2006 IEEE SouthEastCon Robotics Competition Design Document submitted to Dr James Harden ECE 4532 4512 Senior Design I Department of Electrical and Computer Engineering 413 Hardy Road Box 9571 Mississippi State University Mississippi State Mississippi 39762 December 1 2005 prepared by R Bhakta K Cullen V Alfaro R Stranghoener M Lindsey R Owen S Reid B Nichols Faculty Advisor Dr Robert Reese Department of Electrical and Computer Engineering Mississippi State University 413 Hardy Road Box 9571 Mississippi State Mississippi 39762 Executive Summary FedEx has provided a challenge for the IEEE SoutheastCon 2006 Competition The task is to design an autonomous package loading robot that will barcode scan collect and deliver a total of 12 packages to three airplanes before departure The first plane will depart in three minutes the second in four minutes and the third in five minutes The challenge will be simulated using plywood for the airplane loading area a FedEx triangular shipping tube for the package chute cardboard boxes for airplanes and wooden blocks for the packages Universities from across the Southeast will be competing to determine who can create the best robot The winner will be determined by three rounds of competition scored on speed and accuracy of package delivery Mississippi State University s SECon team has designed a robot that quickly and effectively completes the task The robot adheres to SoutheastCon s starting size requirements of 8 x 8 x 12 and avoids added complexity by only extending one arm for package retrieval Despite its lack of expansion the robot is able to collect sort and store all 12 packages during a single visit to the chute This approach requires only 1 12 th of the delivery time needed for a single block collection approach without adding a significant amount of loading and sorting time By stacking the packages externally for storage each plane s packages can be unloaded in a single action This unloading approach requires 1 4th of the time needed for a single block delivery system The robot has been tested on a plywood playing field built to SECon s specifications Numerous package orderings were tested for the chute to ensure the robot s ability to handle any sequence of package collection Figure 1 below shows the playing field and the robot Thorough navigation simulations have been conducted to guarantee that the locomotion software can reliably deliver the robot to each loading and unloading station Due to the nature of the SECon competition reliability is the keystone to the robot s success Victory hinges on the ability to complete the task successfully in three Figure 1 Playing Field and Robot consecutive attempts In order to achieve the necessary reliability power conservation is extremely important to ensure all motors and circuitry function properly throughout an entire round To conserve power the robot disables motors servos and the barcode scanner when they are not in use A first place victory at SoutheastCon 2006 in Memphis on March 30 th would bring deserved recognition and praise to the dedicated faculty and students of the electrical and computer engineering department of Mississippi State University Table of Contents 1 Problem Statement 8 1 1 Historical Information 8 1 2 Problem Definition Rules Regulations and Design Constraints 8 1 3 Competitive Analysis 9 1 4 Implications of Success 10 2 Design Constraints 10 2 1 Technical Design Constraints 10 2 1 1 Dimensions 10 2 1 2 Navigation 11 2 1 3 Speed 11 2 1 4 Package Identification and Manipulation 11 2 1 5 Weight 11 2 1 6 Power 12 2 2 Practical Constraints 12 2 2 1 Cost 13 2 2 2 Health and Safety 13 2 2 3 Ethical 13 2 2 4 Reliability and Repeatability 13 2 2 5 Environmental 14 3 Approach 14 3 1 Functional Overview 14 3 2 Hardware 14 3 2 1 Mechanical Approach 14 3 2 1 1 Dump Truck 15 3 2 1 2 Pentagon 17 3 2 1 3 Three Chute Design 20 3 2 2 Upper Base 25 3 2 2 1 Turntable 26 3 2 2 2 Turntable Servo 28 3 2 2 3 Multiple Platforms 28 3 2 3 Storage Chutes 29 3 2 3 1 Chute Design 30 3 2 3 2 Chute Servos 32 3 2 3 3 Elevators and Linear guides 32 3 2 3 4 Elevator Stepper 33 3 2 4 Lower Body Design 33 3 2 4 1 Wheels and Supports 34 3 2 4 2 Sensor Placement 36 3 2 5 Package Retrieval and Identification System 36 3 2 5 1 Extractor Gripper 36 3 2 5 2 Linear Actuator 37 3 2 5 3 Barcode Scanner 38 3 2 6 Locomotion 39 3 2 6 1 Motors selection 39 3 2 6 1 1 DC Motors 39 3 2 6 1 2 Hobby Servos 40 3 2 6 1 3 Stepper Motors 40 3 2 6 2 Stepper motor operation 41 3 2 6 2 1 Bipolar Motors 41 3 2 6 2 2 Unipolar Motors 41 3 2 6 2 2 1 VEXTA PK244PA Motor 41 3 2 6 2 3 Stepper Motor Control Driving 42 3 2 7 Sensors 44 3 2 7 1 Line Sensors 44 3 2 7 2 Ultrasonic Range Finder 44 3 2 7 3 Sensor Placement Locations 46 3 2 8 Power Supply 47 3 2 8 1 Required Voltages 47 3 2 8 2 Voltage Regulation 47 3 2 8 3 Battery Selection 49 3 2 9 Microcontroller 51 3 2 9 1 PIC18LF4620 51 3 2 9 2 PIC18LF242 51 3 3 Software Design 52 3 3 1 Locomotion 52 3 3 1 1 Stepper Motor Control 52 3 3 1 2 Global Variables 53 3 3 1 2 1 x 53 3 3 1 2 2 y 53 3 3 1 2 3 x new 53 3 3 1 2 4 y new 53 3 3 1 2 5 DISTANCE PER REVOLUTION 53 3 3 1 2 6 direction Front 53 3 3 1 2 7 turn Direction 53 3 3 1 2 8 forward 53 3 3 1 3 Functions 54 3 3 1 3 1 Function turn 54 3 3 1 3 2 Function get Distance 54 3 3 1 3 3 Function get Angle 55 3 3 1 3 4 Function goTo 55 3 3 1 4 Sensors 55 3 3 1 4 1 Line Sensors 55 3 3 1 4 1 1 Line Following 56 3 3 1 4 1 1 1 Mode 1 56 3 3 1 4 1 1 2 Mode 2 56 3 3 1 4 1 1 3 Mode 3 56 3 3 1 4 1 1 4 Mode 4 56 3 3 1 4 1 1 5 Mode 5 56 3 3 1 4 1 1 6 Mode 6 57 3 3 1 4 1 1 7 Mode 7 57 3 3 1 4 1 1 8 Mode 8 57 3 3 1 4 1 2 Angle Calculation 57 3 3 1 4 2 Sonar Sensors 57 3 3 1 4 2 1 I2C Configuration 57 3 3 1 4 2 2 Gain Register 58 3 3 …
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