About this previous year paper
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.