A control system is a set of devices or systems that manage, command, direct, or regulate the behavior of other devices or systems using control loops. It aims to maintain the desired output despite external disturbances.
An open-loop control system acts based on input without feedback, lacking the ability to correct errors. A closed-loop control system (or feedback control system) uses feedback to compare the output with the desired setpoint and adjust accordingly to minimize errors.
Feedback is the process of taking a portion of the output signal of a system and returning it to the input to maintain the desired output. Positive feedback amplifies the input, while negative feedback reduces the difference between the desired and actual output.
Stability in control systems refers to the ability of the system to return to its equilibrium state after a disturbance. A system is stable if, for any bounded input, the output remains bounded and does not diverge over time.
A block diagram is a graphical representation of a control system, showing the flow of signals and the functional relationships among the system components. It simplifies the analysis and design of complex control systems by visually representing the system's structure.
A PID controller is a control loop feedback mechanism widely used in control systems. It consists of three terms: Proportional (P), Integral (I), and Derivative (D). The controller output is a combination of these terms, each contributing to error correction in different ways to improve system stability and performance
Gain margin and phase margin are measures of the stability of a control system in the frequency domain. Gain margin is the amount by which the gain can increase before the system becomes unstable. Phase margin is the additional phase lag required to bring the system to the verge of instability. Both margins provide insights into the robustness of the system.
A root locus plot is a graphical representation of the locations of the poles of a control system's transfer function as a system parameter (usually gain) is varied. It helps in analyzing and designing the stability and transient response of control systems.
The Nyquist criterion is a graphical method used in the frequency domain to determine the stability of a control system. It involves plotting the Nyquist plot (a parametric plot of the open-loop transfer function) and analyzing its encirclement of the critical point (-1,0) to assess system stability.
State-space representation is a mathematical model of a control system using a set of first-order differential equations. It represents the system in terms of state variables, input, output, and matrices that describe the system dynamics. It is particularly useful for analyzing multi-input, multi-output (MIMO) systems.