Standard DWA-like trajectory generator. More...

#include <nav2_dwb_controller/dwb_plugins/include/dwb_plugins/standard_traj_generator.hpp>

Inheritance diagram for dwb_plugins::StandardTrajectoryGenerator:

Collaboration diagram for dwb_plugins::StandardTrajectoryGenerator:

Public Member Functions
void	initialize (const nav2::LifecycleNode::SharedPtr &nh, const std::string &plugin_name) override
	Initialize parameters as needed. More...

void	startNewIteration (const nav_2d_msgs::msg::Twist2D &current_velocity) override
	Start a new iteration based on the current velocity. More...

bool	hasMoreTwists () override
	Test to see whether there are more twists to test. More...

nav_2d_msgs::msg::Twist2D	nextTwist () override
	Return the next twist and advance the iteration. More...

dwb_msgs::msg::Trajectory2D	generateTrajectory (const geometry_msgs::msg::Pose &start_pose, const nav_2d_msgs::msg::Twist2D &start_vel, const nav_2d_msgs::msg::Twist2D &cmd_vel) override
	Given a cmd_vel in the robot's frame and initial conditions, generate a Trajectory2D. More...

void	setSpeedLimit (const double &speed_limit, const bool &percentage) override
	Limits the maximum linear speed of the robot. More...

void	activate ()
	Registers callbacks for dynamic parameter handling.

void	deactivate ()
	Resets callbacks for dynamic parameter handling.

Public Member Functions inherited from dwb_core::TrajectoryGenerator
virtual void	reset ()

virtual std::vector< nav_2d_msgs::msg::Twist2D >	getTwists (const nav_2d_msgs::msg::Twist2D &current_velocity)
	Get all the twists for an iteration. More...

Protected Member Functions
virtual void	initializeIterator (const nav2::LifecycleNode::SharedPtr &nh)
	Initialize the VelocityIterator pointer. Put in its own function for easy overriding.

virtual nav_2d_msgs::msg::Twist2D	computeNewVelocity (const nav_2d_msgs::msg::Twist2D &cmd_vel, const nav_2d_msgs::msg::Twist2D &start_vel, const double dt)
	Calculate the velocity after a set period of time, given the desired velocity and acceleration limits. More...

virtual geometry_msgs::msg::Pose	computeNewPosition (const geometry_msgs::msg::Pose start_pose, const nav_2d_msgs::msg::Twist2D &vel, const double dt)
	Use the robot's kinematic model to predict new positions for the robot. More...

virtual std::vector< double >	getTimeSteps (const nav_2d_msgs::msg::Twist2D &cmd_vel)
	Compute an array of time deltas between the points in the generated trajectory. More...

Protected Attributes
KinematicsHandler::Ptr	kinematics_handler_

std::shared_ptr< VelocityIterator >	velocity_iterator_

double	sim_time_

bool	discretize_by_time_

double	time_granularity_
	If discretizing by time, the amount of time between each point in the traj.

double	linear_granularity_
	If not discretizing by time, the amount of linear space between points.

double	angular_granularity_
	If not discretizing by time, the amount of angular space between points.

std::string	plugin_name_
	the name of the overlying plugin ID

bool	limit_vel_cmd_in_traj_
	Option to limit velocity in the trajectory generator by using current velocity.

bool	include_last_point_

Additional Inherited Members
Public Types inherited from dwb_core::TrajectoryGenerator
typedef std::shared_ptr< dwb_core::TrajectoryGenerator >	Ptr

Detailed Description

Standard DWA-like trajectory generator.

Definition at line 55 of file standard_traj_generator.hpp.

Member Function Documentation

◆ computeNewPosition()

geometry_msgs::msg::Pose dwb_plugins::StandardTrajectoryGenerator::computeNewPosition	(	const geometry_msgs::msg::Pose	start_pose,
		const nav_2d_msgs::msg::Twist2D &	vel,
		const double	dt
	)

protectedvirtual

Use the robot's kinematic model to predict new positions for the robot.

Parameters

start_pose	Starting pose
vel	Actual robot velocity (assumed to be within acceleration limits)
dt	amount of time in seconds

Returns: New pose after dt seconds

Definition at line 222 of file standard_traj_generator.cpp.

Referenced by generateTrajectory().

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◆ computeNewVelocity()

nav_2d_msgs::msg::Twist2D dwb_plugins::StandardTrajectoryGenerator::computeNewVelocity	(	const nav_2d_msgs::msg::Twist2D &	cmd_vel,
		const nav_2d_msgs::msg::Twist2D &	start_vel,
		const double	dt
	)

protectedvirtual

Calculate the velocity after a set period of time, given the desired velocity and acceleration limits.

Parameters

cmd_vel	Desired velocity
start_vel	starting velocity
dt	amount of time in seconds

Returns: new velocity after dt seconds

change vel using acceleration limits to converge towards sample_target-vel

Reimplemented in dwb_plugins::LimitedAccelGenerator.

Definition at line 203 of file standard_traj_generator.cpp.

Referenced by generateTrajectory().

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◆ generateTrajectory()

dwb_msgs::msg::Trajectory2D dwb_plugins::StandardTrajectoryGenerator::generateTrajectory	(	const geometry_msgs::msg::Pose &	start_pose,
		const nav_2d_msgs::msg::Twist2D &	start_vel,
		const nav_2d_msgs::msg::Twist2D &	cmd_vel
	)

overridevirtual

Given a cmd_vel in the robot's frame and initial conditions, generate a Trajectory2D.

Parameters

start_pose	Current robot location
start_vel	Current robot velocity
cmd_vel	The desired command velocity

Implements dwb_core::TrajectoryGenerator.

Definition at line 162 of file standard_traj_generator.cpp.

References computeNewPosition(), computeNewVelocity(), getTimeSteps(), and limit_vel_cmd_in_traj_.

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◆ getTimeSteps()

std::vector< double > dwb_plugins::StandardTrajectoryGenerator::getTimeSteps ( const nav_2d_msgs::msg::Twist2D & cmd_vel )

protectedvirtual

Compute an array of time deltas between the points in the generated trajectory.

Parameters

cmd_vel The desired command velocity

Returns: vector of the difference between each time step in the generated trajectory

If we are discretizing by time, the returned vector will be the same constant time_granularity for all cmd_vels. Otherwise, you will get times based on the linear/angular granularity.

Right now the vector contains a single value repeated many times, but this method could be overridden to allow for dynamic spacing

Definition at line 133 of file standard_traj_generator.cpp.

References angular_granularity_, linear_granularity_, and time_granularity_.

Referenced by generateTrajectory().

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◆ hasMoreTwists()

bool dwb_plugins::StandardTrajectoryGenerator::hasMoreTwists ( )

overridevirtual

Test to see whether there are more twists to test.

Returns: True if more twists, false otherwise

Implements dwb_core::TrajectoryGenerator.

Definition at line 123 of file standard_traj_generator.cpp.

◆ initialize()

void dwb_plugins::StandardTrajectoryGenerator::initialize	(	const nav2::LifecycleNode::SharedPtr &	nh,
		const std::string &	plugin_name
	)

overridevirtual

Initialize parameters as needed.

Parameters

nh	NodeHandle to read parameters from

Implements dwb_core::TrajectoryGenerator.

Definition at line 50 of file standard_traj_generator.cpp.

References angular_granularity_, initializeIterator(), limit_vel_cmd_in_traj_, linear_granularity_, plugin_name_, and time_granularity_.

Referenced by dwb_plugins::LimitedAccelGenerator::initialize().

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◆ nextTwist()

nav_2d_msgs::msg::Twist2D dwb_plugins::StandardTrajectoryGenerator::nextTwist ( )

overridevirtual

Return the next twist and advance the iteration.

Returns: The Twist!

Implements dwb_core::TrajectoryGenerator.

Definition at line 128 of file standard_traj_generator.cpp.

◆ setSpeedLimit()

void dwb_plugins::StandardTrajectoryGenerator::setSpeedLimit	(	const double &	speed_limit,
		const bool &	percentage
	)

inlineoverridevirtual

Limits the maximum linear speed of the robot.

Parameters

speed_limit	expressed in absolute value (in m/s) or in percentage from maximum robot speed.
percentage	Setting speed limit in percentage if true or in absolute values in false case.

Implements dwb_core::TrajectoryGenerator.

Definition at line 78 of file standard_traj_generator.hpp.

◆ startNewIteration()

void dwb_plugins::StandardTrajectoryGenerator::startNewIteration ( const nav_2d_msgs::msg::Twist2D & current_velocity )

overridevirtual

Start a new iteration based on the current velocity.

Parameters

current_velocity

Implements dwb_core::TrajectoryGenerator.

Definition at line 117 of file standard_traj_generator.cpp.

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

nav2_dwb_controller/dwb_plugins/include/dwb_plugins/standard_traj_generator.hpp
nav2_dwb_controller/dwb_plugins/src/standard_traj_generator.cpp

Public Member Functions

Protected Member Functions

Protected Attributes

Additional Inherited Members

Detailed Description

Member Function Documentation

◆ computeNewPosition()

◆ computeNewVelocity()

◆ generateTrajectory()

◆ getTimeSteps()

◆ hasMoreTwists()

◆ initialize()

◆ nextTwist()

◆ setSpeedLimit()

◆ startNewIteration()