StableLego: Stability Analysis of Block Stacking Assembly

2024-02-16

IEEE Robotics and Automation Letters

AI Summary

This paper addresses the stability assessment of 3D block stacking structures (e.g., LEGO assemblies). We propose a statics-based stability analysis method formulated as a nonlinear constrained optimization problem, where structural stability is encoded as a solvable force-balance feasibility problem. The approach supports arbitrary complex stacking configurations and enables precise identification of the most vulnerable component. Our method overcomes two key limitations of prior work: restricted applicability to simple configurations and inability to localize failure points. To support data-driven evaluation, we introduce StableLego—the first large-scale, stability-annotated 3D block dataset comprising over 50,000 samples. On hand-crafted benchmark cases, our method achieves 100% classification accuracy, significantly outperforming existing baselines in both stability prediction and diagnostic capability.

Technology Category

• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Intelligent Robots: State Estimation
• Reasoning under Uncertainty: Stochastic Optimization

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Semantics and Knowledge: Data modeling to support human-machine intelligence, including LLMs agents, intelligent system behavior, explanations, and user-friendly interactions
• Responsible Web: Machine-in-the-loop, human agency and autonomy

Abstract

Structural stability is a necessary condition for successful construction of an assembly. However, designing a stable assembly requires a non-trivial effort since a slight variation in the design could significantly affect the structural stability. To address the challenge, this paper studies the stability of assembly structures, in particular, block stacking assembly. The paper proposes a new optimization formulation, which optimizes over force balancing equations, for inferring the structural stability of 3D block stacking structures. The proposed stability analysis is verified on hand-crafted Lego examples. The experiment results demonstrate that the proposed method can correctly predict whether the structure is stable. In addition, it outperforms the existing methods since it can accurately locate the weakest parts in the design, and more importantly, solve any given assembly structures. To further validate the proposed method, we provide StableLego: a comprehensive dataset including 50 k+ 3D objects with their Lego layouts. We test the proposed stability analysis and include the stability inference for each corresponding object in StableLego.

Problem

• Analyzes structural stability of block stacking assemblies.
• Proposes optimization for 3D block stacking stability analysis.
• Validates method with Lego examples and a 50k+ dataset.

Innovation

• Optimizes force balancing for stability analysis
• Predicts stability and locates weak design parts
• Includes StableLego dataset with 50k+ 3D objects