Mechatronics 302050 Lecture Notes PPT UNIT II Syllabus
Mechatronics – 302050 Lecture Notes / PPT UNIT II
Syllabus Block Diagram Representation Open and Closed loop control system, Identification of key elements of mechatronics systems and represent into block diagram (Electro-Mechanical Systems), Concept of transfer function, Block diagram reduction principles, Applications of mechatronics systems: - Household, Automotive, Shop floor, Industrial.
Objectives 1. Understand 2. 3. 4. 5. 6. key elements of Mechatronics system, representation into block diagram Understand concept of transfer function, reduction and analysis Understand principles of sensors, its characteristics, interfacing with DAQ microcontroller Understand the concept of PLC system and its ladder programming, and significance of PLC systems in industrial application Understand the system modeling and analysis in time domain and frequency domain. Understand control actions such as Proportional, derivative and integral and study its significance in industrial applications.
Outcomes 1. Identification of key elements of mechatronics system and its 2. 3. 4. 5. 6. representation in terms of block diagram Understanding the concept of signal processing and use of interfacing systems such as ADC, DAC, digital I/O Interfacing of Sensors, Actuators using appropriate DAQ micro -controller Time and Frequency domain analysis of system model (for control application) PID control implementation on real time systems Development of PLC ladder programming and implementation of real life system
Assumed Knowledge Dynamics: Engineering Mechanics Mathematics Engineering Mathematics (I, II & III)
Reference Books Alciatore & Histand, Introduction to Mechatronics and Measurement system, 4 th Edition, Mc. Graw Hill publication, 2011 Golnaraghi & Kuo, Automatic Control Systems, John Wiley publications, 2010
Control A Control system performs following functions • For particular input the system output can be controlled to a desired particular value. • If some conditions are satisfied it can give a particular sequence of events as output corresponding to given input Actual Response Desired Response
Controllability (Out of Syllabus) Before a controller is implemented it is necessary to test the “Controllability” of the system Controllability is the ability of the system, to be controlled / provide desired performance, provided an external disturbance is available.
Open Loop Control • Output is dependent on input but controlling action is totally independent of the changes in output, is an Open Loop Control System. • No feedback is used, so the controller must independently determine what signal to send to the actuator. Input Control Law u Plant Output Plant = Mathematical model of Input Amplifier + Actuator + Physical System Input = Reference / Desired Input or Set Point Input Output = Measured Output Control Law = Mathematical model of the Controller
Examples of Open Loop Control
Advantages and Dis-advantages of Open Loop Control Advantages: Simple in construction Low cost Convenient to implement when output is difficult to measure Disadvantages: The controller never actually knows if the actuator did what it was supposed to do, i. e. it is inaccurate Unable to sense the environmental changes or disturbances
Closed Loop Control • Controlling action is dependent on the changes in output Input e + ∑ Control Law u Plant _ e = Error = Input – Output u = Control Input Output
Examples of Closed Loop Control
Examples of Automatic Closed Loop Control
Advantages and Dis-advantages of Closed Loop Control Advantages: Accurate, since the controller modifies and manipulates the actuating signal such that the error in the system will be zero. Self-correcting Senses the environmental changes, and disturbances in the system. Disadvantages: Complicated to design Costly Instable, since due to feedback , system tries to correct the error.
Key Elements in Mechatronic System
Key Elements in Mechatronic System: Example of Electro. Mechanical System
Response of System
Transfer Function Models Why TF? Because it is easier / better to assess some things using classical techniques, such as gain and phase margin. How to determine TF? Derive the Governing Differential Equation Assume I. C=Zero and Take Laplace transform of output Laplace transform of input Transfer function = L (output) / L (input)
Translational Mechanical Example 1
Translational Mechanical Example 1
Block Diagram • Block diagram is a diagram of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks
Block Diagram Subsystem is represented as a Comparator Input/Reference/Output/Distur bance / Feedback Signal When multiple subsystems are Blocks to represent: Sensor, Actuator, block with an input, an output, and a transfer function Plant, interconnected, a few more schematic elements must be added to the block diagram Controller, Amplifier etc (in symbolic form / transfer function form) These new elements are summing junctions and pickoff points.
Block Diagram: Domain & Comparator
Block Diagram: Series & Parallel
Block Diagram: Feedback
Reduction techniques 1. Combining blocks in cascade or in parallel 2. Moving a summing point behind a block
3. Moving a summing point ahead of a block 4. Moving a pickoff point behind a block 5. Moving a pickoff point ahead of a block
6. Eliminating a feedback loop 7. Swap with two neighboring summing points
Moving Blocks to Create Familiar Forms
Moving Blocks to Create Familiar Forms
Example 1
Example 1
Example 2
Example 2
Example 3
Example 3
Example 4
Example 5
Example 5
Example 5
Example 5
Applications of Mechatronic System • Household • Refrigerator • Washing m/c • Microwave • Automotive • Fuel injection system • Power steering • Air conditioner • Shop floor • Tool monitoring system • Automated guided vehicle • Conveyor system • Bottle filing plant.
Fuel Injection
Electric Power Steering
- Slides: 45
