Lecture 1: Introduction To Control Systems PDF

CHAPTER 1: INTRODUCTION TO CONTROL SYSTEMS MECHANICAL AND MECHATRONICS ENGINEERING DEPARTMENT: CONTROL OF MACHINES(CMH316B) BACHELOR OF ENGINEERING TECHNOLOGY IN MECHANICAL ENGINEERING : YEAR 3 By Mr. D MOKWELE CHAPTER 1 SESSION 1: OVERVIEW OF CONTROL SYSTEMS EXPECTED OUTCOMES ALL...

CHAPTER 1: INTRODUCTION TO CONTROL SYSTEMS MECHANICAL AND MECHATRONICS ENGINEERING DEPARTMENT: CONTROL OF MACHINES(CMH316B) BACHELOR OF ENGINEERING TECHNOLOGY IN MECHANICAL ENGINEERING : YEAR 3 By Mr. D MOKWELE CHAPTER 1 SESSION 1: OVERVIEW OF CONTROL SYSTEMS EXPECTED OUTCOMES ALL OUTCOMES OF CHAPTER 1 ARE FOUND IN CONTENT OF THE STUDY GUIDE IN SECTION D 4.5. EACH SLIDE WILL DESCRIBE AND ADDRESS OUTOMES IN THE STUDY GUIDE. THIS CHAPTER WILL CONTRIBUTE 50% to SEMESTER TEST 1 AND 30% TO THE EXAMINATION. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Fundamentals of Control Systems OUTCOMES: 1. Comprehend the Understand the scope and block diagram of a importance of control systems in engineering. simple control Explain the fundamentals of system. control system. 2. Provide examples of Understand development and control systems. purpose of control systems. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Fundamentals of Control Systems What is control? To exercise restraint or direction over; dominate; command. To test or verify (a scientific experiment) by a parallel experiment or other standard of comparison Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Fundamentals of Control Systems Objective understanding of control systems: It is all around us Hardly notice them Simple to very advance Physical and non physical Automated systems, therefore, Automatic Control Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Definition of control system OUTCOMES: 1. Importance in Define control systems and engineering recognize their significance in applications. various engineering fields. Recognize types of control 2. Diagram showing systems in various everyday life various applications scenarios. (e.g., robotics, Know the terminology and solve automotive, HVAC, relevant problems human interaction). Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Definition of control system What is a system? A system is a set of interacting or interdependent components forming an integrated whole Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Definition of control system Characteristics of a system: Structure, it contains parts (or components) that are directly or indirectly related to each other; Behaviour, it contains processes that transform inputs into outputs (material, energy or data); interconnectivity: the parts and processes are connected by structural and/or behavioural relationships. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Definition of control system Control systems: Control systems in engineering is the process of designing, analyzing, and optimizing systems that regulate the behavior of other devices or systems. Control systems are used in many industries to improve the efficiency and safety of processes. Other relevant definitions of descriptions exist Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Types of Control Systems OUTCOMES: 1. Description of Open- Differentiate between loop and Closed-loop systems. open-loop and closed- 2. Characteristics, loop control systems. discussion and Recognize and examples of each. compare types of 3. Side-by-side comparison control systems in diagram of open-loop various everyday life and closed-loop scenarios systems. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Types of Control System configurations Input Output Control System Desired response Actual response Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Types of Control Systems Closed-loop control systems: The output of the system is fed back to the input to adjust it. For example, a car's cruise control system uses the speed of the car to adjust the throttle position. Open-loop control systems: The output is not fed back to the input for comparison and correction. These systems are often used in applications where error handling is not required. Natural control systems: Control systems created by nature, such as the solar system or an animal's digestive system. Man-made control systems: Control systems created by humans, such as automobiles or power plants. Combinational control systems: A combination of natural and man-made control systems, such as driving a car. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Types of Control Systems configurations Open-Loop configuration Closed-Loop configuration Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Types of Control Systems configurations Open- Loop configuration Closed-Loop configuration System relatively insensitive to Used when inputs are known external disturbances and before and no disturbances internal system parameter Simple to construction variations. Maintenance simple and easy Can handle unpredictable Fairly inexpensive disturbances. Convenient when output is hard Maintenance expensive to measure Convenient when output Complex construction measuring is economically not Expensive due to sensors feasible Calibration often required Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Components of a Control System OUTCOMES: 1. Key components: Identify elements of Sensors, actuators, complete control system controllers, and between open-loop and feedback. closed-loop. 2. Block diagram Describe and implement illustrating the control systems components of a components of elements control system in various everyday life 3. Fundamental elements scenarios of control systems Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Components of a Control System 1. Controlled variable 5. System Quantity/condition - measured & controlled Combination of components acting/working Output together to perform a certain objective. 6. Disturbances 2. Control Signal Variable A signal that tends to adversely affect the output of a system. Quantity/condition varied by controller Internal – Generated within 3. Plant External – Generated outside and considered an input. Piece of equipment or a set of components working 7. Feedback Control together to perform an operation. Operation tends to reduce the difference between the output of the system and some reference input 4. Process This is done on the basis of the difference. Natural, progressive continuing operation marked by a Unpredictable disturbances series of gradual changes succeeding one another in a Predictable disturbances can be compensated for by system. fixed way and lead to a particular result. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Elements of a Control System Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Elements of a Control System 1. Comparison element: Compares the reference value with the controlled variable and Produce error signal. 2. Feedback: Negative or Positive. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Elements of a Control System 3. Control Unit: Evaluates error signal, decide what action to take and produce action to take. 4. Correction Unit: Actuator, Applies the change and Produce action Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Elements of a Control System 5. Process Unit: What is being controlled. e.g. Room in house – Temp, Tank of Water - level 6. Measuring device: Senses information relating to the controlled variable and produce a measured value 7. Error Signal: Difference between actual and desired output. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Elements of a Control System Example exercise : Person controlling the temperature in a room (Closed loop system), identify the various elements of control system. Solution : 1.Controlled variable- Room Temperature 2.Reference Value- Desired room temperature 3.Comparison Element- Person comparing measured value to desired 4.Error Signal- Difference between actual and desired temp 5.Control Unit- Person 6.Correction Unit- Switch on heater 7.Process- Heating by heater 8.Measuring Device- Thermometer (Person Department feeling) Faculty of Engineering and the Built Environment of Mechanical and Mechatronics Engineering Intro: Elements of a Control System Solution CONT: Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Importance of Control Systems Why do engineers implement control systems? To achieve desired results; Precision Accuracy Repeat-ability Efficiency Performance Compensate for changes Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Importance of Control Systems System response: Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Importance of Control Systems System response: Transient response Important it affects the speed of the system Avoid permanent damage Steady state response After transients have decayed to zero Indicator of accuracy of system Stability To produce proper transient response and steady state response Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Examples of Control Systems OUTCOMES: 1. Key components: Illustrate how Sensors, actuators, feedback controllers, and mechanisms operate feedback. in a practical control 2. Image: Block diagram system. illustrating the Determine system components of a control properties based system. open and closed- 3. Fundamental elements loop. of control systems. Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Examples of Control Systems Human being Blood sugar Eyes following Grasping and holding objects Adjusting “things” Heater Car Robotics and Automation Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Examples of Control Systems Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Intro: Examples of Control Systems Proportional: Corrects current error Makes controller quick Integral Builds memory Corrects past errors Differential Rate of change Predict next error Speed up response Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Review/ summary Control systems can be open-loop or closed-loop. Open-loop doesn’t monitor desired output Closed-loop monitors the output and compares it to the input. If an error then the system takes corrective action. Control system analysis and objectives; Producing desired transient response, Reducing steady state errors, Achieving stability. Control systems contribute to every aspect of modern society. Wide spread of applications, Exist naturally. Control systems used where power gain, remote control or conversion of the form of input is required. A control system has an input, a process and an output. PID CONTROL Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering Review / summary System must be stable: To produce proper Control Engineer: transient response and steady state response Responsible for the design, Transient response: Important it affects the development and management of speed of the system control dynamic systems in large Steady state response: Determines accuracy organizations. of system, how close it is to the desired Stability to systems that are response constantly changing. Design of a control system: What do control systems engineers 1) Determine physical system and specification do? 2) Draw functional Block diagram Tasks 3) Physical system as schematic Background 4) Obtain mathematical model Skills 5) Reduce block diagram Salary 6) Analyse and design the system Faculty of Engineering and the Built Environment Department of Mechanical and Mechatronics Engineering