Engineering branch
Automation and Control Engineering
Automation and control engineering entries on feedback control, stability, PID design, control history, exercises, projects, and practical guides.
Entries · 34
Topic Control Systems An engineering field concerned with making dynamic systems follow desired behaviour despite disturbances, uncertainty, limits, and changing operating conditions. Glossary term Actuator A device that converts a control signal and supplied energy into controlled motion, force, torque, pressure, flow, or another physical output. Glossary term Bode Plot A pair of frequency-response plots showing magnitude and phase of a linear system as functions of frequency. Glossary term Closed-Loop Control Control action in which measured output is fed back, compared with a reference, and used to adjust the input to reduce error or shape system behaviour. Glossary term Damping Ratio A dimensionless measure of how strongly oscillations decay in a dynamic system relative to critical damping. Glossary term Dead Time A delay between a change at a system input and the first observable effect at the output. Glossary term Encoder A sensor or device that converts position, angle, speed, displacement, or another state into an electrical, optical, magnetic, or digital signal. Glossary term Feedback A control mechanism in which information about a system's output is used to adjust its input or internal behaviour. Glossary term Feedforward Control A control strategy that uses measured disturbances, commands, or models to act before an error is produced at the output. Glossary term Frequency Response The steady-state relationship between input frequency and output magnitude and phase in a dynamic system. Glossary term Gain Margin A frequency-domain stability margin that states how much loop gain can increase before a feedback system reaches the verge of instability. Glossary term Impulse Response The time-domain output of a dynamic system when excited by an ideal impulse input under specified initial conditions. Glossary term Negative Feedback Feedback that subtracts a portion of output from input to reduce error and stabilize behaviour. Glossary term Nyquist Plot A complex-plane frequency-response plot used to assess feedback-loop stability, encirclements, gain margin, and phase margin. Glossary term Open-Loop Control Control action that applies commands without using measured output feedback to correct error or reject disturbances. Glossary term Oscillation Repeated variation of a system variable around an equilibrium or reference value. Glossary term Phase Margin A frequency-domain stability margin measuring additional phase lag required to reach instability. Glossary term PID Controller A feedback controller that computes a control action from the proportional, integral, and derivative of the error signal. Glossary term Proportional Valve A valve whose opening or flow command varies continuously with a control signal. Glossary term Quadrature Encoder A position encoder producing two phase-shifted signals to infer direction and displacement. Glossary term Root Locus A control-design plot showing how closed-loop poles move as a gain or parameter changes. Glossary term Sensitivity Function A transfer function that quantifies how disturbances and reference errors are attenuated or amplified by a feedback control loop. Glossary term Stability Margin A quantitative measure of how far a feedback control system is from the boundary of instability. Glossary term State-Space Model A mathematical representation of a dynamic system using state variables, inputs, outputs, and evolution equations. Glossary term Time Constant A characteristic time scale that describes how quickly a first-order system approaches a new steady state after a disturbance. Glossary term Transfer Function A mathematical representation of the input–output relationship of a linear time-invariant system in the Laplace domain. Glossary term Zero-Order Hold A sample-and-hold model that keeps each sampled value constant until the next sampling instant. Glossary term Ziegler-Nichols Method An empirical PID tuning method based on process reaction behaviour or sustained closed-loop oscillation. Principle How Feedback Control Works A detailed explanation of the closed-loop mechanism that lets engineered systems correct error, reject disturbances, and maintain desired behaviour. History History of Feedback Control Feedback control history from governors and Maxwell stability to amplifiers, cybernetics, state-space control, digital implementation, and modern control engineering. Formula sheet Control Systems Formula Sheet Control systems formulas for closed-loop transfer, sensitivity, second-order response, steady-state error, PID, margins, state-space, and discrete-time implementation. Project PID-Controlled DC Motor Speed Project A practical engineering project for designing, modelling, implementing, tuning, and validating a PID speed-control loop for a brushed DC motor with encoder feedback. Exercise set Control System Stability Exercises Control stability exercises covering Routh-Hurwitz, second-order response, closed-loop gain limits, steady-state error, frequency margins, delay, and discrete poles. Guide Beginner's Guide to Control Systems A structured learning path for understanding control systems, from dynamic models and feedback to stability, PID control, frequency response, state-space methods, and implementation.