Goal that minimizes deviation of the Zero Moment Point (ZMP) from a desired location. More...

#include <MocoZMPGoal.h>

Inheritance diagram for MocoZMPGoal:

[legend]

Public Member Functions
void	setExponent (int ex)
	Set the exponent for the goal.

bool	getExponent () const
	Get the current exponent value.

void	setExponent (int ex)
	Set the exponent for the deviation term.

bool	getExponent () const
	Get the current exponent value.

void	setDivideByDisplacement (bool tf)
	Set whether to divide by displacement.

bool	getDivideByDisplacement () const
	Get whether the goal is divided by displacement.

Constructors
	MocoZMPGoal ()
	Default constructor.

	MocoZMPGoal (std::string name)
	Constructor with name.

	MocoZMPGoal (std::string name, double weight)
	Constructor with name and weight.

	MocoZMPGoal ()
	Default constructor.

	MocoZMPGoal (std::string name)
	Constructor with name.

	MocoZMPGoal (std::string name, double weight)
	Constructor with name and weight.

Protected Member Functions
Required implementations of virtual methods
Mode	getDefaultModeImpl () const override
	Get the default mode for this goal.

bool	getSupportsEndpointConstraintImpl () const override
	Whether this goal supports endpoint constraint mode.

void	initializeOnModelImpl (const Model &) const override
	Initialize the goal with the model.

void	calcIntegrandImpl (const IntegrandInput &input, double &integrand) const override
	Calculate the integrand value for the cost function.

void	calcGoalImpl (const GoalInput &input, SimTK::Vector &cost) const override
	Calculate the goal value.

Mode	getDefaultModeImpl () const override
	Get the default mode for this goal.

bool	getSupportsEndpointConstraintImpl () const override
	Whether this goal supports endpoint constraint mode.

void	initializeOnModelImpl (const Model &) const override
	Initialize the goal with the model.

void	calcIntegrandImpl (const IntegrandInput &input, double &integrand) const override
	Calculate the integrand value for the cost function.

void	calcGoalImpl (const GoalInput &input, SimTK::Vector &cost) const override
	Calculate the goal value.

SimTK::Matrix	FlattenSpatialVec (const SimTK::SpatialVec &S) const
	Convert a spatial vector to a matrix representation.

Private Member Functions
	OpenSim_DECLARE_CONCRETE_OBJECT (MocoZMPGoal, MocoGoal)

void	constructProperties ()
	Initialize the goal's properties.

	OpenSim_DECLARE_CONCRETE_OBJECT (MocoZMPGoal, MocoGoal)

void	constructProperties ()
	Initialize the goal's properties.

Properties
	OpenSim_DECLARE_PROPERTY (exponent, int, "The exponent applied to the output value in the integrand. " "The output can take on negative values in the integrand when the " "exponent is set to 1 (the default value). When the exponent is " "set to a value greater than 1, the absolute value function is " "applied to the output (before the exponent is applied), meaning " "that odd numbered exponents (greater than 1) do not take on " "negative values.")

	OpenSim_DECLARE_PROPERTY (divide_by_displacement, bool, "Divide by the model's displacement over the phase (default: " "false)")

	OpenSim_DECLARE_PROPERTY (exponent, int, "The exponent applied to the output value in the integrand. " "The output can take on negative values in the integrand when the " "exponent is set to 1 (the default value). When the exponent is " "set to a value greater than 1, the absolute value function is " "applied to the output (before the exponent is applied), meaning " "that odd numbered exponents (greater than 1) do not take on " "negative values.")

Private Attributes
Internal working variables
std::vector< std::string >	m_force_names

std::function< double(const double &)>	m_power_function
	Function to compute power of ZMP deviation.

OpenSim::Model	m_model
	Reference to the model.

Detailed Description

Goal that minimizes deviation of the Zero Moment Point (ZMP) from a desired location.

Goal that minimizes the deviation of the Zero Moment Point (ZMP) from a target.

This goal minimizes the distance between the actual Zero Moment Point (ZMP) and a target location. The ZMP is the point where the horizontal component of the moment of ground reaction forces equals zero. The integrand is:

$|p_{zmp} - p_{target}|^p$

where $p_{zmp}$ is the current ZMP location, $p_{target}$ is the target location, and is the exponent (default: 2).

This goal is useful for:

Maintaining dynamic balance during motion
Controlling the center of pressure location
Generating stable walking motions

The ZMP is computed using ground reaction forces and moments from contact forces in the model.

This goal minimizes the deviation of the model's Zero Moment Point (ZMP) from a desired target location, integrated over the phase. The ZMP is calculated using the ground reaction forces and moments acting on the model.

The ZMP is a point on the ground where the net moment of the inertial forces and gravity forces has no component along the horizontal axes. It is commonly used in balance control and gait analysis.

This goal can be useful for:

Improving dynamic balance during motion
Generating more stable walking patterns
Controlling weight transfer during stance
Reducing risk of falls

The deviation can optionally be divided by the total displacement of the model during the phase to make the cost invariant to the distance traveled.

Constructor & Destructor Documentation

◆ MocoZMPGoal() [1/6]

MocoZMPGoal ( )

inline

Default constructor.

◆ MocoZMPGoal() [2/6]

MocoZMPGoal ( std::string name )

inline

Constructor with name.

Parameters

name	The name of the goal

◆ MocoZMPGoal() [3/6]

MocoZMPGoal	(	std::string	name,
		double	weight )

inline

Constructor with name and weight.

Parameters

name	The name of the goal
weight	Weight for this goal term in the optimization

◆ MocoZMPGoal() [4/6]

MocoZMPGoal ( )

inline

Default constructor.

◆ MocoZMPGoal() [5/6]

MocoZMPGoal ( std::string name )

inline

Constructor with name.

Parameters

name	The name of the goal

◆ MocoZMPGoal() [6/6]

MocoZMPGoal	(	std::string	name,
		double	weight )

inline

Constructor with name and weight.

Parameters

name	The name of the goal
weight	Weight for this goal term in the optimization

Member Function Documentation

◆ calcGoalImpl() [1/2]

void calcGoalImpl	(	const GoalInput &	input,
		SimTK::Vector &	cost ) const

overrideprotected

Calculate the goal value.

Parameters

input	Input data containing the integral
cost	Vector to store the calculated cost

◆ calcGoalImpl() [2/2]

void calcGoalImpl	(	const GoalInput &	input,
		SimTK::Vector &	cost ) const

overrideprotected

Calculate the goal value.

Parameters

input	Input data containing the integral
cost	Vector to store the calculated cost

◆ calcIntegrandImpl() [1/2]

void calcIntegrandImpl	(	const IntegrandInput &	input,
		double &	integrand ) const

overrideprotected

Calculate the integrand value for the cost function.

Parameters

input	Input data for the current state
integrand	Reference to store the calculated integrand value

◆ calcIntegrandImpl() [2/2]

void calcIntegrandImpl	(	const IntegrandInput &	input,
		double &	integrand ) const

overrideprotected

Calculate the integrand value for the cost function.

Parameters

input	Input data for the current state
integrand	Reference to store the calculated integrand value

◆ constructProperties() [1/2]

void constructProperties ( )

private

Initialize the goal's properties.

◆ constructProperties() [2/2]

void constructProperties ( )

private

Initialize the goal's properties.

◆ FlattenSpatialVec()

SimTK::Matrix FlattenSpatialVec ( const SimTK::SpatialVec & S ) const

protected

Convert a spatial vector to a matrix representation.

Parameters

S	Spatial vector to flatten

Returns: Matrix representation

◆ getDefaultModeImpl() [1/2]

Mode getDefaultModeImpl ( ) const

inlineoverrideprotected

Get the default mode for this goal.

◆ getDefaultModeImpl() [2/2]

Mode getDefaultModeImpl ( ) const

inlineoverrideprotected

Get the default mode for this goal.

◆ getDivideByDisplacement()

bool getDivideByDisplacement ( ) const

inline

Get whether the goal is divided by displacement.

Returns: True if divided by displacement, false otherwise

◆ getExponent() [1/2]

bool getExponent ( ) const

inline

Get the current exponent value.

Returns: The exponent applied to the ZMP deviation

◆ getExponent() [2/2]

bool getExponent ( ) const

inline

Get the current exponent value.

Returns: The exponent value

◆ getSupportsEndpointConstraintImpl() [1/2]

bool getSupportsEndpointConstraintImpl ( ) const

inlineoverrideprotected

Whether this goal supports endpoint constraint mode.

◆ getSupportsEndpointConstraintImpl() [2/2]

bool getSupportsEndpointConstraintImpl ( ) const

inlineoverrideprotected

Whether this goal supports endpoint constraint mode.

◆ initializeOnModelImpl() [1/2]

void initializeOnModelImpl ( const Model & model ) const

overrideprotected

Initialize the goal with the model.

◆ initializeOnModelImpl() [2/2]

void initializeOnModelImpl ( const Model & ) const

overrideprotected

Initialize the goal with the model.

◆ OpenSim_DECLARE_CONCRETE_OBJECT() [1/2]

OpenSim_DECLARE_CONCRETE_OBJECT	(	MocoZMPGoal	,
		MocoGoal	)

private

◆ OpenSim_DECLARE_CONCRETE_OBJECT() [2/2]

OpenSim_DECLARE_CONCRETE_OBJECT	(	MocoZMPGoal	,
		MocoGoal	)

private

◆ OpenSim_DECLARE_PROPERTY() [1/3]

OpenSim_DECLARE_PROPERTY	(	divide_by_displacement	,
		bool	,
		"Divide by the model's displacement over the phase (default: " "false)"	)

private

◆ OpenSim_DECLARE_PROPERTY() [2/3]

OpenSim_DECLARE_PROPERTY	(	exponent	,
		int	,
		"The exponent applied to the output value in the integrand. " "The output can take on negative values in the integrand when the " "exponent is set to 1 (the default value). When the exponent is " "set to a value greater than	1,
		the absolute value function is " "applied to the	outputbefore the exponent is applied,
		meaning " "that odd numbered exponents(greater than 1) do not take on " "negative values."	)

private

◆ OpenSim_DECLARE_PROPERTY() [3/3]

OpenSim_DECLARE_PROPERTY	(	exponent	,
		int	,
		"The exponent applied to the output value in the integrand. " "The output can take on negative values in the integrand when the " "exponent is set to 1 (the default value). When the exponent is " "set to a value greater than	1,
		the absolute value function is " "applied to the	outputbefore the exponent is applied,
		meaning " "that odd numbered exponents(greater than 1) do not take on " "negative values."	)

private

◆ setDivideByDisplacement()

void setDivideByDisplacement ( bool tf )

inline

Set whether to divide by displacement.

Parameters

tf	True to divide by displacement, false otherwise

Here is the caller graph for this function:

◆ setExponent() [1/2]

void setExponent ( int ex )

inline

Set the exponent for the goal.

Parameters

ex	The exponent value. For ex > 1, absolute value is applied first

◆ setExponent() [2/2]

void setExponent ( int ex )

inline

Set the exponent for the deviation term.

Parameters

ex	The exponent value

Member Data Documentation

◆ m_force_names

std::vector< std::string > m_force_names

mutableprivate

Names of forces to consider for ZMP calculation

Names of forces used in calculations

◆ m_model

OpenSim::Model m_model

mutableprivate

Reference to the model.

Reference to the model being used.

◆ m_power_function

std::function< double(const double &)> m_power_function

mutableprivate

Function to compute power of ZMP deviation.

Function to compute power of values.

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

F:/dev/projects/MocoExtendProblem/custom_goals/MocoZMPGoal/MocoZMPGoal.h
F:/dev/projects/MocoExtendProblem/custom_goals_compat/MocoZMPGoal/MocoZMPGoal.h
F:/dev/projects/MocoExtendProblem/custom_goals/MocoZMPGoal/MocoZMPGoal.cpp
F:/dev/projects/MocoExtendProblem/custom_goals_compat/MocoZMPGoal/MocoZMPGoal.cpp

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ MocoZMPGoal() [1/6]

◆ MocoZMPGoal() [2/6]

◆ MocoZMPGoal() [3/6]

◆ MocoZMPGoal() [4/6]

◆ MocoZMPGoal() [5/6]

◆ MocoZMPGoal() [6/6]

Member Function Documentation

◆ calcGoalImpl() [1/2]

◆ calcGoalImpl() [2/2]

◆ calcIntegrandImpl() [1/2]

◆ calcIntegrandImpl() [2/2]

◆ constructProperties() [1/2]

◆ constructProperties() [2/2]

◆ FlattenSpatialVec()

◆ getDefaultModeImpl() [1/2]

◆ getDefaultModeImpl() [2/2]

◆ getDivideByDisplacement()

◆ getExponent() [1/2]

◆ getExponent() [2/2]

◆ getSupportsEndpointConstraintImpl() [1/2]

◆ getSupportsEndpointConstraintImpl() [2/2]

◆ initializeOnModelImpl() [1/2]

◆ initializeOnModelImpl() [2/2]

◆ OpenSim_DECLARE_CONCRETE_OBJECT() [1/2]

◆ OpenSim_DECLARE_CONCRETE_OBJECT() [2/2]

◆ OpenSim_DECLARE_PROPERTY() [1/3]

◆ OpenSim_DECLARE_PROPERTY() [2/3]

◆ OpenSim_DECLARE_PROPERTY() [3/3]

◆ setDivideByDisplacement()

◆ setExponent() [1/2]

◆ setExponent() [2/2]

Member Data Documentation

◆ m_force_names

◆ m_model

◆ m_power_function