Introduction Control Engineering Kim, Do Wan HANBAT NATIONAL UNIVERSITY

Outline  Course introduction  What is the control engineering?  Analysis and design objectives  Course objectives

Course introduction  Automatic control  For junior student  Text book:  Control Systems Engineering by Norman S. Nise  2 major tests (45%+45%), homeworks (5%), attendance (5%)

Course introduction  Covers  Introduction (chap. 1)  Modeling in frequency and time domain (chap. 2-3)  Model reduction (chap. 5)  Time responses (chap. 4)  Steady-state errors (chap. 7)  Stability (chap. 6)  Root locus techniques (chap. 8)

Course introduction  Instructor: Kim, Do Wan Yonsei University UC, Berkeley B.S. M.S.Ph.D. Researcher Postdoc Research Professor HANBAT NATIONAL UNIVERSITY

Course introduction  Instructor: Do Wan Kim  Research interests: discrete-time, sampled-data, and digital nonlinear control systems, linear and nonlinear systems with nonlinear perturbations, fuzzy systems, and digital redesign.   N3 215

What is the control engineering?  Definition of control systems  A control system is a set of devices (plant, controller) that can provide a desired system response.

What is the control engineering?  Definition of control systems  A control system is a set of devices (plant, controller) that can provide a desired system response.  In input-output sense  An example in the morning

What is the control engineering?  In elevator  Input? Output?

What is the control engineering?  Control systems attempt to either Regulation or Tracking  Regulation – to maintain systems response at CONSTANT desired values system response time desired value constant

What is the control engineering?  Regulation – to maintain systems response at CONSTANT desired values system response time desired value constant

What is the control engineering?  Tracking – to make system response follow continually CHANGING desired values continually changing system response time desired value

What is the control engineering?  Tracking – to make system response follow continually CHANGING desired values continually changing system response time desired value

What is the control engineering?  Representation of control system  Differential equation  Kirchhoff’s voltage law and current law, Newton’s laws  Transfer function  State space equation  nth order differential equation= n 1 st order differential equations  Ex)

What is the control engineering?  Representation of control system  Block Diagram  Signal flow graph

What is the control engineering?  Open-loop vs Closed-loop (Feedback control)  Open-loop systems  No direct comparison between the input and the output.  Sensitive to disturbances  Feedforward control.  Closed-loop (feedback control) systems  Direct comparison between the input and the output.  Less sensitive to disturbances  Feedback Control. Plant Controller Input Output Plant Controller Input Output error + -

What is the control engineering?  Open-loop vs Closed-loop (Feedback control)  Open-loop systems  No direct comparison between the input and the output.  Sensitive to disturbances  Feedforward control.  Closed-loop (feedback control) systems  Direct comparison between the input and the output.  Less sensitive to disturbances  Feedback Control. Plant Controller Input Output Plant Controller Input Output error + -

What is the control engineering?  Examples

What is the control engineering?  Classification

What is the control engineering? Control system DistributedLumped  Classification

What is the control engineering? Control system DistributedLumped StochasticDeterministic  Classification

What is the control engineering? Control system DistributedLumped StochasticDeterministic Discrete-timeContinuous-time  Classification

What is the control engineering? Control system DistributedLumped StochasticDeterministic Discrete-timeContinuous-time Nonlinear Linear (L)  Classification

What is the control engineering? Control system DistributedLumped StochasticDeterministic Discrete-timeContinuous-time Nonlinear Linear (L) Time-varyingTime-invariant (TI)  Classification

Classification  Linear vs Nonlinear  Linear system satisfies the following superposition principle:  Time-invariant vs Time-varying  Check whether its parameter is a function in time or not.

Classification  Examples:

What is the control engineering?  Examples: robot, missile,….

What is the control engineering?  Control engineering is concerned with analysis, design, and implementation of control systems

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives If it returns to its original position, it is STABLE.

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives If it returns to its original position, it is STABLE. If it does NOT returns to its original position, it is UNSTABLE.

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives Controller

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives steady-state error:

 Stability  Steady-state response (steady-state error)  Transient response (Response speed) Analysis and Design Objectives Slow ResponseFast Response

Analysis and Design Objectives  An example: inverted pendulum control system

Analysis and Design Objectives  An example: inverted pendulum control system desired system response

Analysis and Design Objectives  An example: inverted pendulum control system desired system response

Analysis and Design Objectives  An example: inverted pendulum control system desired system response

Analysis and Design Objectives  An example: inverted pendulum control system

Analysis and Design Objectives  An example: inverted pendulum control system

Design procedure  Process

Design procedure  Test input

Course objectives  Students completing control engineering should:  Understand control theory.  Understand utility of computer tools.

Course objectives  Students completing control engineering should:  Understand control theory.  Understand utility of computer tools. Control yourself !