QuadRotorDynamics Class Reference

Class for the calculation of the Quadrotor Dynamics. More...

#include <quadrotor_dynamics.hh>

List of all members.

Public Member Functions
	QuadRotorDynamics (double k_t=1.0, double k_m=1.0, double moment_arm=0.220, int error_type=NO_ERROR, double K=1.0, double C=0.0, double T=0.0, double dead_time=0.0)
	Constructor.
virtual	~QuadRotorDynamics ()
	Destructor.
Mechanics	update (ActuationVal actuation_value, double deltaT)
	Updates the Thrusts and Torques.
void	activate_limit_constant (bool active)
	Makes check_limits() limit the maximal rotor speed.
void	activate_limit_transient (bool active)
	Makes check_limits() limit the maximal rotor acceleration.
void	set_limit_const (double rotor_speed_max)
	Set maximal rotor speed for check_limits()
void	set_limit_transient (double rotor_acceleration_max)
	Set maximal rotor acceleration for check_limits()
void	activate_gyroscopic_torque (bool active)
	Activates/Deactivates consideration of gyroscopic effect in roll_pitch_torque()
void	set_k_pt1 (double K)
	Set K coefficient for pt1_element()
void	set_t_pt1 (double T)
	Set T coefficient for pt1_element()
void	set_c_pt1 (double C)
	Set C coefficient for pt1_elmennt()
void	set_dead_time_pt1 (double dead_time)
	Set dead time for pt1_element() (not supported yet)
Mechanics	getMechanics ()
	Returns the Mechanics on the quadrotor frame including Thrust Forces and Drag Torques.
Thrust	getThrust ()
	Returns Thrust Forces produced by the motors.
Torque	getTorque ()
	Returns Torque on the quadrotor frame.
void	setErrorType (int error_type)
	Sets the error type needed by disturbance() (NO_ERROR, GAUSSIAN_NOISE and SINE_ERROR supported)
Private Member Functions
void	check_limits ()
	Check limits of maximal rotor speed and maximal rotor acceleration.
void	aerodynamics ()
	Calculates the Thrust Forces and Drag Torque on the quadrotor frame created by the rotors angular velocities.
void	roll_pitch_torque ()
	Calculates the roll and pitch torques on the quadrocopter frame.
void	disturbance ()
	Provides disturbance to the Thrust.
void	pt1_element ()
	PT1 element K*u + C = T*(d/dt)omega + omega.
Private Attributes
AngularVel	_rotor_speed
	Current rotor speed.
AngularVel	_rotor_speed_prev
	Previous rotor speed.
AngularVel	_rotor_acceleration
	Current rotor acceleration.
ActuationVal	_actuation_value
	Current actuation value.
Mechanics	_mechanics
	Current Mechanics, containing Thrust Forces and Drag Torques.
double	_dT
	Simulation time, which has passed since the last simulation step.
double	_k_t
	Thrust coefficient.
double	_k_m
	Moment coefficient.
double	_moment_arm
	Distance between rotor axis and center of quadrotor frame.
int	_error_type
	Error for the error provided by disturbance and set by setErrorType(int error_type)
double	_sine_index
	Index needed by disturbance for the error type SINE_ERROR.
double	_K
	K coefficient for pt1_element()
double	_C
	C coefficient for pt1_element()
double	_T
	T coefficient for pt1_element()
double	_dead_time
	Dead Time for pt1_elment() (not supported yet)
double	_rotor_speed_max
	Maximal rotor speed limited by check_limits()
double	_rotor_acceleration_max
	Maximal rotor accaleration limited by check_limits()
bool	_limit_const_act
bool	_limit_transient_act
bool	_gyroscopic_torque_active

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Detailed Description

Class for the calculation of the Quadrotor Dynamics.

This class calculates the Torques and Forces on the quadrotor. Since gazebo does not support aerodynamics, this class calculates the Thrust Forces and the Yaw Torques produced by the the rotor speeds of the motors, which is resulting from the current actuation value.

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Constructor & Destructor Documentation

QuadRotorDynamics::QuadRotorDynamics	(	double	k_t = 1.0,
		double	k_m = 1.0,
		double	moment_arm = 0.220,
		int	error_type = NO_ERROR,
		double	K = 1.0,
		double	C = 0.0,
		double	T = 0.0,
		double	dead_time = 0.0
	)

Constructor.

constructor with default values

Parameters:

k_t	thrust coefficient
k_m	moment coefficient
moment_arm	distance between motor axis and center of frame
error_type	error type for disturbance function()
K	K-constant for pt1_element()
C	C-constant for pt1_element()
T	T-constant for pt1_element()
dead_time	dead_time for pt1_element() (not supported yet)

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Member Function Documentation

void QuadRotorDynamics::check_limits

(

)

[private]

Check limits of maximal rotor speed and maximal rotor acceleration.

If activated by activate_limit_constant(bool) and if the maximal rotor speed (_rotor_speed_max) the maximal rotor acceleration is limited to the maximal value, set by set_limit_const. If activated by activate_limit_transient(bool) and if the maximal rotor acceleration value, set by set_limit_transient.

void QuadRotorDynamics::disturbance

(

)

[private]

Provides disturbance to the Thrust.

Provides one of the supported kinds of disturbance to the Thrust, calculated by aerodynamics(). The supported error-types are NO_ERROR, GAUSSIAN_NOISE, SINE_ERROR. They are set by setErrorType(int error_type) and stored to the private member _error_type.

void QuadRotorDynamics::roll_pitch_torque

(

)

[private]

Calculates the roll and pitch torques on the quadrocopter frame.

This function calculates the roll and pitch torques, resulting the thrust forces, calculated by aerodynamics. If activated by activate_gyroscopic_torque(bool) also the torques resulting from the gyroscopic effect are being considered

Mechanics QuadRotorDynamics::update	(	ActuationVal	actuation_value,
		double	deltaT
	)

Updates the Thrusts and Torques.

This function updates the values of the Thrusts and Torques resulting from the current rotor speeds. It is intended to be called in every simulation step.

Parameters:

actuation_value	actuation value corresponding to desired rotor speed
deltaT	simulatin time passed since the last simulation step

Returns:

The Thrust and Torque on the quadrotor frame

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Member Data Documentation

bool QuadRotorDynamics::_gyroscopic_torque_active [private]

If set true, the gyroscopic effect is considered by roll_pitch_torque() it is set by activate_gyroscopic_torque( bool activate )

bool QuadRotorDynamics::_limit_const_act [private]

If set true, maximal rotor speed limit is checked by check_limits(), it is set by activate_limit_constant( bool activate )

bool QuadRotorDynamics::_limit_transient_act [private]

If set true, maximal rotor acceleration limit is checked by check_limits(), it is set by activate_limit_transient( bool activate )

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

• /home/usappz/DeadalusSim/source/quadrotor_dynamics/quadrotor_dynamics.hh
• /home/usappz/DeadalusSim/source/quadrotor_dynamics/quadrotor_dynamics.cc