1. Introduction to Control Systems: Basic elements of control system • Open loop and closed loop systems • Tracking System, Regulators • Differential equation • Transfer function 2. Modeling of electric systems: Translational and rotational mechanical systems • Block diagram reduction techniques. • Signal flow graph, Mason’s Gain Formula. 3. Feedback characteristics of Control Systems: Effect of negative feedback on sensitivity. • Bandwidth, Disturbance. • Linearizing effect of feedback, Regenerative feedback. 4. Control Components: D.C. Servomotors, A.C. Servomotors. • A.C. Tachometer. • Synchros, Stepper Motors. Module‐II 5. Time response Analysis: Standard Test Signals • Time response of first order systems to unit step and unit ramp inputs. • Time Response of Second order systems to unit step input. • Time Response specifications, Steady State Errors. • Generalised error series and Gensalised error coefficients. 6. Stability Theory: Stability and Algebraic Criteria • Concept of stability, Necessary conditions of stability. • Hurwitz stability criterion, Routh stability criterion. • Application of the Routh stability criterion to linear feedback system. • Relative stability by shifting the origin in s‐plane. 7. Root locus Technique: Root locus concepts, Rules of Construction of Root locus • Determination of Roots from Root locus for a specified open loop gain. • Effect of adding open loop poles and zeros on Root locus. • Root contours. 8. Compensation Technique: Systems with transportation lag. • Lead compensation. • Lag compensation • Lead-Lag compensation Module‐III 9. Frequency Response Analysis: Frequency domain specifications • Correlation between Time and Frequency Response with
10. Stability in frequency domain: Principle of argument, Nyquist stability criterion. • Application of Nyquist stability criterion for linear feedback system. • Constant Mcircles. • Constant N‐Circles. • Nichol’s chart. 11. Controllers: Concept of Proportional, Derivative and Integral Control actions. • P, PD, PI, PID controllers. • Zeigler‐Nichols method of tuning PID controllers.
Control Systems Module ‐1 Introduction to Control Systems: Basic elements of control system Open loop and closed loop systems, Tracking System, Regulators, and Differential equation, Transfer function. Modeling of electric systems ‐ Translational and rotational mechanical systems. Block diagram reduction techniques. Signal flow graph, Mason’s Gain Formula. Feedback characteristics of Control Systems: Effect of negative feedback on sensitivity. Bandwidth, Disturbance. Linearizing effect of feedback, Regenerative feedback. Control Components: D.C. Servomotors, A.C. Servomotors. A.C. Tachometer, Synchros, Stepper Motors. Lecture‐1 Basic Concepts of Control Systems, Open loop and closed loop systems 1. Basic elements of control system: In recent years, control systems have gained an increasingly importance in the development and advancement of the modern civilization and technology. Figure shows the basic components of a control system. Disregard the complexity of the system; it consists of an input (objective), the control system and its output (result). Practically day‐to‐day activities are affected by some type of control systems. There are two main branches of control systems: 1) Open‐loop systems and 2) Closed‐loop systems. Open-loop systems: The open‐loop system is also called the non‐feedback system. This is the simpler of the two systems. A simple example is illustrated by the speed control of an automobile as shown in Figure 1‐2. In this open‐ loop system, there is no way to ensure the actual speed is close to the desired speed automatically. The actual speed might be way off the desired speed because of the wind speed and/or road conditions, such as uphill or downhill etc. Example‐Automatic washing Machine, immersion rod, A field control d.c motor and automatic control of traffic lamp. . (Fig1.2 Basic open-loop system) Closed-loop systems: The closed‐loop system is also called the feedback system. A simple closed‐system is shown in Figure 1‐3. It has a mechanism to ensure the actual speed is close to the desired speed automatically. In closed loop control systems the control action is dependent on desired output .If any system having one or more feedback paths forming a closed loop system. Example‐air conditioners are provided with thermostat. BPUT Page 4
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