autonomous control of scalextric slot car on user-defined track
DESCRIPTION
Autonomous Control of Scalextric Slot Car on User-Defined Track. Siddharth Kamath Souma Mondal Dhaval Patel. School of Electrical and Computer Engineering Georgia Institute of Technology. http://www.scalextric-usa.com/. What is Slot Car Racing?. Motor. Electric Contacts. Power Pack. - PowerPoint PPT PresentationTRANSCRIPT
Autonomous Control of Autonomous Control of Scalextric Slot Car on Scalextric Slot Car on
User-Defined TrackUser-Defined Track
Siddharth KamathSiddharth Kamath
Souma MondalSouma Mondal
Dhaval PatelDhaval Patel
School of Electrical and Computer Engineering
Georgia Institute of Technology
http://www.scalextric-usa.com/
What is Slot Car Racing?What is Slot Car Racing?Electric Contacts
Motor
Rails
Resistor
Control
ler
Power Pack
http://www.wikipedia.com
Project OverviewProject Overview
Race slot car autonomously against Race slot car autonomously against human playerhuman player
Target existing customers who Target existing customers who cannot easily find opponentscannot easily find opponents
Keep user base active and boost Keep user base active and boost number of repeat customersnumber of repeat customers
System ImplementationSystem ImplementationPosition Data
Digital In
USBAnalog Out
Electric Contacts
Motor
Power Pack
http://www.wikipedia.com
Powered Rails
Design Advantages
Line detector and reflective strips Cheap to implement Easy for end user Scalable
LabVIEW and NI DAQ Rapid prototyping environment Integrated data collection Potential software updates
Main SubsystemsMain Subsystems
Control AlgorithmControl
Algorithm
Data Transmissi
on
Data Transmissi
on
Position/Speed
Detection
Position/Speed
Detection
Position and Speed Detection
Position – Increment counter once per Position – Increment counter once per checkpointcheckpoint
Velocity – Velocity – (One value per (One value per checkpoint)checkpoint)
5V
0VTime
Reflective Strip
50mm
Δt
50mm
Δt
Spacing Requirements
Max slot car speed = 2500 mm/sMax distance between checkpoints =
170 mmMax ping rate = 15 pings/secTransmission rate = 56,000 bits/sec
< 17cm
Checkpoint n Checkpoint n+1
Checkpoint Detect
HIGH
5V
0VTime
Checkpoint Pass
LOW
5V
0VTime
Data TransmissionData Transmission
Data transmitted from car to PCData transmitted from car to PC Wireless transfer using Linx HP3Wireless transfer using Linx HP3 Data read in through NI DAQ into Data read in through NI DAQ into
LabVIEW on PCLabVIEW on PC
Voltage from PC to trackVoltage from PC to track Control voltage from NI DAQControl voltage from NI DAQ DAQ output voltage amplified to DAQ output voltage amplified to
meet voltage specifications of meet voltage specifications of tracktrack
http://www.linxtechnologies.comhttp://www.ni.com
Wireless Transmission Captures
Crack within pulse
16 pulses/la
p
Power SupplyPower Supply CR2450 Button cell – Powers the line CR2450 Button cell – Powers the line
detector, wireless transmitter on cardetector, wireless transmitter on car 5V Voltage regulator – Power efficient, 5V Voltage regulator – Power efficient,
steady outputsteady output
http://www.wikipedia.com
Voltage Regulator
Amplifier LM 741 – Non-inverting amplifier circuit Input – 0-5V from NI DAQ Output – 0-12V to track
Amplifier Screen Capture
Input to Amplifier (0-5V)
Output from Amplifier (0-12V)
Control AlgorithmControl Algorithm
Get Upcoming
Track Layout
Get Upcoming
Track Layout
Position
Speed
Calculate Track
Complexity
Calculate Track
Complexity
Determine Optimal Track
Voltage
Determine Optimal Track
Voltage
Desired Track Voltage
Track Input by User
Calculating ComplexityCalculating Complexity
x – Distance from the front of the car
K – Curvature of the track at that point
50cm – The horizon
c - Tunes the importance of the Tunes the importance of the curvature relative to distance curvature relative to distance from carfrom car
Complexity Complexity ImplementationImplementation
CurrentlyCurrently Precision of position is one track segmentPrecision of position is one track segment Next three track segments consideredNext three track segments considered Single voltage calculated per track Single voltage calculated per track
segmentsegment
In progressIn progress Estimate position between checkpointsEstimate position between checkpoints Consider fixed distance ahead of carConsider fixed distance ahead of car Attain more accurate speed profileAttain more accurate speed profile
Data Errors
Problem Solution
Missing a checkpoint– Change batteries – Adjust line detector
False checkpoint detection
– Apply noise filter (10ms threshold)– Recombine cracked pulses (2ms threshold)
Example Data
Pulse due to noise
(<10ms)
Crack in Pulse
(<2ms)
Voltage
Time
Race Replay Feature
Sample track voltage during a race Data acquired at 10,000 Hz Save profile to file Plays profile back
Potential uses of race replay feature Compete against their own race profiles Compete against other competitor
saved profiles
Budget and Cost AnalysisBudget and Cost Analysis NI USB 6008 (DAQ)NI USB 6008 (DAQ) $150$150 HP3 Series Receiver HP3 Series Receiver $30$30
Base StationBase Station $180$180
HP3 Series Transmitter HP3 Series Transmitter $25$25 Line Tracker Line Tracker $20$20 Five 3V Coin BatteriesFive 3V Coin Batteries $5$5
CarCar $50$50
Unit CostUnit Cost $230$230
Demonstration PlanDemonstration Plan Main demoMain demo
System drives slot car around circuit System drives slot car around circuit without derailingwithout derailing
In case of derailing, slot car can be In case of derailing, slot car can be placed onto last checkpoint and resume placed onto last checkpoint and resume normal operationnormal operation
Supplemental demoSupplemental demo Race slot car against a human opponent Race slot car against a human opponent Scale system’s performance based on Scale system’s performance based on
difficulty settingdifficulty setting
ResultsResults
Parameter ValuePosition Sensing – Checkpoint
detection99.4%
Velocity Sensing Error 0.6%
Pulse Error Rate 12.5%
Control Voltage onto Track0-12V (DC)
Speed Range0-
2500mm/s
Failures per Lap 0.1
Car Development
Original weight of car= 85g New weight of car = 110g
Attach line detector and circuit board to slot car with Velcro
Line detector no more than 0.5’’ above track
Optional use of antennae for receiver and transmitter
Car Dimensions
75mm
Car ViewsBattery
with Switch
Line Detector
Wireless Transmitt
er
Voltage Regulator
System OverviewSystem OverviewPosition Data
Digital In
USBAnalog Out
Electric Contacts
Motor
Power Pack
http://www.wikipedia.com
Powered Rails
System Hierarchy
Position Data
Digita
l In
USB
Analog Out
Demonstration Video
Current TasksCurrent Tasks
Better position estimates required to improve control
Ability to differentiate start checkpoint from other checkpoints
Control algorithm needs more fine tuning
Current StatusCurrent Status
Position detectionPosition detectionVelocity detectionVelocity detectionData transmissionData transmissionApplying amplified voltage to Applying amplified voltage to tracktrackDisplay last checkpoint passedDisplay last checkpoint passedCar developmentCar developmentRecord and play voltage profileRecord and play voltage profileImprove control algorithmImprove control algorithm
Questions?Questions?
Position Detection Position Detection SensorSensor
http://www.lynxmotion.com/
Line DetectorLine Detector
LOW
HIGH
IR LED
Phototransistor
Wireless Transmitter
Car Components