Data Acquisition and Analysis 
Data acquisition and analysis has been around since our predecessors first gained the ability to make decisions. You use it everyday. When you want to buy something, you gather information about your options, you analyze these options, then you make your decision. Simple. Data acquisition and analysis is all about collecting information, reviewing the information and making decisions based on the information.
Early data systems used in motorsports consisted of mechanical instruments that could be read by a test operator. Data was recorded on paper, results were calculated by hand and graphs were plotted on graph paper. As technology advanced, mechanical strip chart recorders automated the data recording process.
Data systems have been used in motorsports long before the current trend of compact electronics. Some of the successful pioneers include Jim Hall with the Chaparral and the Penske-Donahue team that used their analysis skills to come up with concepts such as the circle of friction.
Today, many high performance data systems are available at very reasonable cost. A system can be purchased for under $1000. Before you run out and buy a system stop and think. Think about why you want it and what you are going to do with it. You don't want your data system to end up on the shelf collecting dust with your cappuccino maker and your thigh master.
We have over 20 years experience designing, installing and maintaining data systems in the aerospace and automotive industries. During this time we have worked with many different clients including engine designers, overhaul facilities and individual competitors. It is interesting that many of these groups and individuals share a common characteristic. They all want data acquisition, but once they get a system, many don't know what to do with the data that they have collected.
Some enthusiasts buy data systems, install them in their vehicle, collect some data, get excited by the graphs then stop using the systems because they lack purpose. Don't let this happen to you.
We can help
We can get you headed in the right direction by:
-helping you define your requirements
-helping you design an experiment that will produce results
-helping you pick the system that best fits your needs
-helping you integrate the system with your car
-providing track side support and training
-analyzing your data
-helping you make the decisions to improve your performance
What to Collect
The key to be successful with data acquisition and analysis is not to bite
off more than you can chew. It is easy to hook up lots of sensors and log
lots of data. The danger is that you collect more data than you can analyze
and you get so overwhelmed with the volume of data that you can't find what
you are looking for.
Keep it simple
Pick a few parameters, learn to analyze these parameters then add more. A
good place to start is:
-speed
-longitudinal acceleration (acceleration and braking forces)
-lateral acceleration (side to side g force measured in corners)
From these three parameters you can determine quite a bit about
the performance of the driver and the car. The latest trend of low cost GPS
based data systems can use these parameters to calculate:
-track maps
-sector and lap times
-G-G Maps (Friction Circle)
-Speed Comparison graphs
Once you master this data, you will have a better feel for the
capabilities of the system. Now you can design experiments to analyze areas
such as:
-engine performance
-suspension set ups
-transmission and differential capabilities
-braking characteristics
-driver capacity
Designing a realistic experiment is a very important step in the data logging and analysis process.
Step 1: List your requirements
-What do you want to learn?
-What are your expected results?
-How do you want to see the data? Tabular, Graphs
Step 2: Create a test plan
-Layout a detailed plan for the day
-If you have 4 sessions, define exactly what you are going to do in each session
-Make one change at a time (there are ways to test multiple changes during
a session but keep it simple at first)
-Define a base line set up that can be used as a test control
-Be realistic: How much can you achieve during your test time
-Create contingency plans: weather, track conditions, damage etc
-Assign tasks to your crew, make sure they know what to do when
-one crew member should be in charge of the test (not the driver)
-one crew member should be responsible for data analysis
Step 3: Identify the sensors that will
be used to measure your parameters
-What sensors do you need?
-Can you get the sensors, are they affordable?
-How do you interface the sensors to your data system?
-What kind of power or signal conditioning is required?
Step 4: Install the data system in the
car
-install the sensors
-create a wiring harness
-calibrate the sensors
-ensure the data system is logging correct values
Step 5: Dry run before arriving at the
track
-ensure you know what you are doing before going to the track
-test all the sensors
-prepare your software, graph templates etc
-ensure your team members know what they are expected to do
Step 6: Track Testing
-testing is not lapping
-drive the program, don't get distracted
-your first test should include establishing a baseline
-be prepared to modify the plan if weather or incidents affect your track
time
-drive consistently (an inconsistent driver will make data analysis very difficult)
-at the end of the test, drive the baseline again to ensure that the control
parameters have not changed.
Step 6: Analyze the data
-one person should be responsible for analyzing the data
-if you are a one man show, you will not have time to analyze the data at
the track (do this in your hotel room later at night)
Step 7: Record your results and establish
a baseline for future reference
Designing an experiment may sound intimidating at first, but it will create much better results in the long term.
Sensors
A sensor is an electro/mechanical device that changes a mechanical characteristic
into a measurable electrical signal.
Example |
Mechanical Property | Sensor Type |
Electrical Signal |
| engine RPM | crankshaft rotation | magnetic or hall sensor | frequency |
| wheel speed | wheel rotation | magnetic or hall sensor | frequency |
| vehicle speed | GPS receiver | digital | |
| oil temperature | heat | RTD or thermocouple | dc voltage |
| oil pressure | pressure | pressure transducer | dc voltage |
| suspension travel | linear translation | potentiometer or LVDT | dc voltage |
| throttle position | rotary displacement | rotary potentiometer | dc voltage |
Wiring Harness
Once you have selected your sensors you must connect the sensors to the data
logger. This is done using a wiring harness. You may be required to power
the sensor or condition the sensor output before connecting it to the data
logger.
Logging System
The data logging system is the device that measures and records the electrical
signals from the sensors.
Logging Rate
Many people use the word telemetry when talking about data acquisition. Telemetry and data acquisition are not interchangeable terms. Telemetry is the transmission of data across a wireless network to a remote receiver. Nothing more, nothing less.
Telemetry is generally used when data is required immediately (analysis on the pit wall during a race) or when the test vehicle is not retrievable. Rocketry is an example. For most motorsports applications, telemetry is not worth the expense or the trouble.
Data analysis is the process of examining your data. Today's software packages provide easy to use tools that allow the data to be viewed in tabular or graphical format.
Track Maps
Track maps are very useful for finding and referencing your data.
Tables
Tables are very valuable for looking at discrete parameters such as lap times.
Tables can also be used for calculating sector times, rates of change.
Graphs
Graphs can be used to compare large quantities of data in an easy to view
format. Many graphs plot data vs time or distance. For example, you can plot
vehicle speed or rpm vs distance. If you know the position of the start/finish
line, you can plot multiple laps on a single graph. This allows you to review
parameters such as:
-peak speeds
-cornering speeds
-the driver's consistency
The data shown in the graph above was used to help improve the fuel map of a carbureted Porsche 911. The lambda data shows that the accelerator pumps were injecting too much fuel after a gear change. Based on this graph we were able to adjust the accelerator pumps to improve the engine's throttle response.
The graph also highlights the wheel spin and clutch slip. We were not able to separate the influence of the wheel spin from the clutch slip based on this data. To separate these parameters we could add a rear wheel speed sensor which would clearly measure the wheel slip.
This graph breaks down a segment of a lap at Mosport. The acceleration plot shows that the cornering force in 5b and 8 is less than the 1.2g peak cornering force achieved in corner 5a and corner 4. This could indicate that the driver could carry a higher mid corner speed in 5b and 8 without running out of grip.
Another very useful graph is the G-G diagram or friction circle. This graph shows the cars acceleration, braking and cornering forces all on one page. Not bad for street tires.
We have over 20 years of data acquisition and analysis experience. Let us use this experience to help you reach your goals.
Wether you are an experienced team or new to data systems, we can help you to understand your requirements, purchase and install a system and run some experiments. We can also provide track side support and training to help you get the most out of your investment.
For information on our availability and rates please contact us.
We use the Race Technology DL1 system for our data acquisition needs.
This low cost system provides interesting insight of not only the vehicle behaviour but also the interaction of the driver. The system uses GPS signals to determine speed and location information.
The DL1 was initially designed for autosport applications including drag racers, single seater racing cars, rally cars or road car - however it is also ideal for use on power boats, go karts and motorbikes. It is also a high quality platform for use in the auto industry for car testing of all types, from long term monitoring to competitor benchmarking.
The DL1 can store data from a number of sources including its built in high accuracy GPS and accelerometers, wheel speeds, shaft speeds, engine speeds, temperatures, pressures, lap times, sector times etc. The DL1 comes packaged with the excellent Race Technology data analysis package for Windows. The software allows super accurate track mapping, user defined channels, powerful graphing and allows direct comparison of up to 10 data sets (races) simultaneously with almost unlimited laps.
Cutting edge features of the DL1 include: Built in 5Hz GPS receiver, digital accelerometers, compact flash memory, 8 12bit analogue inputs, dual RPM inputs, 4 wheel/shaft speed inputs, lap beacon input, serial input for ECU/OBDII data, output to drive a dashboard, video overlay system or a telemetry link ( options).
A complete DL1 data logging system, ready to use includes:
- DL1 main unit
- magnetic mounting GPS antenna
- aluminum mounting brackets
- one set of screw connector blocks
- 2m serial lead
- Software CD
The only thing you will need to add is a compact flash card and a suitable card reader for your PC.
Price: $1,300 CDN
Please contact us for further information.
Analysis Software
The strength of the DL1 system lies in its easy to use data analysis software.
The data analysis software can be used to analyze data logged on closed circuits, open circuits (hill climbs and rallies for example), straight line performance testing, to name just a few. Drivers, technical support staff, instructors, racing teachers and students use the software extensively. Because the software runs under windows using familiar controls and presentation, it can be picked up by anyone with even a little experience on computers, quickly and easily.
Race Technologies software can be downloaded for free.
DL1 Options
The DL1 system comes complete and ready to use. Within minutes you can have the system installed in your vehicle and you can be collecting data. We can provide many different options and sensors to help you collect the data you need, however, if you are new to data logging, we suggest that you start with the base system and learn it's capabilities before adding additional channels of information.
Sensors
The DL1 is equipped with 7 analog input channels, 4 frequency channels
and an rpm input. Typical parameters that you might want to measure may include:
-rpm
-throttle position
-steering angle
-Lambda or Air Fuel Ratio from an oxygen sensor
-MAP
-suspension travel
-temperatures
We can provide drawings, sensors and wiring harnesses for any parameter you wish to measure. Please contact us for sensor information.
Video Logging
The standard DL1 system the video sections of the analysis are disabled and require you to purchase an optional additional licence.
Price: $250 CDN
Data Analysis and Technical Support
The DL1 system is easy to use but you may wish to have some help getting the
most out of the system. We have years of experience providing data acquisition
support and analysis to the automotive and aerospace industries. We can help
provide some of the expertise that you may need including:
- Specifications
- Wiring Harnesses
- Track Side Support
- Testing
- Data Analysis
Please contact us for details.
