(SEM V) THEORY EXAMINATION 2023-24 MECHATRONICS SYSTEMS

SECTION A – Short Answers (2 × 10 = 20 Marks)

(a) Define Mechatronics and give four examples.

Mechatronics:  An interdisciplinary field combining mechanical, electrical, electronics, control, and computer engineering for automated systems.

Examples:                                                CNC machines

ABS (Anti-lock braking system)                Automatic washing machine

Industrial robots

(b) Define Autotronics and write their applications.

Autotronics: Integration of electronics and computer control in automotive systems for safety, performance, and automation.

Applications:                                         Engine management systems

Electronic fuel injection                          Anti-lock braking (ABS)

Airbag control system

(c) Principle and Working of Inductive Proximity Sensor

Principle: Based on electromagnetic induction — detects metallic objects without physical contact.

Working:

An oscillator generates an electromagnetic field.

When a metal object enters this field, eddy currents are induced.

This changes the oscillator amplitude → detected by a trigger circuit → output signal generated.

Applications: Metal detection, automation lines, position sensing.

(d) Define Sensors and Transducers with examples

Sensor: Detects physical quantity (e.g., temperature, pressure) → converts into a readable signal.
Example: Thermistor for temperature.

Transducer: Converts one form of energy into another.
Example: LVDT converts linear displacement into electrical voltage.

(e) Advantages and Applications of Stepper Motor

Advantages:                                      Precise position control

No feedback system needed              Excellent repeatability

Applications:                                     3D printers

CNC machines                                    Robotics arm positioning

(f) What are Servo Motors?

Servo Motor: A rotary actuator providing precise control of angular position, velocity, and acceleration using feedback signals.
Used in robotics, CNC, camera autofocus, and automatic control systems.

(g) Advantages and Uses of PLCs

Advantages:                                  Easy programming (ladder logic)

Reliable and flexible                       Real-time operation and maintenance-free

Applications:                                 Conveyor systems

Industrial automation                     Packaging machines

(h) Criteria for Selecting a PLC                  Number of input/output points

Memory size and processing speed         Type of communication interface

Expansion capability                                                   Environmental conditions

(i) Application of Mechatronics in Manufacturing      Flexible Manufacturing Systems (FMS)

CNC & DNC control                                                  Robotic assembly lines

Automated inspection & quality control

(j) Working of Pick and Place Robot                    Uses actuators, sensors, and end-effectors.

Robot arm moves to pick an object (using gripper or suction) → transfers → releases at target location.

Controlled via microprocessor or PLC with feedback from position sensors.

SECTION B – Descriptive (Any 3 × 10 = 30 Marks)

(a) Stages of Mechatronic System Design

Need Identification                                 Concept Design

Modeling and Simulation                       Hardware & Software Design

Integration & Testing

Evolution: From purely mechanical → electro-mechanical → intelligent computer-controlled systems.

(b) Position Sensors – Hall Effect Sensor

Working Principle:
When a current-carrying conductor is placed in a magnetic field, a voltage is produced perpendicular to current & field — Hall Voltage.
Advantages: Non-contact, reliable, accurate.
Applications: Speed sensing, brushless DC motors, automotive ignition.

(c) 3-Phase Induction Motor

Principle: Based on electromagnetic induction — rotating magnetic field induces current in rotor → torque produced.

Advantages: Robust, low cost, minimal maintenance.

Disadvantages: Speed control is complex.

(d) Programmable Logic Controller (PLC) & Scan Cycle

PLC: Digital computer for automation; executes control programs.

Scan Cycle: Sequence → Input read → Logic execute → Output update.
Each cycle repeats continuously for real-time control.

(e) Examples of Mechatronic Systems

Bottling Plant: Uses sensors, actuators, conveyors, PLCs for automatic filling and capping.

Flexible Manufacturing System (FMS): Integrates robots, CNC, AGVs for automated and adaptive production.

SECTION C – Long Answers (Any 1 from each)

3(a) Control Systems

Definition: A system that manages, commands, and regulates the behavior of other systems.

Types:

Open-loop (no feedback)            Closed-loop (uses feedback)
Example: Temperature control with thermostat.   Advantages: Accurate, stable; Disadvantages: Expensive, complex.

4(b) LVDT (Linear Variable Differential Transformer)

Working:

Consists of one primary & two secondary coils with movable ferromagnetic core.

Movement of core changes mutual inductance → differential voltage indicates displacement.
Advantages: High accuracy, infinite resolution.
Applications: Displacement and vibration measurement.

5(a) Hydraulic Actuator

Components: Pump, reservoir, control valves, actuator (cylinder), filter.
Advantages: High force, smooth control.          Disadvantages: Leakage, maintenance.
Applications: Aircraft landing gear, presses.

6(a) PLC Architecture

Processor Unit (CPU) – executes logic.  Input/Output Modules – interface for sensors/actuators.

Memory – stores program and data.      Power Supply – provides regulated power.

Timers & Counters:                                Timer: Delays output for set time.

Counter: Counts input pulses to trigger output.

7(a) Mechatronic System Examples

Engine Management System (EMS):

Controls fuel injection, ignition, and air-fuel ratio using sensors and ECU.

Automatic Washing Machine:

Uses sensors for water level, temperature, and motor control with microcontroller.

7(b) Automatic Camera & Car Parking

Automatic Camera:

Uses IR sensors and microcontroller to auto-focus and adjust exposure.

Automatic Car Parking:

Employs ultrasonic sensors, motors, and control units to park vehicle autonomously.