Defines the parameters of the Walking Pattern Generator. More...

#include <WMG.h>

Public Member Functions
	WMG (const unsigned int N_, const unsigned int T_, const double step_height_=0.0135, double bezier_weight_1_=1.0, double bezier_weight_2_=2.0, double bezier_inclination_1_=0.01, double bezier_inclination_2_=0.008, bool use_fsr_constraints=false)
	Initializes a WMG object. More...

	~WMG ()
	Destructor. More...

void	setFootstepParameters (const unsigned int def_periods, const unsigned int ds_periods, const unsigned int ds_number, bool use_user_constraints_=false)
	Set default parameters of footsteps, a wrapper around not so safe setFootstepParametersMS function. More...

void	setFootstepParametersMS (const unsigned int def_time_ms_, const unsigned int ds_time_ms_, const unsigned int ds_number, bool use_user_constraints_=false)
	Set default parameters of footsteps. More...

void	addFootstep (const double, const double, const double, fs_type type=FS_TYPE_AUTO)
	Adds a footstep to FS. More...

WMGret	formPreviewWindow (smpc_parameters &)
	Forms a preview window. More...

void	getFeetPositions (const unsigned int shift_from_current_ms, double left_foot_pos, double right_foot_pos)
	Determine position and orientation of feet. More...

bool	isSupportSwitchNeeded ()
	Checks if the support foot switch is needed. More...

void	changeNextSSPosition (const double *posture, const bool zero_z_coordinate)
	Changes position of the next SS. More...

void	repositionFootsteps (const double diff_x, const double diff_y)
	Reposition all subsequent footsteps that are not fixed at the current moment. More...

void	FS2file (const std::string filename, const bool plot_ds=true)
	Outputs the footsteps in FS to a Matlab/Octave script for plotting. More...

void	getFootsteps (std::vector< double > &x_coord, std::vector< double > &y_coord, std::vector< double > &angle_rot)
	Return coordinates of footstep reference points and rotation angles of footsteps (only for SS). More...

Public Attributes
std::vector< footstep >	FS
	A vector of footsteps. More...

unsigned int	N
	Number of iterations in a preview window. More...

unsigned int *	T_ms

unsigned int	sampling_period

int	current_step_number
	This is the step in FS that is at the start of the current preview window. More...

int	first_preview_step
	The first step in the current preview window. More...

double	step_height
	The maximum height, that can be reached by a swing foot. More...

defConstraints	def_constraints
	Default SS and DS constraints. More...


double	user_constraints [4]
	Constraints given by the user, initialized to the default values on initialization. More...

double	user_constraints_auto_ds [4]
	Constraints given by the user, initialized to the default values on initialization. More...

bool	use_user_constraints
	Constraints given by the user, initialized to the default values on initialization. More...


double	bezier_weight_1

double	bezier_weight_2

double	bezier_inclination_1

double	bezier_inclination_2

Private Member Functions
void	getDSFeetPositions (const int, double , double )
	Determine position and orientation of feet in DS. More...

void	getSSFeetPositions (const int, const double, double , double )
	Determine position and orientation of feet (parabolic trajectory) More...

void	getSSFeetPositionsBezier (const int, const double, double , double )
	Determine position and orientation of feet (using cubic Bezier curves) More...

int	getNextSS (const int, const fs_type type=FS_TYPE_AUTO)
	Returns index of the next SS. More...

int	getPrevSS (const int, const fs_type type=FS_TYPE_AUTO)
	Returns index of the previous SS. More...

Private Attributes
unsigned int	def_time_ms

unsigned int	ds_time_ms

unsigned int	ds_num

unsigned int	last_time_decrement

Detailed Description

Defines the parameters of the Walking Pattern Generator.

Definition at line 240 of file WMG.h.

Constructor & Destructor Documentation

◆ WMG()

WMG::WMG	(	const unsigned int	N_,
		const unsigned int	T_,
		const double	step_height_ = `0.0135`,
		double	bezier_weight_1_ = `1.0`,
		double	bezier_weight_2_ = `2.0`,
		double	bezier_inclination_1_ = `0.01`,
		double	bezier_inclination_2_ = `0.008`,
		bool	use_fsr_constraints = `false`
	)

Initializes a WMG object.

Parameters

[in]	N_	Number of sampling times in a preview window
[in]	T_	Sampling time [ms.]
[in]	step_height_	step height (for interpolation of feet movements) [meter]
[in]	bezier_weight_1_	see bezier_weight_1
[in]	bezier_weight_2_	see bezier_weight_2
[in]	bezier_inclination_1_	see bezier_inclination_1
[in]	bezier_inclination_2_	see bezier_inclination_2
[in]	use_fsr_constraints	Use constraints determined by positions of FSR sensors.

Note: The 'CenterOfPressure' value of the NAO robot can be computed correctly only when CoP lies within the polygon determined by force sensitive resistors (FSR) located on each foot. From the documentation: "If the real center of pressure go outside the 4 FSR parallelogram, the value of weight and centre of pressure could become bad, due to internal mechanical constraint". The rectanle that fits within the FSR polygon is smaller than our default constraint rectangle, which was selected based on the measurements of the feet. See also defConstraints.

Definition at line 15 of file WMG.cpp.

◆ ~WMG()

WMG::~WMG ( )

Destructor.

Definition at line 65 of file WMG.cpp.

Member Function Documentation

◆ addFootstep()

void WMG::addFootstep	(	const double	x_relative,
		const double	y_relative,
		const double	angle_relative,
		fs_type	type = `FS_TYPE_AUTO`
	)

Adds a footstep to FS.

Parameters

[in]	x_relative	x_relative X position [meter] relative to the previous footstep.
[in]	y_relative	y_relative Y position [meter] relative to the previous footstep.
[in]	angle_relative	angle_relative Angle [rad.] relative to the previous footstep.
[in]	type	(optional) type of the footstep.

Note: Coordinates and angle are treated as absolute for the first step in the preview window.

Definition at line 102 of file WMG.cpp.

◆ changeNextSSPosition()

void WMG::changeNextSSPosition	(	const double *	posture,
		const bool	zero_z_coordinate
	)

Changes position of the next SS.

Parameters

[in]	posture	a 4x4 homogeneous matrix representing new position and orientation
[in]	zero_z_coordinate	set z coordinate to 0.0

Todo:: DS must be adjusted as well.

Definition at line 300 of file WMG.cpp.

◆ formPreviewWindow()

WMGret WMG::formPreviewWindow ( smpc_parameters & par )

Forms a preview window.

Returns: WMG_OK or WMG_HALT (simulation must be stopped)

Definition at line 331 of file WMG.cpp.

◆ FS2file()

void WMG::FS2file	(	const std::string	filename,
		const bool	plot_ds = `true`
	)

Outputs the footsteps in FS to a Matlab/Octave script for plotting.

Parameters

[in]	filename	output file name.
[in]	plot_ds	enable/disable plotting of double supports

Definition at line 423 of file WMG.cpp.

◆ getDSFeetPositions()

void WMG::getDSFeetPositions	(	const int	support_number,
		double *	left_foot_pos,
		double *	right_foot_pos
	)

private

Determine position and orientation of feet in DS.

Parameters

[in]	support_number	number of the support
[out]	left_foot_pos	4x4 homogeneous matrix, which represents position and orientation
[out]	right_foot_pos	4x4 homogeneous matrix, which represents position and orientation

Definition at line 90 of file WMG_private.cpp.

◆ getFeetPositions()

void WMG::getFeetPositions	(	const unsigned int	shift_from_current_ms,
		double *	left_foot_pos,
		double *	right_foot_pos
	)

Determine position and orientation of feet.

Parameters

[in]	shift_from_current_ms	a positive shift in time (ms.) from the current time (allows to get positions for the future supports)
[out]	left_foot_pos	4x4 homogeneous matrix, which represents position and orientation
[out]	right_foot_pos	4x4 homogeneous matrix, which represents position and orientation

Attention: This function requires the walking pattern to be started and finished by single support.; Cannot be called on the first or last SS => must be called after FormPreviewWindow().

Definition at line 230 of file WMG.cpp.

◆ getFootsteps()

void WMG::getFootsteps	(	std::vector< double > &	x_coord,
		std::vector< double > &	y_coord,
		std::vector< double > &	angle_rot
	)

Return coordinates of footstep reference points and rotation angles of footsteps (only for SS).

Parameters

[out]	x_coord	x coordinates
[out]	y_coord	y coordinates
[out]	angle_rot	angles

Definition at line 488 of file WMG.cpp.

◆ getNextSS()

int WMG::getNextSS	(	const int	start_ind,
		const fs_type	type = `FS_TYPE_AUTO`
	)

private

Returns index of the next SS.

Parameters

[in]	start_ind	start search from this index.
[in]	type	search for a footstep of certain type, by default (FS_TYPE_AUTO) both left and right are searched.

Returns: index of the next SS.

Definition at line 23 of file WMG_private.cpp.

◆ getPrevSS()

int WMG::getPrevSS	(	const int	start_ind,
		const fs_type	type = `FS_TYPE_AUTO`
	)

private

Returns index of the previous SS.

Parameters

[in]	start_ind	start search from this index.
[in]	type	search for a footstep of certain type, by default (FS_TYPE_AUTO) both left and right are searched.

Returns: index of the previous SS.

Definition at line 58 of file WMG_private.cpp.

◆ getSSFeetPositions()

void WMG::getSSFeetPositions	(	const int	support_number,
		const double	theta,
		double *	left_foot_pos,
		double *	right_foot_pos
	)

private

Determine position and orientation of feet (parabolic trajectory)

Parameters

[in]	support_number	number of the support
[in]	theta	a number between 0 and 1, a fraction of support time that have passed
[out]	left_foot_pos	4x4 homogeneous matrix, which represents position and orientation
[out]	right_foot_pos	4x4 homogeneous matrix, which represents position and orientation

Definition at line 122 of file WMG_private.cpp.

◆ getSSFeetPositionsBezier()

void WMG::getSSFeetPositionsBezier	(	const int	support_number,
		const double	theta,
		double *	left_foot_pos,
		double *	right_foot_pos
	)

private

Determine position and orientation of feet (using cubic Bezier curves)

Parameters

[in]	support_number	number of the support
[in]	theta	a number between 0 and 1, a fraction of support time that have passed
[out]	left_foot_pos	4x4 homogeneous matrix, which represents position and orientation
[out]	right_foot_pos	4x4 homogeneous matrix, which represents position and orientation

Definition at line 184 of file WMG_private.cpp.

◆ isSupportSwitchNeeded()

bool WMG::isSupportSwitchNeeded ( )

Checks if the support foot switch is needed.

Returns: true if the support foot must be switched.

Definition at line 273 of file WMG.cpp.

◆ repositionFootsteps()

void WMG::repositionFootsteps	(	const double	diff_x,
		const double	diff_y
	)

Reposition all subsequent footsteps that are not fixed at the current moment.

Parameters

[in]	diff_x	change in position along x axis
[in]	diff_y	change in position along y axis

Definition at line 306 of file WMG.cpp.

◆ setFootstepParameters()

void WMG::setFootstepParameters	(	const unsigned int	def_periods,
		const unsigned int	ds_periods,
		const unsigned int	ds_number,
		bool	use_user_constraints_ = `false`
	)

Set default parameters of footsteps, a wrapper around not so safe setFootstepParametersMS function.

Parameters

[in]	def_periods	default number of sampling periods in a support (SS or DS depending on the type of added footstep)
[in]	ds_periods	default number of sampling periods in an automatically generated DS.
[in]	ds_number	number of DS to be generated automatically.
[in]	use_user_constraints_	use user_constraints and user_constraints_auto_ds instead of the default constraints.

Definition at line 75 of file WMG.cpp.

◆ setFootstepParametersMS()

void WMG::setFootstepParametersMS	(	const unsigned int	def_time_ms_,
		const unsigned int	ds_time_ms_,
		const unsigned int	ds_number,
		bool	use_user_constraints_ = `false`
	)

Set default parameters of footsteps.

Parameters

[in]	def_time_ms_	default time spent in a support (SS or DS depending on the type of added footstep)
[in]	ds_time_ms_	default time spent in an automatically generated DS.
[in]	ds_number	number of DS to be generated automatically.
[in]	use_user_constraints_	use user_constraints and user_constraints_auto_ds instead of the default constraints.

Definition at line 89 of file WMG.cpp.

Member Data Documentation

◆ bezier_inclination_1

double WMG::bezier_inclination_1

The foot trajectories, that are build using Bezier curve have four control points (0,1,3,4). The first and the last points are defined by positions of adjacent steps of a foot on the floor. The 1 and 2 points are computed depending on the given parameters.

The step height is fixed in the middle (theta = 0.5) of the step, note, that this is not the geometrical middle.

The control points have weights, the weights of the first and the last points are always equal to 1.0. The weights of other two points can be given by the user.

The 1 and 2 points also have inclination, i.e. the shift along y axis (in the frame fixed in the step reference point). The values of inclinations are given in meters.

Definition at line 472 of file WMG.h.

◆ bezier_inclination_2

double WMG::bezier_inclination_2

The foot trajectories, that are build using Bezier curve have four control points (0,1,3,4). The first and the last points are defined by positions of adjacent steps of a foot on the floor. The 1 and 2 points are computed depending on the given parameters.

The step height is fixed in the middle (theta = 0.5) of the step, note, that this is not the geometrical middle.

The control points have weights, the weights of the first and the last points are always equal to 1.0. The weights of other two points can be given by the user.

The 1 and 2 points also have inclination, i.e. the shift along y axis (in the frame fixed in the step reference point). The values of inclinations are given in meters.

Definition at line 473 of file WMG.h.

◆ bezier_weight_1

double WMG::bezier_weight_1

The foot trajectories, that are build using Bezier curve have four control points (0,1,3,4). The first and the last points are defined by positions of adjacent steps of a foot on the floor. The 1 and 2 points are computed depending on the given parameters.

The step height is fixed in the middle (theta = 0.5) of the step, note, that this is not the geometrical middle.

The control points have weights, the weights of the first and the last points are always equal to 1.0. The weights of other two points can be given by the user.

The 1 and 2 points also have inclination, i.e. the shift along y axis (in the frame fixed in the step reference point). The values of inclinations are given in meters.

Definition at line 470 of file WMG.h.

◆ bezier_weight_2

double WMG::bezier_weight_2

The foot trajectories, that are build using Bezier curve have four control points (0,1,3,4). The first and the last points are defined by positions of adjacent steps of a foot on the floor. The 1 and 2 points are computed depending on the given parameters.

The step height is fixed in the middle (theta = 0.5) of the step, note, that this is not the geometrical middle.

The control points have weights, the weights of the first and the last points are always equal to 1.0. The weights of other two points can be given by the user.

The 1 and 2 points also have inclination, i.e. the shift along y axis (in the frame fixed in the step reference point). The values of inclinations are given in meters.

Definition at line 471 of file WMG.h.

◆ current_step_number

int WMG::current_step_number

This is the step in FS that is at the start of the current preview window.

Definition at line 431 of file WMG.h.

◆ def_constraints

defConstraints WMG::def_constraints

Default SS and DS constraints.

Definition at line 441 of file WMG.h.

◆ def_time_ms

unsigned int WMG::def_time_ms

private

Definition at line 483 of file WMG.h.

◆ ds_num

unsigned int WMG::ds_num

private

Definition at line 485 of file WMG.h.

◆ ds_time_ms

unsigned int WMG::ds_time_ms

private

Definition at line 484 of file WMG.h.

◆ first_preview_step

int WMG::first_preview_step

The first step in the current preview window.

Definition at line 434 of file WMG.h.

◆ FS

std::vector<footstep> WMG::FS

A vector of footsteps.

Definition at line 420 of file WMG.h.

◆ last_time_decrement

unsigned int WMG::last_time_decrement

private

Definition at line 487 of file WMG.h.

◆ N

unsigned int WMG::N

Number of iterations in a preview window.

Definition at line 424 of file WMG.h.

◆ sampling_period

unsigned int WMG::sampling_period

Definition at line 427 of file WMG.h.

◆ step_height

double WMG::step_height

The maximum height, that can be reached by a swing foot.

Definition at line 437 of file WMG.h.

◆ T_ms

unsigned int* WMG::T_ms

Definition at line 426 of file WMG.h.

◆ use_user_constraints

bool WMG::use_user_constraints

Constraints given by the user, initialized to the default values on initialization.

Definition at line 447 of file WMG.h.

◆ user_constraints

double WMG::user_constraints[4]

Constraints given by the user, initialized to the default values on initialization.

Definition at line 445 of file WMG.h.

◆ user_constraints_auto_ds

double WMG::user_constraints_auto_ds[4]

Constraints given by the user, initialized to the default values on initialization.

Definition at line 446 of file WMG.h.

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

include/WMG.h
WMG/WMG.cpp
WMG/WMG_private.cpp

Public Member Functions

Public Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ WMG()

◆ ~WMG()

Member Function Documentation

◆ addFootstep()

◆ changeNextSSPosition()

◆ formPreviewWindow()

◆ FS2file()

◆ getDSFeetPositions()

◆ getFeetPositions()

◆ getFootsteps()

◆ getNextSS()

◆ getPrevSS()

◆ getSSFeetPositions()

◆ getSSFeetPositionsBezier()

◆ isSupportSwitchNeeded()

◆ repositionFootsteps()

◆ setFootstepParameters()

◆ setFootstepParametersMS()

Member Data Documentation

◆ bezier_inclination_1

◆ bezier_inclination_2

◆ bezier_weight_1

◆ bezier_weight_2

◆ current_step_number

◆ def_constraints

◆ def_time_ms

◆ ds_num

◆ ds_time_ms

◆ first_preview_step

◆ FS

◆ last_time_decrement

◆ N

◆ sampling_period

◆ step_height

◆ T_ms

◆ use_user_constraints

◆ user_constraints

◆ user_constraints_auto_ds