Multi-Task Visual Perception Network with LLM Conditioning for Autonomous Navigation
Authors: Praveen Kumar, K. R. Guruprasad, Tushar Sandhan
Organizations: Department of Electrical Engineering, Indian Institute of Technology Kanpur, India · Department of Mechanical Engineering, Indian Institute of Technology Kanpur, India
Long-term navigation for service robots faces crit- ical challenges like the accumulation of odometry drift and sensor error, which progressively degrade 2D maps and renders traditional path planning algorithms (e.g., A*, RRT*, DiPPer, ViT-A*) ineffective over time. To address this, we propose a user-friendly, interactive framework that eliminates the reliance on globally consistent maps. Our approach integrates visual perception with Large Language Models (LLM) to interpret user commands via text or voice. Instead of relying on a drift- prone global map, the system generates a sequential action plan based on local visual cues and egocentric geometric instructions. These action plans are executed sequentially, allowing the robot to navigate known and unknown environments safely. By reset- ting localization relative to immediate targets, our framework effectively works with a minimum accumulation drift strategy, ensuring accurate, efficient, and collision-free navigation without the maintenance overhead of traditional mapping. Experiments on real-world and simulated data have shown significant improve- ments over other methods. Our source code is publicly accessible at https://github.com/PraveenSingh24/VL-Navigation.
Figures & tables
Fig. 1: Overview of the proposed scenario. The user leverages prior spatial knowledge of the environment to provide natural language task instructions to the service robot. The robot interprets these instructions and interacts with the environment through continuous observation and action, executing navigation tasks sequentially without relying on a global map.
Fig. 2: Overview of the proposed vision-language navigation framework, which is distributed across two nodes: the onboard client (Husky A200) and an offboard GPU server for heavy computation. The workflow begins with Oracle Task Instructions (Natural Language), which are processed by LLM to generate an action plan. The Action Classifier parses this plan into geometric or visual sub-goals. To enable safe navigation, the Scene Parsing module generates a Segmented (Seg.) Point Cloud—representing specific semantic regions—which is concatenated with the filtered terrain point cloud. Finally, the Motion Primitive Local Planner computes optimal velocity commands (υ,ω) to drive the robot toward the Proximal Target.
Fig. 3: The multi-layered architecture for converting user task instructions into robot action plan. The system resolves lexical ambiguity and distinguishes between geometric goal and semantic target constraints before grounding them into a unified robot system for execution.
Fig. 4: Structured prompt is created via injecting static system constraints into the context window alongside the user task instruction. LLM translates the natural language request into a machine-readable format.
Fig. 5: Visual perception to point cloud generation pipeline. The RGB–D stream acquired from the Intel RealSense D455 camera is processed by an RGB-D semantic segmentation network (ESANet) to extract task-relevant regions. The resulting segmented mask is projected into 3D space using depth information to generate a semantic point cloud, which is subsequently utilized for terrain analysis and context-aware navigation.
Fig. 6: (a) Set of candidate motion trajectories produced using the motion primitive framework. These trajectories represent feasible forward motions under kinematic constraints and are evaluated against environmental and semantic constraints to select an optimal navigation path. (b) Data flow of the local planner. The process begins by synchronizing the pre-computed path library and sensor data to the robot’s current state. Feasible paths are filtered through a voxel-grid collision check, and the final trajectory is chosen by minimizing a cost function to ensure safe and efficient navigation.
Fig. 7: Illustration of odometry drift estimation during navigation. The robot moves through intermediate subgoals G1 – G3 toward the final destination D , and the drift is computed based on the deviation between the robot pose and the corresponding target.
Fig. 8: Experimental validation in the Gazebo simulation environment. (Left) The 3D test workspace containing the Husky A200 robot and various semantic obstacles labeled as: 2) Statue, 3) Chair, 4) Bicycle, 5) Color-marked restricted zone, and 6) Moving pedestrian. (Right) Top-down view of the generated point cloud map illustrating the autonomous navigation performance, showing the Start Point, Goal Point, and the resulting collision-free Traversed Path
Fig. 9: Explored environment and traversed paths for two distinct navigation tasks. The left and right panels display the top-down occupancy map, where black regions represent physical barriers and context-aware constraints. The robot successfully navigates from the Start Point to the Goal Point by executing a sequence of semantic actions. Key landmarks are labeled as S (Statue/Human), C (Visitor Chair), and B (Bicycle). The planner also accounts for dynamic and static constraints, such as the Moving Pedestrian (MP) and the designated Restricted Zone.
Method
Global Map
Drift Sensitivity
Long-Term Nav.
Unknown Env.
Semantic Understanding
Context Awareness
User Interaction
Replanning
A* / RRT*
✓
✓
✗
✗
✗
✗
✗
Limited
DiPPer
✓
✓
△
✗
✗
✗
✗
Limited
ViT-A*
✓
✓
△
△
△
✗
✗
Limited
Vision-Aided A* [ 20 ]
✓
✓
✗
✓
✗
✓
✗
Online
SemExp (Semantic Exploration) [ 21 ]
✗
△
△
✓
✓
✓
✗
Moderate
CARe (Context-Aware Replanning) [ 22 ]
✗
△
✓
✓
✓
✓
✗
Advanced
TABLE I: Comparison of Modern Navigation Paradigms (Extended). ✓ Supported, ✗ Not supported, △ Partial.
Case 1: Complex Navigation
User Input: “Buddy go to the statue (human), take a right turn and move a little ahead, then find the visitor chair to reach close to it, and on the right you may see a bicycle.”
User Input: “Buddy take left turn, move 4 m ahead, then find the standing person to reach close to it, In your right you may see the visitor chair follow it. Finally go at spot where bicycle is standing.”
TABLE II: Qualitative Evaluation of LLM-Guided Instruction Parsing.
Fig. 10: Indoor experimental environment with the Husky A200 robot and onboard Intel RealSense D455 camera. The scene includes multiple visual targets and restricted regions in a confined workspace used for real-world navigation evaluation.
Fig. 11: ESANet model input and output: The frame (left) shows the settings: the marked objects are placed on the surface, the red-marked box is drawn on the ground, and the remaining items are at a significant height. The segmentation model output is shown (right), where we show the segmented region of the labeled items, which the user defines.
Fig. 12: Real-world navigation results across multiple trials. The robot starts from S and first moves toward an egocentric geometric goal (G1), followed by visually detected semantic targets (G2–G4). White regions indicate free space, black regions represent obstacles, and the colored path shows the executed trajectory.
Fig. 13: Experimental results of the visual navigation system. (a) The wheeled robot successfully tracking and following a dynamic human target. (b) Estimation of the fixed visual target point; note that despite the spatial spread of the estimated points, the robot successfully navigated to the visual destination. (c) The view of the red-marked box target, showing lateral shifts caused by the robot’s to-and-fro motion during navigation.
Module
Task
Latency (ms)
Execution Mode
Server Platform (NVIDIA RTX A4000)
RedNet
RGB-D Segmentation
29.2±1.8
Continuous
ESANet
RGB-D Segmentation
34.8±0.7
Continuous
OSNet
Person Re-ID
50±5
On-demand
YOLOv8
Object Detection
12.3±1.4
On-demand
LLM (Gemini Pro)
Instruction Parsing
150±30
Per command
TABLE III: Inference Time Performance Across Computing Platforms
Scenario
Constraint
Geometric
Visual
Hybrid (Ours)
Featureless Corridor
No visual landmarks
92.0
15.0
95.0
Symmetric Room
Geometric ambiguity
40.0
94.0
96.0
Occluded Target
Target not visible
85.0
30.0
91.0
Precise Positioning
Exact stopping required
96.0
65.0
98.0
Complex Mission
Sequential task execution
10.0
25.0
88.0
TABLE IV: Performance Comparison of Navigation Modalities Under Different Environmental Constraints
Environment
Success Rate (%)
Soft Collision (%)
Hard Collision (%)
Avg. Path Length (m)
Drift Error (m)
Simulation
Indoor
100
10.0
0.0
12.4
0.03±0.01
Garage
100
8.5
0.0
20.8
0.05±0.03
Campus
98
10.0
0.0
30.5
0.05±0.02
Forest
95
15.2
0.3
15.5
0.08±0.01
Tunnel
98
14.0
0.0
25.2
0.05±0.02
TABLE V: Performance Evaluation Results Over 50 Trials per Scenario. The simulation scenarios (Indoor, Garage, Campus, Forest, Tunnel) are given in detail [ 17 , 25 ] . These setups are modified to include visual objects and semantic context-aware items (soft collision) for our system performance evaluation. We consider the environmental structure (hard collision) that obstructs the navigation path.