IAB-RC Inverted Autonomous Balancer Remote Controlled
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Transcript of IAB-RC Inverted Autonomous Balancer Remote Controlled
IAB-RCInverted Autonomous Balancer
Remote Controlled
April 18, 2008
Jude CollinsChristopher Madsen
Final Presentation
➲ Technical aspects of the robot➲ Prior art➲ Schedule➲ Finances
Overview
➲ Robot system overview—Chris Capabilities How it works Robot hardware
➲ Remote control—Jude Controller hardware PC N64 Controller PDA
Overview
➲ Literature/product search—Chris “Trajectory Tracking Control for Navigation of
Self-contained Mobile Inverse Pendulum” (1994).
Segway (2002). David P. Anderson's “nBot” (2003).
➲ Schedule and finances—Jude➲ Questions
Robot overview
Capabilities
➲ Balance➲ Stand up➲ Lay down➲ Slide➲ Jump curbs➲ Crash➲ ?????
How does it work?
➲ Hardware calculates “lean” of the robot➲ Wheels turn to prevent “lean”➲ Forcing the robot to lean causes the robot to
drive➲ The robot learns to lean into external forces
to keep balanced➲ Spinning one wheel faster than the other
causes the robot to turn➲ Kicking the robot may make the robot angry
Robot system overview
Microcontroller
➲ MSP430F1611➲ Running 4 MHz➲ 12 bit A/D with 8 pin-
accessible inputs➲ Two 16 bit timers➲ 1.8-3.6v➲ Programmed in C
Inertial Measurement Unit
➲ IDG-300Gyroscope
➲ ADXL-330Accelerometer
IDG-300 Gyroscope
➲ Dual-Axis rate gyroscope➲ Operates by oscillating masses and
capacitively measuring vibration caused by Coriolis effect.
➲ Sensitivity: 2 mV/deg/s➲ Max rate: 500 deg/s➲ Operating voltage: 3.0-3.3v
ADXL-330 Accelerometer
➲ Triple-axis accelerometer➲ Micro-machined structure suspended
over silicon by polysilicon springs. Plates mounted on moving structure and a fixed structure act as a variable capacitor in a filter circuit to measure acceleration.
➲ Sensitivity: ~300mV/g➲ Max acceleration: ±3.0g➲ Operating voltage: 2.0-3.6v (sensitivity is
ratiometric)
PID Controller
Estimating pendulum orientation
➲ Integrating rate gyros is subject to drift errors.
➲ Accelerometers only work to determine orientation when not accelerating.
➲ Using both estimates together gives better estimate of orientation.
Bluetooth Radio
➲ Basically a breakout board for NXP's BGB203.
➲ Class 1 so has a 100m range
➲ 100 mW max transmitted power
➲ 3.3 volts➲ 1 Mbps max UART
Remote Control
Computer
➲ Communicates via Bluetooth dongle➲ Used for early verification of control law➲ Jitter in transmission limited stability
The Remote Control
➲ Needed Peripherals Joystick A few buttons
➲ Modify old N64 controller.
Exceeds requirements Cheap ($5-$15 on
Amazon.com)
Control Flow
The microcontroller
➲ Needed peripherals UART High clock frequency Low Vcc
➲ ATMEGA8515L UART 20 MHz 2.7 – 5.5 V Low Cost ($3.06-$5.27 Digikey.com)
PDA
➲ Can also be used to remotely control robot.
➲ And ?????
Prior art
➲ First appearance of similar two-wheeled inverted pendulum that can navigate in 2 dimensions on a plane: “Trajectory Tracking Control for Navigation of Self-contained Mobile Inverse Pendulum” by Yunsu Ha and Shin'ichi Yuta of Japan in 1994.
Position encoders on wheels (2000 step) Sensors to detect obstacles No remote-control
Prior art
➲ Segway Most popular inverted-pendulum type product. Patented just about everything imaginable
concerning inverted pendulum human transportation.
Have several Robotic Mobility Platform (RMP) models
Prior art
➲ David P. Anderson's nBot Received NASA's Cool Robot of the Week award
and subsequently became well-known in the minds of robotics enthusiasts (2003).
Launched a revolution of inverted-pendulum robot building.
Homebrew shaft encoders.
How are we different?
➲ Back EMF encoders rather than mechanical encoders.
➲ Bluetooth radios enabling hardware-in-the-loop simulation.
➲ Stands up autonomously.➲ Lays itself down gently.➲ And ?????
Schedule
Date Goal (Wireless controller) Goal (Robot)
February 8, 2008 Functioning prototype robot
February 15, 2008 N64 Controller prototype Math model complete
February 22, 2008 N64 Controller testing completeDecision on use and design ofencoders
February 29, 2008Make provisions for wireless controllercommunications
March 7, 2008N64 Controller communicationscomplete
N64 Controller communicationscomplete
March 14, 2008 Preliminary Design Presentation Preliminary Design Presentation
March 21, 2008Incorporate other wireless devices(PDAs, etc)
Robot can lay itself down gently
March 28, 2008 Robot can "pop a wheelie"
April 4, 2008 Bigger batteries?
April 11, 2008 Final Testing - Hand it over to mom.
April 18, 2008 Demonstration Demonstration
Finances—RobotItem Type Quantity Individual Price Item Total
Gearhead Motors 12v Globe Motors #415A410 2 ~$25.00 ~$50.00
Wheel Mounts 5mm RC Airplane propellerholder
2 ~$8.00 ~$16.00
Wheels 15500 Golden Age5" (WBR15500)
2 (one pack from RC hobbies) $13.23 $26.46
Frame Aluminum (L shaped and flatpieces from Home Depot)
---- ~$3.00 ~$10.00
Microcontroller MSP430 (on Softbaugh B169breakout board)
1 $49.00 $49.00
Bluetooth Controller Sparkfun WRL-08461breakout board based onNXT's BGB203
1 $59.95$59.95
Inertial Measurement Unit
Sparkfun SEN-00741breakout board based onAnalog Device's IDG300 2axis rate gyro and ADXL330 3axis accelerometer
1 $109.95 $109.95
H-Bridge LMD18200 2 $14.40 $28.80
Voltage Regulator LM317 1 ~$1.00 ~$1.00
Resistors and capacitors ---- ~$1.00 total $1.00
Batteries NiCd 9.6v batteries 2 $8.00 $16.00
Total: $368.16
Finances—Remote Control
Item Type Quantity Individual Price Item Total
Nintendo64 Controller Original Nintendo 1 ~$10.00 ~$10.00
Bluetooth Controller Sparkfun WRL-08461breakout board based onNXT's BGB203
1 $59.95 $59.95
Voltage Regulator LM317 1 ~$1.00 ~$1.00
BJT Transistor 2N3904 1 ~$1.00 ~$1.00
20 MHz Crystal Oscillator ?? Japan Made 1 $2.00 $2.00
Capacitors and Resistors ----- ----- ----- ~$1.00
Microcontroller ATMEGA8515L 1 $5.27 $5.27
Total: $80.22
Finances
➲ Allotted budget: $1000➲ Expenditures: ~$500➲ Main expenses:
1 IMU -- $110 2 Bluetooth radios -- $120 1 MSP430 on breakout board -- $50 2 Motors and H-Bridges -- $80
Questions?