graphs which show how a system goes from equilibrium state to another Capacitor Can be seen as battery, stores electrical energyq = itq = charge of battery, i = constantIf 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 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. 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. 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 20-sim 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 voltageMust have an internal resistance of zero Power P = ui Modulated voltage source Modulated by sinusoidal signal. Ideal current source Element that delivers constant currentMust 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 quantitiesextract 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 One-port element Elements for which there is a single variable which determines the flow of energy to and from this element Two-port 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 1-junction Neutral symbol 1 which replaces the domain-dependent variables I and vRepresents heat flows 0-junction 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 Double-sides rectification or full-wave rectification Extra diodes that ensure that both parts of the sinusoidal signal contribute to charging the capacitor Ramp signal ?? Feed-forward 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 doesnt 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 Op-amp Operational amplifier Active component Component with external power supply Non-inverting 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 Low-pass 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 dont see (implemented in microwaves etc), fitted with embedded control systems Digital control systems Embedded control systems Ad-converter Analog to digital converter Hold circuit Equipped in DA-converter. Circuit that holds the voltage until a new conversion is performed Zero-order 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 ρ flow ζ Damping ratio Φ Magnetic flux λ Flux linkage L Self-inductance q Charge ω Angular velocity Se Voltage source Hookes law Relation between the force F acting on a spring and the deformation of the spring, the change in length x:F = kxk = the spring constantalso correct:x=1/k*F or x=cFc = 1/k = the compliance Newtons law F = maa = (1/m)* FF = ma = m(d(v)/dt) Ohm`s law u = Ri Kirchoffs law Sum of all currents = 0Sum of all voltages = 0 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. .remove_background_ad { border: 1px solid #555555; padding: .75em; margin: .75em; background-color: #e7e7e7; } .rmbg_image { max-height: 80px; } Authormrpoodle21 ID223552 Card Setbla2.txt Descriptionsldfglksjdf Updated2013-06-12T14:06:08Z Show Answers