Vehicle curving

shrewdPanther46
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Vehicle curving

Post by shrewdPanther46 » December 9th, 2017, 1:30 pm

Hi guys!

So my partner and I were testing today, and we were having some slight deviations from the center line that puts us in danger of missing the bonus. When we line our car up straight, it curves off to the right by about 14 cm over a 10.5 meter run. Any possible solutions? We didn't implement the adjustable steering thing that everyone warned us about, so we are kind of in a pickle :?

I heard that some people sand their wheels to get it to go straight, but that seemed a bit risky to me personally. Has anyone tried this?
I also want to avoid distributing weight differently, especially since our motor and batteries are streamlined along the center of the car (like its centered on the central axis). Nearly everything about the car is symmetrical about the central axis, so I am not sure how exactly the car is even veering off to the side anyways (our axles aren't visibly bent, and 3d printed parts ensures that they are parallel).

Also, how difficult would it be to change a car to implement adjustable steering? Currently, we have the central portion of our car super glued to the other two portions, so it may be possible to dissolve it and then drill some sort of pivot point between them to adjust steering.

Tips anyone?

Thanks!

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Re: Vehicle curving

Post by cheese » December 9th, 2017, 6:49 pm

shrewdPanther46 wrote:Hi guys!

So my partner and I were testing today, and we were having some slight deviations from the center line that puts us in danger of missing the bonus. When we line our car up straight, it curves off to the right by about 14 cm over a 10.5 meter run. Any possible solutions? We didn't implement the adjustable steering thing that everyone warned us about, so we are kind of in a pickle :?

I heard that some people sand their wheels to get it to go straight, but that seemed a bit risky to me personally. Has anyone tried this?
I also want to avoid distributing weight differently, especially since our motor and batteries are streamlined along the center of the car (like its centered on the central axis). Nearly everything about the car is symmetrical about the central axis, so I am not sure how exactly the car is even veering off to the side anyways (our axles aren't visibly bent, and 3d printed parts ensures that they are parallel).

Also, how difficult would it be to change a car to implement adjustable steering? Currently, we have the central portion of our car super glued to the other two portions, so it may be possible to dissolve it and then drill some sort of pivot point between them to adjust steering.

Tips anyone?

Thanks!
I wouldn't sand the wheels as that is a lot less consistent. I would recommend attempting to implement the adjustable steering. Ours also was made up of 3d printed parts and everything "should" be perfectly aligned. But we noticed that when we adjusted the axles by millimeters, it would change how much it curved by a large factor at that distance.
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Re: Vehicle curving

Post by SPP SciO » December 9th, 2017, 9:50 pm

Before you try sanding a wheel, you could try wrapping the other wheel with a piece of electrical tape. The effect will be the same (car will veer in the direction away from larger diameter wheel) but you won’t permanently ruin an otherwise good wheel.

I’m assuming you’ve almost maxed out the wheelbase - if you’ve got room to expand though, that may help. But the biggest culprits are definitely misaligned axles and uneven weight distribution, and you seem to have fixed that already.

Also maybe try testing on a different floor or in a different direction and see if the results are consistent - maybe there’s a slight slope where you’ve been measuring?
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Re: Vehicle curving

Post by Almandine » December 17th, 2017, 7:57 pm

I placed a DS 402 Rotary-Vane Pump on my buggy to achieve a fast speed, while maintaining a path with a tolerance of 2 mm.
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Re: Vehicle curving

Post by builder83 » December 17th, 2017, 8:44 pm

Almandine wrote:I placed a DS 402 Rotary-Vane Pump on my buggy to achieve a fast speed, while maintaining a path with a tolerance of 2 mm.
What is that? I googled and came up with a $2000 part.

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Re: Vehicle curving

Post by kinghong1970 » December 18th, 2017, 5:46 am

builder83 wrote:
Almandine wrote:I placed a DS 402 Rotary-Vane Pump on my buggy to achieve a fast speed, while maintaining a path with a tolerance of 2 mm.
What is that? I googled and came up with a $2000 part.

Just put that along with us “soft gamma repeater” in the circular file...?

Way to be helpful...

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Re: Vehicle curving

Post by Almandine » December 18th, 2017, 5:04 pm

Yes
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Re: Vehicle curving

Post by builder83 » December 18th, 2017, 5:07 pm

kinghong1970 wrote:
builder83 wrote:
Almandine wrote:I placed a DS 402 Rotary-Vane Pump on my buggy to achieve a fast speed, while maintaining a path with a tolerance of 2 mm.
What is that? I googled and came up with a $2000 part.

Just put that along with us “soft gamma repeater” in the circular file...?

Way to be helpful...
Lol figured it was a troll. Thanks

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Re: Vehicle curving

Post by shrewdPanther46 » April 3rd, 2018, 3:35 pm

Hi guys,

We are dealing with an ongoing issue with our vehicle which is limiting our accuracy. We managed to get the car to go straight, but when the power is cut from the motor, our car starts curving to the right. Our car is front wheel drive. When dynamically braking, the car "fishtails" a lot (10 cm to right), but if I simply cut the power, its probably around 5 cm. Regardless, it is resulting in a lot of variance in testing. I'm relatively sure this is simply due to wheel slippage/lack of friction. We tried adding a lot of weight (we doubled the mass of the car using a total of about 1kg of blocks) and we tried distributing the weight in different spots on the car. It still had no impact :(

Is anyone else experiencing similar issues? Please advise!

Thanks :)

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Re: Vehicle curving

Post by sciolyrules107 » April 3rd, 2018, 3:58 pm

shrewdPanther46 wrote:Hi guys,

We are dealing with an ongoing issue with our vehicle which is limiting our accuracy. We managed to get the car to go straight, but when the power is cut from the motor, our car starts curving to the right. Our car is front wheel drive. When dynamically braking, the car "fishtails" a lot (10 cm to right), but if I simply cut the power, its probably around 5 cm. Regardless, it is resulting in a lot of variance in testing. I'm relatively sure this is simply due to wheel slippage/lack of friction. We tried adding a lot of weight (we doubled the mass of the car using a total of about 1kg of blocks) and we tried distributing the weight in different spots on the car. It still had no impact :(

Is anyone else experiencing similar issues? Please advise!

Thanks :)
This is an easy fix: just move your dowel rod the number of cm to the left that it's curving. We built and centered an attachment at the front of the car so that we could slide the dowel rod to the left and right.
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