Lifecycle

Introducing Lifecycle

Overview

A lifecycle defines the operational boundaries of a mode, from its activation to its completion or transition to another mode. It is responsible for initializing, managing, and safely terminating a mode's operation, ensuring predictable transitions, consistent state handling, and controlled execution of mode-specific logic.

A mode represents a functional state of the robot, such as Guard, SLAM, or Navigation, and each mode runs within a lifecycle that determines how and when it starts, executes, and ends.

Conceptual Model

Concept	Description
Lifecycle	Defines the start, execution, and end of a mode
Stage	Represents a logical phase within the lifecycle (e.g., startup, entry, active, exit)
Hook	A programmable event point that executes specific actions at key stages
Mode	The operational context governed by the lifecycle

In short: Lifecycle controls the flow → Stages define phases → Hooks perform actions → Mode defines behavior.

Stages and Hooks

Each lifecycle is composed of several stages. Hooks are executed at specific points in these stages to perform initialization, cleanup, or handling tasks.

Stage	Hook	Description
Startup	ON_STARTUP	Executes system-level initialization before any mode begins
Entry	ON_ENTRY	Runs when entering a mode; prepares mode-specific resources and context
Active	—	Main operational phase; mode logic runs continuously (no fixed hook)
Exit	ON_EXIT	Executes cleanup, saves state, and prepares for the next transition
Timeout	ON_TIMEOUT	Handles cases where a mode exceeds its defined duration or fails to complete expected actions
Shutdown	ON_SHUTDOWN	Performs final cleanup and safe termination of the lifecycle management system

Startup Stage

Triggered by ON_STARTUP. Executes system-level initialization before any mode begins.

Entry Stage

Triggered by ON_ENTRY. Runs when entering a mode; prepares mode-specific resources and context.

Active Stage

Represents the main operational phase of the mode. No fixed hook; mode logic runs continuously during this stage.

Exit Stage

Triggered by ON_EXIT. Executes cleanup, saves state, and prepares for the next transition.

Timeout Stage

Triggered by ON_TIMEOUT. Handles cases where a mode exceeds its defined duration or fails to complete expected actions.

Shutdown Stage

Triggered by ON_SHUTDOWN. Performs final cleanup and safe termination of the lifecycle management system.