1/4 www.ni.com

Bookmark and Share

Explore the NI DeveloperCommunity

Discover and collaborate on the latestexample code and tutorials with aworldwide community of engineers andscientists.

(http://decibel.ni.com/content/community/zone)‌Check‌ out‌ the‌ NI‌ Community (http://decibel.ni.com/content/community/zone)

Who is National Instruments?National Instruments provides agraphical system design platform fortest, control, and embedded designapplications that is transforming theway engineers and scientists design,prototype, and deploy systems.

(http://www.ni.com/company/standardize.htm)‌Learn‌ more‌ about‌ NI (http://www.ni.com/company/standardize.htm)

High-Performance Electronics for a Formula Student Race Car

""NI hardware and software allows us to be open to experimentation andfast adaption, which is very important in automotive development.""- Abhi Mittal , University of Manchester (http://formulastudent.manchester.ac.uk)

ReadtheFullCaseStudy

Author(s):Abhi Mittal - University of Manchester (http://formulastudent.manchester.ac.uk)

We are creating a system to acquire data and show whether or not a car is running in accordance with the IMechE safetyregulations. The system will give designers an insight into the vehicle dynamics for future design decisions in real-time fortrackside fault detection, and in the form of logged data for future reference. The data acquisition system should be portable andscalable to accommodate multiple cars or stand-alone parts of the vehicle in the workshop or dynamometer (dyno) room.

With , we can to simulate the entire wiring loom and power distribution circuits of a vehicle priorMultisim (http://ni.com/multisim)to buying any components or PCBs, saving us time and unnecessary costs. provides usCompactRIO (http://ni.com/compactrio)with a rugged and re-programmable data logger capable of accepting inputs from a multiple sensors. Using LabVIEW (

and a standard Wi-Fi router, we implemented a wireless telemetry system that handles around 20http://ni.com/labview)channels of analogue data together with another 18 channels of CAN bus data. With , we canLabVIEW (http://ni.com/labview)view the data in a useful format and create custom alarms.

The Institution of Mechanical Engineers’ Formula Student competition challenges engineering students to conceive, design,fabricate, and compete with small Formula-style racing cars. The cars are built over a period of one year, and are then taken toSilverstone for judging and comparison with other competitors from across the world. Ninety-five teams competed in 2008 in themain and low-emission cars categories.Virtual Wiring LoomThe loom simulation in ensures that the system functions in accordance with safety rules byMultisim (http://ni.com/multisim)allowing us to check the operation of various safety cut-outs. We can simulate current flows to estimate battery performanceand optimise PCBs to handle those loads in UltiBoard, particularly the very wide tracks for starter motor currents. Using themechanical CAD facilities, we can be sure that our circuits will fit inside the enclosures.Data Acquisition and TelemetryThe chassis frame, suspension, cooling and drive-train are some of the key areas where validation of designs based on analysisof real-world data is crucial. Weaknesses or areas for optimisation cannot easily be seen by simple simulation in CAD packages.Data is not only used in the design stages of the vehicle but also in trackside tweaking of suspension and cooling systems.

CompactRIO (http://ni.com/compactrio) provides us with an all-in-one data acquisition and real-time monitoring system withunparalleled flexibility on input types and data viewing. With 512 MB of onboard storage, high-resolution data capture ispossible. It provides a much higher channel density (number of inputs to size ratio) than most other solutions, even thosedesigned for motorsports. Thanks to a simple Wi-Fi link, we don’t even need to hold a radio license for telemetry. Theremovable and wide-selection of C-series modules make a sustainable choice. We canCompactRIO (http://ni.com/compactrio)change the configuration as our needs grow or we identify new areas for measurement. It also allows for a wide operatingvoltage, important in automotive supplies with frequent engine restarts when the voltage can fall by up to 25%.

We worked closely with NI field engineers to tailor hardware to suit our purpose. Our unit has an eight-module chassis with theNI 9237 simultaneous bridge module, the NI 9205 analogue input module, the NI 9411 digital input module, the NI 9211thermocouple module, the NI 9233 dynamic signal acquisition module for IEPE measurements and the NI 9853 high-speedCAN input module. The CAN input allows us to monitor data from the ECU connected sensors such as RPM, oil temperatureand oil pressure. This avoids installing duplicate sensors or fabricating sensor buffer circuits. The combination of quickre-programming and single-unit portability means we can easily use CompactRIO both on the car and in the dyno room for moredetailed, engine-specific measurements. It’s just a matter of uploading the appropriate VI over the network and connecting thesensors.Live MonitoringThe ability to monitor the data in real time is important for finding problems before their consequences are severe. Duringtesting, the team can check that the engine remains at constant temperature without having to stop the car. Testing sessionsare more productive as the team can prepare to make suspension changes while the car is still running, meaning the drivers getmore practice behind the wheel.

Immediate feedback to the driver is also an effective way to improve his driving style. A good racing driver must always keep thecar in control, just within the limits of traction. By viewing throttle position, brake pressure and steering angle data while driving,a driver is informed of areas of improvement in his technique.Vehicle DynamicsUsing linear and rotary potentiometers, the car’s weight transfer characteristics can be quantifiably observed. By measuring thesuspension and steering angle, we can see how car tilts around corners. The shock absorbers can then be tuned to minimizetravel and maximise grip.

On a racing car, it is important to look at the behaviour of all four wheels. We use a Hall effect sensor mounted on the uprights

The Challenge:Implementing a portable and scalable data acquisition system for the University of Manchester Formula Student single-seat racingcar that can test multiple vehicles.

The Solution:Using Multisim and LabVIEW software with NI CompactRIO programmable automation controller (PAC) to simulate the vehicle,collect data, and use the data to create custom alarms.

(/cms/images/casestudies/manchesta.jpg?size)

(/cms/images/casestudies/manchestb.jpg?size)

2/4 www.ni.com

On a racing car, it is important to look at the behaviour of all four wheels. We use a Hall effect sensor mounted on the uprightsto measure the speed of each wheel. A specially-designed toothed disc placed behind the brake disc triggers the sensors as thewheel rotates. These provide a transistor–transistor logic (TTL) compatible switched output. Using the NI 9411 digital inputmodule and a high-priority timed loop in LabVIEW, we can ensure the sensors are sampled at a sufficient rate. The wheel speeddata, coupled with intended direction data from the steering angle sensor, is used to understand and verify the operation of thelimited slip differential, traction control and launch control. The engine control unit ( ) provides controls for adjusting theECUaggressiveness of the latter two. By measuring the wheel speeds around corners, or off the start line, we can find the optimalsettings.

We use the NI 9237 Bridge modules to interface with strain gauges on the suspension wishbones and chassis tubes. Althoughthere is little we can do with this data on a car already built, this data will be very useful when designing future cars. Forexample, parts can be re-engineered to save weight if they are not being stressed as much as initially predicted.

The NI 9233 module has four simultaneously-sampled 24-bit inputs, enabling simple 2-wire connection to accelerometers.Lateral-acceleration can be quantified and compared against different combinations of camber and tyre pressures. Gettingthese right means our car can speed around tighter corners at higher speeds.ConclusionNI hardware and software allows us to be open to experimentation and fast adaption, which is very important in automotivedevelopment. The Formula Student team produces a new car every year (much like any professional racing team), so the abilityto ‘chop-and-change’ is crucial. Most off-the-shelf automotive data loggers do not offer the wide connectivity of the CompactRIO,particularly to passive sensors like strain gauges. The MAN09 car, due to compete in July 2009, is our first vehicle to carry theCompactRIO onboard. This first set of data will deepen our insight into automotive design.

The CompactRIO has been highlighted for future use as a controller as well as a logger. Its FPGA-based operation would besuited to applications such as active suspension, anti-lock brakes and hybrid drive train management.

Author Information:Abhi Mittal

University of Manchester (http://formulastudent.manchester.ac.uk)Tel: 07878732643formulastudent@manchester.ac.uk (mailto:formulastudent@manchester.ac.uk)

3/4 www.ni.com

Formula Student Race Car.

4/4 www.ni.com

Formula Stduent Race Car.

LegalThis case study (this "case study") was developed by a National Instruments ("NI") customer. THIS CASE STUDY IS PROVIDED "AS IS"WITHOUT WARRANTY OF ANY KIND AND SUBJECT TO CERTAIN RESTRICTIONS AS MORE SPECIFICALLY SET FORTH INNI.COM'S TERMS OF USE ( ).http://ni.com/legal/termsofuse/unitedstates/us/ (http://ni.com/legal/termsofuse/unitedstates/us/)

COMPANY

About National Instruments (http://www.ni.com/company/)

Events (http://www.ni.com/events/)

Careers (http://www.ni.com/careers/)

SUPPORT

Submit a service request (https://sine.ni.com/srm/app/myServiceRequests)

Manuals (http://www.ni.com/manuals/)

Drivers (http://www.ni.com/downloads/drivers/)

Alliance Partners (http://www.ni.com/alliance/)

PRODUCT

Order status and history (http://www.ni.com/status/)

Order by part number (http://sine.ni.com/apps/utf8/nios.store?action=purchase_form)

Activate a product (http://sine.ni.com/myproducts/app/main.xhtml?lang=en)

Order and payment information (http://www.ni.com/how-to-buy/)

MISSIONNI equips engineers and scientists with systems that accelerate productivity, innovation, and discovery.

(http://twitter.com/niglobal) (http://www.facebook.com/NationalInstruments) (http://www.linkedin.com/company/3433?trk=tyah) (http://www.ni.com/rss/)

(http://www.youtube.com/nationalinstruments)

Contact Us (http://www.ni.com/contact-us/)

© National Instruments. All rights reserved. Legal (http://www.ni.com/legal/) | | Site map (http://www.ni.com/help/map.htm)

(http://privacy.truste.com/privacy-seal/National-Instruments-Corporation/validation?rid=bc6daa8f-7051-4eea-b7b5-fb24dcd96d95)