arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1901.03315eess.SYcs.SCcs.SYmath.DSmath.OC
收藏

采样随机非线性系统安全数字控制器的自动综合

Automated Synthesis of Safe Digital Controllers for Sampled-Data Stochastic Nonlinear Systems

Fedor Shmarov, Sadegh Soudjani, Nicola Paoletti, Ezio Bartocci, Shan Lin, Scott A. Smolka, Paolo Zuliani

摘要:

我们提出了一种新的方法,为系统的非线性动态,噪声输出测量,和随机干扰的数字控制器的自动合成与正式的安全保证。我们的方法推导出数字控制器,使相应的闭环系统,建模为一个采样数据的随机控制系统,满足安全规格的概率高于给定的阈值。所提出的合成方法交替两个步骤:生成候选控制器PC,和验证的候选人。通过最大化安全概率的蒙特卡罗估计,并通过使用未经验证的ODE求解器来模拟系统,可以找到pc。因此,这样的候选是次优的,但是可以非常快速地生成。为了排除不稳定的候选控制器,我们证明并利用李雅普诺夫的采样数据非线性系统的不稳定性的间接方法。在随后的验证步骤中,我们使用基于SMT(可满足性模理论)的经验证的求解器来计算pc安全概率的数值和统计有效置信区间。如果这样获得的概率不高于阈值,我们通过增加控制器度来扩展候选者的搜索空间。我们评估我们的技术在三个案例研究:人工胰腺模型,动力系统控制模型,和一个四槽过程。

英文摘要:

We present a new method for the automated synthesis of digital controllers with formal safety guarantees for systems with nonlinear dynamics, noisy output measurements, and stochastic disturbances. Our method derives digital controllers such that the corresponding closed-loop system, modeled as a sampled-data stochastic control system, satisfies a safety specification with probability above a given threshold. The proposed synthesis method alternates between two steps: generation of a candidate controller pc, and verification of the candidate. pc is found by maximizing a Monte Carlo estimate of the safety probability, and by using a non-validated ODE solver for simulating the system. Such a candidate is therefore sub-optimal but can be generated very rapidly. To rule out unstable candidate controllers, we prove and utilize Lyapunov's indirect method for instability of sampled-data nonlinear systems. In the subsequent verification step, we use a validated solver based on SMT (Satisfiability Modulo Theories) to compute a numerically and statistically valid confidence interval for the safety probability of pc. If the probability so obtained is not above the threshold, we expand the search space for candidates by increasing the controller degree. We evaluate our technique on three case studies: an artificial pancreas model, a powertrain control model, and a quadruple-tank process.

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。

↑