Michal Sojka

TORSCHE Scheduling toolbox for Matlab

This paper presents a Matlab based scheduling toolbox TORSCHE (time optimization of resources, scheduling). The toolbox offers a collection of data structures that allow the user to formalize various off-line and online scheduling problems. Algorithms are simply implemented as Matlab functions with fixed structure allowing users to implement new algorithms. A more complex problem can be formulated as an integer linear programming problem or satisfiability of Boolean expression problem. The toolbox is intended mainly as a research tool to handle control and scheduling co-design problems. Therefore, we provide an interface to a real-time Matlab/Simulik based simulator TrueTime and a code generator allowing to generate parallel code for FPGA

Modular software architecture for flexible reservation mechanisms on heterogeneous resources

Management, allocation and scheduling of heterogeneous resources for complex distributed real-time applications is a challenging problem. Timing constraints of applications may be fulfilled by the proper use of real-time scheduling policies, admission control and enforcement of timing constraints. However, it is not easy to design basic infrastructure services that allow for easy access to the allocation of multiple heterogeneous resources in a distributed environment. In this paper, we present a middleware for providing distributed soft real-time applications with a uniform API for reserving heterogeneous resources with real-time scheduling capabilities in a distributed environment. The architecture relies on standard POSIX OS facilities, such as time management and standard TCP/IP networking services, and it is designed around CORBA, in order to facilitate modularity, flexibility and portability of the applications using it. However, real-time scheduling is supported by proper extensions at the kernel-level, plugged within the framework by means of dedicated resource managers. Our current implementation on Linux supports the reservation of the CPU, disk and network bandwidth. However, additional resource managers supporting alternative real-time schedulers for these resources, as well as additional types of resources, may be easily added. We present experimental results gathered on both synthetic applications and a real multimedia video streaming case study, showing the advantages deriving from the use of the proposed middleware. Finally, overhead figures are reported, showing the sustainability of the approach for a wide class of complex, distributed, soft real-time applications.

Measurement automation and result processing in timing analysis of a Linux-based CAN-to-CAN gateway

The aim of this paper is to describe the method used to analyze timing properties of a Linux-based CAN-to-CAN gateway and to briefly present some of the analysis results. The considered gateway, implemented as an embedded system, can significantly simplify rapid prototyping of CAN-based distributed systems such as those used in automotive applications. The main interest was to measure the latencies induced by the gateway under the wide range of conditions such as various types of traffic, gateway configurations, additional system load and Linux kernel versions. The combinations of these conditions resulted in almost 400 different experiments and more than 600 graphs visualizing the results. A simple method to automate the experiments and to effectively draw conclusions from such a high number of experiments is proposed.

A comparison of Linux CAN drivers and their applications

The aim of this paper is to introduce LinCAN, a CAN driver system for Linux, developed at the Department of Control Engineering of the Czech Technical University in Prague, and to provide a thorough comparison with SocketCAN, which is the most common CAN solution for Linux nowadays. Thorough timing analysis and performance comparison with Socket CAN are presented, with several case-studies and applications of LinCAN shown in the end. LinCAN has been developed since 2003 and supports many CAN controllers from various manufacturers. It is designed with emphasis on strict real-time properties and reliability, making it ideally suitable for networked control systems (as is also demonstrated in the case-studies). LinCAN is also portable to other Operating Systems and can be used even system-less (without any OS) on less-powerful microcontrollers. A timing analysis and performance tests of both drivers were performed using various types of load with several recent Linux kernels. Obtained results indicate that LinCAN seems better suited for hard real-time applications, its performance being either better or on-par with SocketCAN in presented tests. Both LinCAN and SocketCAN drivers are completely open-source as well as our testing tools, so any researcher interested in our results is welcome to download all relevant source codes, check our testing methodology in detail and perhaps recreate our results or extend them by performing other test, providing valuable feedback and independent verification of our work.

Case study on combined validation of safety & security requirements

In the automotive domain, it is of paramount importance to ensure safety, and recently also security, of the developed products. In many cases safety and security are handled separately by independent teams. In this paper we deal with testing and validation of safety- and security-related properties of control software in the AUTOSAR architecture and show that the strict separation of those two activities is not necessary and that combining them can bring economic benefits. We demonstrate that by developing software-in-the-loop and hardware-in-the-loop testbeds and use them for both safety-and security-related testing activities. We evaluate a prototype of electric motors control software, that is currently under development by Infineon Technologies, and perform a number of tests to verify correct functionality of implemented safety measures even under the presence of attacks. The motor control software is integrated with a message authentication protocol on CAN bus. The results show, that apart from few minor problems, the implemented safety measures function correctly.

Formal Security Analysis of the MaCAN Protocol

Embedded real-time network protocols such as the CAN bus cannot rely on off-the-shelf schemes for authentication, because of the bandwidth limitations imposed by the network. As a result, both academia and industry have proposed custom protocols that meet such constraints, with solutions that may be deemed insecure if considered out of context. MaCAN is one such compatible authentication protocol, proposed by Volkswagen Research and a strong candidate for being adopted by the automotive industry.

Modular architecture for real-time contract-based framework

Component-based development of distributed real-time applications is a challenging task since satisfying timing requirements of individual components after system integration requires support from the component middleware which is not common today. This paper presents a software architecture of contract-based on-line resource reservation framework which can be used as a basis for a real-time component-based middleware. The main contribution of this architecture is its modularity which allows for support of many different resources such as CPU, networks, disks, FPGAs etc. The paper describes algorithms used to integrate the management of multiple resources and presents some experimental results from Linux implementation.

Experiments for real-time communication contracts in IEEE 802.11e EDCA networks

In this paper we describe basic experiments measuring communication delays in IEEE 802.11e EDCA networks. Based on results of these experiments we have designed a simple utilization based admission test to support wireless networks in a contract framework.

SPEJBL—The biped walking robot

Abstract Construction of a biped walking robot, its hardware, basic software and control design is presented. Primary goal achieved is a static walking with non-instantaneous double support phase and fixed trajectory in joint coordinates. The robot with two legs and no upper body is capable to walk with fixed, manually created, static trajectory using simple SISO proportional controller, yet it is extendable to use MIMO controllers, flexible trajectory, and dynamic gait. Distributed servo motor control over a CAN fieldbus is used. Important points in construction and kinematics, motor current cascaded control and fieldbus timing are emphasized. The project is open and full documentation is available.

A Software Stack for Next-Generation Automotive Systems on Many-Core Heterogeneous Platforms

The advent of commercial-of-the-shelf (COTS) heterogeneous many-core platforms is opening up a series of opportunities in the embedded computing market. Integrating multiple computing elements running at lower frequencies allows obtaining impressive performance capabilities at a reduced power consumption. These platforms can be successfully adopted to build the next-generation of self-driving vehicles, where Advanced Driver Assistance Systems (ADAS) need to process unprecedently higher computing workloads at low power budgets. Unfortunately, the current methodologies for providing real-time guarantees are uneffective when applied to the complex architectures of modern many-cores. Having impressive average performances with no guaranteed bounds on the response times of the critical computing activities is of little if no use to these applications. Project HERCULES will provide the required technological infrastructure to obtain an order-of-magnitude improvement in the cost and power consumption of next generation automotive systems. This paper presents the integrated software framework of the project, which allows achieving predictable performance on top of cutting-edge heterogeneous COTS platforms. The proposed software stack will let both real-time and non real-time application coexist on next-generation, power-efficient embedded platform, with preserved timing guarantees.