Understanding Control Systems using MATLAB

Introduction

Explore real-life examples to understand and gain insights into fundamental control systems concepts. These MATLAB® Tech Talks cover control systems topics ranging from introductory to advanced.

The first series introduces the working principles behind open-loop and closed-loop control systems. You will also learn the basic components of a feedback control system and how these components are referred to in control theory.

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Part 1: Open-Loop Control Systems

Explore open-loop control systems by walking through some introductory examples. Learn how open-loop systems are found in every day appliances like toasters or showers, and discover how they can be tuned by trial-and-error to achieve a desired output.

The first example shows how open-loop control is used to toast bread to the desired color. The second example outlines how open-loop control can help regulate water temperature in a shower. In these open-loop systems, you will explore the input and output to the system, and learn how to find the required input for a desired output by performing experiments.

Also, explore situations where open-loop control may fail due to unexpected environmental changes or variations in the system. In the next video, you will learn how you can handle the shortcomings of open-loop control by using feedback control.

Part 2: Feedback Control Systems

Explore introductory examples to learn about the basics of feedback control systems. Learn how feedback control is used to automate processes, and discover how it deals with system variations and unexpected environmental changes. Watch other MATLAB Tech Talks: https://goo.gl/jD0uOH Get a free Product Trial: https://goo.gl/C2Y9A5

The examples utilize everyday appliances, like a toaster and a shower, to help you understand the basic structure and working principles of a feedback control loop. The first example shows how a toaster can be controlled to cook bread perfectly by continuously monitoring the bread’s color. It also shows how feedback control deals with system variations (like different types of bread).

The second example outlines how feedback control can help regulate water temperature in a shower. It demonstrates how the feedback control system can compensate for unexpected environmental changes acting on the system – such as someone running a dishwasher at the same time as the shower.

In sum, feedback control measures the actual output of a system (like toast in the first example or water temperature in the second) by using a sensor (eyes in both of the examples). Based on the difference between the desired and the measured output, a controller (human in both of the examples) sends a signal to a device (in these cases, the toaster or the shower). The signal makes the device’s output achieve the desired value despite system variations or unexpected environmental events.

Part 3: Components of a Feedback Control System

Discover the components of a feedback control system and how they interact with each other.

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Learn basic terminology by walking through examples that include driving a car manually and using cruise control. 

The examples explore how driving a car manually or using cruise control forms a feedback control system. 

The video provides insights into the components and terminology in control systems, such as plants, actuators, sensors, and the desired output. You will learn about disturbance signals, which act on the plant and cause undesired effects on the output. You’ll also learn about noise, which is an unwanted signal that can enter the system through measurement.

Part 4: Simulating Disturbance Rejection in Simulink

This demonstration uses a car to show how you can simulate open- and closed-loop systems in Simulink®.

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First, you will learn how to model and tune open-loop systems. The goal of the demonstration is to maintain the speed of a car. Then, you’ll explore the behavior of the open-loop system in the presence of a disturbance. To illustrate disturbance rejection, the video shows how to model and simulate a feedback control system . You will gain insight into how feedback control compensates for disturbance. You’ll investigate signals such as error (in this example, the error is the difference between the measured and desired output), actuating signal (here, the actuating signal is the pedal’s position) and system output (in this example, the output is speed).

Part 5: Simulating Robustness to System Variations in Simulink

This demonstration uses a car to show how you can use Simulink® to simulate robustness to system variations. 

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Get a free Product Trial: https://goo.gl/C2Y9A5 The video models and simulates the car with variations such as different number of passengers. The goal is to maintain the speed of the car at a certain value. The video shows that system variations affect open-loop system behavior and open-loop control needs calibration each time system parameters vary. You will see how feedback control deals with system variations such as a different number of passengers.