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  • RAYFRONTS // IROS 2025
  • OPEN-SET LABELS
  • FRONTIER EXPLORATION

NEXUS

THE CONNECTING POINT

Robots operating in unstructured environments need to understand what they see. NEXUS solves open-set semantic mapping: label arbitrary objects on-the-fly, build consistent 3D representations, and explore efficiently to maximize information gain. Built on RayFronts (IROS 2025).

MODULE STATUS: ACTIVE

Semantic Encoding

OPEN

DIVISION
ANIMA
WAVE
W3
DOMAIN
UNDERSTANDING
WAVE 3 // ANIMA SUITE
OPEN-SET SEMANTIC MAPPING
NEXUS // W3 // 053/079
01THE CHALLENGE

ROBOTS CAN'T NAME WHAT THEY SEE

Robots operating in unstructured environments need to understand what they see. Off-the-shelf object detectors only recognize pre-trained classes — they fail on novel objects, rare materials, and task-specific entities. This forces expensive manual annotation.

Building persistent, searchable 3D maps requires both geometry (where is everything?) and semantics (what is everything?). Current systems treat these as separate problems, leading to fragmented representations. NEXUS unifies them.

02THE SOLUTION

WHAT NEXUS DELIVERS

NEXUS is a containerized semantic mapping and exploration service built on RayFronts (IROS 2025). Maps semantically, explores intelligently, processes online.

PIPELINE

  1. 01Maps semantically — assigns open-set labels (any category) to 3D surfaces in real-time
  2. 02Explores intelligently — frontier-based, entropy-driven, and information gain strategies
  3. 03Processes online — updates maps incrementally as new sensor data arrives
  4. 04REST and gRPC APIs — designed for the ANIMA manipulation pipeline

CAPABILITIES

  • MULTI-RUNTIMECPU, GPU, and Apple Silicon (MLX M1–M5) runtimes→ ~60ms on M5, 4× M1 throughput
  • FLEXIBLE MODELSDeterministic baseline encoder + optional CLIP for custom vocabularies→ No retraining required for new object categories
  • ADMISSION CONTROLBounded admission control for concurrent inference requests→ Production-grade reliability under load
03ENGINEERING

WHY THIS IS HARD

Open-set recognition without task-specific training requires grounding visual embeddings to arbitrary language:

  1. 01CLIP integration for custom vocabularies requires careful offline caching and fallback
  2. 02Frontier discovery and entropy-driven viewpoint selection when the semantic space is unbounded
  3. 03gRPC service contracts, protobuf schema versioning, health checks, and bounded admission control
  4. 04Real-time latency constraints for robotic systems — no batch processing allowed
  5. 05Cross-team integration across REST and gRPC with consistent protobuf schemas

NEXUS wraps all this behind clean async APIs with deterministic baselines and optional CLIP enhancement.

04BENCHMARKS

REAL HARDWARE PERFORMANCE

Measured with RayFronts encoder + semantic pipeline:

REAL HARDWARE PERFORMANCE
METRICVALUE
Semantic Encoding~60ms (M5 MLX), ~25ms (RTX 4090)
Apple M5 (MLX)~60ms per frame (4× M1)
Map Update RateReal-time incremental (no batch)
Exploration StrategiesFrontier, entropy, information gain
API ProtocolsREST + gRPC
Admission ControlBounded queue per deployment
Model CacheOffline-safe with mounted volumes
05BUILD STATUS

WHAT'S BUILT TODAY

8/9 COMPONENTS COMPLETE
WHAT'S BUILT TODAY
COMPONENTSTATUSNOTES
Core ModelsCOMPLETERayFronts encoder + semantic pipeline, production-ready
API LayerIN PROGRESSPublic API, pending dataset infrastructure
REST APICOMPLETEFastAPI with /docs auto-gen
gRPC ServiceCOMPLETEProtobuf contract + reflection
Semantic Baseline (MLX)COMPLETEDeterministic, no network calls
CLIP IntegrationCOMPLETELocal offline cache, offline-safe
Exploration StrategiesCOMPLETEFrontier, entropy, information gain
Admission ControlCOMPLETEBounded queue per deployment
Quality GatesCOMPLETEruff, pytest, mypy passing
06APPLICATIONS

WHERE NEXUS DEPLOYS

  • APP_01

    ROBOTIC INTEGRATORS

    Building SLAM + semantic understanding stacks. Plug NEXUS in for open-set object labeling on top of geometric maps.

  • APP_02

    MANIPULATION TEAMS

    Scene graphs for grasping and object search. Know what's on the table before reaching for it.

  • APP_03

    AUTONOMOUS EXPLORATION

    Search and rescue, inspection drones. Explore unknown environments and build semantic maps in real-time.

  • APP_04

    COLLABORATIVE ROBOTS

    Sharing maps across heterogeneous agents. One robot maps, all robots understand.

  • APP_05

    WAREHOUSE AUTOMATION

    Semantic inventory mapping and search. Find any object by name, not by coordinates.

  • APP_06

    SMART BUILDINGS

    Object-level understanding for facility management. Track assets, monitor spaces, automate responses.

07TECHNOLOGY

UNDER THE HOOD

FOUNDATION: RAYFRONTS

  • Open-set semantic mapping from egocentric streams (IROS 2025)
  • Frontier-based exploration with global loop closure
  • MIT-licensed reference implementation
  • Deterministic baseline encoder with optional CLIP

NEXUS IMPLEMENTATION

FastAPI REST Server
Pydantic schemas with /docs auto-generation
gRPC Service
Protobuf 3 contract with reflection
Device Abstraction
MLX (Apple Silicon) → CUDA → CPU fallback chain
Model Caching
Offline-mode fallbacks with mounted volumes
Admission Control
Bounded queues for concurrent request management

INTEGRATION POINTS

  • Feeds 3D semantic maps to SYNTHESIS (collaborative SLAM)
  • Provides object labels to TACTIS (vision-touch fusion)
  • Supplies scene context to downstream manipulation modules
08PAPERS

RESEARCH BASIS

  1. [01]RayFronts — open-set semantic mapping for production robotics (IROS 2025)