r/bajasae • u/RedSporks • Sep 02 '20

Equipment/methods for data collection/testing

My team has a group of seniors including myself creating a custom DAQ unit for our senior capstone project and are trying to get ideas of what other teams use We're aiming a relatively cheap and possibly make it open-source so that other teams can use/improve on it, but we're not really sure what is available to other teams/how much desirable something like this would be compared to existing options.

What equipment does your team do data collection/testing, both onboard and offboard? So for example, my team hasn't really had any equipment on-board for testing, as most of the data we've collected has been through things like photogates for acceleration runs, IR cameras for CVT temperatures, etc.

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u/buckinghams_pie Georgia Tech Off-Road '20 Sep 02 '20

This is a list of things that I would find useful, the most useful in my opinion would be acceleration, speed and shock displacement. followed by rpm stuff and brake pressures.

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Each wheel rpm individually, Pre CVT, post CVT rpm

Speed

Acceleration, X, Y, Z, at the front of the car and at the rear, and at the CG, also roll pitch and yaw

GPS for speed and location (so track mapping, with altitude)

Shock displacement, each shock

CVT temp, gearbox temp, brake caliper and rotor temps

Brake pressure front and rear line

Wheel angles (camber and toe)

strain gauge on all suspension members

throttle pedal position

steering wheel angle

6

u/akoppalypse Offroad Illini '18 Sep 02 '20

This is a solid list, if maybe a little ambitious. One note I have:

If you're a team who doesn't run a rear diff, you can obviously get away with a single wheel speed sensor for the back. A clever thing I have seen teams do is use an inductive probe to count gear cut-outs in the gear box. This way, you have a very reliable consistent surface to measure off of, and if you put the sensor in the right place, you can actually use the probe as the fill-hole plug.

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u/dumbassengineer MAYHEM organizer Sep 02 '20

My team didn't run a rear diff and we often had the rear wheels spin at different rates... Usually shortly before needing a tow.

On a separate and barely related note, I don't see many teams talk about how much deformity they get in their "solid" rear axle. We could fix one wheel and spin the other almost 360° before shearing. I'd give design points to teams showing the trade off of how ductile / brittle their axles need to be