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...

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 212 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 193 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 152 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 123 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 113 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 118 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 107 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()