HYCON-EECI, Spring 2013

	Specification, Design, and Verification
	of Networked Control Systems
	Richard M. Murray, Ufuk Topcu, and Nok Wongpiromsarn
	18-22 March 2013, Belgrade (Serbia)

Course Description

Increases in fast and inexpensive computing and communications have enabled a new generation of information-rich control systems that rely on multi-threaded networked execution, distributed optimization, sensor fusion and protocol stacks in increasingly sophisticated ways. This course will provide working knowledge of a collection of methods and tools for specifying, designing and verifying networked control systems. We combine methods from computer science (temporal logic, model checking, synthesis of control protocols) with those from dynamical systems and control (Lyapunov functions, trajectory generation, receding horizon control) to analyze and design partially asynchronous control protocols for continuous systems. In addition to introducing the mathematical techniques required to formulate problems and prove properties, we also describe a software toolbox (TuLiP) that is designed for analyzing and synthesizing hybrid control systems using linear temporal logic and robust performance specifications.

Reading

The following papers and textbooks will be used heavily throughout the course:

• Principles of Model Checking, C. Baier and J.-P. Katoen, The MIT Press, 2008.

• Synthesis of Control Protocols for Autonomous Systems, N. Wongpiromsarn, U. Topcu and R. M. Murray. Unmanned Systems, 2013 (submitted)

Additional references for individual topics are included on the individual lecture pages.

Course information

• Instructors: Richard M. Murray (Caltech, CDS) and Ufuk Topcu (Caltech, CDS), and Nok Wongpiromsarn (MIT-Singapore)
• Date and location: 18-22 May 2013, Belgrade (Serbia)
• Sponsor: HYCON-EECI Graduate School on Control

Lecture Schedule

The schedule below lists the lectures that will be given as part of the course. Each lecture will last approximately 90 minutes. The individual lecture pages give an overview of the lecture and links to additional information.

Lec	Date/time	Title	Topics
L1 RM	Mon, 9:00	Introduction: Protocol-Based Control Systems	Introduction to networked control systems (NCS) Overview of control "protocols" Examples: Alice, RoboFlag
L2 UT	Mon, 11:00	Automata Theory	Finite transition systems Paths, traces and composition of finite transition systems Linear time properties; safety and liveness Examples: traffic light
L3 RM	Mon, 14:00	Temporal Logic	Linear temporal logic Omega regular properties Buchi automata, representation of LTL using NBA Examples: traffic light, (RoboFlag), autonomous driving
L4 UT	Mon, 16:00	Model Checking and Logic Synthesis	Basic concepts in model checking Use of model checking for logic synthesis Examples: traffic light, farmer puzzle
C1 RM	Tue, 9:00 Tue, 11:00	Computer Session: Spin	Introduction to Promela and Spin (statements, processes, messages) Verification examples: traffic light, distributed traffic light, gcdrive Synthesis examples: traffic light, farmer puzzle, robot navigation
L5 RM (1h)	Wed, 9:00	Deductive Verification of Hybrid Systems	Brief introduction to hybrid systems and verification techniques (deductive, algorithmic) Deductive verification using barrier certificates Guarded command languages and CCL for asynchronous control protocols Examples: multi-agent systems, RoboFlag
L6 UT (2h)	Wed, 11:00	Algorithmic Verification of Hybrid Systems	Abstraction hierarchies for control systems Finite state abstractions (discretization) and model checking Discretization of continuous state systems Approximate bi-simulation (if time) Examples: gear changing (?), ???
L7 RM (2h)	Wed, 14:00	Synthesis of Reactive Control Protocols	Open system and reactive system synthesis Satisfiability, realizability Game structures, reachability/safety games Mu-calculus (if time) and GR(1) games Examples: runner-blocker
L8 UT(1h)	Wed, 16:00	Receding Horizon Temporal Logic Planning	Receding horizon control Examples: reactive motion planning
C2 UT	Thu, 9:00 Thu, 11:00	Computer Session: TuLiP	Introduction to TuLiP Synthesis of protocols for discrete systems Discretization of continuous systems (and protocol synthesis) Examples: reactive motion planning
L9 UT	Fri, 9:00	Advanced Topics	Distributed protocols Switched systems Optimal synthesis
L10 RM	Fri, 11:00	Summary and Open Questions	Review of control trends and course contents Discussion of open problem areas and preliminary results Optimization-based techniques Probabilistic techniques Others: Robustness, switching systems, timed systems Examples: robot motion planning, electric power systems (timed)

Software Installation

We will make use of two programs during the lab sessions:

• Spin - model checker for formal verification of distributed systems
• TuLiP - python-based toolbox for temporal logic planning and controller synthesis

During the course, we will access these programs on a remote machine using ssh. For some parts of the course it will be useful to have a local installation of MATLAB that can be used for visualizing some simulation results.

If you would like to install the software on your own, here are some basic directions for installing the two packages:

• Spin: if you are using Windows, you can download a binary installation. For Mac's, you need to compile from source. For this you will need a C compiler, such as the one that is part of the Xcode developer toolbox
• TuLiP: you will need a python installation (2.6 or greater) with SciPy (0.9 or greater) installed. You might consider using the Enthought Python distribution. Once you have scipy installed, you will need to install several other python packages, including cvxopt and yices. A list of required package is available on the TuLiP project page.