My Senior design project - a "Swamp Thing" tracked vehicle clone

Garauld · Dec 18, 2020

They plowed our road out yesterday with a front-end loader.

Garauld · Dec 21, 2020

Today's testing: We had a warm day so the snow has started to soften and sink down to about 20" from about 36" the other day. I decided to take Snowzer for a test run which was mostly successful. No movies yet as my movie-taker (wife) wanted to be my co-pilot. I drove it around my lower yard and had several instances where one track obviously was "spinning" since I do not have posi-traction. I could not tell which one or I would have added some steering brake to add torque to the gripping one. I have a couple thoughts on how to monitor this such as a pair of tachs measuring each drive axle rpm. Does anyone have a different idea?

Fallon · Dec 22, 2020

Wouldn't it turn if one track broke traction with the ground? Or are we talking about the drive tire breaking traction with the track? Although that should result in the same turning.

ArlyA · Dec 22, 2020

Fallon said:
Wouldn't it turn if one track broke traction with the ground? Or are we talking about the drive tire breaking traction with the track? Although that should result in the same turning.

He has drive sprockets... He'd sure feel that if that jumped! Makes a terrible noise too.

texasranger556 · Dec 22, 2020

Re: My Senior design project - a &amp;quot;Swamp Thing&amp;quot; tracked vehicle clone

With an open diff, once one track spins it becomes the path of least resistance for nearly all engine power. The rest of the machine would come to a halt if pushing through deep snow or up a hill. If Garauld had a locker or at least a limited slip, then yes the track that didn't slip would start the machine turning toward the one slipping. Applying turning brake to the slipping side would accomplish a similar effect as an LSD in theory. Analogous to how traction control works in modern vehicles.

As to a solution, wheel tachometers (speedometers, whatever you'd want to call them) would help for sure. Depending how fancy you want to get, a pair of old bicycle cable driven speedometers would work although you'd have to train your brain how to interpret them instantaneously. You seem quite comfortable with electronics, so I'd probably go down the track of a microcontroller with hall effect sensor or similar on each axle, then light up a series of LEDs on the dash to show the relative speed of each track...maybe a couple green ones in the center when track speeds are within 5-10%, red or yellow ones to each side of the green that would light up depending which track is spinning.

I'm sure there are other mechanical ways to do it too. Will be interested to see what you come up with.

The Fred · Dec 22, 2020

gOOgle Quaife differential. One wheel can only spin the same amount that the other side spins the other way. The price has come down significantly over the years though you might not find an application for your little watch winder Coyote.

I used 3 of these in Volvo rear differential V8 conversions, they work flawlessly.

Toyota Scion tC Quaife ATB Helical LSD differential

Garauld · Dec 22, 2020

I think I am going to try a simple and cheap approach first. I am buying a Ace 11 plc for $49 which can accept a couple of speed sensors, one mounted on each drive axle. I can then program it to monitor each of the rpm signals and then, when they differ by a certain amount, light up the respective led showing which track is slipping. Neat?

Garauld · Dec 23, 2020

Fresh Snowzer tracks. It definitely turns easier in the snow. :thumbsup:

ArlyA · Dec 23, 2020

I found the same thing with 4 pods on atv's and utv's. Snow is your friend for steering.

GolfAddict · Dec 23, 2020

Garauld said:
Today's testing: We had a warm day so the snow has started to soften and sink down to about 20" from about 36" the other day. I decided to take Snowzer for a test run which was mostly successful. No movies yet as my movie-taker (wife) wanted to be my co-pilot. I drove it around my lower yard and had several instances where one track obviously was "spinning" since I do not have posi-traction. I could not tell which one or I would have added some steering brake to add torque to the gripping one. I have a couple thoughts on how to monitor this such as a pair of tachs measuring each drive axle rpm. Does anyone have a different idea?

I was thinking a couple of tiny plexi-covered windows on the forward flooring on each side to allow you to see the track movement. Your ideas is way cooler.