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Simracing Academy: l'intervento di Aristotelis Vasilakos

Il mitico Aris ci ha parlato naturalmente di dinamica del veicolo, ma non sono mancati i suoi consigli, svelando qualche piccolo segreto rispondendo alle domande degli allievi...
L'intervento di Aris Vasilakos

F1 2020: guida al circuito di Imola

Il Mondiale F1 2020, dopo 14 anni di assenza, torna sul mitico Autodromo Enzo e Dino Ferrari di Imola, per il Gran Premio dell’Emilia-Romagna.... Scopriamo tutti i segreti del glorioso tracciato sulle rive del Santerno.
Guida al circuito di Imola

Parte 2 Simracing Academy: traiettoria ed uso della pista

Per risultare efficienti ed efficaci in pista è necessario comprendere che la guida in circuito è differente da quella a cui siamo abituati. La prima differenza che salta subito all’occhio? Scopriamolo con la seconda parte della Simracing Academy. Iscriviti alle lezioni pratiche che partono il 29 Ottobre!
Parte 2 Simracing Academy

netKar PRO patch 1.0.3 progress...


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e' come spiegato da Miles. Il "problema" e' nella definizione di slip angle e, soprattutto di slip ratio.

lo slip ratio e' il rapporto fra la velocita' del battistrada e la velocita' della strada con cui e' a contatto. lo slip ratio e' definito (una delle possibili definizioni):

sr= (Vb-Vs)/ |Vs|

Vb e' la velocita' del battistrada... ie.. velocita' di rotazione della ruota * raggio gomma. Vs e' la velocita' della strada.

E' facile vedere che:

Con Vs=0 sr perde significato... un numero diviso per zero e' indefinito.

Con Vs basso una piccola variazione di Vb genera enormi varazioni dello slip ratio.

In condizioni normali lo slip ratio si aggira intorno a 0.15 0.2 in cui ottiene il grip massimo. A basse velocita' si rischia di ottenere slip ratio con valori molto alti anche con piccole variazioni di velocita' di rotazione delle gomme.

Bisogna ricorda che un motore fisico funziona "a campionamenti" della realta' (il famoso rate fisico) e piu' i valori diventano prossimi allo zero e piu' il rate fisico e' basso piu' le variazioni di espressioni simili allo slip ratio diventano incontrollabili.

Lo slip angle soffre dello stesso problema essendo definito piu' o meno come:

Sa=arctan(Vl/Vs) . Vl e' la componente laterale della velocita' nel sistema di riferimento del pneumatico.

Quindi nuovamente Vs sotto una divisione con i problemi esposti sopra.

Le soluzioni al problema sono 4:

1) Utilizzare un sistema piu' semplice sotto una certa velocita'.. come faccio io

2) Implementare un sistema basato sulle "relaxation lenght".. che e' fisicamente piu' corretto ma che richiede alcuni parametri sperimentali tarati sulla singola applicazione.

3) Aumentarre il rate fisico del sistema. Ma esistera' sempre una velocita' V sotto la quale il sistema diventa instabile.

4) Utilizzare un sistema piu' o meno ad elementi finiti

Ho provato piu' di una volta a dare uno sguardo alla 2.. ma mi sono sempre trovato a lasciar perdere in quanto il sistema andava a "sporcare" il codice senza offrire evidenti vantaggi rispetto alla 1, molto piu' semplice e pulita.

Non ho mai detto che sia una soluzione corretta, ho solo detto che, considerata l'applicazione in cui viene utilizzata si tratta di una semplificazione accettabile. Nel 2006 ho dovuto rinunciare ad un progetto per BMW con BRD perche' volevano una simulazione di manovre di "off road estremo" tutte basate su velocita' inferiori a 3-4km/h e su cui il mio sistema non garantisce nessun tipo di velleita' simulative.

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  • DrivingItalia.NET Crew

Jaap:

Do you think that it gives me any pleasure to have to test, fix, test, fix, test, fix and test 1.0.3 all the time now? It's been like that for the past 3 months and I want it to be ready as well.

We're getting closer and closer. We were, until last week, indeed struggling with CTD's of which it was hard to find the real cause. That one is fixed now. The big thing we are now struggling are two things:

- a sound bug causing CTD's (sometimes, which sucks and makes it hard to fix)

- laggy other cars in TV view (looks really bad, also sometimes)

I don't want this sim to be released with bugs like this and I think you don't want that, too.

We are working hard on fixing the problems. I think it's a good thing that the team strives for quality and learns from the mistakes from the past and I hope you will enjoy that once the sim is out.

By the way, we have always avoided naming a release date. I have made one mistakes with that, but in general we have always said: it will be released when it's ready.

If you think you can help making the process smoother, please contact me. We are always looking for people who want to help out testing. After all, even for me this is a hobby project for me (I don't earn anything with it and have to do it all besides a seriously busy fulltime job as BI architect).

Again: I do understand the disappointment, but understand that I am feeling exactly the same! The issue is: this is software and stuff like this happens when developing software. I think the best we can do is communicate about what is happening and I think I am doing a reasonable job at that given the situation and possibilities.

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  • DrivingItalia.NET Crew

The customers will receive a brand-new 1.0.3 release of nKP without having to pay for it. Yes, it is taking (much!) longer than expected, but it is coming.

Besides, I haven't seen a lot of complaints with regard to customer support. Remember the time where people were complaining about the non-existent support?

I am supporting the sim where possible and have helped numerous people by providing tips and new activations.

If you or anyone has any support problem, please contact me (as is explained in one of the sticky posts in this forum).

Does anyone knows if this Abarth is going to be in the public release? tnx

Yes, the Abarth will see the final consumer version of nKP. It will not appear in 1.0.3 though. This would only cause more delay on 1.0.3. The nKP team is focusing on finishing deals which also benefit the paying customer and the Abarth is an example of this.

The FSingTel release was also an example of this, even though it is not known yet if and how this car will end up in the consumer nKP. Hope this clears some things up.

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  • DrivingItalia.NET Crew

I think it is not good that the Osella & Trento are not released yet, but it was always the plan to release them after 1.0.3. The whole problem is that 1.0.3 has been delayed so much all the time.

I am not asking you to believe what I say. All I am doing is putting as much information to the community to inform you about what is going on. I can't say that I trust some of the information myself, simply because I am not at the controls (I am not setting priorities for example). However, I still bring the information to you, simply because communicating about the situation is better than being silent. It's also why I don't give release dates myself. All I say comes directly from what Stefano tells me.

With regard to my role. It was clearly stated in this forum and on other places. I am the 'community guy', which means I give you as much information as possible to keep the people out there in the link. I am not the "official market leader/PR of netkar pro" as you wrote it.

I am part of the team (I am doing the community work, working on support@netkar-pro.com and have my nkp e-mail address). Fact is that I do it as a hobby and that I'm not not a paid member of the team (don't want to be that as well at this stage, btw). Stefano is probably referring to that when he stated to you that I'm not an 'official member' of the team.

Just do with the information that you want. I know that a lot of people appreciate getting information about the progress and that's most important for me. This is no life-or-death situation for me personally, so I approach it relaxed and just do the best possible. I think everyone should be a bit more relaxed, maybe everyone expect the devteam working on getting the new stuff out

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