TigerBot IV Rochester Institute of Technology
Group Members Mike 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)
Objectives Balance and walk with human gait Recover to upright position after a fall Autonomous, untethered operation for up to 30 minutes Support 125% of total robot weight Obstacle avoidance Voice activated Able to withstand a fall Designed, built, and debugged currently 20 weeks Budget: $2500 (Actual Budget: ~$3100)
TigerBot Family TigerBot TigerBot 2 TigerBot 3
Human Theme Shell 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 Back Plate Front Chest Component Layout
System Design 23 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 Concept Lighter weight 18.5 lbs Improved joint performance Future expandability with rod design
Structural Design Knee - Exploded View Elbow Close Up
Inverse Kinematics Concept
Integrated Controls 32-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 Design Power 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 Hall Effect Custom PCB - Powerboard Custom PCB Current Sensing
Results Current State Operates autonomously Responds to multiple commands Challenges Time constraint Manufacturing limitations
Results: Customer Needs Customer Need # Importance Description Comments/Status CN1 1 Mobile - can walk straight and turn CE's did not get to this code (time) CN2 Autonomous CN2.1 1 Voice Activated CN2.2 1 Non-tethered CN2.3 1 Obstacle avoidance capable Capability is there, not coded CN2.4 1 Self-balancing Capability is there, not coded CN2.5 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 Freedom CN5.1 1 4 DOF for each leg and arm CN5.2 1 2 DOF for head: up/down and right/left CN5.3 1 2 DOF for torso: up/down and right/left CN6 Humanoid Design CN6.1 1 Human Torso Design CN6.2 1 Human Leg and Ankle design Slightly Large Ankles CN6.3 1 Humanoid Shell / Armor to cover robot CN6.4 1 Humanoid Proportions Shell and Head offset proportions to legs CN7 Manuals In Progress CN7.1 1 Operation Manual In Progress CN7.2 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 Recommendations CE s to work on coding on previous TigerBot early in MSDII Relieve end of quarter scramble after mechanical build is completed Tower 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?