INTRODUCTION TO ROBOTICS Part 2 Structural System Robotics

Robot Systems • Structural System • Physical system that provides support and stability • Propulsion System (motion) • Drive system includes motors, wheels, and gears • Control System • Microcontroller, operating program, electrical power, and joystick • Tool and Actuator system • Arms, grippers, manipulators • Sensor and feedback system • Perception, transducers Copyright © Texas Education Agency, 2012. All rights reserved.

Structural System • The structural subsystem of the robot is responsible for physical support. • Holds everything in place • Also provides physical protection • The durable “skeleton” of the robot to which all the other subsystems are attached • The Structure and Motion subsystems are tightly integrated to form the chassis of the robot. Copyright © Texas Education Agency, 2012. All rights reserved. Photo Credit: VEX Robotics, Inc.

Before You Begin • Many types of tools and parts are necessary. • Some tools and parts are required, others are simply nice to have. • The larger the variety of supplies, the more creative the design can be. • Systems can look better and be more • structurally sound. Also increases the need for a tool/part inventory and management system. Copyright © Texas Education Agency, 2012. All rights reserved.

Recommended Tools • Allen wrench set (also called an L-wrench) • Open ended wrench • Screwdrivers • Flat head and Phillips Photo Credit: VEX Robotics, Inc. • Needle nose pliers and diagonal cutters • Wire strippers • Crescent wrench Copyright © Texas Education Agency, 2012. All rights reserved.

Additional Tools • Drill and drill bit set • Saws for metal, wood, and plastic • Examples: • Hacksaw, band saw, chop saw, scroll saw • A variety of screws, nuts, bolts • Vise • Multi-purpose rotary power tool to cut and smooth metal • Wire, soldering iron, electrical connectors Copyright © Texas Education Agency, 2012. All rights reserved.

Example Parts • Types of bolts • 6 -32 and 8 -32 • Keps nuts • Square drive shaft • Bearing flat Photos Credit: VEX Robotics, Inc. • Spacers and friction reducers • Metal sized by number of holes 5 X 15 1 X 25 Copyright © Texas Education Agency, 2012. All rights reserved.

Photos Credit: VEX Robotics, Inc. Copyright © Texas Education Agency, 2012. All rights reserved.

The Robot Base • The platform or base determines the stability, the durability, the maneuverability, and the functionality of the robot. • Usually made from wood or metal • Provides the support structure for the rest of the robot • Everything connects and mounts here • The frame or skeleton Copyright © Texas Education Agency, 2012. All rights reserved.

Robot Stability • Stability is defined as when the center of gravity is over the points of support for the base (called the support polygon). • To increase stability, lower the center of gravity. • Long arms need additional support. • With one point of support an arm will rotate. • If the center of gravity is moved outside the support polygon the robot will tip over. Copyright © Texas Education Agency, 2012. All rights reserved.