Base class encoding the 6DOF hydrodynamic model of a marine vehicle. More...

#include <SystemDynamicsBase.h>

Inheritance diagram for SystemDynamicsBase:

Public Member Functions
	SystemDynamicsBase (const bool is3DOF)
	Constructs the dynamics base and sets the DOF flag. More...

virtual	~SystemDynamicsBase ()=default
	Virtual destructor. More...

const Matrix6d &	getM () const
	Returns the total mass matrix M = Mrb + Ma. More...

const Matrix6d &	getMrb () const
	Returns the rigid-body mass matrix Mrb. More...

const Matrix6d &	getMaMatrix () const
	Returns the added-mass matrix Ma. More...

const Matrix6d &	getDlMatrix () const
	Returns the linear damping matrix Dl. More...

const Matrix6d &	getDnlMatrix () const
	Returns the quadratic damping matrix Dnl. More...

const Vector3d &	getRgbVec () const
	Returns the centre of gravity in the body frame. More...

const Vector3d &	getRbbVec () const
	Returns the centre of buoyancy in the body frame. More...

const Vector3d &	getFgn () const
	Returns the gravitational force vector in the world frame. More...

const Vector3d &	getFbn () const
	Returns the buoyancy force vector in the world frame. More...

double	getMassValue () const
	Returns the vehicle mass in kg. More...

double	getWeight () const
	Returns the vehicle weight in N. More...

double	getBuoyancyValue () const
	Returns the net buoyancy force in N. More...

Matrix6d	getD (const Vector6d &velocity) const
	Evaluates the total damping matrix D(v) = Dl + Dnl*diag(\|v\|) More...

Matrix6d	getCrb (const Vector6d &velocity) const
	Evaluates the rigid-body Coriolis matrix Crb(v) More...

Matrix6d	getCa (const Vector6d &velocity) const
	Evaluates the added-mass Coriolis matrix Ca(v) More...

Matrix6d	getC (const Vector6d &velocity) const
	Evaluates the total Coriolis matrix C(v) = Crb(v) + Ca(v) More...

Vector6d	getG (const Quaterniond &q) const
	Evaluates the 6DOF gravitational and buoyancy restoring vector G(q) More...

Vector6d	getG (const Vector3d &rpy) const
	Evaluates the 6DOF gravitational and buoyancy restoring vector G(rpy) More...

virtual Vector6d	getInverseDynamics (const Vector6d &velocity, const Vector6d &acceleration, const Quaterniond &orientation) const
	Computes the inertial + Coriolis + damping force Ma + C(v)v + D(v)*v. More...

void	setMass (double m)
	Sets vehicle mass and recomputes weight, buoyancy, and the rigid-body mass matrix. More...

void	setBuoyancy (double factor)
	Sets the buoyancy force as a scale factor relative to vehicle weight. More...

void	setI (const std::array< double, 6 > &I)
	Sets the rigid-body inertia tensor. More...

void	setMa (const std::array< double, 6 > &m)
	Sets the diagonal added-mass coefficients. More...

void	setDl (const std::array< double, 6 > &d)
	Sets the diagonal linear damping coefficients. More...

void	setDnl (const std::array< double, 6 > &d)
	Sets the diagonal quadratic (nonlinear) damping coefficients. More...

void	setRbb (const std::array< double, 3 > &rbb)
	Sets the centre-of-buoyancy position in the body frame. More...

void	setRgb (const std::array< double, 3 > &rgb)
	Sets the centre-of-gravity position in the body frame. More...

Public Attributes
const bool	isSystem3DOF
	True if the vehicle is constrained to the XY-Yaw plane (3DOF surface vehicle) More...

Detailed Description

Base class encoding the 6DOF hydrodynamic model of a marine vehicle.

Stores mass, inertia, damping, and buoyancy parameters and provides methods to evaluate the Coriolis matrix C(v), damping matrix D(v), restoring vector G(q), and the inertial + Coriolis + damping expression M*a + C(v)*v + D(v)*v. G(q) is computed separately and applied by BuoyancyController. Subclasses may override getInverseDynamics() to zero out irrelevant DOFs.

Invariant: M_ = Mrb_ + Ma_ must hold after every mutation. All setters that modify Mrb_ or Ma_ call updateMass() to re-establish this.

Constructor & Destructor Documentation

◆ SystemDynamicsBase()

SystemDynamicsBase::SystemDynamicsBase ( const bool is3DOF )

explicit

Constructs the dynamics base and sets the DOF flag.

Parameters

is3DOF [in] True for a surface vehicle constrained to XY-Yaw

◆ ~SystemDynamicsBase()

virtual SystemDynamicsBase::~SystemDynamicsBase ( )

virtualdefault

Virtual destructor.

Member Function Documentation

◆ getBuoyancyValue()

double SystemDynamicsBase::getBuoyancyValue ( ) const

inline

Returns the net buoyancy force in N.

◆ getC()

Matrix6d SystemDynamicsBase::getC ( const Vector6d & velocity ) const

Evaluates the total Coriolis matrix C(v) = Crb(v) + Ca(v)

Parameters

velocity [in] 6DOF body-frame velocity

Returns: 6x6 total Coriolis matrix

◆ getCa()

Matrix6d SystemDynamicsBase::getCa ( const Vector6d & velocity ) const

Evaluates the added-mass Coriolis matrix Ca(v)

Parameters

velocity [in] 6DOF body-frame velocity

Returns: 6x6 added-mass Coriolis matrix

◆ getCrb()

Matrix6d SystemDynamicsBase::getCrb ( const Vector6d & velocity ) const

Evaluates the rigid-body Coriolis matrix Crb(v)

Parameters

velocity [in] 6DOF body-frame velocity

Returns: 6x6 rigid-body Coriolis matrix

◆ getD()

Matrix6d SystemDynamicsBase::getD ( const Vector6d & velocity ) const

Evaluates the total damping matrix D(v) = Dl + Dnl*diag(|v|)

Parameters

velocity [in] 6DOF body-frame velocity

Returns: 6x6 velocity-dependent damping matrix

◆ getDlMatrix()

const Matrix6d& SystemDynamicsBase::getDlMatrix ( ) const

inline

Returns the linear damping matrix Dl.

◆ getDnlMatrix()

const Matrix6d& SystemDynamicsBase::getDnlMatrix ( ) const

inline

Returns the quadratic damping matrix Dnl.

◆ getFbn()

const Vector3d& SystemDynamicsBase::getFbn ( ) const

inline

Returns the buoyancy force vector in the world frame.

◆ getFgn()

const Vector3d& SystemDynamicsBase::getFgn ( ) const

inline

Returns the gravitational force vector in the world frame.

◆ getG() [1/2]

Vector6d SystemDynamicsBase::getG ( const Quaterniond & q ) const

Evaluates the 6DOF gravitational and buoyancy restoring vector G(q)

Parameters

q	[in] Vehicle orientation as a unit quaternion

Returns: 6-element restoring force/torque vector in N and Nm

◆ getG() [2/2]

Vector6d SystemDynamicsBase::getG ( const Vector3d & rpy ) const

Evaluates the 6DOF gravitational and buoyancy restoring vector G(rpy)

Parameters

rpy	[in] Vehicle orientation as roll-pitch-yaw in radians

Returns: 6-element restoring force/torque vector in N and Nm

◆ getInverseDynamics()

Vector6d SystemDynamicsBase::getInverseDynamics	(	const Vector6d &	velocity,
		const Vector6d &	acceleration,
		const Quaterniond &	orientation
	)		const

virtual

Computes the inertial + Coriolis + damping force M*a + C(v)*v + D(v)*v.

Does NOT include the gravitational/buoyancy restoring term G(q); that is handled separately by BuoyancyController. Subclasses may override this to zero out DOFs that are not actuated (e.g. Z, Roll, Pitch for a 3DOF vehicle).

Parameters

velocity	[in] 6DOF body-frame velocity
acceleration	[in] 6DOF body-frame acceleration
orientation	[in] Vehicle orientation as a unit quaternion (unused in base implementation)

Returns: 6-element force/torque vector in N and Nm

Reimplemented in AsvSystemDynamics.

◆ getM()

const Matrix6d& SystemDynamicsBase::getM ( ) const

inline

Returns the total mass matrix M = Mrb + Ma.

◆ getMaMatrix()

const Matrix6d& SystemDynamicsBase::getMaMatrix ( ) const

inline

Returns the added-mass matrix Ma.

◆ getMassValue()

double SystemDynamicsBase::getMassValue ( ) const

inline

Returns the vehicle mass in kg.

◆ getMrb()

const Matrix6d& SystemDynamicsBase::getMrb ( ) const

inline

Returns the rigid-body mass matrix Mrb.

◆ getRbbVec()

const Vector3d& SystemDynamicsBase::getRbbVec ( ) const

inline

Returns the centre of buoyancy in the body frame.

◆ getRgbVec()

const Vector3d& SystemDynamicsBase::getRgbVec ( ) const

inline

Returns the centre of gravity in the body frame.

◆ getWeight()

double SystemDynamicsBase::getWeight ( ) const

inline

Returns the vehicle weight in N.

◆ setBuoyancy()

void SystemDynamicsBase::setBuoyancy ( double factor )

Sets the buoyancy force as a scale factor relative to vehicle weight.

Parameters

factor [in] Buoyancy scale factor (1.0 = neutrally buoyant)

◆ setDl()

void SystemDynamicsBase::setDl ( const std::array< double, 6 > & d )

Sets the diagonal linear damping coefficients.

Parameters

d	[in] Array of 6 diagonal linear damping values [Dl_x, ..., Dl_r]

◆ setDnl()

void SystemDynamicsBase::setDnl ( const std::array< double, 6 > & d )

Sets the diagonal quadratic (nonlinear) damping coefficients.

Parameters

d	[in] Array of 6 diagonal quadratic damping values [Dnl_x, ..., Dnl_r]

◆ setI()

void SystemDynamicsBase::setI ( const std::array< double, 6 > & I )

Sets the rigid-body inertia tensor.

Parameters

I	[in] Array of 6 inertia components [Ixx, Iyy, Izz, Ixy, Ixz, Iyz]

◆ setMa()

void SystemDynamicsBase::setMa ( const std::array< double, 6 > & m )

Sets the diagonal added-mass coefficients.

Parameters

m	[in] Array of 6 diagonal added-mass values [Ma_x, Ma_y, Ma_z, Ma_p, Ma_q, Ma_r]

◆ setMass()

void SystemDynamicsBase::setMass ( double m )

Sets vehicle mass and recomputes weight, buoyancy, and the rigid-body mass matrix.

The existing buoyancy-to-weight ratio is preserved when mass changes.

Parameters

m	[in] Vehicle mass in kg

◆ setRbb()

void SystemDynamicsBase::setRbb ( const std::array< double, 3 > & rbb )

Sets the centre-of-buoyancy position in the body frame.

Parameters

rbb	[in] Array of 3 coordinates [x, y, z] in metres

◆ setRgb()

void SystemDynamicsBase::setRgb ( const std::array< double, 3 > & rgb )

Sets the centre-of-gravity position in the body frame.

Parameters

rgb	[in] Array of 3 coordinates [x, y, z] in metres

Member Data Documentation

◆ isSystem3DOF

const bool SystemDynamicsBase::isSystem3DOF

True if the vehicle is constrained to the XY-Yaw plane (3DOF surface vehicle)

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

include/dynamics/SystemDynamicsBase.h
src/dynamics/SystemDynamicsBase.cpp

Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SystemDynamicsBase()

◆ ~SystemDynamicsBase()

Member Function Documentation

◆ getBuoyancyValue()

◆ getC()

◆ getCa()

◆ getCrb()

◆ getD()

◆ getDlMatrix()

◆ getDnlMatrix()

◆ getFbn()

◆ getFgn()

◆ getG() [1/2]

◆ getG() [2/2]

◆ getInverseDynamics()

◆ getM()

◆ getMaMatrix()

◆ getMassValue()

◆ getMrb()

◆ getRbbVec()

◆ getRgbVec()

◆ getWeight()

◆ setBuoyancy()

◆ setDl()

◆ setDnl()

◆ setI()

◆ setMa()

◆ setMass()

◆ setRbb()

◆ setRgb()

Member Data Documentation

◆ isSystem3DOF