Data Acquisition Sensors

[Nigel Lavers]

Our team is currently in the process of designing an ECU with a data acquisition system.

The data we are wishing to take for suspension analysis is: front and rear wheels speeds, chassis yaw velocity and/or yaw angle, steering input angle or rack travel, shock/damper velocities, and of course lateral and long. g's.

The problem is that there are so many sensors our there that we are not sure which ones to use. Hall sensors, potentiometers, accelerometers, etc.

Basically, I would like to get help from other teams who have designed their own DAQ systems to see what type of sensors they've used for which measurements and what they're experiences were with them. We all know that there is no ONE way to do anything and this might narrow it down to see which might be the best.

Any suggestions would be appreciated.

Nigel Lavers
Suspension and Steering Design Leader
Formula SAE, University of Alberta

[Nigel Lavers]

Our team is currently in the process of designing an ECU with a data acquisition system.

The data we are wishing to take for suspension analysis is: front and rear wheels speeds, chassis yaw velocity and/or yaw angle, steering input angle or rack travel, shock/damper velocities, and of course lateral and long. g's.

The problem is that there are so many sensors our there that we are not sure which ones to use. Hall sensors, potentiometers, accelerometers, etc.

Basically, I would like to get help from other teams who have designed their own DAQ systems to see what type of sensors they've used for which measurements and what they're experiences were with them. We all know that there is no ONE way to do anything and this might narrow it down to see which might be the best.

Any suggestions would be appreciated.

Nigel Lavers
Suspension and Steering Design Leader
Formula SAE, University of Alberta

[MikeWaggoner at UW]

I think for wheel speed sensors, hall effect is the way to go. The frequency variations from inductance coils require an extra step to get good numbers from my experience (using stock ABS sensors...). Haven't really put much thought into acceleration sensors, would suggest buying prepacked ones if possible...

Western Washington University FSAE
dot.etec.wwu.edu/fsae

[David Money]

We looked at doing some Data Acq on our 2002 car that could be transferred over to the 2003 car. We looked at placing 3 infared temperature sensors per tire to measure instantaneous tire temperature on the outside, middle, and inside of the tire (yields camber, oversteer/understeer, and proper inflation data). We also looked at placing another infared temperature sensor looking directly on each brake rotor right behind the pad to determine how our pads behave. Beyond that, we also looked at placing potentiometers to measure steering angle, bellcrank displacement, throttle angle. Furthermore, we also looked at measuring the accelerations in X and Y via accelerometers as well as measuring yaw via 3 (establishing a theoretical plane) proximity sensors that measure the distance to the ground. Then finally, there is the typical rpm, exhaust gas, and fuel consumption (flow meter). Ironically, in the end none of it came to be.

[Spike]

David save yourself a big headache. Don't use infrared sensors for tire measurement they will get you nothing but trouble. I used three per wheel on my GSX-R 600 race bike. They don't like the vibration, and they will get dust, dirt, and rubber on the lens and they will not read correct. Buy a good handheld IR temp meter and take measurements as soon as the car comes to a stop. Tires don't cool super quick so there should be very little temp drop.

[SKYLO]

Hey Spike,

Taking the temp when you come to a stop will give you an accurate reading of the operating temp, however, it will not tell you very accuretly how fast the tires get up to that tempature which is a very important detail in these short events

[Schumi_Jr]

Any success stories with data acquisition methods? I can tell you that I want to plaster my suspension with strain gauges and use two lateral accelerometers to measure my yaw rate but we don't have the time/money to do it. On an unrelated note, can anyone recommend a brand of linear potentiometer that will effectively measure wheel displacements and is less than $300 US? Is that even possible? thanks

Aaron Johnston
UW FSAE

[Andres]

I think that it´s imposible to find an linear displacement potentiometer on the market cheaper than 300$. We are in the same situation, and waht we are doing is to fit a small potentiometer with our won designed mounting, when you get to do this you will find why the others are so expensive. About the acelerometers i think that you´ll need to do the same thing, buy a chip, and do you own mounting. /infopop/emoticons/icon_eek.gif

[Steven Dyck]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>On an unrelated note, can anyone recommend a brand of linear potentiometer that will effectively measure wheel displacements and is less than $300 US?<HR></BLOCKQUOTE>

Goto Bourns.com and look for part number EAW0J-B24-AE0128. It is an absolute rotary encoder. They were very helpful in finding the right part for our needs. If you do contact them, please mention that Steven Dyck from Formula UVic sent you.

If you contact me off list I can send you some contact info.

Steve

Visit Formula UVic at
http://uvic.fsae.ca

[Barry]

If you are looking for some advise on sensors, send me a e-mail off line on exactly what you are looking for. My job is vehicle dynamics development, I instrument and test cars all the time. I will be testing some of our previous cars at LTU this spring with my companies equipment. I can help you with selecting what sensors will be best for your application. At most companies that supply the sensors, I can give you a contact name and perhaps they will be willing to help you out on cost.

blenart@visteon.com

Barry Lenart
LTU FSAE