TrajGATFormer: A Graph-Based Transformer Approach for Worker and Obstacle Trajectory Prediction in Off-site Construction Environments

As the demand grows within the construction industry for processes that are not only faster but also safer and more efficient, offsite construction has emerged as a solution, though it brings new safety risks due to the close interaction between workers, machinery, and moving obstacles. Predicting the future trajectories of workers and taking into account social and environmental factors is a crucial step for developing collision-avoidance systems to mitigate such risks. Traditional methods often struggle to adapt to the dynamic and unpredictable nature of construction environments. Many rely on simplified assumptions or require hand-crafted features, limiting their ability to respond to complex, real-time interactions between workers and moving obstacles. While recent data-driven methods have improved the modeling of temporal patterns, they still face challenges in capturing long-term behavior and accounting for the spatial and social context crucial to collision risk assessment. To address these limitations, this paper proposes a framework integrating YOLOv10n and DeepSORT for precise detection and tracking, along with two novel trajectory prediction models: TrajGATFormer and TrajGATFormer-Obstacle. YOLOv10n serves as the backbone for object detection, accurately identifying workers and obstacles in diverse scenes, while DeepSORT efficiently tracks them over time with unique IDs for continuity. Both models employ a transformer encoder-decoder with Graph Attention Networks (GAT) to capture temporal and spatial interactions. TrajGATFormer predicts worker trajectories with an ADE of 1.25 m and FDE of 2.3 m over a 4.8 s horizon, while TrajGATFormer-Obstacle extends prediction to both workers and obstacles, achieving higher accuracy (ADE 1.15 m, FDE 2.2 m). Comparative analysis shows both models outperform traditional methods, reducing ADE and FDE by up to 35% and 38%, respectively.