PxVehicleSuspensionData Class Reference
[Vehicle]

#include <PxVehicleComponents.h>

List of all members.

Public Member Functions
	PxVehicleSuspensionData ()
PX_FORCE_INLINE PxReal	getRecipMaxCompression () const
	Reciprocal of maximum compression.
PX_FORCE_INLINE PxReal	getRecipMaxDroop () const
	Reciprocal of maximum droop.
void	setMassAndPreserveNaturalFrequency (const PxReal newSprungMass)
	Set a new sprung mass for the suspension and modify the spring strength so that the natural frequency of the spring is preserved.
Public Attributes
PxReal	mSpringStrength
	Spring strength of suspension unit.
PxReal	mSpringDamperRate
	Spring damper rate of suspension unit.
PxReal	mMaxCompression
	Maximum compression allowed by suspension spring.
PxReal	mMaxDroop
	Maximum elongation allowed by suspension spring.
PxReal	mSprungMass
	Mass of vehicle that is supported by suspension spring.
PxReal	mCamberAtRest
	Camber angle (in radians) of wheel when the suspension is at its rest position.
PxReal	mCamberAtMaxCompression
	Camber angle (in radians) of wheel when the suspension is at maximum compression.
PxReal	mCamberAtMaxDroop
	Camber angle (in radians) of wheel when the suspension is at maximum droop.
Private Member Functions
bool	isValid () const
Private Attributes
PxReal	mRecipMaxCompression
	Cached value of 1.0f/mMaxCompression.
PxReal	mRecipMaxDroop
	Cached value of 1.0f/mMaxDroop.
PxReal	mPad [2]
Friends
class	PxVehicleWheels4SimData

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Constructor & Destructor Documentation

PxVehicleSuspensionData::PxVehicleSuspensionData

(

)

[inline]

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Member Function Documentation

PX_FORCE_INLINE PxReal PxVehicleSuspensionData::getRecipMaxCompression

(

)

const [inline]

Reciprocal of maximum compression.

Note:

Not necessary to set this value because it is set by PxVehicleWheelsSimData::setSuspensionData

Range: [0, PX_MAX_F32)

PX_FORCE_INLINE PxReal PxVehicleSuspensionData::getRecipMaxDroop

(

)

const [inline]

Reciprocal of maximum droop.

Note:

Not necessary to set this value because it is set by PxVehicleWheelsSimData::setSuspensionData

Range: [0, PX_MAX_F32)

bool PxVehicleSuspensionData::isValid

(

)

const [private]

void PxVehicleSuspensionData::setMassAndPreserveNaturalFrequency

(

const PxReal

newSprungMass

)

[inline]

Set a new sprung mass for the suspension and modify the spring strength so that the natural frequency of the spring is preserved.

Parameters:

[in]

newSprungMass

is the new mass that the suspension spring will support.

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Friends And Related Function Documentation

friend class PxVehicleWheels4SimData [friend]

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Member Data Documentation

PxReal PxVehicleSuspensionData::mCamberAtMaxCompression

Camber angle (in radians) of wheel when the suspension is at maximum compression.

Note:

For compressed suspensions the camber angle is a linear interpolation of mCamberAngleAtRest and mCamberAtMaxCompression

Specified in radians.

Range: [-pi/2, pi/2]

PxReal PxVehicleSuspensionData::mCamberAtMaxDroop

Camber angle (in radians) of wheel when the suspension is at maximum droop.

Note:

For extended suspensions the camber angle is linearly interpolation of mCamberAngleAtRest and mCamberAtMaxDroop

Specified in radians.

Range: [-pi/2, pi/2]

PxReal PxVehicleSuspensionData::mCamberAtRest

Camber angle (in radians) of wheel when the suspension is at its rest position.

Note:

Specified in radians.

Range: [-pi/2, pi/2]

PxReal PxVehicleSuspensionData::mMaxCompression

Maximum compression allowed by suspension spring.

Note:

Specified in metres (m).

Range: [0, PX_MAX_F32)

PxReal PxVehicleSuspensionData::mMaxDroop

Maximum elongation allowed by suspension spring.

Note:

Specified in metres (m).

Range: [0, PX_MAX_F32)

PxReal PxVehicleSuspensionData::mPad[2] [private]

PxReal PxVehicleSuspensionData::mRecipMaxCompression [private]

Cached value of 1.0f/mMaxCompression.

Note:

Not necessary to set this value because it is set by PxVehicleWheelsSimData::setSuspensionData

PxReal PxVehicleSuspensionData::mRecipMaxDroop [private]

Cached value of 1.0f/mMaxDroop.

Note:

Not necessary to set this value because it is set by PxVehicleWheelsSimData::setSuspensionData

PxReal PxVehicleSuspensionData::mSpringDamperRate

Spring damper rate of suspension unit.

Note:

Specified in kilograms per second (kg s^-1).

Range: [0, PX_MAX_F32)

PxReal PxVehicleSuspensionData::mSpringStrength

Spring strength of suspension unit.

Note:

Specified in kilograms per second-squared (kg s^-2).

Range: [0, PX_MAX_F32)

PxReal PxVehicleSuspensionData::mSprungMass

Mass of vehicle that is supported by suspension spring.

Note:

Specified in kilograms (kg).

Each suspension is guaranteed to generate an upwards force of |gravity|*mSprungMass along the suspension direction when the wheel is perfectly at rest and sitting at the rest pose defined by the wheel centre offset.

The sum of the sprung masses of all suspensions of a vehicle should match the mass of the PxRigidDynamic associated with the vehicle. When this condition is satisfied for a vehicle on a horizontal plane the wheels of the vehicle are guaranteed to sit at the rest pose defined by the wheel centre offset. The mass matching condition is not enforced.

As the wheel compresses or elongates along the suspension direction the force generated by the spring is F = |gravity|*mSprungMass + deltaX*mSpringStrength + deltaXDot*mSpringDamperRate where deltaX is the deviation from the defined rest pose and deltaXDot is the velocity of the sprung mass along the suspension direction. In practice, deltaXDot is computed by comparing the current and previous deviation from the rest pose and dividing the difference by the simulation timestep.

If a single suspension spring is hanging in the air and generates zero force the remaining springs of the vehicle will necessarily sit in a compressed configuration. In summary, the sum of the remaining suspension forces cannot balance the downwards gravitational force acting on the vehicle without extra force arising from the deltaX*mSpringStrength force term.

Theoretically, a suspension spring should generate zero force at maximum elongation and increase linearly as the suspension approaches the rest pose. PxVehicleSuspensionData will only enforce this physical law if the spring is configured so that |gravity|*mSprungMass == mMaxDroop*mSpringStrength. To help decouple vehicle handling from visual wheel positioning this condition is not enforced. In practice, the value of |gravity|*mSprungMass + deltaX*mSpringStrength is clamped at zero to ensure it never falls negative.

See also:

PxVehicleComputeSprungMasses, PxVehicleWheelsSimData::setWheelCentreOffset, PxVehicleSuspensionData::mSpringStrength, PxVehicleSuspensionData::mSpringDamperRate, PxVehicleSuspensionData::mMaxDroop

Range: [0, PX_MAX_F32)

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The documentation for this class was generated from the following file:

• PxVehicleComponents.h