A unified framework for interpretable elevator fault diagnosis and predictive maintenance via style-aware CoT
Yuhao Wang1,2, Junjie Huang2, Qiang Zhang1,2
1Zhejiang University, Hangzhou, China.
Plos One
|July 7, 2026
Summary
Small Language Models (SLMs) with a Unified Style-Aware Chain-of-Thought (SA-CoT) framework overcome industrial AI challenges. This approach enhances predictive maintenance by improving diagnostic accuracy and sensor data interpretation.
Area of Science:
- Artificial Intelligence
- Industrial IoT
- Machine Learning
Background:
- Large Language Models (LLMs) show industrial promise but struggle with domain specificity and interpreting physical states.
- Challenges include hallucinations and lack of specialized knowledge in vertical applications like elevator maintenance.
Purpose of the Study:
- To bridge the semantic-physical gap in industrial AI by proposing a novel framework for Small Language Models (SLMs).
- To enhance predictive maintenance capabilities in specialized industrial scenarios.
Main Methods:
- Developed a Unified Style-Aware Chain-of-Thought (SA-CoT) framework for SLMs.
- Created a robust instruction dataset using style-aware augmentation to simulate real-world data and noise.
- Textualized raw sensor data to enable SLMs to generate high-dimensional embeddings for numerical analysis.
Main Results:
- SA-CoT framework significantly outperformed general models in generative diagnosis, achieving a 5.6-fold improvement in BLEU-4 scores over GPT-4o.
- Generated embeddings effectively captured physical features, showing competitive accuracy in Alarm Type Classification and Vibration Magnitude Regression.
- Demonstrated that domain-aligned SLMs offer a cost-effective solution for autonomous predictive maintenance.
Conclusions:
- Domain-aligned SLMs, particularly when utilizing frameworks like SA-CoT, provide a robust and efficient solution for industrial predictive maintenance.
- Knowledge density is more critical than parameter scale for specialized industrial AI applications.
- The proposed framework effectively addresses limitations of LLMs in vertical industrial settings.
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