# Dragon Notes

UNDER CONSTRUCTION
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# Control Systems

Subtopics

Basics

System Configurations

Two parallel systems

Negative feedback system

Open-loop system

Closed-loop system

Open- vs. Closed-loop system

 Open-loop Closed-loop - Cannot correct for disturbances- Output corrupted by: $$\hspace{50px}$$(1) signals added to controller$$\hspace{50px}$$(2) disturbances at the output   Examples   $$\bb{1}$$ Controller: electronic amplifier$$\hspace{46px}$$Disturbance 1: noise$$\hspace{22px}\vphantom{\frac{a}{a}}\rightarrow$$Output: corrupt with amplified noise   $$\bb{2}$$ Toaster$$\hspace{46px}$$Controlled variable: toast color  - toast assumed to be darker the longer it is subject to heat   - toaster does not measure toast color  - toaster does not correct for toast type - rye, white,  sourdough, or thickness - Corrects for disturbances by:$$\hspace{30px}$$measuring the output response $$\hspace{12px}\rightarrow$$feeding the measurement back through a feedback path $$\hspace{12px}\rightarrow$$comparing the response to the input at the summing$$\hspace{32px}$$junction $$\hspace{12px}\rightarrow$$If the two responses differ, the system drives the plant via the actuating signal to make a correction - Actuating signal$$\ \vplup=\t{ input signal}-\t{output signal}$$, processed by the first summing junction - Input transducer: converts the form of the input to the form used by the controller - Output transducer / sensor: measures the output response and converts it into the form used by the controller - Greater accuracy & stability than open-loop systems - Transient response and steady-state error subject to greater control and flexibility - Usually more costly than open-loop systems   Examples   $$\bb{1}$$ Controller uses elecrtical signals to operate the valves of  a temperature control system   - input position is converted to a voltage by a potentiometer  - output temperature converted to a voltage by a thermistor