Simulink动态仿真中Stateflow建模存在问题

Matlab是现在工程领域中一套最为出色的科学计算软件,Simulink/Stateflow是Matlab自带的工具箱,主要用来实现对工程问题的模型化和动态仿真。Simulink/Stateflow基于模块化设计和系统级仿真的具体思想,使得建模仿真如同搭积木一样简单。Simulink/Stateflow对仿真的实现可以应用于动力系统、信号控制、通信设计等各个领域的研究中。但它也有不完善的地方,如果使用不慎就会得出错误的仿真结果。该文就以一个很简单的例子来进行了说明,并在此基础上提出了解决方案。     

Bayesian statistical model checking with application to Stateflow/Simulink verification

We address the problem of model checking stochastic systems, i.e., checking whether a stochastic system satisfies a certain temporal property with a probability greater (or smaller) than a fixed threshold. In particular, we present a Statistical Model Checking (SMC) approach based on Bayesian statistics. We show that our approach is feasible for a certain class of hybrid systems with stochastic transitions, a generalization of Simulink/Stateflow models. Standard approaches to stochastic discrete systems require numerical solutions for large optimization problems and quickly become infeasible with larger state spaces. Generalizations of these techniques to hybrid systems with stochastic effects are even more challenging. The SMC approach was pioneered by Younes and Simmons in the discrete and non-Bayesian case. It solves the verification problem by combining randomized sampling of system traces (which is very efficient for Simulink/Stateflow) with hypothesis testing (i.e., testing against a probability threshold) or estimation (i.e., computing with high probability a value close to the true probability). We believe SMC is essential for scaling up to large Stateflow/Simulink models. While the answer to the verification problem is not guaranteed to be correct, we prove that Bayesian SMC can make the probability of giving a wrong answer arbitrarily small. The advantage is that answers can usually be obtained much faster than with standard, exhaustive model checking techniques. We apply our Bayesian SMC approach to a representative example of stochastic discrete-time hybrid system models in Stateflow/Simulink: a fuel control system featuring hybrid behavior and fault tolerance. We show that our technique enables faster verification than state-of-the-art statistical techniques. We emphasize that Bayesian SMC is by no means restricted to Stateflow/Simulink models. It is in principle applicable to a variety of stochastic models from other domains, e.g., systems biology.     

基于Matlab／Simulink的无人机飞行仿真研究

该文以某小型无人机为研究对象,基于其数学模型,在Matlab／Simulink环境下并结合Stateflow的有限状态机实现了对该无人机飞行过程的仿真模拟。首先利用Matlab／Simulink,对小型无人机搭建了非线性数学模型,对其飞行控制律进行了研究;然后利用Stateflow模拟了无人机的飞行管理器,实现无人机多模态之间的转换;最后对无人机的控制规律进行了验证。其结果表明了该控制规律的合理性和有效性。     

An operational semantics for Stateflow

We present a formal operational semantics for Stateflow, the graphical Statecharts-like language of the Matlab/Simulink tool suite that is widely used in model-based development of embedded systems. Stateflow has many tricky features but our operational treatment yields a surprisingly simple semantics for the subset that is generally recommended for industrial applications. We have validated our semantics by developing an interpreter that allows us to compare its behavior against the Matlab simulator. We have used the semantics as a foundation for developing prototype tools for formal analysis of Stateflow designs.     

Refinement-based verification of implementations of Stateflow charts

Simulink’s Stateflow is a graphical notation widely adopted in industry. Since it is frequently used to model safety-critical systems, correctness of implementations of Stateflow charts is a major concern. In previous work, we have shown how we can generate formal models for refinement of Stateflow charts automatically. Here, we define a refinement strategy that supports the automated verification of implementations with respect to these models. We consider the verification of implementations that follow architectural patterns used in the Stateflow code generator. We present a detailed procedure for application of refinement laws. If the implementation is correct, the procedure succeeds. If a law application fails, the implementation is either incorrect or does not use the expected architectural pattern. The very low proof burden associated with the refinement verification makes a high level of automation possible.     

基于Matlab/Simulink的混联式混合动力电动汽车建模与仿真

在Matlab/Simulink环境下建立混联式混合动力电动汽车(Parallel Series Hybrid Electric Vehicle,PSHEV)模型,并用Stateflow建立整车控制器的模式逻辑模型。在欧洲城市道路循环工况(European Urban Road Driving Cycle,CYC_ECE_EUDC)下对整车动力性能、燃油经济性能与排放性能进行仿真分析。仿真结果表明：与Advisor/Prius在相同工况下的仿真结果相比,所建立模型符合混联式混合动力电动汽车的整车动力学要求,模型具有正确性和可行性,且采用所建立的能量分配控制策略,百公里油耗为5.056L,较Advisor/Prius模型同比下降2.8%,CO排放量和NOx排放量分别降低16.9%和2.7%,实现控制策略的有效性,达到节能减排的目的。     

四旋翼无人机可视化轨迹跟踪仿真系统

为了便于对四旋翼无人机控制算法进行实验仿真和验证,联合Solidworks和Matlab/SimMechanics工具箱设计了一种四旋翼无人机可视化轨迹跟踪仿真系统;利用Solidworks搭建了四旋翼无人机三维实体模型,并通过Solidworks和Matlab转换接口将该实体模型导入到Matlab/SimMechanics中;Matlab/SimMechanics提供了了三维可视化窗口,可以显示无人机的实时仿真状态;仿真平台在Matlab/SimMechanics环境中实现,与Matlab/Simulink通信方便,可方便的将Simulink设计好的控制算法添加到仿真系统中,以进行验证和参数整定,还具有姿态分析和数据分析等功能;轨迹跟踪仿真结果表明,四旋翼无人机可视化轨迹跟踪仿真系统直观可视,准确可靠,能较好地对控制算法进行研究和测试,对四旋翼无人机以及控制算法的研究和开发具有重要价值。     

基于STeC-Stateflow转换系统的实时系统仿真与验证方法

物联网以及信息物理融合系统对形式化建模提出了新的挑战, 引入了实时系统规范语言STeC, 为刻画实时系统的时空一致性提供了规范语言。针对STeC语言建立STeC至Stateflow自动转换系统, 提出一种基于STeC至Stateflow转换的仿真及验证方法, 该方法使用STeC语言对实时系统进行形式化建模, 再建立实时监控的Simulink仿真模型, 并使用Checkmate对系统进行安全性验证。通过对京沪高铁运行的实例研究, 表明该方法对高铁运行系统实时仿真的有效性, 并能够验证高铁运行系统的安全性。     

A mathematical model of a digital control system with variable parameters

An approach is suggested for analysis of digital control systems with variable parameters; the approach involves the method of event-driven simulation. In addition, we describe a mathematical model of a discrete-continuous control system, implemented in MATLAB/Simulink/Stateflow.     

Formal modeling and validation of Stateflow diagrams

Stateflow is an industrial tool for modeling and simulating control systems in model-based development. In this paper, we present our latest work on automatic verification of Stateflow using model-checking techniques. We propose an approach to systematically translate Stateflow diagrams to a formal modeling language called CSP# by precisely following Stateflow’s execution semantics, which is described by examples. A translator is developed inside the Process Analysis Toolkit (PAT) model checker to automate this process with the support of various Stateflow advanced modeling features. Formal analysis can be conducted on the transformed CSP# with PAT’s simulation and model-checking power. Using our approach, we can not only detect bugs in Stateflow diagrams, but also discover subtle semantics flaws in Stateflow user’s guide and demo cases.     

Simulink/Stateflow仿真程序的HLA兼容性改造设计

该文从数据结构入手，宏观分析了Simulink／Stateflow仿真模型在进行HLA(高层体系结构)兼容性改造过程中所涉及的主要问题及步骤。主要包括由RTW(实时工作室)所生成的Simulink／Stmeflow模型C代码的通用运行框架，模型程序的SOM(仿真对象模型)开发，模型程序的HLA软件接口设计等。特别是针对HLA软件接口的设计与实现过程中存在许多重复性的工作，提供了一个将Simulink／Stateflow模型程序自动转化为HLA联邦成员且能适用于不同联邦的工具软件框架结构，从而为基于HAL仿真系统的Simulink／Stateflow仿真模型开发提供一条优化途径。     

The art of modeling and simulation of induction generator in wind generation applications using high-order model

Both fixed-speed squirrel-cage induction generators and variable-speed doubly fed induction generators are used in wind turbine generation technology. Modeling and simulation of induction machines using vector computing technique in Matlab/Simulink provides an efficient approach for further research on wind generation system integration and control. In this paper, the vector computing technique is applied in modeling and simulation of induction machines. Free acceleration of squirrel-cage induction generator, active power and reactive power control of DFIGs in a power system as well as inter-area oscillation damping control are demonstrated using the proposed model. The modeling approach in Matlab/Simulink makes controller design and simulation verification effective.     

PHAVer: algorithmic verification of hybrid systems past HyTech

In 1995, HyTech broke new ground as a potentially powerful tool for verifying hybrid systems. But due to practical and systematic limitations it is only applicable to relatively simple systems. We address the main problems of HyTech with PHAVer, a new tool for the exact verification of safety properties of hybrid systems with piecewise constant bounds on the derivatives, so-called linear hybrid automata. Affine dynamics are handled by on-the-fly overapproximation and partitioning of the state space based on user-provided constraints and the dynamics of the system. PHAVer features exact arithmetic in a robust implementation that, based on the Parma Polyhedra Library, supports arbitrarily large numbers. To force termination and manage the complexity of the polyhedral computations, we propose methods to conservatively limit the number of bits and constraints of polyhedra. Experimental results for a navigation benchmark and a tunnel diode circuit demonstrate the effectiveness of the approach. A preliminary version of this paper appeared in the Proceedings of Hybrid Systems: Computation and Control (HSCC 2005), Lecture Notes in Computer Science 3414, Springer-Verlag, 2005, pp. 258–273.     

Time Domain Verification of Oscillator Circuit Properties

The application of formal methods to analog and mixed signal circuits requires efficient methods for constructing abstractions of circuit behaviors. This paper concerns the verification of properties of oscillator circuits. Generic monitor automata are proposed to facilitate the application of hybrid system reachability computations to characterize time domain features of oscillatory behavior, such as bounds on the signal amplitude and jitter. The approach is illustrated for a nonlinear tunnel-diode circuit model using PHAVer, a hybrid system analysis tool that provides sound verification results based on linear hybrid automata approximations and infinite precision computations.     

基于Stateflow和xPC的监控系统实现

Stateflow是MATLAB提供的一种基于有限状态机理论的图形化建模和仿真工具。本文介绍了Stateflow的重要概念和基本用法。并使用MATLAB的Simulink、Stateflow和RTW／xPC工具箱,完成一仓厍监控系统从建模、仿真到实时代码生成的完整过程,大大缩短了监控系统的开发周期。     

红外光幕在地铁屏蔽门障碍物探测中的研究

针对现有地铁屏蔽门通过门速曲线的改变来探测障碍物的方法在检测最小尺寸为4 mm×40 mm的障碍物中所存在的不足,提出一种利用红外光幕的障碍物探测方法,并结合数字信号处理器(DSP)的无刷直流电动机控制技术和模糊PID控制算法来实现地铁屏蔽门障碍物的探测,最后在Matlab/Simulink环境中构建了整个系统的数学模型,并对系统在正常情况和遇到障碍物时的关门过程进行仿真分析。仿真结果表明:基于该方法设计的地铁屏蔽门障碍物探测系统可以解决现有地铁屏蔽门在障碍物探测方面的不足。     

Order-reduction abstractions for safety verification of high-dimensional linear systems

Order-reduction is a standard automated approximation technique for computer-aided design, analysis, and simulation of many classes of systems, from circuits to buildings. To be used as a sound abstraction for formal verification, a measure of the similarity of behavior must be formalized and computed, which we develop in a computational way for a class of asymptotic stable linear systems as the main contributions of this paper. We have implemented the order-reduction as a sound abstraction process through a source-to-source model transformation in the HyST tool and use SpaceEx to compute sets of reachable states to verify properties of the full-order system through analysis of the reduced-order system. Our experimental results suggest systems with thousand of state variables can be reduced to systems with tens of state variables such that the order-reduction overapproximation error is small enough to prove or disprove safety properties of interest using current reachability analysis tools. Our results illustrate this approach is effective in tackling the state-space explosion problem for verification of high-dimensional linear systems.     

基于状态机的自动变速控制器仿真研究

针对汽车发动机自动变速装置在不同运行状态下仿真建模的研究,提出基于有限状态机的建模方法.该方法通过将汽车行驶阶段的不同状态,建模为多状态事件的迁移,借助发动机厂家提供的变速器换挡点图以及发动机工作特性图,利用Matlab/Simulink建立了整车动力性能仿真模型和基于Matlab/     

SLDG: a metamodel for Simulink/Stateflow models and its applications

Simulink and Stateflow (SL/SF) models are being widely used to design and develop embedded systems. Often the SL/SF models of embedded controllers turn out to be large and consist of many subsystems and hierarchies. When such a system is maintained, it becomes difficult to manually analyse the model to identify the impacted elements due to the existence of several explicit and implicit dependencies among the model elements. To automate the analysis of an SL/SF model, we propose a metamodel to capture various types of dependencies existing across the basic blocks. We have named this metamodel Simulink dependency graph (SLDG). We investigate the use of SLDG in change impact visualization and regression test selection. We have developed a prototype tool by implementing our approach for the aforementioned applications.     

有限状态机在导弹防御系统分析中的应用

介绍了有限状态机的基本概念,基于UML详细分析了导弹防御系统的作战过程.由于UML状态机无法直接运行而实现系统状态的动态转换,研究了基于有限状态机理论的图形化建模与仿真工具Stateflow.在分析了导弹防御系统作战过程中各子系统状态以及状态转换的基础上建立了Stateflow状态机模型,并与Matlab其它建模和仿真工具有机结合,建立了导弹防御系统的仿真模型,该模型可实现不同条件下系统性能的分析与评估.