First Year Robotics PlatformBy: Andria Farnham, Adam Selinger, Curtis

Langley

Topics of Discussion

• Introduction

• Project Goals

• Project Overview

• Detailed Description

• Summary and Future Works

IntroductionThe First Year Robotics Platform project involves the development of a design project for first year ENGR 120 students involving a simple robot platform. The platform will provide students with a starting point and leave room for further expansion and students input.

ENGR 120 Project Outline

Each group will be provided with a Vex Robotics Design Kit which will be used in the design of a Robot to perform a variety of outlined tasks which may include:

• Point detection• Line tracking• Sonar maze navigation

Vex Robotics Design System

The Vex Robotics Design System is a robotic kit designed as an introduction into the world of robotics. The system offers programming in RobotC for simplified user interface, and comes with a number of building parts and sensors including:

• Structural components: metal braces, wheels, treads, and gears.

• Sensors: ultra sonic, line tracking, light sensors, bumper switches, and limit switches.

• Electrical components: motors, pneumatics, power packs, transmitters, and receivers.

ENGR 120 Project Motivation

This project is designed to give first year students exposure to Electrical and Computer Engineering to give them a better idea which area of Engineering they would like to major in.

Project Goals

Overall Goal

Come up with a design for a robot cart that will be constructed with VEX robotics pieces that students will be able to use with provided sensors in order for the robot to locate a specific end-point location.

Project Goals

Design Goals

Device Design

• Robot should be able to perform 2 -3 different tasks

• Electronic complexity should not be too high, uses 1-2 sensors

• Mechanical complexity should be low, the cart should be easy to build and fit within the provided tool box.

Project Goals

Design Goals

Design Constraints

• Uses packed sensors provided to the students from the department

• Sensor should preferably be able to have a varying view independent of cart movement

• New sensors that are not currently in department inventory can be used in design

• Cart design should be able to be easily modified by the students in order for project expansion

Cost Constraints

• All parts provided by the departments, no costs should be acquired by students

• Reclaimed sensors can be used if the complexity of using them is not too high

• Preferably no new VEX components should be acquired

• Sensors used should be quite low in cost

Project Goals

Design Goals

Project OverviewConsidering all design criteria, each team member independently generated 3 ideas for the cart design and type of target-point utilizing the 5-3-5 design method. The list of initial designs were individually and independently ranked by each team member against the outlined design constraints and project goals.  The individual team member rankings for the 9 cart and point-locater designs were combined and averaged. The resulting averages were ordered from lowest to highest with the top ranking 3 being selected for further analysis.

Evaluate

Design

Weight

Review

Cart DesignsDesign 1: “Moe”

• Modeled after standard VEX “Tumbler” Design.• Four wheels, four drive motors:

• One per each wheel• Fixed Front-Facing Sensor Array

Design 2 : “LS Navigator”• Modeled after standard VEX “Tumbler” Design.• Four wheels, three drive motors:

• One per front wheel• Single rear-drive via differential

• Rotating Sensor Mount for 360° field of view

Design 3 : “Flying Wedge”• Triangular shaped• Three Wheels, one drive motor:

• Single rear drive via differential• Single direction controlled front wheel.

• Rotating Sensor Mount for 360° field of view

Task DesignsDesign 1: “Hot-Spot”

• Robot finds a definite point.• Possible challenges:

• Radiation (Heat) source.• Intersection of two lasers.• Light intensity (high/low) detection.

Design 2: “Line Snooper”• Robot tracks a solid colour line• Possible challenges:

• Manages broken lines.• Manages 90o turns.• Determines correct path between varying shades of grey.

Design 3 : “Maze Runner”• Robot Completes a non pre-defined maze.• Possible Methods of attack:

• Trial and error (Try-Bump-Stop).• Sonar.

Design Evaluation

A standard weighting scheme was generated through close analysis of the proposed design goals and criteria. To further refine the weighting metrics, a Criteria Prioritization Questionnaire was completed by the project’s acting supervisor: Dr. M. McGuire. 

Each of the top 3 designs for both the cart and task categories were then individually and independently evaluated by each team member. These independent evaluations were summed, averaged and had the appropriate category weighting metric applied. 

The final weighted rankings were compared with the highest being taken as the design which best fits both the assumed and department defined project goals and objectives.

Evaluation Results

Design

Cost Operation

Total

Moe 0.594 0.608 0.1 1.302

LS Navigator

0.441 0.608 0.2 1.249

Flying Wedge

0.288 0.495 0.2 0.983

Design

Cost

Hot Spot 0.735 0.75

Line Snoop 0.525 0.75

Maze Runner

0.295 0.5

• Ease of construction • Footprint• Complexity of Mechanical and Electrical systems• Programming complexity• Additional base cart costs• Additional sensor costs• Number of tasks completed

• Ease of detection• Requires prioritization• Arena complexity• Arena re-usability• Difficulty of point location change•Uses recycled parts• Construction costs• Value per dollar spent.

Final Cart DesignModified version of the LS

Navigator.

• Offers good balance between mechanical electrical complexity and experience

• Moderate build time – Between 1 and 2 hours

• Zero additional VEX parts required for cart construction

• Small form factor fits inside provided equipment case

• Versatile design based off of an existing standardized VEX robot.

Final Point of Interest Design

Hot Spot Locator

• Low cost

• Simplistic design

• Offers a range of complexity

• Low costs associated with task changes

• Varying levels of system complexity available

SummaryThree leading designs were created for cart design and point detection. Based on a weighting algorithm that incorporated a number of aspects such as cost, feasibility, and function, a final decision was made for cart design and point detection method.

Future Works (499 continuation)

• Generate prototype designs

• C-code template

• Testing

• Arena specifications and design

• Instruction Manual outlining building design and tasks to be performed

Questions

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