TigerBot IVRochester Institute of Technology

Group MembersMike Lew (ISE)Dan Wiatroski (ME)Tom Whitmore (ME)Geoff Herman (ME)Sean Lillis (CE)Brian Stevenson (EE)James O’Donoghue (CE)Mohammad Arefin (EE)Sasha Yevstifeev (EE)

ObjectivesBalance and walk with human gaitRecover to upright position after a fallAutonomous, untethered operation for up

to 30 minutesSupport 125% of total robot weightObstacle avoidanceVoice activatedAble to withstand a fallDesigned, built, and debugged – currently

20 weeksBudget: $2500 (Actual Budget: ~$3100)

TigerBot Family

TigerBot

TigerBot 2

TigerBot 3

Human ThemeShell theme

“Ironman”, enables easy definition of future shell enclosures

Designed using Pepakura software

Made from 0.016” aluminum to be as light as possible

Head Design

Front Chest

Back Plate

Component Layout

System Design23 Rotational Degrees of Freedom (4

per arm, 6 per leg, 1 in torso, 2 in head)

Full load bearing joint design at every axis of rotation, allowing completely free and unrestricted servo rotation◦ Servo motors take no structural loads

Low center of gravity ~2 inches below pelvis plate (avoids falling, assists recovery)

Higher torque servos (legs) and lower torque servos (upper body)

Structural ConceptLighter weight

◦18.5 lbsImproved joint

performanceFuture

expandability with rod design

Structural Design

Knee - Exploded View

Elbow – Close Up

Inverse Kinematics Concept

Integrated Controls32-bit Roboard Vortex86

CPU with 256MB DDR2 RAM and 16GB Class 10 SD Card running Ubuntu

ATmega2560 Arduino with 16 analog input ports

9-Axis IMU (Accelerometer, Magnetometer, and Gryoscope)

EasyVR Voice Recognition with 26 pre-programmed commands and up to 9 minutes of audio playback

Roboard RB-100 CPU

9-Axis IMU

EasyVR Voice Recognition

Software Design

Electronic Block Diagram

Electrical DesignPower Distribution Fuse and switches for

circuit protection Low battery indicator I2C communication bus

with up to 4 slaves

Current Monitoring Determine servo strain

to determine forces acting on robot

Measure currents drawn by each servo

Capable of sensing current for up to 25 servos

High side and low side current sensing

Custom PCB - Powerboard

Custom PCB – Current Sensing

Hall Effect

ResultsCurrent State

◦Operates autonomously◦Responds to multiple commands

Challenges◦Time constraint◦Manufacturing limitations

Results: Customer NeedsCustomer

Need #Importance Description Comments/Status

CN1 1 Mobile - can walk straight and turn CE's did not get to this code (time)

CN2 AutonomousCN2.1 1 Voice ActivatedCN2.2 1 Non-tetheredCN2.3 1 Obstacle avoidance capable Capability is there, not codedCN2.4 1 Self-balancing Capability is there, not codedCN2.5 1 Wireless Comunication

CN3 2 Can survive and get up from backward, forward, and sideways fall Un-tested

CN4 2 Fall resistance Un-tested

CN5 Target 20 Degrees of FreedomCN5.1 1 4 DOF for each leg and armCN5.2 1 2 DOF for head: up/down and right/leftCN5.3 1 2 DOF for torso: up/down and right/left

CN6 Humanoid DesignCN6.1 1 Human Torso DesignCN6.2 1 Human Leg and Ankle design Slightly Large AnklesCN6.3 1 Humanoid Shell / Armor to cover robotCN6.4 1 Humanoid Proportions Shell and Head offset proportions to legs

CN7 Manuals In ProgressCN7.1 1 Operation Manual In ProgressCN7.2 1 Software Manual for Software Libraries In Progress

CN8 1 Able to hold 1/4 total weight of robot

CN9 1 Center of balance below the waist

CN10 1 Uses a small factor computer with an OS

CN11 2 Stay with in budget of 2500 Total Spent: $3100

Future RecommendationsCE’s to work on coding on previous

TigerBot early in MSDII◦ Relieve end of quarter scramble after

mechanical build is completedTower layout for electrical boards

◦ As more and more boards/components are introduced, wiring becomes difficult

Individual current shutoff for each servo

More design focus on servo coupling

Questions?