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Mekatronic - Coggle Diagram
Mekatronic
Electric component
Actuators, transform electrical energy to mechanical energy
Motor
Permanent magnent, either in stator or on rotor
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Charachteristist
- Field is generated and constant by one or several PM
- Used for position and speed control
- Easy to control due to linearity
- Weighs less then other DC motors
- Turns both clockwise and counterclockwise, change direction with current
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Parameters
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Tomgångsvarvtal, uppnås då:
$$T_{motor}=T_{last}$$
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Servo-motor
A type of PMDC motor with position or velocity control by a sensor that speaks with the controll system that drives the motor
Stepper-motor
A type of DC-motor
- Stator: electromagnet
- Rotor: permanent magnet
Idea is control in discrete steps
How can we controll them?
- Control the suppluy voltage, a lowering in voltage will parallel move the T-omega curve downwwards
- Control the armature current
- Control the field
Select motor, rules of thumb:
At continuousoperation:
•Nominal power: 1.5-2 times the desired continuous power
•Desired operating speed ≈ 0.7 * max speed
•Check nominal torque and speed
During transient operation:
•Check maximum torque curve (torque-speed characteristics)
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Solenoids, two positions, typical for opening och closing valve
Sensors
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Different parameters
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Precision
Spread of the errors, variance
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Inductor
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Measured in flux where
$$ B= \mu*\frac{N}{I}*i$$
Where N is the amount of laps and l is the laps. NEVER BREAK A CIRCUIT THAT CONTAINS A COIL. Serie/parallel wrks like resistor. Has no power because no resistance. Stores energy
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Capacitor
Measured in farad and has unit C. Acts the opposist way for serie/parallel as for resistors. Const will create and explosion. Acts like a spring in a mechanical system
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Transformer
Component to amplify the amplitudeof AC (voltageand current) or galvanicisolation.
•Generates magneticflux on the primary side and in the secondary side a currentis induced dur to the magneticflux
- Where primary side is the current in and secondary is the side where the current goes out.
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Diode (rectifier)
* Starts conduct first when 0.7v is applied, dosen't let current through in the other way as long as the breakdown current is not exceed, because then the diode will let through current.
Zendiode has a defined not steep breakdown with a well defined curve, still has a value that need to exceed to start breakdown. V_z is the breakdown voltage for the diode, when it starts letting through current backwards
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Encoder
Measure angleor angular velocity.•Absolute or incremental.•Typical resolution 500-2000 pulses/turn.•Special circuits for counting pulses (recallT flip-flop).
Digital sensor (on/off), SPST, NO_puch button,SPDT, NC-ouch button, see lecture 12
Microtrollers:
- CPU, control processing unit
- Data bus, communication
- Memory, store information
- Input/Output (I/O)
Amplifiers
Desirable
- High impedance,R_in
- Low out impedance, R_out
- Selectable gain
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Difference amplifier,
$$V_{out}=-\frac{R_f}{R_1}*V_1+(1+\frac{R_f}{R_1})(\frac{R_f}{R_2+R_f})V_2$$
Diff amp=inverting + noninverting
Whenever we have multiple inputs are applied to a linear system as op, we can analyze them individually and sum the contrubutions togheter
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Filter
A filter is a process which changes a material or a signals properties by seperatyn their components
Lowpass filter, rc filter with c parallel to vin and vout with r on the vin side
Notch filter, can be built by two rc-filters
Highpass filter, rc filter with r parallel with vin and vout, and c on the vin side
Bandpass filter, built by HP and LP
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Gates
How to change a circuit to just one gate, calculate the end result and then change the expression to the right from.
How to find a logic expression, sum of product or product of sum, see anki for more photo
Different term
Phasor
In physics and engineering, a phasor is a complex number representing a sinusoidal function whose amplitude (Va), angular frequency (ω), and initial phase(φ) are time-invariant.
Impedance.
- Impedance is a complexnumber:
Polarform:
$$Z=
|Z| e^{j arg(z)}$$
Rectangularform:
$$Z=RE+jlm$$
generalized Ohm’slaw appliesthe same rules for calculations as for complexnumbers
Impedance matching
In electronics,impedance matchingis used to maximize the power transfer or minimize signal reflection from the load.
pn-junction, a uneaven spread of electrion creates a flow of current, used in sun panels
Transients is a measure of how fast or slow a system is, measured in how fast the output reaches 63% of its final value. t=R*C
Signals
A periodic signal can be described as a sum of weighted sinusioded signals
$$F(t)=C_0 + \sum^\infty_{n=1} A_n*cos(n*\omega_o t) + \sum^\infty_{n=1} B_n*sin(n*\omega_o t)$$
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Electric circuits
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General calculations
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Equivalent circuits
Thevenin equivalent
Steps to follow for Thevenin's Theorem:
1.Find the Thevenin source voltage by removing the load resistor from the original circuit and calculating voltage across the open connection points where the load resistor used to be.
2.Find the Thevenin resistance by removing all power sources in the original circuit (voltage sources shorted and current sources open) and calculating total resistance between the open connection points.
3.Draw the Thevenin equivalent circuit, with the Thevenin voltage source in series with the Thevenin resistance. The load resistor re-attaches between the two open points of the equivalent circuit. 4.Analyze voltage and current for the load resistor following the rules for series circuits.
Norton equivalent
Steps to follow for Norton's Theorem:
1.Find the Norton source current by removing the load resistor from the original circuit and calculating current through a short (wire) jumping across the open connection points where the load resistor used to be.
2.Find the Norton resistance by removing all power sources in the original circuit (voltage sources shorted and current sources open) and calculating total resistance between the open connection points.
3.Draw the Norton equivalent circuit, with the Norton current source in parallel with the Norton resistance. The load resistor re-attaches between the two open points of the equivalent circuit.4.Analyze voltage and current for the load resistor following the rules for parallel circuits.
$$j\omega-method$$
Steps for doing the J-omega method
1. Convert to complex representation of currents and voltages
$$i(t)=I_0*sin(\omega t + \theta) \rightarrow I(t)=I_0*e^{j(\omega t + \theta)}$$
$$v(t)=V_\alpha sin(\omega+ \theta) \rightarrow V=V_\alpha e^{j(\omega t + \theta})$$
2. Replace with complex impedance
$$L\rightarrow Z_L=J \omega L=\omega L e^{j\frac{\pi}{2}}$$
$$C \rightarrow Z_C=\frac{1}{j \omega C}=\frac{1}{\omega C}e^{-j \frac{\pi}{2}}$$
3. Apply DC-theory
$$\theta=arctan(\frac{I_m}{Re})=arctan(\frac{y}{x})$$
Där arg för en kvot är arg(täljare)-arg(nämnare)
Kolla med anki ifall Re=0 samt att ta arg för Z och inte |z|
$$V_{\alpha}=|Z_{tot}|=\sqrt{x^2+ R^2}$$
4. Transform back to time domain, see (2.46)
$$v(t)=V_\alpha sin(\omega+ \theta)$$
$$i(t)=I_0*sin(\omega t + \theta)$$
Vanligt att man skriver på polär form från exponentiel form
$$z=|z|e^{j \omega +\theta}=\sqrt{x^2+y^2}e^{j \omega +\theta}$$
Detta vet vi från arg(z)
$$argz=arctan(\frac{Im}{Re}) \text{ om }Re>0$$
$$argz=arctan(\frac{Im}{Re}) + \pi \text{ om } Re<0 \text{ och } Im \geq 0$$
$$argz=arctan(\frac{Im}{Re}) - \pi \text{ om } Re<0 \text{ och } Im < 0$$
$$argz=\frac{\pi}{2} \text{ om } Re=0 \text{ och } Im > 0$$
$$argz=-\frac{\pi}{2} \text{ om } Re=0 \text{ och } Im < 0$$
Impedance is the voltage to current ratio, like R but more general
z=R+jX, where R is resistance and x is called reactance
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Finding a logic expression
•Sum-of-productsmethod: Form a product for every rowin the truth table that results in an output of 1 and take the sum of the products. In order to do this, an y input whose valueis 0 in the row must be inverted in the product.
•Product-of-sumsmethod:Form a sum for every row in the truthtable that results in an output of 0 and take the product of the sums. In order to do this, an y input whose value is 1 in the row must be inverted in the sum.
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