chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU Class Reference

Description

Definition of the GPU granular terrain node (using Chrono::Gpu).

#include <ChVehicleCosimTerrainNodeGranularGPU.h>

Inheritance diagram for chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU:

Collaboration diagram for chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU:

Public Member Functions
	ChVehicleCosimTerrainNodeGranularGPU (double length, double width)
	Create a Chrono::Granular terrain node.
	ChVehicleCosimTerrainNodeGranularGPU (const std::string &specfile)
	Create a Chrono::Granular terrain node and set parameters from the provided JSON specfile.
virtual ChSystem *	GetSystem () override
	Return a pointer to the underlying Chrono system.
void	SetFromSpecfile (const std::string &specfile)
	Set full terrain specification from JSON specfile.
void	SetGranularMaterial (double radius, double density)
	Set properties of granular material. More...
void	SetMaterialSurface (const std::shared_ptr< ChContactMaterialSMC > &mat)
	Set the material properties for terrain. More...
void	SetTangentialDisplacementModel (gpu::CHGPU_FRICTION_MODE model)
	Set the normal contact force model (default: Hertz). /void SetContactForceModel(ChSystemSMC::ContactForceModel model);. More...
void	SetSamplingMethod (utils::SamplingType type, double init_height, double sep_factor=1.001, bool in_layers=false)
	Set sampling method for generation of granular material. More...
void	SetIntegratorType (gpu::CHGPU_TIME_INTEGRATOR type)
	Set the integrator type (default: CENTERED_DIFFERENCE)
void	SetInputFromCheckpoint (const std::string &filename)
	Initialize granular terrain from the specified checkpoint file (which must exist in the output directory). More...
void	SetSettlingTime (double time)
	Set simulation length for settling of granular material (default: 0.4).
void	SetSettlingKineticEneryThreshold (double threshold)
	Set total kinetic energy threshold as stopping criteria for settling (default: 1e-3).
void	EnableSettlingOutput (bool output, double output_fps=100)
	Enable/disable output during settling (default: false). More...
void	Settle ()
	Obtain settled terrain configuration. More...
virtual void	OnInitialize (unsigned int num_objects) override
	Initialize this Chrono terrain node. More...
virtual void	WriteCheckpoint (const std::string &filename) const override
	Write checkpoint to the specified file (which will be created in the output directory).
double	CalculatePackingDensity (double &depth)
	Estimate packing density (eta) of granular material in current configuration. More...
virtual void	OutputVisualizationData (int frame) override final
	Output post-processing visualization data.
Public Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
Type	GetType () const
	Return the type of this terrain node.
void	SetProxyFixed (bool fixed)
	Set the proxy bodies as fixed to ground.
virtual double	GetInitHeight () const override final
	Return the terrain initial height.
void	AddRigidObstacle (const RigidObstacle &obstacle)
	Add a rigid obstacle.
Public Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNode
virtual NodeType	GetNodeType () const override
	Return the node type as NodeType::TERRAIN.
void	SetDimensions (double length, double width)
	Set the terrain patch dimensions. More...
void	GetDimensions (double &length, double &width)
	Get the terrain patch dimensions.
virtual void	Initialize () override final
	Initialize this node. More...
virtual void	Synchronize (int step_number, double time) override final
	Synchronize this node. More...
virtual void	Advance (double step_size) override final
	Advance simulation. More...
virtual void	OutputData (int frame) override final
	Output logging and debugging data.
Public Member Functions inherited from chrono::vehicle::ChVehicleCosimBaseNode
std::string	GetNodeTypeString () const
	Return the node type as a string.
bool	IsCosimNode () const
	Return true if this node is part of the co-simulation infrastructure.
void	SetStepSize (double step)
	Set the integration step size (default: 1e-4).
double	GetStepSize () const
	Get the integration step size.
void	SetOutDir (const std::string &dir_name, const std::string &suffix="")
	Set the name of the output directory and an identifying suffix. More...
void	SetVerbose (bool verbose)
	Enable/disable verbose messages during simulation (default: true).
void	EnableRuntimeVisualization (double render_fps=100, bool save_img=false)
	Enable run-time visualization (default: false). More...
void	SetCameraPosition (const ChVector3d &cam_pos, const ChVector3d &cam_target=VNULL)
	Set camera location and target point.
void	SetCameraTracking (bool track)
	Enable/disable tracking of objects (default: true).
void	EnablePostprocessVisualization (double render_fps=100)
	Enable Blender postprocessing (default: false). More...
const std::string &	GetOutDirName () const
	Get the output directory name for this node.
double	GetStepExecutionTime () const
	Get the simulation execution time for the current step on this node. More...
double	GetTotalExecutionTime () const
	Get the cumulative simulation execution time on this node.
void	Render (double step_size)
	Render simulation frame. More...

Additional Inherited Members
Public Types inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
enum	Type {   Type::RIGID, Type::SCM, Type::GRANULAR_OMP, Type::GRANULAR_GPU,   Type::GRANULAR_SPH, Type::UNKNOWN }
	Type of Chrono terrain. More...
Public Types inherited from chrono::vehicle::ChVehicleCosimBaseNode
enum	NodeType { NodeType::MBS_WHEELED, NodeType::MBS_TRACKED, NodeType::TERRAIN, NodeType::TIRE }
	Type of node participating in co-simulation. More...
enum	InterfaceType { InterfaceType::BODY, InterfaceType::MESH }
	Type of the vehicle-terrain communication interface. More...
Static Public Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
static std::string	GetTypeAsString (Type type)
	Return a string describing the type of this terrain node.
static Type	GetTypeFromString (const std::string &type)
	Infer the terrain node type from the given string.
static bool	ReadSpecfile (const std::string &specfile, rapidjson::Document &d)
	Read a JSON specification file for a Chrono terrain node.
static Type	GetTypeFromSpecfile (const std::string &specfile)
	Get the terrain type from the given JSON specification file.
static ChVector2d	GetSizeFromSpecfile (const std::string &specfile)
	Get the terrain dimensions (length and width) from the given JSON specification file.
Static Public Member Functions inherited from chrono::vehicle::ChVehicleCosimBaseNode
static std::string	OutputFilename (const std::string &dir, const std::string &root, const std::string &ext, int frame, int frame_digits)
	Utility function for creating an output file name. More...
Protected Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
	ChVehicleCosimTerrainNodeChrono (Type type, double length, double width, ChContactMethod method)
	Construct a base class terrain node. More...
virtual void	CreateMeshProxy (unsigned int i)
	Create the i-th proxy mesh. More...
Protected Member Functions inherited from chrono::vehicle::ChVehicleCosimTerrainNode
	ChVehicleCosimTerrainNode (double length, double width)
	Construct a terrain node to wrap a terrain patch of given length and width.
virtual void	OnSynchronize (int step_number, double time)
	Perform any additional operations after the data exchange and synchronization with the MBS node. More...
virtual void	UpdateMeshProxy (unsigned int i, MeshState &mesh_state)
	Update the state of the i-th proxy mesh. More...
virtual void	GetForceMeshProxy (unsigned int i, MeshContact &mesh_contact)
	Collect cumulative contact forces on the i-th proxy mesh. More...
Protected Member Functions inherited from chrono::vehicle::ChVehicleCosimBaseNode
	ChVehicleCosimBaseNode (const std::string &name)
void	SendGeometry (const utils::ChBodyGeometry &geom, int dest) const
	Utility function to pack and send a struct with geometry information.
void	RecvGeometry (utils::ChBodyGeometry &geom, int source) const
	Utility function to receive and unpack a struct with geometry information.
void	ProgressBar (unsigned int x, unsigned int n, unsigned int w=50)
	Utility function to display a progress bar to the terminal. More...
Protected Attributes inherited from chrono::vehicle::ChVehicleCosimTerrainNodeChrono
Type	m_type
	terrain type
ChContactMethod	m_method
	contact method (SMC or NSC)
std::shared_ptr< ChContactMaterial >	m_material_terrain
	material properties for terrain bodies
double	m_init_height
	terrain initial height
std::vector< std::shared_ptr< Proxy > >	m_proxies
	proxies for solid objects
bool	m_fixed_proxies
	are proxies fixed to ground?
std::vector< RigidObstacle >	m_obstacles
	list of rigid obstacles
Protected Attributes inherited from chrono::vehicle::ChVehicleCosimTerrainNode
double	m_dimX
	patch length (X direction)
double	m_dimY
	patch width (Y direction)
bool	m_wheeled
	comm node (true: TIRE nodes, false: tracked MBS node)
InterfaceType	m_interface_type
	communication interface (body or mesh)
int	m_num_objects
	number of interacting objects
std::vector< ChVector3d >	m_init_loc
	initial locations of interacting objects
std::vector< ChAABB >	m_aabb
	AABB of collision models for interacting objects.
std::vector< utils::ChBodyGeometry >	m_geometry
	contact geometry and materials for interacting objects
std::vector< double >	m_load_mass
	vertical load on interacting objects
std::vector< int >	m_obj_map
	mapping from interacting object to shape
std::vector< MeshState >	m_mesh_state
	mesh state (used for MESH communication)
std::vector< BodyState >	m_rigid_state
	rigid state (used for BODY communication interface)
std::vector< MeshContact >	m_mesh_contact
	mesh contact forces (used for MESH communication interface)
std::vector< TerrainForce >	m_rigid_contact
	rigid contact force (used for BODY communication interface)
Protected Attributes inherited from chrono::vehicle::ChVehicleCosimBaseNode
int	m_rank
	MPI rank of this node (in MPI_COMM_WORLD)
double	m_step_size
	integration step size
std::string	m_name
	name of the node
std::string	m_out_dir
	top-level output directory
std::string	m_node_out_dir
	node-specific output directory
std::ofstream	m_outf
	output file stream
bool	m_renderRT
	if true, perform run-time rendering
bool	m_renderRT_all
	if true, render all frames
double	m_renderRT_step
	time step between rendered frames
bool	m_writeRT
	if true, write images to file
bool	m_renderPP
	if true, save data for post-processing
bool	m_renderPP_all
	if true, save data at all frames
double	m_renderPP_step
	time step between post-processing save frames
bool	m_track
	track objects
ChVector3d	m_cam_pos
	camera location
ChVector3d	m_cam_target
	camera target (lookat) point
unsigned int	m_num_wheeled_mbs_nodes
unsigned int	m_num_tracked_mbs_nodes
unsigned int	m_num_terrain_nodes
unsigned int	m_num_tire_nodes
ChTimer	m_timer
	timer for integration cost
double	m_cum_sim_time
	cumulative integration cost
bool	m_verbose
	verbose messages during simulation?
Static Protected Attributes inherited from chrono::vehicle::ChVehicleCosimBaseNode
static const double	m_gacc = -9.81

Member Function Documentation

CalculatePackingDensity()

double chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::CalculatePackingDensity

(

double &

depth

)

Estimate packing density (eta) of granular material in current configuration.

Note that porosity is phi=1-eta and void ratio is e=(1-eta)/eta=phi/(1-phi). The function also returns the current depth of granular material.

EnableSettlingOutput()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::EnableSettlingOutput	(	bool	output,
		double	output_fps = 100
	)

Enable/disable output during settling (default: false).

If enabled, output files are generated with the specified frequency.

OnInitialize()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::OnInitialize ( unsigned int  num_objects )

overridevirtual

Initialize this Chrono terrain node.

Construct the terrain system and the proxy bodies, then finalize the underlying system.

Reimplemented from chrono::vehicle::ChVehicleCosimTerrainNodeChrono.

SetGranularMaterial()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::SetGranularMaterial	(	double	radius,
		double	density
	)

Set properties of granular material.

Parameters

radius	particle radius (default: 0.01)
density	particle material density (default: 2000)

SetInputFromCheckpoint()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::SetInputFromCheckpoint

(

const std::string &

filename

)

Initialize granular terrain from the specified checkpoint file (which must exist in the output directory).

By default, particles are created uniformly distributed in the specified domain such that they are initially not in contact.

SetMaterialSurface()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::SetMaterialSurface

(

const std::shared_ptr< ChContactMaterialSMC > &

mat

)

Set the material properties for terrain.

These parameters characterize the material for the container and the granular material. Object contact material is received from the rig node.

SetSamplingMethod()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::SetSamplingMethod	(	utils::SamplingType	type,
		double	init_height,
		double	sep_factor = 1.001,
		bool	in_layers = false
	)

Set sampling method for generation of granular material.

The granular material is created in the volume defined by the x-y dimensions of the terrain patch and the specified initial height, using the specified sampling type, layer by layer or all at once. Note: for correct HCP, do not initialize in layers!

Parameters

type	volume sampling type (default POISSON_DISK)
init_height	height of granular material at initialization (default 0.2)
sep_factor	radius inflation factor for initial separation
in_layers	initialize material in layers

SetTangentialDisplacementModel()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::SetTangentialDisplacementModel

(

gpu::CHGPU_FRICTION_MODE

model

)

Set the normal contact force model (default: Hertz). /void SetContactForceModel(ChSystemSMC::ContactForceModel model);.

Set the tangential contact displacement model (default: SINGLE_STEP).

Settle()

void chrono::vehicle::ChVehicleCosimTerrainNodeGranularGPU::Settle

(

)

Obtain settled terrain configuration.

This is an optional operation that can be performed for granular terrain before initiating communictation with the rig node. For granular terrain, a settled configuration can be obtained either through simulation or by initializing particles from a previously generated checkpointing file.

---

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

• /builds/uwsbel/chrono/src/chrono_vehicle/cosim/terrain/ChVehicleCosimTerrainNodeGranularGPU.h
• /builds/uwsbel/chrono/src/chrono_vehicle/cosim/terrain/ChVehicleCosimTerrainNodeGranularGPU.cpp