Control System Terminology PDF

FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 control system terminology Ms.chloe laserna, ect FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAM A block diagram is a pictorial representation of the cause-and-effect relationship in a phy...

FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 control system terminology Ms.chloe laserna, ect FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAM A block diagram is a pictorial representation of the cause-and-effect relationship in a physical system. It helps in characterizing the functional relationships among the components of a control system. System components in a block diagram are also known as elements of the system. It consists of unidirectional, operational blocks representing the transfer function of the systems of interest. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAM The simplest form of the block diagram is the single block, with one input and one output. BLOCK input output FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 Arrows BLOCK input output The arrows represent the direction of information or signal flow. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 arrows Example: input Control output Element x d/dt y= dx/dt FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 summing point Addition and subtraction operations are represented by a summing point. The summing point is depicted as a small circle with plus (+) or minus (−) signs associated with the arrows entering the circle. The output of the summing point is the algebraic sum of the inputs. Multiple inputs can enter the summing point. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 summing point Example: x + x+y x + x-y + - y y FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 summing point z + x + x+y+z + y FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 summing point Some authors put a cross in the circle. This notation is avoided here because it is sometimes confused with the multiplication operation. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 takeoff point A takeoff point is used to send the same signal or variable to multiple blocks or summing points. It allows the signal to proceed unaltered along different paths to reach multiple destinations. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 takeoff point takeoff point x x x x x x x FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAMS OF CONTINUOUS (ANALOG) FEEDBACK CONTROL SYSTEMS Blocks in a control system are connected to represent their functional relationships. A simple closed-loop (feedback) control system has a single input and single output (SISO). This configuration is used to manage continuous signals in the system. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAMS OF CONTINUOUS (ANALOG) FEEDBACK CONTROL SYSTEMS  FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAMS OF CONTINUOUS (ANALOG) FEEDBACK CONTROL SYSTEMS Arrows in a closed-loop system represent the flow of control signals or information between parts. The control flow is not the main power source for the system. Example: In a thermostat-controlled heating system, the main energy comes from burning fuel (oil, coal, gas), which is separate from the control loop. The control loop manages the process, while the main energy source performs the actual work. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM Lowercase letters represent the input and output variables in a closed-loop block diagram. Symbols like g_1, g_2, and h refer to the blocks within the system. These variables and symbols typically represent functions of time, unless stated otherwise. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM Capital letters are used to represent quantities after Laplace or z- transforms. These quantities are functions of the complex variable s (Laplace) or z (z-transform). Fourier transformed quantities are functions of the pure imaginary variable jω. Functions of s or z may be abbreviated to the capital letter alone, but frequency functions are never abbreviated. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 Frequency functions Frequency functions describe how a system responds to different frequencies of input signals. They are often used in signal processing and control systems to analyze the behavior of systems in the frequency domain, rather than in the time domain. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM R(s) may be abbreviated as R, or F(z) as F. R(jo) is never abbreviated. Letters like r, c, e are used in block diagrams to maintain their generic nature. Plant (g_2) - The system or process being controlled by the feedback control system. Controlled Output (c) - The output variable of the plant controlled by the feedback system. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM Forward Path - The path from the summing point to the controlled output c. Feedforward Elements (g_1) - Components in the forward path generating the control signal U or m; includes controllers, compensators, and amplifiers. Control Signal (U or m) - The output of the feedforward elements applied as input to the plant g_2. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM Feedback Path - The path from the controlled output c back to the summing point. Feedback Elements (h) - Establish the relationship between the controlled output c and the primary feedback signal b; typically includes sensors, compensators, or controllers. Reference Input (r) - An external signal commanding the desired action of the plant, usually representing ideal output behavior. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM Primary Feedback Signal (b) - Derived from the controlled output c and algebraically summed with the reference input r to obtain the actuating (error) signal e. Actuating (Error) Signal (e) - The difference (or sum) between the reference input r and the feedback signal b; it drives the control action in the feedback system. Negative Feedback - The summing point subtracts feedback, so e = r - b. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM Positive Feedback - The summing point adds feedback, so e = r + b. Open-Loop System - Lacks a primary feedback signal, making the actuating signal equal to r. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 TERMINOLOGY OF THE CLOSED-LOOP BLOCK DIAGRAM Positive Feedback - The summing point adds feedback, so e = r + b. Open-Loop System - Lacks a primary feedback signal, making the actuating signal equal to r. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAMS OF DISCRETE-TIME (SAMPLED-DATA, DIGITAL) COMPONENTS, CONTROL SYSTEMS, AND COMPUTER- CONTROLLED SYSTEMS Discrete-time control systems include discrete-time signals or components at various points. "Discrete" stands for discrete-time, and "continuous" for continuous-time, when the context is clear. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAMS OF DISCRETE-TIME (SAMPLED-DATA, DIGITAL) COMPONENTS, CONTROL SYSTEMS, AND COMPUTER- CONTROLLED SYSTEMS Example: A digital computer or microprocessor is a discrete-time (discrete or digital) device, a common component in digital control systems. The internal and external signals of a digital computer are typically discrete-time or digitally coded. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAMS OF DISCRETE-TIME (SAMPLED-DATA, DIGITAL) COMPONENTS, CONTROL SYSTEMS, AND COMPUTER- CONTROLLED SYSTEMS Example: A discrete system component (or components) with discrete- time input U(t_k) and discrete-time output y(t_k) signals, where t, are discrete instants of time, k = 1,2,... , etc., may be represented by a block diagram FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 BLOCK DIAGRAMS OF DISCRETE-TIME (SAMPLED-DATA, DIGITAL) COMPONENTS, CONTROL SYSTEMS, AND COMPUTER- CONTROLLED SYSTEMS Example: A discrete system component (or components) with discrete-time input U(t_k) and discrete-time output y(t_k) signals, where t, are discrete instants of time, k = 1,2,... , etc., may be represented by a block diagram  FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 sampler A sampler is a tool that takes a continuous signal, like a smooth wave, and captures specific values from it at regular time intervals. Input Signal: The original signal is continuous and can be represented as u(t). Output Signal: The sampler converts this into a discrete sequence of values, such as u(t_1), u(t_2), and so on, where each t_i is a specific time when the signal is measured. Purpose: This process allows continuous signals to be analyzed and processed using digital systems by breaking them down into a series of discrete points. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 sampler FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 sampled-data signal The figure shows an example of a signal being sampled at different points in time. This type of signal is known as a sampled-data signal. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 sampled-data signal Instead of writing the signal as a function of time t_k, it can be written more simply using an index k. For example, the sequence of sampled values u(t_1), u(t_2), u(t_3), and so on, can be represented as u(1), u(2), u(3), etc. The main idea is that signals can be sampled at discrete time points, and these samples can be represented simply using an index. Uniform sampling assumes equal time intervals between samples. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 hold or data hold A hold device takes the discrete samples from a sampler and turns them into a continuous or smooth signal. Function: It "holds" each discrete value and creates a continuous signal by connecting these values with straight lines or other methods. Purpose: This helps to maintain a steady, continuous signal based on the sampled data, making it easier to process or analyze using analog systems. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 hold or data hold Zero-Order Hold (Simple Hold): This method keeps (or "holds") the value of a sampled signal constant until the next sample is taken. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 hold or data hold Zero-Order Hold (Simple Hold): This method keeps (or "holds") the value of a sampled signal constant until the next sample is taken. Constant Value Between Samples: In the example shown (Fig. 2-11), after taking a sample at time t_1​, the value is held steady until the next sample at time t_2​, and so on.  FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 hold or data hold Piecewise-Continuous Signal: The result of this method is a signal that is continuous (smooth) but changes in steps at each sampling time. This type of signal is called a "piecewise-continuous" signal. Fig. 2-12 shows a block diagram where the signal u(t_k) is passed through a "Zero-Order Hold" block, producing the output y_H0(t), which is the held signal.  FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 analog-to-digital (A/D) converter An analog-to-digital (A/D) converter is a device that converts an analog or continuous signal into a discrete or digital signal. digital-to-analog (D/A) converter A digital-to-analog (D/A) converter is a device that converts a discrete or digital signal into a continuous- time or analog signal. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY A transducer is a device that converts one energy form into another. For example, one of the most common transducers in control systems applications is the potentiorneter, which converts mechanical position into an electrical voltage. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY The command u is an input signal, usually equal to the reference input y. But when the energy form of the command u is not the same as that of the primary feedback b, a transducer is required between the command u and the reference input r. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY When the feedback element consists of a transducer, and a transducer is required at the input, that part of the control system is called the error detector. A stimulus, or test input, is any externally (exogenously) introduced input signal affecting the controlled output c. Note: The reference input r is an example of a stimulus, but it is not the only kind of stimulus. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY A disturbance n (or noise input) is an undesired stimulus or input signal affecting the value of the controlled output c. It may enter the plant with u or m, or at the first summing point, or via another intermediate point. The time response of a system, subsystem, or element is the output as a function of time, usually following application of a prescribed input under specified operating conditions. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY A multivariable system is one with more than one input (multiinput, MI-), more than one output (multioutput, -MO), or both (multiinput- multioutput, MIMO). The term controller in a feedback control system is often associated with the elements of the forward path, between the actuating (error) signal e and the control variable u. But it also sometimes includes the summing point, the feedback elements, or both, and some authors use the term controller and compensator synonymously. The context should eliminate ambiguity.  FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY The following five definitions are examples of control laws, or control algorithms. An on-off controller (two-position, binary controller) has only two possible values at its output u, depending on the input e to the controller. A proportional (P) controller has an output u proportional to its input e, that is, u= K_pe, where K_p, is a proportionality constant. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY A derivative (D) controller has an output proportional to the derivative of its input e, that is, u = K_D de/dt, where K_D is a proportionality constant. An integral (I) controller has an output u proportional to the integral of its input e, that is, u = K_1∫e(t) dt, where K_1 is a proportionality constant. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY PD, PI, DI, and PID controllers are combinations of proportional (P), derivative (D), and integral (I) controllers. A servomechanism is a power-amplifying feedback control system in which the controlled variable c is mechanical position, or a time derivative of position such as velocity or acceleration. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 SUPPLEMENTARY TERMINOLOGY A regulator or regulating system is a feedback control system in which the reference input or command is constant for long periods of time, often for the entire time interval during which the system is operational. Such an input is often called a setpoint. FEEDBACKS AND CONTROLS SYSTEM LESSON 2 FCS71 THANK YOUUUU!!!!