easynav_serest_controller

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README

easynav_serest_controller

Description

A SeReST (Smooth Error-Responsive Speed and Turning) controller for path tracking.

Authors and Maintainers

• Authors: Intelligent Robotics Lab

• Maintainers: Francisco Martín Rico fmrico@gmail.com

Supported ROS 2 Distributions

Distribution	Status
humble
jazzy
kilted
rolling

Plugin (pluginlib)

• Plugin Name: easynav_serest_controller/SerestController

• Type: easynav::SerestController

• Base Class: easynav::ControllerMethodBase

• Library: easynav_serest_controller

• Description: A SeReST (Smooth Error-Responsive Speed and Turning) controller for path tracking.

Parameters

All parameters are declared under the plugin namespace, i.e., /<node_fqn>/easynav_serest_controller/SerestController/....

This plugin derives from easynav::ControllerMethodBase.
See that section for shared collision-checking parameters and debug markers common to all controllers.

Name	Type	Default	Description
<plugin>.a_acc	double	0.8	Comfortable forward acceleration (m/s²).
<plugin>.a_brake	double	1.2	Comfortable braking deceleration (m/s²).
<plugin>.a_lat_max	double	1.5	Maximum lateral acceleration (m/s²).
<plugin>.a_lat_soft	double	1.1	Soft lateral acceleration bound (m/s²).
<plugin>.allow_reverse	bool	false	Allow reversing when beneficial.
<plugin>.apex_ey_des	double	0.05	Desired lateral error at apex for shaping (m).
<plugin>.blend_base	double	0.6	Base blending factor for curvature tracking.
<plugin>.blend_k_per_v	double	0.6	Additional blending proportional to speed.
<plugin>.corner_boost_omega	double	0.8	Omega boost when cornering.
<plugin>.corner_gain_eth	double	0.7	Cornering gain for heading error.
<plugin>.corner_gain_ey	double	1.5	Cornering gain for lateral error.
<plugin>.corner_gain_kappa	double	0.4	Cornering gain for curvature error.
<plugin>.corner_guard_enable	bool	true	Enable cornering guard logic.
<plugin>.corner_min_alpha	double	0.35	Minimum blending near corners.
<plugin>.d0_margin	double	0.30	Base obstacle clearance margin (m).
<plugin>.d_hard	double	0.20	Hard-stop distance threshold (m).
<plugin>.dist_search_radius	double	2.0	Search radius when matching to path (m).
<plugin>.ell	double	``	Lookahead distance (m).
<plugin>.eps	double	1e-3	Small epsilon to avoid division by zero.
<plugin>.final_align_k	double	2.0	Gain used during final alignment.
<plugin>.final_align_wmax	double	0.6	Max angular speed during final alignment (rad/s).
<plugin>.goal_pos_tol	double	0.05	Goal position tolerance (m).
<plugin>.goal_yaw_tol_deg	double	5.0	Goal yaw tolerance (degrees).
<plugin>.k_s	double	``	Gain on progress along path (s).
<plugin>.k_s_share_max	double	0.5	Max share of speed from s-progress term.
<plugin>.k_theta	double	``	Heading error gain.
<plugin>.k_y	double	``	Lateral error gain.
<plugin>.kappa_max	double	2.5	Maximum allowed curvature (1/m).
<plugin>.max_angular_acc	double	2.0	Angular acceleration limit (rad/s²).
<plugin>.max_angular_speed	double	1.5	Angular speed limit (rad/s).
<plugin>.max_linear_acc	double	0.8	Linear acceleration limit (m/s²).
<plugin>.max_linear_speed	double	0.6	Speed limit (m/s).
<plugin>.slow_min_speed	double	0.03	Minimum speed within slow zone (m/s).
<plugin>.slow_radius	double	0.60	Radius to start slowing down near goal (m).
<plugin>.t_emerg	double	0.25	Emergency stop time horizon (s).
<plugin>.tau_latency	double	0.10	Actuation latency (s).
<plugin>.v_progress_min	double	0.05	Minimum forward speed to ensure progress (m/s).
<plugin>.v_ref	double	0.6	Nominal reference speed (m/s).

Interfaces (Topics and Services)

Subscriptions and Publications

This controller communicates through NavState (no direct ROS topics in this plugin).

Services

This package does not create service servers or clients.

NavState Keys

Key	Type	Access	Notes
path	nav_msgs::msg::Path	Read	Reference path.
robot_pose	nav_msgs::msg::Odometry	Read	Robot odometry.
points	PointPerceptions	Read	Obstacle point cloud(s).
closest_obstacle_distance	double	Read	Precomputed dynamic obstacle metric.
cmd_vel	geometry_msgs::msg::TwistStamped	Write	Commanded velocity.
serest.debug.e_y	double/int	Write	Debug metric
serest.debug.e_theta	double/int	Write	Debug metric
serest.debug.kappa_hat	double/int	Write	Debug metric
serest.debug.d_closest	double/int	Write	Debug metric
serest.debug.v_safe	double/int	Write	Debug metric
serest.debug.v_curv	double/int	Write	Debug metric
serest.debug.alpha	double/int	Write	Debug metric
serest.debug.allow_reverse	double/int	Write	Debug metric
serest.debug.dist_to_end	double/int	Write	Debug metric
serest.debug.goal.dist_xy	double/int	Write	Debug metric
serest.debug.goal.gamma_slow	double/int	Write	Debug metric
serest.debug.goal.in_final_align	double/int	Write	Debug metric
serest.debug.goal.arrived	double/int	Write	Debug metric

TF Frames

This controller reads pose from nav_msgs/Odometry (NavState key robot_pose). TF is not directly used in this plugin.

License

Apache-2.0