Gazebo Gazebo

API Reference

6.16.0
AckermannSteering Class Reference

Ackermann steering controller which can be attached to a model with any number of left and right wheels. More...

#include <AckermannSteering.hh>

Public Member Functions

 AckermannSteering ()
 Constructor. More...
 
 ~AckermannSteering () override=default
 Destructor. More...
 
void Configure (const Entity &_entity, const std::shared_ptr< const sdf::Element > &_sdf, EntityComponentManager &_ecm, EventManager &_eventMgr) override
 Configure the system. More...
 
void PostUpdate (const UpdateInfo &_info, const EntityComponentManager &_ecm) override
 
void PreUpdate (const gz::sim::UpdateInfo &_info, gz::sim::EntityComponentManager &_ecm) override
 
- Public Member Functions inherited from System
 System ()=default
 Constructor. More...
 
virtual ~System ()=default
 Destructor. More...
 

Detailed Description

Ackermann steering controller which can be attached to a model with any number of left and right wheels.

System Parameters

<left_joint>: Name of a joint that controls a left wheel. This element can appear multiple times, and must appear at least once.

<right_joint>: Name of a joint that controls a right wheel. This element can appear multiple times, and must appear at least once.

<left_steering_joint>: Name of a joint that controls steering for left wheel. This element must appear once. Vehicles that steer rear wheels are not currently correctly supported.

<right_steering_joint>: Name of a joint that controls steering for right wheel. This element must appear once.

<wheel_separation>: Distance between wheels, in meters. This element is optional, although it is recommended to be included with an appropriate value. The default value is 1.0m.

<kingpin_width>: Distance between wheel kingpins, in meters. This element is optional, although it is recommended to be included with an appropriate value. The default value is 0.8m. Generally a bit smaller than the wheel_separation.

<wheel_base>: Distance between front and rear wheels, in meters. This element is optional, although it is recommended to be included with an appropriate value. The default value is 1.0m.

<steering_limit>: Value to limit steering to. Can be calculated by measuring the turning radius and wheel_base of the real vehicle. steering_limit = asin(wheel_base / turning_radius) The default value is 0.5 radians.

<wheel_radius>: Wheel radius in meters. This element is optional, although it is recommended to be included with an appropriate value. The default value is 0.2m.

<odom_publish_frequency>: Odometry publication frequency. This element is optional, and the default value is 50Hz.

<min_velocity>: Minimum velocity [m/s], usually <= 0. <max_velocity>: Maximum velocity [m/s], usually >= 0. <min_acceleration>: Minimum acceleration [m/s^2], usually <= 0. <max_acceleration>: Maximum acceleration [m/s^2], usually >= 0. <min_jerk Minimum>: jerk [m/s^3], usually <= 0. <max_jerk Maximum>: jerk [m/s^3], usually >= 0.

<topic>: Custom topic that this system will subscribe to in order to receive command velocity messages. This element if optional, and the default value is /model/{name_of_model}/cmd_vel.

<odom_topic>: Custom topic on which this system will publish odometry messages. This element if optional, and the default value is /model/{name_of_model}/odometry.

<tf_topic>: Custom topic on which this system will publish the transform from frame_id to child_frame_id. This element is optional, and the default value is /model/{name_of_model}/tf.

<frame_id>: Custom frame_id field that this system will use as the origin of the odometry transform in both the <tf_topic> ignition.msgs.Pose_V message and the <odom_topic> ignition.msgs.Odometry message. This element if optional, and the default value is {name_of_model}/odom.

<child_frame_id>: Custom child_frame_id that this system will use as the target of the odometry transform in both the <tf_topic> ignition.msgs.Pose_V message and the <odom_topic> ignition.msgs.Odometry message. This element if optional, and the default value is {name_of_model}/{name_of_link}.

A robot with rear drive and front steering would have one each of left_joint, right_joint, left_steering_joint and right_steering_joint

References: https://github.com/gazebosim/gz-sim/tree/main/src/systems/ackermann_steering https://www.auto.tuwien.ac.at/bib/pdf_TR/TR0183.pdf https://github.com/froohoo/ackermansteer/blob/master/ackermansteer/

Constructor & Destructor Documentation

◆ AckermannSteering()

Constructor.

◆ ~AckermannSteering()

~AckermannSteering ( )
overridedefault

Destructor.

Member Function Documentation

◆ Configure()

void Configure ( const Entity _entity,
const std::shared_ptr< const sdf::Element > &  _sdf,
EntityComponentManager _ecm,
EventManager _eventMgr 
)
overridevirtual

Configure the system.

Parameters
[in]_entityThe entity this plugin is attached to.
[in]_sdfThe SDF Element associated with this system plugin.
[in]_ecmThe EntityComponentManager of the given simulation instance.
[in]_eventMgrThe EventManager of the given simulation instance.

Implements ISystemConfigure.

◆ PostUpdate()

void PostUpdate ( const UpdateInfo _info,
const EntityComponentManager _ecm 
)
overridevirtual

Implements ISystemPostUpdate.

◆ PreUpdate()

void PreUpdate ( const gz::sim::UpdateInfo _info,
gz::sim::EntityComponentManager _ecm 
)
overridevirtual

Implements ISystemPreUpdate.


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