API 4.4.1-2022-10-19-2c4045e59
For MATLAB, Python, Java, and C++ users
OpenSim::MocoContactTrackingGoal Class Reference
+ Inheritance diagram for OpenSim::MocoContactTrackingGoal:

Public Member Functions

 MocoContactTrackingGoal ()
 
 MocoContactTrackingGoal (std::string name)
 
 MocoContactTrackingGoal (std::string name, double weight)
 
void setExternalLoadsFile (const std::string &extLoadsFile)
 Set the ExternalLoads as an XML file. More...
 
void setExternalLoads (const ExternalLoads &extLoads)
 Set the ExternalLoads as an object. More...
 
void addContactGroup (const std::vector< std::string > &contactForcePaths, const std::string &externalForceName)
 Add a group of contact forces whose sum should track the force data from a single ExternalForce. More...
 
void addContactGroup (MocoContactTrackingGoalGroup group)
 Add a group of contact forces whose sum should track the force data from a single ExternalForce. More...
 
void setProjection (std::string projection)
 Set if the force error should be projected onto either a vector or plane. More...
 
std::string getProjection () const
 
void setProjectionVector (SimTK::Vec3 normal)
 Set the vector to use for projecting the force error. More...
 
void clearProjectionVector ()
 Unset the projection vector. More...
 
SimTK::Vec3 getProjectionVector () const
 
void addScaleFactor (const std::string &name, const std::string &externalForceName, int index, const MocoBounds &bounds)
 Add a MocoParameter to the problem that will scale the tracking reference data associated with a contact force group. More...
 
- Public Member Functions inherited from OpenSim::MocoGoal
 MocoGoal ()
 
 MocoGoal (std::string name)
 
 MocoGoal (std::string name, double weight)
 
void setEnabled (bool enabled)
 Set whether this goal is used in the problem. More...
 
bool getEnabled () const
 
void setWeight (double weight)
 In cost mode, the goal is multiplied by this weight. More...
 
double getWeight () const
 
void setMode (std::string mode)
 Set the mode property to either 'cost' or 'endpoint_constraint'. More...
 
std::string getModeAsString () const
 This returns the default mode of the goal, unless the user overrode the default using setMode(). More...
 
Mode getMode () const
 
bool getModeIsCost () const
 
bool getModeIsEndpointConstraint () const
 
Mode getDefaultMode () const
 Types of goals have a class-level default for whether they are enforced as a cost or endpoint constraint. More...
 
bool getSupportsEndpointConstraint () const
 Can this goal be used in endpoint constraint mode? More...
 
const MocoConstraintInfogetConstraintInfo () const
 Get bounds for the constraints that are enforced when using this goal in endpoint constraint mode. More...
 
MocoConstraintInfoupdConstraintInfo ()
 
int getNumOutputs () const
 Get the length of the return value of calcGoal(). More...
 
int getNumIntegrals () const
 Get the number of integrals required by this cost. More...
 
SimTK::Stage getStageDependency () const
 Obtain the stage that this goal depends on. More...
 
SimTK::Real calcIntegrand (const IntegrandInput &input) const
 Calculate the integrand that should be integrated and passed to calcCost(). More...
 
void calcGoal (const GoalInput &input, SimTK::Vector &goal) const
 In cost mode, the returned cost includes the weight, and the elements of the returned vector should be summed by the caller to obtain the total cost. More...
 
void initializeOnModel (const Model &model) const
 Perform error checks on user input for this goal, and cache quantities needed when computing the goal value. More...
 
std::vector< MocoScaleFactorgetScaleFactors () const
 Get a vector of the MocoScaleFactors added to this MocoGoal. More...
 
void printDescription () const
 Print the name type and mode of this goal. More...
 
- Public Member Functions inherited from OpenSim::Object
virtual ~Object ()
 Virtual destructor for cleanup. More...
 
bool isEqualTo (const Object &aObject) const
 Equality operator wrapper for use from languages not supporting operator overloading. More...
 
Objectoperator= (const Object &aObject)
 Copy assignment copies he base class fields, including the properties. More...
 
virtual bool operator== (const Object &aObject) const
 Determine if two objects are equal. More...
 
virtual bool operator< (const Object &aObject) const
 Provide an ordering for objects so they can be put in sorted containers. More...
 
void setName (const std::string &name)
 Set the name of the Object. More...
 
const std::string & getName () const
 Get the name of this Object. More...
 
void setDescription (const std::string &description)
 Set description, a one-liner summary. More...
 
const std::string & getDescription () const
 Get description, a one-liner summary. More...
 
const std::string & getAuthors () const
 Get Authors of this Object. More...
 
void setAuthors (const std::string &authors)
 Set Authors of this object. More...
 
const std::string & getReferences () const
 Get references or publications to cite if using this object. More...
 
void setReferences (const std::string &references)
 Set references or publications to cite if using this object. More...
 
int getNumProperties () const
 Determine how many properties are stored with this Object. More...
 
const AbstractPropertygetPropertyByIndex (int propertyIndex) const
 Get a const reference to a property by its index number, returned as an AbstractProperty. More...
 
AbstractPropertyupdPropertyByIndex (int propertyIndex)
 Get a writable reference to a property by its index number, returned as an AbstractProperty. More...
 
bool hasProperty (const std::string &name) const
 Return true if this Object has a property of any type with the given name, which must not be empty. More...
 
const AbstractPropertygetPropertyByName (const std::string &name) const
 Get a const reference to a property by its name, returned as an AbstractProperty. More...
 
AbstractPropertyupdPropertyByName (const std::string &name)
 Get a writable reference to a property by its name, returned as an AbstractProperty. More...
 
template<class T >
bool hasProperty () const
 Return true if this Object contains an unnamed, one-object property that contains objects of the given template type T. More...
 
template<class T >
const Property< T > & getProperty (const PropertyIndex &index) const
 Get property of known type Property<T> as a const reference; the property must be present and have the right type. More...
 
template<class T >
Property< T > & updProperty (const PropertyIndex &index)
 Get property of known type Property<T> as a writable reference; the property must be present and have the right type. More...
 
bool isObjectUpToDateWithProperties () const
 Returns true if no property's value has changed since the last time setObjectIsUpToDateWithProperties() was called. More...
 
void readObjectFromXMLNodeOrFile (SimTK::Xml::Element &objectElement, int versionNumber)
 We're given an XML element from which we are to populate this Object. More...
 
virtual void updateFromXMLNode (SimTK::Xml::Element &objectElement, int versionNumber)
 Use this method to deserialize an object from a SimTK::Xml::Element. More...
 
void updateXMLNode (SimTK::Xml::Element &parent, const AbstractProperty *prop=nullptr) const
 Serialize this object into the XML node that represents it. More...
 
bool getInlined () const
 Inlined means an in-memory Object that is not associated with an XMLDocument. More...
 
void setInlined (bool aInlined, const std::string &aFileName="")
 Mark this as inlined or not and optionally provide a file name to associate with the new XMLDocument for the non-inline case. More...
 
std::string getDocumentFileName () const
 If there is a document associated with this object then return the file name maintained by the document. More...
 
int getDocumentFileVersion () const
 If there is a document associated with this object then return its version number. More...
 
void setAllPropertiesUseDefault (bool aUseDefault)
 
bool print (const std::string &fileName) const
 Write this Object into an XML file of the given name; conventionally the suffix to use is ".osim". More...
 
std::string dump () const
 dump the XML representation of this Object into an std::string and return it. More...
 
virtual bool isA (const char *type) const
 The default implementation returns true only if the supplied string is "Object"; each Object-derived class overrides this to match its own class name. More...
 
const std::string & toString () const
 Wrapper to be used on Java side to display objects in tree; this returns just the object's name. More...
 
PropertySetgetPropertySet ()
 OBSOLETE: Get a reference to the PropertySet maintained by the Object. More...
 
const PropertySetgetPropertySet () const
 

Static Public Member Functions

Auto-generated functions
static MocoContactTrackingGoalsafeDownCast (OpenSim::Object *obj)
 For use in MATLAB and Python to access the concrete class. More...
 
- Static Public Member Functions inherited from OpenSim::MocoGoal
static MocoGoalsafeDownCast (OpenSim::Object *obj)
 For use in MATLAB and Python to access the concrete class. More...
 
static const std::string & getClassName ()
 This returns "MocoGoal"
More...
 
- Static Public Member Functions inherited from OpenSim::Object
static void registerType (const Object &defaultObject)
 Register an instance of a class; if the class is already registered it will be replaced. More...
 
static void renameType (const std::string &oldTypeName, const std::string &newTypeName)
 Support versioning by associating the current Object type with an old name. More...
 
static const ObjectgetDefaultInstanceOfType (const std::string &concreteClassName)
 Return a pointer to the default instance of the registered (concrete) Object whose class name is given, or NULL if the type is not registered. More...
 
template<class T >
static bool isObjectTypeDerivedFrom (const std::string &concreteClassName)
 Return true if the given concrete object type represents a subclass of the template object type T, and thus could be referenced with a T*. More...
 
static ObjectnewInstanceOfType (const std::string &concreteClassName)
 Create a new instance of the concrete Object type whose class name is given as concreteClassName. More...
 
static void getRegisteredTypenames (Array< std::string > &typeNames)
 Retrieve all the typenames registered so far. More...
 
template<class T >
static void getRegisteredObjectsOfGivenType (ArrayPtrs< T > &rArray)
 Return an array of pointers to the default instances of all registered (concrete) Object types that derive from a given Object-derived type that does not have to be concrete. More...
 
static bool PrintPropertyInfo (std::ostream &os, const std::string &classNameDotPropertyName, bool printFlagInfo=true)
 Dump formatted property information to a given output stream, useful for creating a "help" facility for registered objects. More...
 
static bool PrintPropertyInfo (std::ostream &os, const std::string &className, const std::string &propertyName, bool printFlagInfo=true)
 Same as the other signature but the class name and property name are provided as two separate strings. More...
 
static ObjectmakeObjectFromFile (const std::string &fileName)
 Create an OpenSim object whose type is based on the tag at the root node of the XML file passed in. More...
 
static const std::string & getClassName ()
 Return the name of this class as a string; i.e., "Object". More...
 
static void setSerializeAllDefaults (bool shouldSerializeDefaults)
 Static function to control whether all registered objects and their properties are written to the defaults section of output files rather than only those values for which the default was explicitly overwritten when read in from an input file or set programmatically. More...
 
static bool getSerializeAllDefaults ()
 Report the value of the "serialize all defaults" flag. More...
 
static bool isKindOf (const char *type)
 Returns true if the passed-in string is "Object"; each Object-derived class defines a method of this name for its own class name. More...
 
static void setDebugLevel (int newLevel)
 Set the amount of logging output. More...
 
static int getDebugLevel ()
 Get the current setting of debug level. More...
 
static ObjectSafeCopy (const Object *aObject)
 Use the clone() method to duplicate the given object unless the pointer is null in which case null is returned. More...
 
static void RegisterType (const Object &defaultObject)
 OBSOLETE alternate name for registerType(). More...
 
static void RenameType (const std::string &oldName, const std::string &newName)
 OBSOLETE alternate name for renameType(). More...
 

Auto-generated functions <br>

static const std::string & getClassName ()
 This returns "MocoContactTrackingGoal"
More...
 
MocoContactTrackingGoalclone () const override
 Create a new heap-allocated copy of the concrete object to which this Object refers. More...
 
const std::string & getConcreteClassName () const override
 Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string. More...
 

Detailed Description

MocoContactTrackingGoal

Minimize the error between compliant contact force elements in the model and experimentally measured contact forces.

This class handles multiple groups of contact forces and a single experimental external loads file. Tracking ground reaction forces for the left and right feet in gait requires only one instance of this goal.

Note
The only contact element supported is SmoothSphereHalfSpaceForce.
This goal does not include torques or centers of pressure.

This goal is computed as follows:

\[ \frac{1}{mg} \int_{t_i}^{t_f} \sum_{j \in G} \|\mathrm{proj}_{\hat{n}}(\vec{F}_{m,j} - \vec{F}_{e,j})\|^2 ~dt \]

We use the following notation:

  • \( t_i \): the initial time of this phase.
  • \( t_f \): the final time of this phase.
  • \( mg \): the total weight of the system; replaced with \( m \) if \( g = 0 \).
  • \( G \): the set of contact groups.
  • \( \hat{n} \): a vector used for projecting the force error.
  • \( \mathrm{proj}_{\hat{n}}() \): this function projects the force error either onto \( \hat{n} \) or onto the plane perpendicular to \( \hat{n} \).
  • \( \vec{F}_{m,j} \) the sum of the contact forces in group \( j \), expressed in ground.
  • \( \vec{F}_{e,j} \) the experimental contact force for group \( j \), expressed in ground.

Tracking a subset of force components

The projection is useful for selecting which components of the force to track. The force can be projected to be onto a vector or onto a plane. For example, with gait, projecting onto the vector (0, 1, 0) allows tracking only the vertical component of a ground reaction force; projecting onto the plane perpendicular to the vector (0, 0, 1) allows ignoring the transverse force. See the projection and projection_vector properties.

Usage

To use this goal, specify the following:

Configuring the ExternalLoads

The ExternalLoads class is the standard way to provide experimental contact forces in OpenSim. This class is a set of ExternalForce objects. For gait, typically the ExternalLoads contains 2 ExternalForces, one for each foot. This goal uses the following information from ExternalLoads:

  • data_file: This scalar file contains all experimental force data with columns named according to each ExternalForce's force_identifier.

This goal uses the following information from each ExternalForce:

  • name: We use the name of the ExternalForce to associate it with a contact force group.
  • applied_on_body: All contact forces in the group with which this ExternalForce is associated must use this body as either the sphere_frame's base frame or the half_space_frame's base frame.
  • force_expressed_in_body: We use this to re-express the experimental force in ground. This is either the absolute path to a PhysicalFrame in the model, or the name of a Body in the model's BodySet.
  • force_identifier: The ExternalLoads data_file must include the 3 columns <force_identifier>x, <force_identifier>y, <force_identifier>z.

All other properties of ExternalLoads and ExternalForce are ignored by this goal. This means that experimental forces are processed differently by this goal than by other OpenSim tools such as Inverse Dynamics, Computed Muscle Control, and Forward.

Note
The ExternalLoads used by this goal is separate from the model. Using this goal implies that the model contains compliant contact forces, so adding ExternalLoads to the model would be redundant. This class uses the ExternalLoads only for computing the force error, not for applying forces to the model.

Scale factors

Add a MocoParameter to the problem that will scale the tracking reference data associated with a contact force group. Scale factors are applied to the tracking error calculations based on the following equation:

 error = modelValue - scaleFactor * referenceValue

In other words, the scale factor is applied when computing the tracking error for each contact force group, not to the reference data directly. You must specify both the external force name associated with the contact force group and the index corresponding to the direction (i.e., X = 0, Y = 1, Z = 2) of the scaled force value. The direction is applied in whatever frame the reference data is expressed in based on the provided ExternalLoads in each contact group.

Adding a scale factor to a MocoContactTrackingGoal.

auto* contactTrackingGoal = problem.addGoal<MocoContactTrackingGoal>();
...
contactTrackingGoal->addScaleFactor(
'RightGRF_vertical_scale_factor', 'Right_GRF', 1, {0.5, 2.0});
MocoContactTrackingGoal()
Definition: MocoContactTrackingGoal.h:191

Constructor & Destructor Documentation

◆ MocoContactTrackingGoal() [1/3]

OpenSim::MocoContactTrackingGoal::MocoContactTrackingGoal ( )
inline

◆ MocoContactTrackingGoal() [2/3]

OpenSim::MocoContactTrackingGoal::MocoContactTrackingGoal ( std::string  name)
inline

◆ MocoContactTrackingGoal() [3/3]

OpenSim::MocoContactTrackingGoal::MocoContactTrackingGoal ( std::string  name,
double  weight 
)
inline

Member Function Documentation

◆ addContactGroup() [1/2]

void OpenSim::MocoContactTrackingGoal::addContactGroup ( const std::vector< std::string > &  contactForcePaths,
const std::string &  externalForceName 
)
inline

Add a group of contact forces whose sum should track the force data from a single ExternalForce.

The externalForceName should be the name of an ExternalForce object in the ExternalLoads.

◆ addContactGroup() [2/2]

void OpenSim::MocoContactTrackingGoal::addContactGroup ( MocoContactTrackingGoalGroup  group)
inline

Add a group of contact forces whose sum should track the force data from a single ExternalForce.

If the contact force elements associated with a single ExternalForce are distributed across multiple bodies use this function instead of the easier-to-use addContactGroup(), and set the group's alternative_frame_paths property accordingly. See MocoContactTrackingGoalGroup for more information.

◆ addScaleFactor()

void OpenSim::MocoContactTrackingGoal::addScaleFactor ( const std::string &  name,
const std::string &  externalForceName,
int  index,
const MocoBounds bounds 
)

Add a MocoParameter to the problem that will scale the tracking reference data associated with a contact force group.

Scale factors are applied to the tracking error calculations based on the following equation:

error = modelValue - scaleFactor * referenceValue

In other words, the scale factor is applied when computing the tracking error for each contact force group, not to the reference data directly. You must specify both the external force name associated with the contact force group and the index corresponding to the direction (i.e., X = 0, Y = 1, Z = 2) of the scaled force value. The direction is applied in whatever frame the reference data is expressed in based on the provided ExternalLoads in each contact group.

◆ calcGoalImpl()

void OpenSim::MocoContactTrackingGoal::calcGoalImpl ( const GoalInput input,
SimTK::Vector &  goal 
) const
inlineoverrideprotectedvirtual

You may need to realize the state to the stage required for your calculations.

Do NOT realize to a stage higher than the goal's stage dependency; doing so will cause an exception to be thrown. The Lagrange multipliers for kinematic constraints are not available.

Implements OpenSim::MocoGoal.

References OpenSim::MocoGoal::GoalInput::integral.

◆ calcIntegrandImpl()

void OpenSim::MocoContactTrackingGoal::calcIntegrandImpl ( const IntegrandInput input,
double &  integrand 
) const
overrideprotected

◆ clearProjectionVector()

void OpenSim::MocoContactTrackingGoal::clearProjectionVector ( )
inline

Unset the projection vector.

◆ clone()

MocoContactTrackingGoal * OpenSim::MocoContactTrackingGoal::clone ( ) const
inlineoverridevirtual

Create a new heap-allocated copy of the concrete object to which this Object refers.

It is up to the caller to delete the returned object when no longer needed. Every concrete object deriving from Object implements this pure virtual method automatically, via the declaration macro it invokes (e.g., OpenSim_DECLARE_CONCRETE_OBJECT()). Note that the concrete class overrides modify the return type to be a pointer to the concrete object; that still overrides the base class method because the return type is covariant with (that is, derives from) Object.

Implements OpenSim::MocoGoal.

◆ getClassName()

static const std::string & OpenSim::MocoContactTrackingGoal::getClassName ( )
inlinestatic

This returns "MocoContactTrackingGoal"

See getConcreteClassName() if you want the class name of the underlying concrete object instead.

◆ getConcreteClassName()

const std::string & OpenSim::MocoContactTrackingGoal::getConcreteClassName ( ) const
inlineoverridevirtual

Returns the class name of the concrete Object-derived class of the actual object referenced by this Object, as a string.

This is the string that is used as the tag for this concrete object in an XML file. Every concrete class derived from Object automatically overrides this method via the declaration macro it uses. See getClassName() to get the class name of the referencing (possibly abstract) class rather than the concrete object.

See also
getClassName()

Implements OpenSim::MocoGoal.

◆ getProjection()

std::string OpenSim::MocoContactTrackingGoal::getProjection ( ) const
inline

◆ getProjectionVector()

SimTK::Vec3 OpenSim::MocoContactTrackingGoal::getProjectionVector ( ) const
inline

◆ initializeOnModelImpl()

void OpenSim::MocoContactTrackingGoal::initializeOnModelImpl ( const Model ) const
overrideprotectedvirtual

Perform any caching before the problem is solved.

You must override this function and invoke setRequirements().

Precondition(s):
The model is initialized (initSystem()) and getModel() is available. The passed-in model is equivalent to getModel(). Use this opportunity to check for errors in user input.

Implements OpenSim::MocoGoal.

◆ printDescriptionImpl()

void OpenSim::MocoContactTrackingGoal::printDescriptionImpl ( ) const
overrideprotectedvirtual

Print a more detailed description unique to each goal.

Reimplemented from OpenSim::MocoGoal.

◆ safeDownCast()

static MocoContactTrackingGoal * OpenSim::MocoContactTrackingGoal::safeDownCast ( OpenSim::Object obj)
inlinestatic

For use in MATLAB and Python to access the concrete class.

Example: cObj = MocoContactTrackingGoal.safeDownCast(obj). This is equivalent to dynamic_cast<MocoContactTrackingGoal*>(obj) in C++.

◆ setExternalLoads()

void OpenSim::MocoContactTrackingGoal::setExternalLoads ( const ExternalLoads extLoads)

Set the ExternalLoads as an object.

This clears the ExternalLoads XML file, if provided.

◆ setExternalLoadsFile()

void OpenSim::MocoContactTrackingGoal::setExternalLoadsFile ( const std::string &  extLoadsFile)

Set the ExternalLoads as an XML file.

This clears the ExternalLoads provided as an object, if one exists.

◆ setProjection()

void OpenSim::MocoContactTrackingGoal::setProjection ( std::string  projection)
inline

Set if the force error should be projected onto either a vector or plane.

Possible values: "none" (default), "vector", and "plane".

◆ setProjectionVector()

void OpenSim::MocoContactTrackingGoal::setProjectionVector ( SimTK::Vec3  normal)
inline

Set the vector to use for projecting the force error.

If the projection type is "vector", the force error is projected onto the vector provided here. If the projection type is "plane", the force error is projected onto the plane perpendicular to this vector.


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