SimuAgent: An LLM-Based Simulink Modeling Assistant Enhanced with Reinforcement Learning

TL;DR

SimuAgent is an LLM-powered tool that improves Simulink modeling by using concise representations, a specialized training architecture, and a novel reinforcement learning method, leading to faster, more accurate, and privacy-preserving engineering workflows.

Contribution

The paper introduces SimuAgent, a novel LLM-based Simulink modeling assistant with a two-stage training architecture and Reflection-GRPO, enhancing modeling accuracy and convergence speed in industrial engineering tasks.

Findings

Outperforms standard RL baselines in SimuBench

Surpasses GPT-4o with few-shot prompting on the same benchmark

Ablation studies confirm benefits of curriculum and data augmentation

Abstract

Large language models (LLMs) have revolutionized text-based code automation, but their potential in graph-oriented engineering workflows remains under-explored. We introduce SimuAgent, an LLM-powered modeling and simulation agent tailored for Simulink. SimuAgent replaces verbose XML with a concise, dictionary-style Python representation, dramatically cutting token counts, improving interpretability, and enabling fast, in-process simulation. A lightweight plan-execute architecture, trained in two stages, equips the agent with both low-level tool skills and high-level design reasoning. To tackle sparse rewards in long-horizon tasks, we propose Reflection-GRPO (ReGRPO), which augments Group Relative Policy Optimization (GRPO) with self-reflection traces that supply rich intermediate feedback, accelerating convergence and boosting robustness. Experiments on SimuBench, our newly released benchmark comprising 5300 multi-domain modeling tasks, show that a Qwen2.5-7B model fine-tuned with SimuAgent converges faster and achieves higher modeling accuracy than standard RL baselines, and even surpasses GPT-4o when evaluated with few-shot prompting on the same benchmark. Ablations confirm that the two-stage curriculum and abstract-reconstruct data augmentation further enhance generalization. SimuAgent trains and runs entirely on-premise with modest hardware, delivering a privacy-preserving, cost-effective solution for industrial model-driven engineering. SimuAgent bridges the gap between LLMs and graphical modeling environments, offering a practical solution for AI-assisted engineering design in industrial settings.