nav2_behavior_tree::RoundRobinNode Class Reference

Type of sequence node that ticks children in a round-robin fashion. More...

#include <nav2_behavior_tree/include/nav2_behavior_tree/plugins/control/round_robin_node.hpp>

Inheritance diagram for nav2_behavior_tree::RoundRobinNode:

Collaboration diagram for nav2_behavior_tree::RoundRobinNode:

Public Member Functions
	RoundRobinNode (const std::string &name)
	A constructor for nav2_behavior_tree::RoundRobinNode. More...
	RoundRobinNode (const std::string &name, const BT::NodeConfiguration &config)
	A constructor for nav2_behavior_tree::RoundRobinNode. More...
BT::NodeStatus	tick () override
	The main override required by a BT action. More...
void	halt () override
	The other (optional) override required by a BT action to reset node state.

Static Public Member Functions
static BT::PortsList	providedPorts ()
	Creates list of BT ports. More...

Detailed Description

Type of sequence node that ticks children in a round-robin fashion.

Type of Control Node | Child Returns Failure | Child Returns Running

RoundRobin | Tick Next Child | Return Running

If the current child return failure, the next child is ticked and if the last child returns failure, the first child is ticked and the cycle continues until a child returns success

As an example, let's say this node has 3 children: A, B and C. At the start, they are all IDLE.

| A | B | C |

| IDLE | IDLE | IDLE | | RUNNING | IDLE | IDLE | - at first A gets ticked. Assume it returns RUNNING

• RoundRobin returns RUNNING and no other nodes are ticked. | FAILURE | RUNNING | IDLE | - A returns FAILURE so B gets ticked and returns RUNNING
• RoundRobin returns RUNNING and C is not ticked yet | FAILURE | SUCCESS | IDLE | - B returns SUCCESS, so RoundRobin halts all children and
• returns SUCCESS, next iteration will tick C. | RUNNING | IDLE | FAILURE | - C returns FAILURE, so RoundRobin circles and ticks A.
• A returns RUNNING, so RoundRobin returns RUNNING.

If all children return FAILURE, RoundRobin will return FAILURE and halt all children, ending the sequence.

Usage in XML: <RoundRobin>

Definition at line 54 of file round_robin_node.hpp.

Constructor & Destructor Documentation

RoundRobinNode() [1/2]

nav2_behavior_tree::RoundRobinNode::RoundRobinNode ( const std::string &  name )

explicit

A constructor for nav2_behavior_tree::RoundRobinNode.

Parameters

name	Name for the XML tag for this node

Definition at line 22 of file round_robin_node.cpp.

RoundRobinNode() [2/2]

nav2_behavior_tree::RoundRobinNode::RoundRobinNode	(	const std::string &	name,
		const BT::NodeConfiguration &	config
	)

A constructor for nav2_behavior_tree::RoundRobinNode.

Parameters

name	Name for the XML tag for this node
config	BT node configuration

Definition at line 27 of file round_robin_node.cpp.

Member Function Documentation

providedPorts()

static BT::PortsList nav2_behavior_tree::RoundRobinNode::providedPorts ( )

inlinestatic

Creates list of BT ports.

Returns

BT::PortsList Containing basic ports along with node-specific ports

Definition at line 85 of file round_robin_node.hpp.

tick()

BT::NodeStatus nav2_behavior_tree::RoundRobinNode::tick ( )

override

The main override required by a BT action.

Returns

BT::NodeStatus Status of tick execution

Definition at line 34 of file round_robin_node.cpp.

References halt().

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

• nav2_behavior_tree/include/nav2_behavior_tree/plugins/control/round_robin_node.hpp
• nav2_behavior_tree/plugins/control/round_robin_node.cpp