Tank Max Speed - Limited by Gears, Torque or...?

[lawman_actual 24]

Hey people.

 

I'm working on config for a tank, using other tanks as references to make sure my values hit at least close to workable.

 

Trouble is...I can't seem to get the damned thing past about 28km/h.

I can't seem to figure what's holding it back since everything I've checked seems to be at least similar to values for the two tanks above that both work fine.

 

Here are my related entries in vehicles.cfg:

 

		accelAidForceCoef = 1.5;
		accelAidForceSpd = 1.4;

		brakeDistance = 12;	
		brakeIdleSpeed = 0.1;

		changeGearMinEffectivity[] = { 0.95, 0.15, 0.95, 0.95, 0.95, 0.95, 0.95 };
		changeGearOmegaRatios[] = {1,0.424242,0.454545,0.333333,0.984848,0.424242,0.984848,0.606061,0.984848,0.575758,1,0.545455};
		changeGearType = "rpmratio"; //Have also tried "effective" with similar issue.

        clutchStrength = 45;	

		dampersBumpCoef = 4.5;
		dampingRateFullThrottle = 1.0;						//1.4: T100			0.8: Kamysh
		dampingRateZeroThrottleClutchDisengaged = 0.65;		//0.8: T100			0.5: Kaymsh		
		dampingRateZeroThrottleClutchEngaged = 0.45;		//5.0: T100			4.0: Kaymsh
		driveOnComponent[] = {"Track_L","Track_R","Slide"};	

		engineMOI = 12;					//12 - T100		7 - Kamysh
		enginePower = 1119;				//kW
		engineStartSpeed = 5;			//common value
		epeImpulseDamageCoef = 18;		//Same for T100 and Kuma

		gearBox[] = {-7,0,11,8,5.7,4.2};	//Same in T100 and Kuma
		
		idleRpm = 1200;

		latency = 0.5;

		maxOmega = 335;
		maxSpeed = 80;
		minOmega = 140;

		normalSpeedForwardCoef = 0.75;
		numberPhysicalWheels = 16;

		peakTorque = 5300;

		redRpm = 3200;

		sensitivity = 2.5;

		simulation = "tankX";
		slowSpeedForwardCoef = 0.25;
		switchTime = 0.3;

		tankTurnForce = 950000;
		tankTurnForceAngMinSpd = 0.7;
		tankTurnForceAngSpd = 0.76;
		thrustDelay = 0.5;
		torqueCurve[] = {{0.424242,0.8},{0.545455,0.95},{0.606061,0.99},{0.636364,1},{0.666667,0.98},{0.727273,0.93},{0.878788,0.76},{1,0.6}};
		tracksSpeed = 1.35;


		class complexGearbox
		{
			driveString = "D";	//String displayed in HUD for Forward Gear
			neutralString = "N";	// string to display in the HUD for neutral gear.
			reverseString = "R";	// string to display in the HUD for reverse gears.
			gearBoxMode = "auto";
			GearboxRatios[] = {"R1",-3.4,"N",0,"D1",4.4,"D2",3,"D3",1.75,"D4",1};	//KUMA
			//GearboxRatios[] = {"R1",-4.5,"N",0,"D1",7.8,"D2",5.6,"D3",4,"D4",2.9,"D5",2.1,"D6",1.5,"D7",1.1}; 	//ANGARA
			moveOffGear = 1;
			transmissionRatios[] = {"High",11.5};
		};

 

 

Can't seem to figure this on my own, so help would be appreciated!
I've checked vehicle mass and it seems to be as expected (about 52 tonnes)

 

 

 

Cheers,

Law

[x3kj 1247]

use EPEVehicle modus in arma3_diag.exe https://community.bistudio.com/wiki/Arma_3_Diagnostics_Exe

to see at what gear it is stuck and what the rpm is.

[lawman_actual 24]

Can't seem to load more than CBA using this new .exe

I'm attempting the following command line:

 

-mod=!Workshop\@CBA_A3;!Workshop\@My Mod;

And while CBA appears to load, with it's correct icon, the VME mod doesn't seem to be working.

 

I've spent a good hour trying different combinations.

HALP PLZ

 

 

Cheers,

Law

[lawman_actual 24]

Accidental re-post

[.kju 3245]

https://community.bistudio.com/wiki/Arma_3_Startup_Parameters#Spaces

[lawman_actual 24]

Knew it would be something like that.

Cheers!

[reyhard 2082]

Max speed of tank is mostly controlled by MOI & dampingRateInAir in wheels config so I guess you could try adjust them first. There are no universal values for those parameters since they are dependent on wheel size & distance from each other. Here you have T-100 config

https://pastebin.com/Q2rjWph8

[lawman_actual 24]

1 hour ago, reyhard said:

Max speed of tank is mostly controlled by MOI & dampingRateInAir in wheels config so I guess you could try adjust them first. There are no universal values for those parameters since they are dependent on wheel size & distance from each other. Here you have T-100 config

https://pastebin.com/Q2rjWph8

 

That's good to know.

I'll investigate further, thanks

[lawman_actual 24]

On 7/9/2018 at 9:37 AM, reyhard said:

Max speed of tank is mostly controlled by MOI & dampingRateInAir in wheels config

 

Thank you clever person.

This turned out to be the limiting factor.

 

The tank now happily goes at 280kmh (I think I need to make some more adjustments...)

 

 

Cheers,

Law

[lawman_actual 24]

Max speed successfully reached.

Gears seems to operating nicely (maybe need a bit of optimisation).

 

Only issue I have now is that if I turn while at the max speed (80kmh on straight, flat road) the tank can slip out.

When this happens it seems to accelerate to silly values, and the tracks lock up and won't animate again even after stopping and moving off at slow speeds.

 

I'm guessing this relates to the frictionVsSlip values, but I haven't had a lot of luck modifying yet.

 

Here's my basic wheel setup:

 

			class L2
			{
				//Modified Vanilla Params
				boneName = "wheel_podkoloL1";
				boundary = "wheel_1_2_bound";
				center = "wheel_1_2_axis";
				dampingRate = 1250;				//1250 close
				dampingRateDestroyed = 4000;
				dampingRateInAir = 2500;		//original: 2150
				frictionVsSlipGraph[] = {[0,0.5],[0.1,1.5],[0.5,0.9]};
				latStiffX = 1;
				latStiffY = 35;
				longitudinalStiffnessPerUnitGravity = 14000;
				mass = 193;
				maxBrakeTorque = 20000;			//working at: 25000
				maxCompression = 0.18;			
				maxDroop = 0.18;
				MOI = 13;						//last change:   8 to 12 (50 to 72)
				side = "left";
				springDamperRate = 30000;
				springStrength = 272000;
				sprungMass = 3358;
				steering = 0;
				suspTravelDirection[] = {-0.125,-1,0};
				width = 0.5;
			};

 

Cheers,

Law

 

[lawman_actual 24]

Fixed it.

Had to knock latStiffX up to 100.

 

It's a lot higher than examples I've looked at, but it works to whatever.

 

Cheers,

Law



UPDATE: 

After further testing...the wheels no longer lock while turning, but other issues have arisen.

Perhaps 100 was too high.

[scotg 204]

It's a tweaking inward spiral. You just have to fine adjust all the factors until you reach your goal - FLUSH! Latstiffx/y controls the grippiness of the "tires." Even for tanks, you probably don't need much more than latStiffX=25. Too little, and your tank will start going faster when turning than it would while going straight forward o_O. Incidentally, you may want a much larger latStiffY, like 200 to 300, if you like climbing hills in your tank. It can also help in slowing it down.

MOI and dampingRateInAir (dRIA) of course affect top speed, but it can be fine-tuned easier if the numbers are higher. You'll just have to play around with their numbers, because afaik there isn't a simple formula. If you have a high MOI, but your tank is launching itself, then keep raising the dRIA until it calms down. If your tank is stopping and starting too quickly, like jerky, it could also be that your MOI is too low. Raise it, but be sure to raise the dRIA as well. EDIT: Be careful not to tweak MOI too high or you could suffer from unstoppable turning syndrome.

Another factor that can slow down or speed up your tank is your wheel bounds in the memLOD. If they are too high close to the hub they can effectively put your high powered engine to a dull crawl - same with virtual wheels of different sizes. You do all the work and tweaking on MOI, dRIA, gears, torque, etc... then you free up your wheel bounds and suddenly you're licking the moon. Back to the drawing board. I suspect you don't have this problem, but I hope future readers might benefit from this understanding.

Edited October 13, 2018 by scotg
added a caveat