Introducing Generator + Selector Architecture for Modular Trajectory Planning

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🚀 Upcoming Changes to the Planning Pipeline Architecture

We are excited to share a major update to Autoware’s planning pipeline architecture! This change improves modularity, introduces support for AI-based planning, and lays the groundwork for more flexible and intelligent trajectory generation.

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🔧 What's Changing?

We're transitioning from a single-path robotics-based planner to a modular dual-path architecture that integrates:

• 🧠 AI-based planners (e.g., Diffusion Planner)
• 🛠️ A Generator that merges candidate trajectories
• 🔍 A Selector that ranks and selects the best trajectory based on safety and traffic rules

This new design enables experimentation with multiple planning strategies without disrupting the current flow.

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📆 Migration Timeline

Phase	Date	Description
✅ Phase 0	Done	New messages introduced
✅ Phase 1	Jul 11, 2025	Dual publishing of trajectory topics
🔜 Phase 2	Aug 11, 2025	Controller updated to use /planning/trajectory only
🔜 Phase 3	Aug 30, 2025	Add Generator (not used yet)
🔜 Phase 4	Sep 30, 2025	Add Selector (not used yet)
🔜 Phase 5	Oct 15, 2025	Enable Generator + Selector as launch options
🔜 Phase 6	Oct 30, 2025	Fully integrated modular pipeline and deprecate old trajectory topic

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🗺️ Current vs Future Architecture

Before

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graph TD
    MissionPlanner[🗺️ Mission Planner] -->
    MsgRoute(["✉️ /planning/mission_planning/route<br>🗂️ **autoware_planning_msgs/msg/LaneletRoute**"]) -->
    Planning["⚙️ **Robotics-Based** Planner"] -->
    MsgTrajectory(["✉️ /planning/scenario_planning/trajectory<br>🗂️ **autoware_planning_msgs/msg/Trajectory**"]) -->
    Control["🎮 Control Component"]

    classDef class_msg fill:#9BE7DF,stroke:#008274;

    class MsgRoute,MsgTrajectory class_msg;

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After

---
config:
  theme: 'base'
  themeVariables:
    lineColor: '#7e7e7eff'
    primaryColor: '#fffde7ff'
    primaryTextColor: '#000000'
    primaryBorderColor: '#b3a400ff'
  flowchart:
    markdownAutoWrap: false
    wrappingWidth: 600
---

graph TD
    MissionPlanner[🗺️ Mission Planner] -->
    MsgRoute(["✉️ /planning/mission_planning/route<br>🗂️ **autoware_planning_msgs/msg/LaneletRoute**"]) -->
    PlannerRobo["⚙️ **Robotics-Based** Planner"]
    MsgRoute --> PlannerAi["🤖 **AI-Based** Planner"]

    subgraph Generator["🛠️ **Generator**"]
        PlannerRobo -->
        MsgCandidateTrajectoryRobo(["✉️ /planning/generator/robotics_based/candidate_trajectories<br>🗂️ **autoware_internal_planning_msgs/CandidateTrajectories**"]) -->
        TrajectoryConcat

        PlannerAi -->
        MsgCandidateTrajectoryAi(["✉️ /planning/generator/ai_based/candidate_trajectories<br>🗂️ **autoware_internal_planning_msgs/CandidateTrajectories**"]) -->
        TrajectoryConcat
    end

    TrajectoryConcat[📎 Trajectory Concatenator] -->
    MsgCandidateTrajectories(["✉️ /planning/generator/candidate_trajectories<br>🗂️ **autoware_internal_planning_msgs/CandidateTrajectories**"]) -->
    SafetyGate

    subgraph Selector["🔍 **Selector**"]
        SafetyGate["🛡️ Safety Gate"] -->
        TrafficRuleValidation["🚦 Traffic Rule Validation"] -->
        Ranking["📊 Ranking"] -->
        MsgScoredTrajectores(["✉️ /planning/selector/scored_candidate_trajectories<br>🗂️ **autoware_internal_planning_msgs/ScoredCandidateTrajectories**"]) -->
        TrajectoryAdapter[🔌 Trajectory Adapter]
    end

    TrajectoryAdapter -->
    MsgTrajectory(["✉️ /planning/trajectory<br>🗂️ **autoware_planning_msgs/msg/Trajectory**"]) -->
    Control["🎮 Control Component"]

    classDef class_msg fill:#9BE7DF,stroke:#008274;
    classDef class_subgraph fill:#fce4ec,stroke:#8a002e;

    class MsgRoute,MsgCandidateTrajectoryRobo,MsgCandidateTrajectoryAi,MsgCandidateTrajectories,MsgScoredTrajectores,MsgTrajectory class_msg;
    class Generator,Selector class_subgraph;

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This evolution enables:

• Optional AI-based planners
• Ranking and validation of multiple candidate trajectories
• Safe fallback and expand-ability for future planners

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🧠 Learn More

• Tracked in this issue: Enable generator-selector planning framework #6292
• New Planning Framework Wiki
• Selector module details
• Current Issues and Future Directions of Autoware Architecture #5032
• The difficulty in handling complex scenarios due to the hierarchical architecture of Planning and the modularization of functionalities #5033

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💬 Feedback Welcome

We encourage the community to try out the new modules as they’re introduced and share feedback.