Team 2: Hoard Robotics

Trenton Andres

Jamis Martin

Jay Zifer

Brad Nowak

Project Overview

Swarm of 8 identical wheeled robots Each robot (agent) follows a set of

simple behavioral patterns The robots work together to accomplish

tasks through emergent behavior

PSSCs An ability for each agent to avoid obstacles

autonomously. An ability to detect direction and proximity of

other objects to agent using IR sensors. An ability to transmit data packets among

agents using an ad-hoc RF network. An ability to utilize swarm behavior to find a

simulated chemical spill. An ability to utilize swarm behavior to avoid

a predator.

Agent Block Diagram

Design Constraint Outline

Major Design Considerations Interface Requirements Computation Requirements On-Chip Peripherals Off-Chip Peripherals Power Constraints Packaging Constraints Cost Constraints Component Selection

Major Design Constraints

Minimum number of agents to successfully display swarm behavior

Cost:Cost increase; swarm size decreases

Production and fabrication:Simplicity vs functionality

Computation Requirements Gather sensor data Proximity calculations from sensor data Network communication “Safe” Motor Control Behavioral algorithms

Interface Requirements

Each Micro must:Communicate with the rest of the swarm

through wireless moduleControl left and right drive speed and

directionShow behavior dependent information on

indicator LEDsGather agent/object proximity through IR

receiversControl IR emitters

On-Chip Peripheral Requirements 8 A/D Inputs (2 for ambient light, 6 for IR) 2 PWM Outputs (L/R motor speed control) 4 SPI Lines for Wireless module 5 Pins for programming header 9 General Purpose I/O

2 Forward/Reverse Select Lines for H-Bridge3 DIP inputs (Reset and debugging)3 LED indicator lights (Behavior-Mode

dependent, Network activity, Errors)1 IR Emitter array enable

Off-Chip Peripheral Requirements RF Module for inter-agent

communicationTransceiver ChipAntenna

H-Bridges for motors LED Drivers Power supply and battery sensing

Power Constraints

Mobile application dictates using batteries

We intend to use standard 9 Volt batteries:Not preferredRequired for economic reasons

Will require an on-board power supply:Microcontroller and RF Module will run at

3.3V

Packaging Constraints Replicable, Replaceable, Interchangeable

All parts should be able to be easily swapped between agents in case of breakdown

Minimize size:Agent size should be determined by functional

components, not packaging Minimize weight:

Minimize motor sizeUse less power

Cost Constraints

Current target per robot is approximately $40

Small increases in cost manifest as large increases for entire swarm

Less expensive robots -> more robots -> more effective swarm

Intention of project is to do less with more

Component Selection: Drive Train

Solarbotics GM3Motor and gear-head

combinationSpecifically design for

robotic applicationsCost effectiveCommonly used224:1 Gear RatioInternal Clutch to

prevent motor stall

Component Selection: Microcontroller PIC18F26J13 Microcontroller

48 MHz (12 MIPS)64k program memory3.8 RAMSuitable number of A/D and GPI/O pinsPrevious experience with PIC familyEconomically priced

Component Selection: RF Module

MRF24J40MAComplete 2.4 GHz

TransceiverSmall sizeLow powerMatched to

microcontroller series

QUESTIONS?