Algobox - B8 Dragster (contest entry) v2

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B8 Dragster (contest entry) v2

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Author: The Linkage

Group: Default

Filesize: 313.1 kB

Date added: 2014-02-26

Rating: 6.3

Downloads: 3451

Comments: 13

Ratings: 4

Times favored: 0

Made with: Algodoo v2.0.2 Edu

Tags:

----THIS IS AN ENTRY FOR KILINICH'S CONTEST ----

This is a boxer 8 dragster with plenty of torque. I've chosen a boxer engine because it gets rid of most drag.
It's capable of reaching 0-100 km/H in 4.3 secs and 1/4 mile in 12.3 secs (not SO bad!).
Also I had to fix scene.my.start because I build most things in 2.0.2b15 because of 2003 hardware (tho it performs really well overclocked :tup:

).
Whatever, press RETURN to start (HOLD it for half a sec!). Shift gears with A-Z and if you want you can toggle automatic gearbox with X (works realisticly: when engine gets to 700 RPM it shifts up, and when on 450 it shifts down.)
Try to shift up at 700 rpm

v2: Fixed automatic gearbox (thanks s_noonan!) and added 0-100 km/h time (now you need to hold RETURN for half a second)

Last edited at 2014/02/28 00:16:48 by The Linkage

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Kilinich

2014/02/27 04:36:08

Good design! Could you add 0-100km/h code too? :tup:

s_noonan

2014/02/27 23:16:51

Very good. :tup:

Automatic gearbox with X does not work in v2.1.0 because flux capacitor needs adjustment.

Last edited at 2014/02/28 10:04:19 by s_noonan

The Linkage

2014/02/27 23:47:37

OK, thanks for pointing that.
Kilinich: I'm working on that

s_noonan

2014/02/28 10:01:45

Automatic gearbox now works well in v2.1.0. I noticed that both your and Kilinich's cars have improved performance at higher sim.frequency. My interpretation of this is that the inaccuracy at the lower sim.frequency is holding you guys back.

Last edited at 2014/02/28 10:07:07 by s_noonan

The Linkage

2014/02/28 17:12:54

It's not the inaccuracy, but that our engines get a lot stronger at higher frequencies. They get stronger because balls collide more ticks with the cylinder.
Otherwise 100 Hz is enough for the gearing and all

s_noonan

2014/02/28 22:04:33

I respectfully disagree. Try running your car at sim.frequency = 10 Hz. I think that higher frequency is more accurate because it is using smaller time steps. It is similar to the fact that a high resolution image is more accurate than a low res image. If the scene was the same accuracy at all frequencies, then the behavior would be the same at all frequencies and the only effect we might notice is image flicker at low frequencies. In regards to "balls collide more ticks with the cylinder", this is probably true, but if you have 10X the ticks then each tick should have 1/10 the effect.

The Linkage

2014/02/28 23:27:19

Yes, I meant that if you replaced the whole engine with a motor of infinite torque and high RPM then if you ran the scene at 100 or 1000 Hz the only change would be in the gearbox and traction wheel.
Also engines work better with higher frequencies, and my thought is that as Algodoo tries to separate the cylinder and the spawned ball with the maximum force it can apply (because it's unrealistic to have two geometries overlapped) then it does the same force at higher frequencies, but in each tick. Then if Algodoo could apply 100 Nm in one tick of a sim at low frequency (let's say 100 Hz), it will apply 100 Nm in ten ticks, if you raise sim.frequency to 1000 Hz. Again, my thought.

Hope i explained myself.

s_noonan

2014/03/01 14:45:14

I think I understand what you are saying, but I am not sure if I agree.

I did an experiment with two concentric 1 meter diameter circles and plotted the final kinetic energy (gravity off, air off) of one circle as a function of frequency. What I found out was the kinetic energy at 1000 Hz was less than 10% greater than the KE at 100 Hz.

I came up with the following equation:

KE=A*2*ATAN(sim.frequency/12.18)/pi

where A is the KE at theoretically infinite frequency (which is essentially equal to KE @ 1000 Hz)

The Linkage

2014/03/01 20:53:34

I'd like to have that piece of code. I've made a little test too (like yours) with two 1 meter circles, but measuring sim.ticks, and i've found that even if those circles are concentric or are overlapped 1 pixel, Algodoo will take 8 ticks at 100 Hz (7 counted by eye at 0.025x simulation speed, must be my thyme code to detect this) to sepair them, and 53 ticks at 1000 Hz. No matter how much the circles are overlapped, Algodoo will apply a certain force to sepair them, always lasting 8 or 7 ticks at 100 Hz.

s_noonan

2014/03/01 22:08:46

Regarding "I'd like to have that piece of code", there is no code, I just used the ShowPlot menu item and plotted kinetic energy vs. time. Everything you mentioned may be true, but I don't believe you will get more than 10% increase in energy from a spawned circle running at 1000 Hz than you will at 100 Hz. If you plot the position of a 1 meter circle being ejected from a vertical plane for a time span of 0.07 sec, you will see that the trajectory (gravity = on, air = off, sim speed = 0.01x) is more accurate at 1000 Hz then it is at 100 Hz. If you let the ball fall a few meters and hit the ground, you will see that the ball does not hit ground much further at 1000 Hz than it does at 100 Hz.

The Linkage

2014/03/02 15:58:07

I meant Algodoo's code. anyways, it's a fact that collision and spawn engines have more strenght.

s_noonan

2014/03/02 16:10:23

Now I understand. If we had Algodoo's code, then we can see what's going on. Regarding "collision and spawn engines have more strength", more strength than what? I'm not sure what the comparison is against. Unless I hear otherwise, I'll assume "more strength at higher frequencies", in which case we both agree.

The Linkage

2014/03/02 18:13:51

Yep, that's what i wanted to say.