New Release Vehicle simulation

[Donamy]

Could you use this mesh ?

 

[Hlynkacg]

What seems to happen in the lower lunar gravity is that if the vehicle is at a high gear then the engine force is quite high and this causes the front wheels to rise & leave the ground. The front wheels take time to settle down again but till then, direction control is tough. Don't know if it will be true on a faster machine.

This is actually a known issue with real-life rovers. I'd say its working.

 

[dumbo2007]

Donamy,

Can you send me the mesh to my mail id ? I have PMed you the id. I guess I can separate the wheel and chassis parts because they are required to be separate meshes ?

 

[Donamy]

I wouldn't mind doing that for you. I could also modify them somewhat too.

 

[dumbo2007]

cool, yes well I guess you might have modeled them as separate groups, which too is fine. I can separate them in 3d max.

 

[jedidia]

What seems to happen in the lower lunar gravity is that if the vehicle is at a high gear then the engine force is quite high and this causes the front wheels to rise & leave the ground. The front wheels take time to settle down again but till then, direction control is tough. Don't know if it will be true on a faster machine.

Sounds pretty much like what I would expect, except that I would expect it to happen in low gears, where most of the force of the motor goes into torque.

I assume the vehicle is driven on all four wheels?

 

[dumbo2007]

Yes, however the gear model I use is too simple. It simply applies higher engine force for higher gears. It doesn't vary the torque in inverse proportion(?) to the gear. If anyone has pointers to a better gear model that relates gears to applied torque by more or less accurate math , I can try to integrate it.

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Actually if you think about it, for higher gears the torque is reduced but the angular speed transmitted by the engine to the wheels is increased (to keep the total power transfer same perhaps ?)....hmm have to think about it.

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The vehicle is driven only by the 2 rear wheels, the front wheels receive no engine power , only steering direction.

 

[jedidia]

Yes, however the gear model I use is too simple. It simply applies higher engine force for higher gears.

Ah, makes perfect sense then.

If anyone has pointers to a better gear model that relates gears to applied torque by more or less accurate math , I can try to integrate it.

Don't have the equation in mind right now, but simply calculating the two components is pretty easy as far as I remember. Applying those forces in context of the physics simulation might be a lot trickier.

The vehicle is driven only by the 2 rear wheels, the front wheels receive no engine power , only steering direction.

And that's why either 4-wheel or front-wheel drives are the prevalent method nowadays

Especially in conditions with reduced gravity, and lightweight construction, rear-wheel drive must end in disaster. There's just nothing to act against the torque...

 

[dumbo2007]

Yes I can try reversing the wheel roles :lol:, that would look kinda funny

Or apply engine power and steering to front wheels, hmm options options...

 

[Donamy]

All wheel drive, which is what the rover should be.