EI25401 Automatic Control Systems – Semester IV – EIE – R-2025

Subject Code & Name: EI25401 – Automatic Control Systems

Regulation: R-2025

Semester: IV (Fourth Semester)

Branch: B.E. Electronics and Instrumentation Engineering (EIE)

Credits / L-T-P: 3 Credits | L-T-P: 3-0-0

Course Objectives

• This course introduces the components and mathematical modeling of control systems using transfer functions and their graphical representations.
• It enables analysis in time and frequency domains, explores system stability using classical and state-space methods, and provides a foundation in compensator design techniques relevant to real-time industrial systems.

Full Unit-wise Syllabus

Unit I – System Components and their Representation

Control System: Terminology and basic structure, Feedforward and feedback control theory, Electrical and mechanical transfer function models, Block diagram models, Signal flow graph models, DC and AC servo systems.

Activities: Identification and modeling of mechanical and electrical systems using transfer functions, Development of block diagram models using simulation tools, Realization of signal flow graphs.

Unit II – Time Response Analysis

Transient response, Steady state response, Measure of performance of the standard first-order and second-order systems, Time domain specifications, Effect of an additional zero and an additional pole, Steady state error, Type number, PID control, Effect of PD, PI, PID control systems.

Activities: Time response analysis of first-order and second-order systems, Implementation of PID controllers using simulation tools, Evaluation of steady-state error for standard inputs, Real-time response analysis using software tools.

Unit III – Frequency Response Analysis

Closed-loop frequency response, Performance specification in frequency domain, Bode plot, Polar plot

Activities: Bode plot analysis of open-loop systems, Frequency domain specification validation, Polar plot construction, and interpretation.

Unit IV – System Analysis

Design of compensators using Bode plots, Cascade lead compensation, Cascade lag compensation, Cascade lag-lead compensation.

Activities: Design and verification of lead, lag, and lag-lead compensators using simulation software.

Unit V – Concepts of Stability Analysis

Concept of stability, Bounded-input bounded-output stability, Routh–Hurwitz stability criterion, Relative stability, Root locus concept, Guidelines for sketching root locus, Nyquist stability criterion.

Activities: Routh–Hurwitz criterion implementation using symbolic computation tools, Root locus plot and analysis using control design software, Nyquist plot generation and stability assessment, Simulation of stable and unstable systems.

Unit VI – Control System Analysis Using State Variable Method

State variable representation, Conversion of state variable models to transfer functions, Conversion of transfer functions to state variable models, Solution of state equations, Concepts of controllability and observability, Equivalence between transfer function and state variable representations.

Activities: State-space modeling, Simulation of state response for different inputs, Evaluation of controllability and observability using software, Comparison of transfer function and state-space results.

Course Outcomes (COs)

• CO1: Explain the components, modeling, and representations of control systems including transfer functions, block diagrams, and signal flow graphs.
• CO2: Analyze and evaluate the time and frequency domain response of control systems, including the effect of PID, PI, and PD controllers.
• CO3: Assess system stability using classical methods (Routh– Hurwitz, root locus, Nyquist) and design compensators (lead, lag, lag-lead) to meet performance specifications.
• CO4: Model, simulate, and analyze control systems using state-space methods, and evaluate controllability and observability of MIMO systems.

Assessment Pattern (Quick Note)

• Weightage: Continuous Assessment 40% | End Semester Examinations 60%
• Internal methodology: Assignments (20%), Solution to application-oriented problems using software (20%), Solving of GATE questions (20%), Internal Examinations (40%). Tasks: T1: Model an electrical and mechanical system using transfer function and state- space representations and analyze its time-domain response. T2: Design a P, PI, and PID controllers for the process, also evaluate and compare its performance in terms of transient and steady-state specifications. T3: Analyze the frequency domain specifications of the system using Bode plot and polar plot. T4: Design a lead, lag, or lag–lead compensators using Bode plots to meet the desired performance criteria T5: Investigate the stability of the system using Routh–Hurwitz criterion, Root Locus technique, and Nyquist stability criterion. T6: Examine the controllability and observability of the system for designing a state feedback controller and observer

Source: Official Anna University – B.E. Electronics and Instrumentation Engineering R-2025 Syllabus
Last Updated: October 2026