The QuadrotorDynamics class. Implements quadrotor dynamics The implementation of this class follows the System Modeling section at https://wilselby.com/research/arducopter/modeling/ and https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2324&context=facpub The quadrotor is assumed to have four rotors Each rotor consists of a brushless DC motor and rotor with a fixed pitch. It is assumed that the quadrotor can move in 6 degrees of freedom; 3-translational and 3-rotational, The motion of the quadrotor is controlled via 4 inputs namely the speeds of the 4 motors. The quadrotor model that this class implements assumes the following: More...

#include <quadrotor_dynamics.h>

Inheritance diagram for bitrl::dynamics::QuadrotorDynamics:

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Collaboration diagram for bitrl::dynamics::QuadrotorDynamics:

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Public Types
typedef MotionModelDynamicsBase< SysState< 12 >, DynamicsMatrixDescriptor, RealVec >	base_type

typedef base_type::state_type	state_type
	The type of the state handled by this dynamics object.

typedef base_type::input_type	input_type
	input_t The type of the input for solving the dynamics

typedef base_type::matrix_type	matrix_type
	matrix_t Matrix type that describes the dynamics

typedef base_type::vector_type	vector_type
	vector_t

Public Types inherited from bitrl::dynamics::MotionModelDynamicsBase< SysState< 12 >, DynamicsMatrixDescriptor, RealVec >
typedef SysState< 12 >	state_type

typedef state_type	output_type

typedef RealVec	input_type

typedef DynamicsMatrixDescriptor	matrix_descriptor_type

typedef matrix_descriptor_type::matrix_type	matrix_type

typedef matrix_descriptor_type::vector_type	vector_type

Public Member Functions
	QuadrotorDynamics (QuadrotorDynamicsConfig config, SysState< 12 > &state)
	QuadrotorDynamics Constructor. Specify the configuration parameters of the simulated quadrotor. It is assumed that the mass of the quadrotor remains fixed and the system state to be tracked.

virtual state_type &	evaluate (const input_type &input) override
	Evaluate the new state using the given input it also updates the various matrices if needed.

void	integrate (const RealVec &motor_w)
	Integrate the new state. It also uses error terms.

void	translational_dynamics (const RealVec &motor_w)
	Implements the translational dynamics. It accepts the motors angular velocities. Notice that this model will squared and input velocities.

void	rotational_dynamics (const RealVec &motor_w)
	Implements the translational dynamics. It accepts the motors angular velocities. Notice that this model will squared and input velocities.

RealColVec3d	get_position () const
	Returns the current position NED frame. Note that the z-coordinate has to be multiplied with -1 in order to represent an upwards looking z-axis.

RealColVec3d	get_velocity () const
	Returns the current linear velocity (body frame)

RealColVec3d	get_angular_velocity () const
	Returns the current angular velocity (body frame)

RealColVec3d	get_euler_angles () const
	Returns the Euler angles (0: phi, 1: theta, 2:psi)

real_t	phi () const noexcept
	The phi Euler angle in rad.

real_t	theta () const noexcept
	The theta Euler angle in rad.

real_t	psi () const noexcept
	The psi Euler angle in rad.

Public Member Functions inherited from bitrl::dynamics::MotionModelDynamicsBase< SysState< 12 >, DynamicsMatrixDescriptor, RealVec >
virtual	~MotionModelDynamicsBase ()=default
	Destructor.

virtual state_type &	evaluate (const input_type &input)=0
	Updates and returns the value of the state given the input.

const state_type &	get_state () const
	Read access to the state.

state_type &	get_state ()
	Read/write access to the state.

std::vector< std::string_view >	get_state_variables_names () const
	get_state_variables_names. Returns the name of the variables in the state

matrix_type &	get_matrix (const std::string &name)

const matrix_type &	get_matrix (const std::string &name) const

void	set_matrix (const std::string &name, const matrix_type &mat)

vector_type &	get_vector (const std::string &name)

const vector_type &	get_vector (const std::string &name) const

void	set_vector (const std::string &name, const vector_type &vec)

void	set_matrix_update_flag (bool f)
	set the matrix update flag

bool	allows_matrix_updates () const
	Set the flag for updating or not the matrices describing the model.

bool	has_matrix (const std::string &name) const
	Returns true if the matrix with the given name already exists.

real_t	get_state_property (const std::string &name) const
	Returns the state property with the given name.

void	set_state_property (const std::string &name, real_t value)
	Set the name-th value of the state.

void	set_state_name_value (uint_t i, const std::string &name, real_t val)
	Set the state names.

void	set_state_name_value (uint_t i, const std::pair< std::string, real_t > &val)
	Set the state names.

void	set_time_step (real_t dt)
	Set the time step.

real_t	get_time_step () const
	get_time_step Returns the sampling time the dynamics model is using

real_t	get_tolerance () const
	get_tolerance Returns the general tolerance used in the calculations

void	set_tolerance (real_t tol)
	set_tolerance Set the general tolerance used in the calculations. Default is KernelConsts::tolerance()

Additional Inherited Members
Static Public Attributes inherited from bitrl::dynamics::MotionModelDynamicsBase< SysState< 12 >, DynamicsMatrixDescriptor, RealVec >
static const uint_t	state_dimension
	The dimension of the state.

Protected Member Functions inherited from bitrl::dynamics::MotionModelDynamicsBase< SysState< 12 >, DynamicsMatrixDescriptor, RealVec >
	MotionModelDynamicsBase (bool update_description_matrices_on_evaluate=true)
	Constructor.

	MotionModelDynamicsBase (const state_type &init_state, bool update_description_matrices_on_evaluate=true)
	Constructor.

Protected Attributes inherited from bitrl::dynamics::MotionModelDynamicsBase< SysState< 12 >, DynamicsMatrixDescriptor, RealVec >
state_type	state_
	The object describing the state of the object of which its dynamics are described/modeled by this MotionModel.

matrix_descriptor_type	matrix_description_
	matrix descriptor

bool	update_description_matrices_on_evaluate_
	flag indicating the update of the matrices the model is using to describe itself

real_t	dt_
	The time step the integrator uses.

real_t	tol_
	tolerance

Detailed Description

The QuadrotorDynamics class. Implements quadrotor dynamics The implementation of this class follows the System Modeling section at https://wilselby.com/research/arducopter/modeling/ and https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=2324&context=facpub The quadrotor is assumed to have four rotors Each rotor consists of a brushless DC motor and rotor with a fixed pitch. It is assumed that the quadrotor can move in 6 degrees of freedom; 3-translational and 3-rotational, The motion of the quadrotor is controlled via 4 inputs namely the speeds of the 4 motors. The quadrotor model that this class implements assumes the following:

The quadrotor structure is rigid and symmetrical with a center of mass aligned with the center of the body frame of the vehicle.
The thrust and drag of each motor is proportional to the square of the motor velocity.
The propellers are considered to be rigid and therefore blade flapping is negligible (deformation of propeller blades due to high velocities and flexible material).
The Earth is flat and non-rotating (difference of gravity by altitude or the spin of the earth is negligible)
Surrounding fluid velocities (wind) are negligible.
Ground effect is negligible

The class integrates the translational and rotational dynamics equations on the body frame

Member Typedef Documentation

◆ base_type

typedef MotionModelDynamicsBase<SysState<12>, DynamicsMatrixDescriptor, RealVec> bitrl::dynamics::QuadrotorDynamics::base_type

◆ input_type

typedef base_type::input_type bitrl::dynamics::QuadrotorDynamics::input_type

input_t The type of the input for solving the dynamics

◆ matrix_type

typedef base_type::matrix_type bitrl::dynamics::QuadrotorDynamics::matrix_type

matrix_t Matrix type that describes the dynamics

◆ state_type

typedef base_type::state_type bitrl::dynamics::QuadrotorDynamics::state_type

The type of the state handled by this dynamics object.

◆ vector_type

typedef base_type::vector_type bitrl::dynamics::QuadrotorDynamics::vector_type

vector_t

Constructor & Destructor Documentation

◆ QuadrotorDynamics()

bitrl::dynamics::QuadrotorDynamics::QuadrotorDynamics	(	QuadrotorDynamicsConfig	config,
		SysState< 12 > &	state
	)

QuadrotorDynamics Constructor. Specify the configuration parameters of the simulated quadrotor. It is assumed that the mass of the quadrotor remains fixed and the system state to be tracked.

Member Function Documentation

◆ evaluate()

QuadrotorDynamics::state_type & bitrl::dynamics::QuadrotorDynamics::evaluate ( const input_type & input )

overridevirtual

Evaluate the new state using the given input it also updates the various matrices if needed.

◆ get_angular_velocity()

RealColVec3d bitrl::dynamics::QuadrotorDynamics::get_angular_velocity ( ) const

inline

Returns the current angular velocity (body frame)

◆ get_euler_angles()

RealColVec3d bitrl::dynamics::QuadrotorDynamics::get_euler_angles ( ) const

inline

Returns the Euler angles (0: phi, 1: theta, 2:psi)

◆ get_position()

RealColVec3d bitrl::dynamics::QuadrotorDynamics::get_position ( ) const

inline

Returns the current position NED frame. Note that the z-coordinate has to be multiplied with -1 in order to represent an upwards looking z-axis.

◆ get_velocity()

RealColVec3d bitrl::dynamics::QuadrotorDynamics::get_velocity ( ) const

inline

Returns the current linear velocity (body frame)

◆ integrate()

void bitrl::dynamics::QuadrotorDynamics::integrate ( const RealVec & motor_w )

Integrate the new state. It also uses error terms.

◆ phi()

real_t bitrl::dynamics::QuadrotorDynamics::phi ( ) const

inlinenoexcept

The phi Euler angle in rad.

◆ psi()

real_t bitrl::dynamics::QuadrotorDynamics::psi ( ) const

inlinenoexcept

The psi Euler angle in rad.

◆ rotational_dynamics()

void bitrl::dynamics::QuadrotorDynamics::rotational_dynamics ( const RealVec & motor_w )

Implements the translational dynamics. It accepts the motors angular velocities. Notice that this model will squared and input velocities.

◆ theta()

real_t bitrl::dynamics::QuadrotorDynamics::theta ( ) const

inlinenoexcept

The theta Euler angle in rad.

◆ translational_dynamics()

void bitrl::dynamics::QuadrotorDynamics::translational_dynamics ( const RealVec & motor_w )

Implements the translational dynamics. It accepts the motors angular velocities. Notice that this model will squared and input velocities.

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

libs/bitrl/src/bitrl/dynamics/quadrotor_dynamics.h
libs/bitrl/src/bitrl/dynamics/quadrotor_dynamics.cpp

Public Types

Public Member Functions

Additional Inherited Members

Detailed Description

Member Typedef Documentation

◆ base_type

◆ input_type

◆ matrix_type

◆ state_type

◆ vector_type

Constructor & Destructor Documentation

◆ QuadrotorDynamics()

Member Function Documentation

◆ evaluate()

◆ get_angular_velocity()

◆ get_euler_angles()

◆ get_position()

◆ get_velocity()

◆ integrate()

◆ phi()

◆ psi()

◆ rotational_dynamics()

◆ theta()

◆ translational_dynamics()