The Robotics Primer Workbook Developed by  USC, iRobot® and Microsoft® Robotics Studio

Reactive Control

Contents 1 Purpose 2 Overview 3 Hardware 4 Exercise1 Safety and Obstacle avoidance 5 Exercise2 Wall following

Purpose

Study reactive controllers, and how they can be used to fast and responsive systems. Refer to chapter 14 of "The Robotics Primer".

Overview

Reactive controllers are probably the most widely used type of contollers for robotics. They are capable of reacting very quickly to state changes, and this is where the name is derived from. In order to achieve this fast response time, reactive controllers have very tight code loops and are limited to making relatively simple decisions. One of the most common areas of application is obstacle avoidance. Almost every robot must be able to avoid hitting objects in the environment. The key problem is that the world is dynamic (things move about), and the robot can move at fairly high rates. Therefore, the robot must have a very efficient and robust controller capable of stopping it before collisions occur. In these exercises we will implement a controller for obstacle avoidance, and one for wallfollwing.

Hardware

Exercise	Command Module	Gumstix	Misc
Exercise 1	Yes	Yes	IR Sensor
Exercise 2	Yes	Yes	IR Sensor

Exercise1 Safety and Obstacle avoidance

We will begin with a simple safety task, obstacle avoidance. These exercises will examine how to use the various sensors on the Create as well as add-on sensors for added safety. Once you complete the exercise, you will understand how to use reactive control for simple, safe movement of a robot. Reactive:Exercise1-Safety and Obstacle Avoidance

Exercise2 Wall following

For this exercise, will will employ a more complex form of reactive control, wall following. This exercise will use the sensors described above in order to move the robot in a more principled way. Reactive:Exercise2-Wall Following