arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2405.18554cs.LGcs.ROcs.SYeess.SY
收藏

使用组合与展开对基于图像的神经网络控制系统进行可扩展的代理验证

Scalable Surrogate Verification of Image-based Neural Network Control Systems using Composition and Unrolling

Stony Brook University(石溪大学);Massachusetts Institute of Technology(麻省理工学院);Clemson University(克莱姆森大学)

Feiyang Cai, Chuchu Fan, Stanley Bak

AI总结:

针对基于图像的神经网络控制系统验证中的过度过近似问题,提出通过组合系统动力学与网络并展开多步控制循环的方法,显著提升了可达集计算的准确性和可扩展性。

摘要:

验证使用图像作为输入的神经网络控制系统的安全性是一个困难的问题,因为从给定的系统状态出发,目前没有已知的方法能够在数学上建模现实世界中可能出现的图像。我们基于近期考虑代理验证方法的研究,训练一个条件生成对抗网络(cGAN)作为图像生成器来代替现实世界。这使得能够对闭环系统进行基于集合的形式化分析,提供超越仿真和测试的分析。虽然现有工作在小规模示例上有效,但单个控制周期内和跨多个控制周期的过度过近似限制了其可扩展性。我们提出了克服这两种误差源的方法。首先,我们通过组合系统动力学、cGAN和神经网络控制器来克服单步误差,而不会像系统动力学的单调分析中那样失去输入状态和控制输出之间的依赖关系。其次,我们通过重复单步组合来减少多步误差,本质上将控制循环的多个步骤展开为一个大神经网络。然后,我们利用现有的网络验证工具来计算多个步骤的精确可达集,避免在每一步累积抽象误差。我们使用两个案例研究展示了该方法在准确性和可扩展性方面的有效性:一个自主飞机滑行系统和一个高级紧急制动系统。在飞机滑行系统上,使用先前的基线方法得到的收敛可达集比我们提出的方法大175%。在紧急制动系统上,当cGAN的图像输出变量数量为24倍时,基线方法无法证明任何状态是安全的,而我们的改进使得基于集合的安全分析成为可能。

英文摘要:

Verifying safety of neural network control systems that use images as input is a difficult problem because, from a given system state, there is no known way to mathematically model what images are possible in the real-world. We build on recent work that considers a surrogate verification approach, training a conditional generative adversarial network (cGAN) as an image generator in place of the real world. This enables set-based formal analysis of the closed-loop system, providing analysis beyond simulation and testing. While existing work is effective on small examples, excessive overapproximation both within a single control period and across multiple control periods limits its scalability. We propose approaches to overcome these two sources of error. First, we overcome one-step error by composing the system's dynamics along with the cGAN and neural network controller, without losing the dependencies between input states and the control outputs as in the monotonic analysis of the system dynamics. Second, we reduce multi-step error by repeating the single-step composition, essentially unrolling multiple steps of the control loop into a large neural network. We then leverage existing network verification tools to compute accurate reachable sets for multiple steps, avoiding the accumulation of abstraction error at each step. We demonstrate the effectiveness of our approach in terms of both accuracy and scalability using two case studies: an autonomous aircraft taxiing system and an advanced emergency braking system. On the aircraft taxiing system, the converged reachable set is 175% larger using the prior baseline method compared with our proposed approach. On the emergency braking system, with 24x the number of image output variables from the cGAN, the baseline method fails to prove any states are safe, whereas our improvements enable set-based safety analysis.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑