CommandGuard Class Reference

Keeps the velocity command sent to the robot from being stale or invalid. More...

#include <CommandGuard.hpp>

Public Member Functions
bool	check_controller_period (double period, const std::string &controller) const
	Checks "cmd_timeout" against the period (s) of controller. Logs if not longer.
double	cmd_timeout () const
bool	configure (rclcpp_lifecycle::LifecycleNode &node)
	Reads and checks the parameters, and starts over. Logs and returns false if invalid.
void	declare_parameters (rclcpp_lifecycle::LifecycleNode &node)
	Declares "cmd_timeout" and "cmd_vel_keepalive_period" in node.
bool	discard_non_finite (NavState &nav_state)
	Consumes this cycle's non-finite proposals.
bool	is_new (const geometry_msgs::msg::TwistStamped &cmd)
	Whether a controller command is new (stamp or value changed). Remembers it.
bool	keepalive_due (const rclcpp::Time &now) const
	Whether the command must be republished at now (keepalive).
double	keepalive_period () const
void	published (const rclcpp::Time &stamp)
	Records that a command stamped stamp was published.
rclcpp::QoS	qos () const
	QoS of the velocity publisher.
void	report (NavState &nav_state, bool discarded, bool fresh)
	Updates "diagnostics.cmd_vel" after this cycle's selection.
void	reset ()
	Forgets the timeout, keepalive and last command (e.g.
VelocityMux::Selection	supervise (const VelocityMux::Selection &selection, const rclcpp::Time &now)
	selection, or zero if its non-zero target is held for longer than the timeout.
bool	timed_out () const
	Whether the target was zeroed because no proposal arrived in time.

Detailed Description

Keeps the velocity command sent to the robot from being stale or invalid.

Around ControllerNode's VelocityMux, every RT cycle:

• only new controller commands (stamp or value changed) are proposed (is_new());
• non-finite proposals are discarded before the mux selects (discard_non_finite());
• a non-zero target with no new proposal for "cmd_timeout" s becomes zero (supervise());
• the command is republished every "cmd_vel_keepalive_period" s (keepalive_due()), and the publisher offers deadline and liveliness QoS of twice that period (qos());
• problems are reported in NavState as "diagnostics.cmd_vel" (report()).

Member Function Documentation

check_controller_period()

bool check_controller_period	(	double	period,
		const std::string &	controller ) const

Checks "cmd_timeout" against the period (s) of controller. Logs if not longer.

cmd_timeout()

double cmd_timeout ( ) const

nodiscard

configure()

bool configure

(

rclcpp_lifecycle::LifecycleNode &

node

)

Reads and checks the parameters, and starts over. Logs and returns false if invalid.

declare_parameters()

void declare_parameters

(

rclcpp_lifecycle::LifecycleNode &

node

)

Declares "cmd_timeout" and "cmd_vel_keepalive_period" in node.

discard_non_finite()

bool discard_non_finite

(

NavState &

nav_state

)

Consumes this cycle's non-finite proposals.

Returns

Whether any was discarded.

is_new()

bool is_new

(

const geometry_msgs::msg::TwistStamped &

cmd

)

Whether a controller command is new (stamp or value changed). Remembers it.

keepalive_due()

bool keepalive_due ( const rclcpp::Time & now ) const

nodiscard

Whether the command must be republished at now (keepalive).

keepalive_period()

double keepalive_period ( ) const

nodiscard

published()

void published

(

const rclcpp::Time &

stamp

)

Records that a command stamped stamp was published.

qos()

rclcpp::QoS qos ( ) const

nodiscard

QoS of the velocity publisher.

report()

void report	(	NavState &	nav_state,
		bool	discarded,
		bool	fresh )

Updates "diagnostics.cmd_vel" after this cycle's selection.

reset()

void reset

(

)

Forgets the timeout, keepalive and last command (e.g.

once the robot is stopped). The last report is kept: NavState outlives a reconfiguration, its ERROR must be cleared.

supervise()

VelocityMux::Selection supervise	(	const VelocityMux::Selection &	selection,
		const rclcpp::Time &	now )

selection, or zero if its non-zero target is held for longer than the timeout.

timed_out()

bool timed_out ( ) const

nodiscard

Whether the target was zeroed because no proposal arrived in time.

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

• easynav_controller/include/easynav_controller/safety/CommandGuard.hpp
• easynav_controller/src/easynav_controller/safety/CommandGuard.cpp