Basic Mechatronics interview questions

150 questions with answers (MTX-001 to MTX-150). Try each one aloud before reading the answer.

Mechatronic System Design

MTX-001 · What is mechatronics?

The synergistic integration of mechanical engineering, electrical and electronic engineering, control engineering and computer engineering to design products and processes. The disciplines are combined from the start of design rather than added one after another.

MTX-002 · What are the main building blocks of a mechatronic system?

A mechanical structure, sensors, signal conditioning, a controller (microcontroller, PLC or computer), actuators with their drives, a power supply and a user or communication interface. Information flows from sensors through the controller to actuators in a loop.

MTX-003 · Give some everyday examples of mechatronic products.

Anti-lock braking systems, camera autofocus, washing machines, inkjet printers, hard disk drives, drones, CNC machines, automatic doors and vending machines. Each combines mechanics, sensing, electronics and embedded software.

MTX-004 · How does mechatronic design differ from traditional sequential design?

Traditional design passes the product from mechanical to electrical to software teams in sequence. Mechatronic design develops all domains concurrently, so functions can be shifted between hardware and software and trade-offs are made at system level.

MTX-005 · What is concurrent engineering?

A product development approach where design, manufacturing, testing and support teams work in parallel and share information early. It shortens development time and catches integration and manufacturability problems before they become expensive.

MTX-006 · What is the V-model in mechatronic design?

A development model (described in VDI 2206) where requirements are decomposed into system and domain-specific designs on the left side, then integrated and verified step by step on the right side. Each design level has a matching test level.

MTX-007 · What is a requirements specification?

A document that defines what the system must do (functions, performance, interfaces) and the constraints it must meet (cost, size, environment, safety, standards). Good requirements are measurable and testable.

MTX-008 · What is an embedded system in a mechatronic product?

A dedicated computer, usually a microcontroller with firmware, built into the product to perform specific control functions in real time. It reads sensors, runs control logic and drives actuators.

MTX-009 · What is system integration?

The process of combining mechanical, electrical, electronic and software subsystems into a working whole and verifying that their interfaces (signals, power, timing, mechanical fits) work together as specified.

MTX-010 · What is modular design?

Dividing a system into self-contained modules with well-defined interfaces, such as a drive module or sensor module. It simplifies development, testing, maintenance and reuse across product variants.

MTX-011 · What is design for manufacturability (DFM)?

Designing parts and assemblies so they are easy and cheap to make and assemble: fewer parts, standard components, achievable tolerances and simple assembly directions. It reduces cost and defects.

MTX-012 · What is a safety interlock?

A mechanism or circuit that prevents a hazardous action unless safe conditions are met, for example stopping a machine when a guard door is opened. It can be mechanical, electrical or software-based, with hardwired types preferred for critical hazards.

MTX-013 · What is FMEA?

Failure Mode and Effects Analysis: a structured method that lists possible failure modes of each component, their effects and causes, and ranks them by severity, occurrence and detection to prioritise design improvements.

Sensors

MTX-014 · What is the difference between a sensor and a transducer?

A transducer converts energy from one form to another. A sensor is a transducer that detects a physical quantity and produces a measurable, usually electrical, signal. All sensors are transducers, but actuators are transducers too.

MTX-015 · What is the difference between active and passive sensors?

A passive (self-generating) sensor produces its own output energy, such as a thermocouple or piezoelectric sensor. An active (modulating) sensor needs external excitation, such as a strain gauge, RTD or LVDT.

MTX-016 · What are common examples of position sensors?

Rotary and linear encoders, potentiometers, LVDTs, resolvers, Hall-effect sensors, capacitive sensors and magnetostrictive sensors. Proximity switches give simple on/off position detection.

MTX-017 · How does a potentiometer work as a position sensor?

A wiper slides along a resistive track connected across a reference voltage. The wiper voltage is proportional to its position, giving a simple, low-cost absolute linear or angular measurement, though the contact wears over time.

MTX-018 · What is an LVDT?

A Linear Variable Differential Transformer: one primary and two secondary coils around a movable ferromagnetic core. The differential secondary voltage is proportional to core displacement. It is contactless, rugged and has very fine resolution.

MTX-019 · What is a strain gauge?

A thin foil or wire resistor bonded to a surface whose resistance changes with strain. Gauge factor GF = (ΔR/R)/ε, about 2 for metal foil gauges. It is used in load cells, torque sensors and pressure sensors.

MTX-020 · What is a thermocouple?

Two dissimilar metal wires joined at a measuring junction. A voltage proportional to the temperature difference between the measuring and reference junctions is produced by the Seebeck effect. Type K gives roughly 41 µV/°C.

MTX-021 · What is an RTD?

A Resistance Temperature Detector, usually platinum, whose resistance rises nearly linearly with temperature. A Pt100 has 100 Ω at 0 °C and a coefficient of about 0.00385 Ω/Ω/°C. It is more accurate and stable than a thermocouple.

MTX-022 · What is a thermistor?

A semiconductor resistor with a large temperature coefficient. NTC types decrease in resistance as temperature rises; PTC types increase. They are sensitive and cheap but strongly nonlinear and have a limited range.

MTX-023 · What is a proximity sensor?

A non-contact sensor that detects the presence of an object nearby. Common types are inductive (metal only), capacitive (most materials), photoelectric (light beam) and ultrasonic (sound echo).

MTX-024 · What is a Hall-effect sensor?

A sensor that produces a voltage across a current-carrying conductor when placed in a magnetic field perpendicular to the current. It is used for position, speed, current sensing and BLDC commutation.

MTX-025 · What is an accelerometer?

A sensor that measures acceleration, typically by detecting the deflection of a proof mass on a spring. MEMS capacitive accelerometers are used in phones and vehicles; piezoelectric types are used for vibration monitoring.

MTX-026 · What is a load cell?

A force transducer, usually a metal element with strain gauges in a Wheatstone bridge, that outputs a voltage proportional to applied force or weight. Output is typically specified in mV/V of excitation.

Actuators

MTX-027 · What is an actuator?

A device that converts an energy input (electrical, hydraulic or pneumatic) into mechanical motion or force under the command of a control signal. It is the "muscle" of a mechatronic system.

MTX-028 · What are the main types of actuators?

Electric (DC, stepper, servo and AC motors, solenoids), hydraulic (cylinders and motors), and pneumatic (cylinders and rotary actuators). Smart-material actuators such as piezoelectric and shape memory alloy are also used.

MTX-029 · What is a solenoid?

A coil wound around a movable ferromagnetic plunger. When energised, the magnetic field pulls the plunger in, giving short-stroke linear motion. Solenoids are used in valves, locks and relays.

MTX-030 · What is a relay?

An electrically operated switch. A small coil current moves contacts that switch a separate, often higher-power circuit, providing electrical isolation between control and load.

MTX-031 · What is the difference between linear and rotary actuators?

A linear actuator produces straight-line motion (cylinder, solenoid, linear motor, screw drive). A rotary actuator produces angular motion (motor, rotary vane actuator). Rotary motion is often converted to linear with screws, belts or rack and pinion.

MTX-032 · What is a ball screw?

A screw and nut with recirculating balls rolling between them, converting rotation to linear motion. Rolling contact gives efficiency typically above 90%, low friction, long life and high precision compared with a sliding lead screw.

MTX-033 · What is a piezoelectric actuator?

An actuator using materials such as PZT that expand when voltage is applied (inverse piezoelectric effect). It gives very small strokes (micrometres) with nanometre resolution, high force and very fast response.

MTX-034 · What is a shape memory alloy actuator?

An actuator made of an alloy such as nickel-titanium (Nitinol) that returns to a remembered shape when heated above its transformation temperature. It is compact and silent but slow, with limited efficiency and cycle life.

MTX-035 · What is a voice coil actuator?

A coil moving in a permanent magnet field, producing force F = B·I·L proportional to current. It gives short-stroke, smooth, fast and hysteresis-free motion, used in loudspeakers, hard disk heads and precision focusing.

MTX-036 · Why are gearboxes used with motors?

Motors run efficiently at high speed and low torque, while loads often need low speed and high torque. A gearbox with ratio N reduces output speed by N and multiplies torque by about N (less efficiency losses).

MTX-037 · What is a rack and pinion?

A circular gear (pinion) meshing with a linear toothed bar (rack) to convert rotary motion to linear motion. Linear travel per revolution equals the pinion pitch circumference, πd.

MTX-038 · What is backlash?

The clearance or lost motion between mating parts, such as gear teeth, when direction reverses. It causes positioning error and can create limit cycles in closed-loop control.

MTX-039 · What is a timing belt drive?

A toothed belt meshing with toothed pulleys to transmit motion without slip. It is used for long, fast linear axes such as 3D printers and pick-and-place machines, but is less stiff than a ball screw.

Electric Motors & Drives

MTX-040 · What is the working principle of a DC motor?

A current-carrying conductor in a magnetic field experiences a force (F = B·I·L). In a DC motor, this force on the armature conductors creates torque, and a commutator reverses current direction to keep rotation continuous.

MTX-041 · What is the difference between a brushed and a brushless DC motor?

A brushed motor uses mechanical brushes and a commutator to switch current. A brushless (BLDC) motor has permanent magnets on the rotor and uses electronic switching driven by rotor position, giving higher efficiency, longer life and less maintenance.

MTX-042 · What is a stepper motor?

A motor that rotates in fixed angular increments (steps) for each input pulse. Position is set by counting pulses, so it can run open-loop. Common types are permanent magnet, variable reluctance and hybrid.

MTX-043 · What is the step angle of a stepper motor?

The angle moved per full step. A common hybrid stepper has 1.8°, giving 360/1.8 = 200 full steps per revolution. Microstepping subdivides each step further.

MTX-044 · What is a servo motor?

A motor used in closed-loop control with a feedback device (encoder or resolver) and a servo drive to accurately control position, speed or torque. Industrial servos are usually permanent-magnet AC (PMSM) motors.

MTX-045 · What is an induction motor?

An AC motor where a rotating stator field induces currents in the rotor (usually a squirrel cage), producing torque. The rotor always turns slightly slower than the field. It is rugged, cheap and the most common industrial motor.

MTX-046 · How is the synchronous speed of an AC motor calculated?

Ns = 120·f/P rpm, where f is supply frequency in Hz and P is the number of poles. A 4-pole motor on 50 Hz has Ns = 120 × 50/4 = 1500 rpm.

MTX-047 · What is slip in an induction motor?

The relative difference between synchronous speed and rotor speed: s = (Ns − N)/Ns. Slip is needed to induce rotor current and is typically a few percent at full load.

MTX-048 · What is a motor driver?

A power electronic circuit that converts low-power control signals from a controller into the voltage and current a motor needs. Examples are H-bridge DC drivers, stepper drivers and three-phase inverters.

MTX-049 · What is a variable frequency drive (VFD)?

A drive that rectifies AC mains to a DC bus and then uses an inverter (PWM switching) to produce variable-frequency, variable-voltage AC. It controls the speed of AC induction or synchronous motors.

MTX-050 · What does the torque-speed curve of a DC motor look like?

For a permanent-magnet DC motor at constant voltage it is a straight line falling from stall torque at zero speed to zero torque at no-load speed. Maximum mechanical power occurs at half the no-load speed.

MTX-051 · What is a commutator?

A segmented copper ring on the armature of a brushed DC motor. As the rotor turns, brushes contact different segments and reverse the current in the coils, keeping torque in one direction.

MTX-052 · What is a PMSM?

A Permanent Magnet Synchronous Motor: an AC motor with permanent magnets on the rotor that rotates in sync with the stator field. It has sinusoidal back-EMF and is used in servos and electric vehicles for high efficiency and power density.

Microcontrollers & Interfacing

MTX-053 · What is the difference between a microcontroller and a microprocessor?

A microcontroller integrates a CPU, memory (flash and RAM) and peripherals such as timers, ADCs and GPIO on one chip for dedicated control. A microprocessor is mainly a CPU needing external memory and peripherals, used for general computing.

MTX-054 · What is GPIO?

General-Purpose Input/Output: microcontroller pins configurable by software as digital inputs or outputs. They read switches and sensors or drive LEDs, transistors and logic signals.

MTX-055 · What is PWM?

Pulse-Width Modulation: switching a signal fully on and off at a fixed frequency while varying the duty cycle (on-time fraction). The average output is duty × supply voltage, which controls motor speed, LED brightness or heater power efficiently.

MTX-056 · What is an ADC?

An Analog-to-Digital Converter that turns a continuous voltage into a digital number. Key specifications are resolution (bits), sampling rate, input range and accuracy.

MTX-057 · What is a DAC?

A Digital-to-Analog Converter that turns a digital code into a proportional analog voltage or current. It is used to command analog drives, valves or set-points.

MTX-058 · What is an interrupt?

A hardware or software signal that pauses the main program so the processor can run an interrupt service routine (ISR) immediately, then resume. It allows fast response to events such as encoder edges or timer overflows.

MTX-059 · What is a timer/counter peripheral?

A hardware counter clocked by the system clock or an external signal. It is used to generate delays, PWM, periodic interrupts, measure pulse widths (input capture) and count external events.

MTX-060 · What is UART?

Universal Asynchronous Receiver-Transmitter: a serial interface sending data bit by bit over TX and RX lines without a shared clock. Both ends must agree on baud rate, data bits, parity and stop bits.

MTX-061 · What is I²C?

Inter-Integrated Circuit: a two-wire synchronous bus (SDA data, SCL clock) supporting multiple devices with 7-bit or 10-bit addresses. Standard speeds are 100 kbit/s and 400 kbit/s. It is used for sensors and EEPROMs on a board.

MTX-062 · What is SPI?

Serial Peripheral Interface: a full-duplex synchronous bus with clock (SCK), MOSI, MISO and a chip-select line per slave. It is faster and simpler than I²C but needs more wires.

MTX-063 · What is a pull-up resistor?

A resistor connecting an input or bus line to the supply so it reads a defined high level when nothing actively drives it low. It prevents floating inputs and is needed for open-drain buses such as I²C.

MTX-064 · What is a watchdog timer?

A hardware timer that resets the microcontroller if software fails to refresh it within a set period. It recovers the system automatically from software hangs or lock-ups.

MTX-065 · What is switch debouncing?

Mechanical contacts bounce for a few milliseconds when operated, producing multiple transitions. Debouncing filters these with an RC circuit, a Schmitt trigger, or software that waits for a stable state before accepting the change.

Signal Conditioning & Data Acquisition

MTX-066 · What is signal conditioning?

Processing a raw sensor signal into a form suitable for measurement: amplification, filtering, isolation, linearisation, excitation, level shifting and conversion (for example current to voltage) before the ADC.

MTX-067 · What is an operational amplifier?

A high-gain differential voltage amplifier with high input impedance and low output impedance. With external feedback components, it builds amplifiers, filters, integrators, comparators and buffers.

MTX-068 · What is an instrumentation amplifier?

A precision differential amplifier with high input impedance, high common-mode rejection and gain set by a single resistor. It amplifies small differential signals, such as from bridges and thermocouples, while rejecting common-mode noise.

MTX-069 · What is a Wheatstone bridge?

Four resistors arranged in a diamond with excitation across one diagonal and output across the other. When balanced (R1/R2 = R3/R4), the output is zero, so small resistance changes in a sensor arm give a measurable output voltage.

MTX-070 · What is a low-pass filter?

A filter that passes frequencies below a cutoff and attenuates higher ones. For a first-order RC filter, the cutoff is fc = 1/(2πRC) and attenuation rises at 20 dB/decade above it.

MTX-071 · What is a data acquisition (DAQ) system?

A system that measures physical signals and converts them into digital data for a computer. It includes sensors, signal conditioning, multiplexer, sample-and-hold, ADC, timing and software.

MTX-072 · What is sampling rate?

The number of samples per second an ADC takes, in samples/s or Hz. It must be high enough to capture the highest frequency of interest in the signal.

MTX-073 · What is the Nyquist sampling theorem?

A band-limited signal can be reconstructed exactly if sampled at more than twice its highest frequency component: fs > 2·fmax. Half the sampling rate, fs/2, is called the Nyquist frequency.

MTX-074 · What is aliasing?

When a signal contains frequencies above fs/2, they appear after sampling as false lower frequencies. Aliased components cannot be separated from real ones afterwards, so they must be removed before sampling.

MTX-075 · What is ADC resolution and quantization error?

An n-bit ADC divides its range into 2ⁿ levels. The step size is 1 LSB = Vref/2ⁿ, and quantization error is up to ±½ LSB. A 10-bit ADC with 5 V reference has LSB ≈ 4.88 mV.

MTX-076 · What is an anti-aliasing filter?

An analog low-pass filter placed before the ADC to attenuate frequency components above the Nyquist frequency. It ensures that out-of-band noise and signals do not fold back into the measured band.

MTX-077 · What is signal-to-noise ratio (SNR)?

The ratio of signal power to noise power, usually in decibels: SNR = 10·log₁₀(Ps/Pn) = 20·log₁₀(Vs/Vn). A higher SNR means a cleaner measurement.

MTX-078 · What is an optocoupler used for?

An optocoupler transfers a signal through light between an LED and a phototransistor, giving galvanic isolation. It protects low-voltage control electronics from high voltages, ground differences and noise on the field side.

Control Systems

MTX-079 · What is a control system?

An arrangement of components that manages the behaviour of a plant so that its output follows a desired reference, such as a set speed, position or temperature, despite disturbances.

MTX-080 · What is the difference between open-loop and closed-loop control?

Open-loop control applies an input without measuring the output, as in a toaster timer. Closed-loop control measures the output and corrects the input based on the error, which rejects disturbances and model errors.

MTX-081 · What is a transfer function?

The ratio of the Laplace transform of the output to that of the input of a linear time-invariant system with zero initial conditions, G(s) = Y(s)/U(s). It describes the system's dynamics in the s-domain.

MTX-082 · What is a PID controller?

A controller whose output is the sum of proportional, integral and derivative terms of the error: u = Kp·e + Ki∫e dt + Kd·de/dt. It is the most widely used feedback controller in industry.

MTX-083 · What is steady-state error?

The difference between the reference and the output after transients have died out. It depends on the system type and input; integral action removes steady-state error for a step input.

MTX-084 · What does stability mean for a control system?

A system is stable if every bounded input produces a bounded output, and its response settles after a disturbance. For a linear continuous system, all closed-loop poles must have negative real parts.

MTX-085 · What is overshoot?

The amount by which the response exceeds its final value in a step response, usually given as a percentage of the final value. Too much overshoot can damage mechanisms or products.

MTX-086 · What are rise time and settling time?

Rise time is the time for the response to go from 10% to 90% of its final value. Settling time is the time after which the response stays within a band, usually ±2% or ±5%, of the final value.

MTX-087 · What is a block diagram?

A graphical representation of a control system showing components as blocks with transfer functions, connected by signal arrows, summing junctions and take-off points. It helps derive the overall transfer function.

MTX-088 · What is on-off control with hysteresis?

The actuator is fully on below a lower threshold and fully off above an upper threshold, as in a thermostat. The hysteresis band (dead band) prevents rapid switching (chattering) but causes the output to oscillate within the band.

MTX-089 · What are set-point and error?

The set-point is the desired value of the controlled variable. The error is the set-point minus the measured value, and it is the input to the controller.

MTX-090 · What is feedforward control?

Control action computed directly from a known reference or a measured disturbance, without waiting for an error to appear. It is combined with feedback to improve tracking and disturbance rejection.

PLC & Industrial Control

MTX-091 · What is a PLC?

A Programmable Logic Controller: a rugged industrial computer that reads inputs, executes a user program cyclically and sets outputs to control machines and processes. It replaced hardwired relay logic.

MTX-092 · What are the main components of a PLC?

A power supply, CPU with memory, digital and analog input/output modules, communication interfaces and a programming device or software. Modular PLCs mount these on a rack or DIN rail.

MTX-093 · What is ladder logic?

A graphical PLC programming language that resembles relay circuit diagrams. Rungs between two vertical power rails contain contacts (conditions) and coils (outputs), making it familiar to electricians.

MTX-094 · What is the PLC scan cycle?

The repeated sequence of reading all inputs into an image table, executing the program from top to bottom, updating outputs from the output image, and performing communication and diagnostics. Typical scan times are a few milliseconds.

MTX-095 · What are the IEC 61131-3 programming languages?

Ladder Diagram (LD), Function Block Diagram (FBD), Structured Text (ST), Sequential Function Chart (SFC) and Instruction List (IL). IL has been deprecated in the latest edition of the standard.

MTX-096 · What is the difference between normally open and normally closed contacts?

A normally open (NO) contact is open in its rest state and closes when actuated. A normally closed (NC) contact is closed at rest and opens when actuated. Stop buttons are usually wired NC.

MTX-097 · What is a seal-in (latching) circuit?

A rung where an output's own contact is placed in parallel with a momentary start button, so the output stays on after the button is released. A series NC stop contact breaks the seal.

MTX-098 · What are PLC timers?

Instructions that delay actions. TON (on-delay) sets its output after the input has been on for a preset time; TOF (off-delay) keeps the output on for a preset time after the input goes off; TP gives a fixed-length pulse.

MTX-099 · What is a PLC counter?

An instruction that counts input transitions. Up counters (CTU) increment and down counters (CTD) decrement; the output turns on when the count reaches the preset value. They count parts, cycles or events.

MTX-100 · What is the difference between sinking and sourcing I/O?

A sourcing device supplies current to the load (connects it to +V); a sinking device provides the path to 0 V. A sourcing sensor (PNP) pairs with a sinking input, and a sinking sensor (NPN) pairs with a sourcing input.

MTX-101 · What is SCADA?

Supervisory Control and Data Acquisition: a software system that collects data from PLCs and remote units, displays it to operators, logs history, raises alarms and sends supervisory commands across a plant or wide area.

MTX-102 · What is an HMI panel?

A Human-Machine Interface touchscreen or panel connected to a PLC that shows machine status, alarms and values, and lets operators enter set-points and commands without changing the PLC program.

Hydraulics & Pneumatics

MTX-103 · What is the difference between hydraulics and pneumatics?

Hydraulics use pressurised oil (typically 100–300 bar) for high force, stiffness and precise control, but risk leaks and need more maintenance. Pneumatics use compressed air (about 6 bar), which is fast, clean and cheap but compressible, so positioning is less precise.

MTX-104 · What is Pascal's law?

Pressure applied to a confined fluid is transmitted equally in all directions. This allows a small force on a small piston to produce a large force on a large piston: F₂ = F₁·(A₂/A₁).

MTX-105 · What are the common types of hydraulic pumps?

Gear pumps (simple, cheap), vane pumps (quieter, medium pressure) and piston pumps (axial or radial, highest pressure and efficiency, can have variable displacement). All are positive-displacement pumps.

MTX-106 · What is a directional control valve?

A valve that directs fluid flow to different ports to start, stop or reverse an actuator. It is described by the number of ports and positions, such as 4/3 (four ports, three positions), and actuated manually, by solenoid or by pilot pressure.

MTX-107 · What does a 5/2 valve mean?

A valve with 5 ports (one supply, two outlets, two exhausts) and 2 switching positions. It is the standard pneumatic valve for driving a double-acting cylinder in and out.

MTX-108 · What is a pressure relief valve?

A normally closed valve that opens when system pressure reaches a set value, diverting flow back to the tank. It protects pumps, hoses and components from overpressure.

MTX-109 · What is the difference between single-acting and double-acting cylinders?

A single-acting cylinder is powered by fluid in one direction and returned by a spring or load. A double-acting cylinder is powered in both directions by applying pressure to either side of the piston.

MTX-110 · What is an FRL unit?

A Filter-Regulator-Lubricator assembly at the inlet of a pneumatic system. The filter removes water and particles, the regulator sets a stable working pressure, and the lubricator adds oil mist where components need it.

MTX-111 · What is a flow control valve?

A valve that adjusts the flow rate to an actuator, controlling its speed. A common type is a throttle with a bypass check valve, which restricts flow in one direction only.

MTX-112 · What is a hydraulic accumulator?

A pressure vessel that stores hydraulic energy using a compressed gas (bladder or piston type) or spring. It supplies peak flows, absorbs shocks and pulsations, and maintains pressure during pump failure.

MTX-113 · What is a solenoid valve?

A valve operated by an electric solenoid that moves a spool or poppet to open, close or switch flow paths. It is the interface between electrical control signals (PLC outputs) and fluid power.

MTX-114 · How do you calculate the force of a pneumatic cylinder?

F = P × A. For a 50 mm bore at 6 bar (0.6 N/mm²), A = π × 25² ≈ 1963 mm², so F ≈ 0.6 × 1963 ≈ 1178 N on extension, before friction losses.

System Modeling & Simulation

MTX-115 · What is system modeling?

Representing a physical system by mathematical equations, block diagrams or software models that capture its behaviour. Models let engineers predict performance, design controllers and test ideas before building hardware.

MTX-116 · What is the difference between physical and empirical models?

A physical (white-box) model is derived from laws such as Newton's and Kirchhoff's. An empirical (black-box) model is fitted to measured input-output data. Grey-box models combine both.

MTX-117 · What is the difference between lumped and distributed parameter models?

Lumped models treat properties such as mass, stiffness and resistance as concentrated at points, giving ordinary differential equations. Distributed models let properties vary in space, giving partial differential equations, as in flexible beams or long transmission lines.

MTX-118 · Why is the Laplace transform used in system modeling?

It converts linear differential equations into algebraic equations in s, making it easy to obtain transfer functions, combine blocks, and analyse stability and transient response.

MTX-119 · What are electrical-mechanical analogies?

Equivalences between domains: in the force-voltage analogy, force ↔ voltage, velocity ↔ current, mass ↔ inductance, damping ↔ resistance, and spring compliance ↔ capacitance. They let one modelling method cover several domains.

MTX-120 · What is the equation of a mass-spring-damper system?

m·ẍ + c·ẋ + k·x = F(t), where m is mass (kg), c is damping (N·s/m), k is stiffness (N/m) and F is applied force. Its transfer function is X(s)/F(s) = 1/(ms² + cs + k).

MTX-121 · What is a state-space model?

A model written as first-order differential equations: ẋ = Ax + Bu, y = Cx + Du, where x is the state vector. It handles multiple inputs and outputs and is the basis of modern control.

MTX-122 · What is simulation?

Numerically solving a model over time to predict how the system will respond to inputs, disturbances and parameter changes. It reduces the need for costly physical prototypes.

MTX-123 · What is Simulink used for?

A graphical block-diagram environment in MATLAB for modelling, simulating and analysing dynamic systems. It is widely used for control design and automatic code generation for embedded targets.

MTX-124 · What is a bond graph?

A graphical modelling method that represents power flow between elements using effort and flow variables. It is domain-independent, so mechanical, electrical, hydraulic and thermal parts can be modelled in one consistent framework.

MTX-125 · What is the difference between linear and nonlinear systems?

A linear system obeys superposition: response to a sum of inputs equals the sum of responses. Nonlinear systems, with effects such as friction, saturation and backlash, do not, and are harder to analyse.

MTX-126 · What is a time constant?

For a first-order system, the time constant τ is the time for the step response to reach 63.2% of its final value. The response is about 98% complete after 4τ.

Machine Vision

MTX-127 · What is machine vision?

The use of cameras, optics, lighting and image processing to automatically inspect, measure, identify or guide objects in industrial applications.

MTX-128 · What are the main components of a machine vision system?

Lighting, lens, camera (image sensor), interface or frame grabber, processing hardware and image analysis software, plus I/O to communicate results to a PLC or robot.

MTX-129 · What is image resolution?

The number of pixels in the image, such as 1920 × 1080. Combined with the field of view, it sets the smallest feature size the system can resolve per pixel.

MTX-130 · What is the difference between CCD and CMOS image sensors?

CCD sensors transfer charge across the chip to a single output amplifier, traditionally giving low noise and uniformity. CMOS sensors have amplifiers in each pixel, giving faster readout, lower power and lower cost, and now dominate machine vision.

MTX-131 · What is image thresholding?

Converting a grayscale image into a binary image by setting pixels above a threshold to white and below to black. It separates objects from the background for counting or measurement.

MTX-132 · What is edge detection?

Finding locations where image intensity changes sharply, usually by computing gradients with operators such as Sobel or Canny. Edges mark object boundaries for measurement and shape analysis.

MTX-133 · Why is lighting so important in machine vision?

Lighting determines contrast between the features of interest and the background. Good lighting, such as backlight for silhouettes or diffuse light for shiny parts, simplifies processing and improves reliability more than software can.

MTX-134 · What is field of view (FOV)?

The area of the scene the camera captures, set by sensor size, lens focal length and working distance. A larger FOV covers more area but at lower resolution per millimetre.

MTX-135 · What is the difference between area scan and line scan cameras?

An area scan camera captures a 2D image in one exposure. A line scan camera captures one row of pixels at a time while the object moves, building a continuous image; it suits webs, rolls and fast conveyors.

MTX-136 · What is a grayscale image?

An image where each pixel holds a single intensity value, typically 0 (black) to 255 (white) for 8 bits. Most industrial measurement uses grayscale because it is simpler and faster than colour.

MTX-137 · What is a smart camera?

A camera with built-in processor, image analysis software and I/O in one housing. It performs inspection directly and sends pass/fail or measurement results to a PLC without a separate PC.

MTX-138 · What is optical character recognition (OCR) in machine vision?

Reading printed or marked text, such as lot codes and expiry dates, from images. With OCV (verification) and barcode reading, it is used for traceability and label checking.

Industry 4.0, IoT & Digital Twins

MTX-139 · What is Industry 4.0?

The fourth industrial revolution: connecting machines, products and people through cyber-physical systems, the industrial internet of things, cloud computing and data analytics to create flexible, self-optimising smart factories.

MTX-140 · What is the Internet of Things (IoT)?

A network of physical devices with sensors, processing and connectivity that collect and exchange data over the internet, allowing remote monitoring and control.

MTX-141 · What is the Industrial IoT (IIoT)?

IoT applied to industrial equipment such as machines, drives and sensors, with emphasis on reliability, determinism, security and integration with control systems for monitoring, analytics and optimisation.

MTX-142 · What is a digital twin?

A virtual model of a physical asset, process or system that is continuously updated with real data from its physical counterpart. It is used to monitor, simulate, predict and optimise behaviour.

MTX-143 · What is a cyber-physical system?

A system in which computation, networking and physical processes are tightly integrated, with embedded computers monitoring and controlling physical processes through feedback loops. Modern mechatronic machines are examples.

MTX-144 · What is the difference between edge and cloud computing?

Edge computing processes data near the machine, giving low latency, less bandwidth and local autonomy. Cloud computing processes data in remote data centres, giving large storage, heavy analytics and fleet-wide views.

MTX-145 · What is MQTT?

A lightweight publish-subscribe messaging protocol over TCP/IP. Devices publish messages to topics on a broker, and subscribers receive them. It suits low-bandwidth IoT devices.

MTX-146 · What is OPC UA?

OPC Unified Architecture: a platform-independent, secure industrial communication standard that exchanges not just data but an information model describing machines and their variables. It connects PLCs, SCADA, MES and cloud systems.

MTX-147 · What is predictive maintenance?

Maintenance scheduled based on the actual condition of equipment, predicted from sensor data such as vibration, temperature and current. It avoids both unexpected breakdowns and unnecessary preventive replacement.

MTX-148 · What is a smart factory?

A highly digitised and connected production facility where machines, systems and people share data in real time, allowing flexible production, automatic adjustment and data-driven decisions.

MTX-149 · What is RFID and how is it used in manufacturing?

Radio-Frequency Identification uses tags read wirelessly by a reader without line of sight. In manufacturing, it tracks parts, tools and work-in-progress, and can store product-specific process data on the item.

MTX-150 · What is industrial Ethernet?

Ethernet-based networks adapted for factory use with real-time capability and rugged hardware. Examples are PROFINET, EtherCAT, EtherNet/IP and Modbus TCP, which have largely replaced older fieldbuses.

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