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Microsoft PowerPoint - Data Acqu

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					Data Acquisition in Motorsports

             MET 490S
             Spring 2007




   Data Acquisition – Goals
Demonstrate the need for data
acquisition in motorsports
Introduce sample data sets and analysis
Relate data acquisition to vehicle
dynamics and other principles




                                          1
 Data Acquisition Background
Race Team Top 3 Budget Allocations
  Engine
  Chassis
  Electronics
Data Acquisition Tidbits
  Began ~mid-late 1980s
  Sensors, data-loggers, controls, etc.
  Became a profession in itself - DAG




     Why Data Acquisition?




                              Δt = 0.09 sec = 0.2%




                                                     2
                       Why Data Acquisition?




                                     ΔSpeed = 0.9 mph = 0.4%




                       Why Data Acquisition?
EXAMPLE: Lateral Accelerometer
Speed                  Turn Radius


                                                                         F & R Lat Geom SW T

Lateral                                          Lat SW Trans.                                    F Elast Lat SW T
Accelerometer                                                                                     (strain gauges)
                        Lat NS W Trans.                                  Lat Elast SW T

                                                                                                  R Elast Lat SW T
        F & R NS Weight                 S Weight                                                  (strain gauges)
        NS Weight Cg Height             S Weight Cg Height


                          Front Track                                            F & R Antiroll Moment
                                                         F Roll Center
                          Rear Track                     R Roll Center


        Spring Rate     Spring / Wheel         Antiroll Bar      Antiroll Bar        Bump Rubber Equation
        Preload         Motion Ratio           Rate              Motion Ratio        Clearance




                                                                                                                     3
                   Why Data Acquisition?                                            Inline Geom SW Trans.

 Inline                                               In line SW Trans.
 Accelerometer         Inline NS W Trans.
                                                                                    Inline Elast. SW Trans.
                                                                                    (strain gauges)


       F & R NS Weight                S Weight                            Antilift
       NS Weight Cg Height            S Weight Cg Height                  Antidive
                                                                          Antisquat
                          Wheelbase                                       Rear Wheel Radius
                                                                          Brake Balance




Vertical                                             NS W Vertical Banking Load
Accelerometer                                        SW Vertical Banking Load

                        Banking Angle.
Lateral
Accelerometer         EXAMPLE: Longitudinal and Vertical Accelerometers




                 IndyCar 2005 Rule Book
         Technical Specifications
                Electronics Categories
                  Engine Sensors
                  Chassis Sensors
                  Other Electronics




                                                                                                              4
     Permitted Engine Sensors
Throttle position (2)   Manifold air temperature
Crank position (2)      Coolant temperature (2)
Cam sensor (2)          Oil temperature (2)
Transmission position   Right bank Lambda
Manifold air pressure
                        Left bank Lambda
Airbox pressure
                        Fuel temperature
Crank case pressure
                        Steering
Fuel pressure
Coolant pressure        Yaw rate
Oil pressure            Lateral G




     Permitted Chassis Sensors
Wheel speed (4)         Steering strain gauge (2)
Steering position       Beacon receiver
Wheel position (4)      Laser ride height
Transmission pressure   Angular rate sensor
Tire pressure (4)       Gyro
Brake pressure          Roll bar(s) position
Brake pedal position    Weightjacker position
Acceleration (3 axis)   Clutch position
Push/pull rod strain    Chassis pressure (any)
gauge (4)               Chassis temperature (any)




                                                    5
               Other Electronics
Stuck throttle sensor         Latest ECU software
No lift shift sensor          Engine running signal to
Ignition cut circuits         impact recorder
Wheel speed link to ECU       Various switches, engine
Beacon receiver link to       and chassis
ECU                           Weightjacker control
Closed loop Lambda            (driver controlled)
control                       Track Condition Radio
Traction control              Driver radio earpiece
ECU-data logger               accelerometer
communication




            Data Acquisition Basics
Input
Signal
(Sensor)



 Input
Amplifier                                          Output
                                                   Signal
                                                    (Time)

  Filter     Sampling     A/D
                        Converter

                                                   Output
                                    Additional
                                    Processing
                                                   Signal
                                                 (Other Format)




                                                                  6
    Data Acquisition Basics
Understand Nature of Signal
  Frequency/rate of change of signal
  Type of signal
    Analog/Digital
    Voltage/Current/Other
  Sampling is often key step
    Need to sample at rate at least 2X highest
    frequency of interest
    Example: if max. Engine Speed = 10,000 RPM




    Data Acquisition Basics
Setup of Measurement System
  Must know nature of signals measured
  Must know signal processing basics and
  hardware capabilities
    Sensor sensitivity and range
    Filter specifications
    A/D conversion capability
    Sampling capability
    Other
  Must know final data format needs




                                                 7
Example Data Acquisition System




    Example Data Analysis
From sample data: Ellis, Lap 22
Vehicle parameter assumptions
  Wheelbase = 120 in = 10 ft
  Track = 78 in = 6.5 ft
  CG Height = 20 in
  Weight = 1600 lbf
    Assume 50/50 lateral distribution
    Assume lateral CG location on vehicle
    centerline




                                            8
       REFERENCES
Pi Research Inc.
http://www.indycar.com/
Indy Racing League IndyCar Series
Rule Book, 2005
www.sae.org




                                    9

				
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