Hans-Ulrich Michel

A unified Car-IT Communication-Architecture: Design guidelines and prototypical implementation

Our research in the field of communication networks for transportation systems lead to a unified car-IT architecture based on IEEE 802.3 Ethernet. In this paper, we present a prototypical implementation of a real-time gigabit Ethernet switch with the use of a freescale MPC8541e development board and an embedded Linux. We show the communication requirements for use in an automotive scenario and present real-time accurate measurements compared to an off-the-shelf hardware design.

A model for sequence based power management in cyber physical systems

This paper develops a model for operating system level power management in cyber physical systems. The core part is a transducing mechanism, forming physical inputs into functional state sequences. Each functional state transition then is allowed to switch in between power management plans. A power management plan is modeled as a directed graph over power states and functional jobs together with timing conditions. Different optimization problems for designing these plans according to scheduling requirements, and for maximizing energy savings under both constrained management complexity and constrained supply voltage stability are presented.

A unified Car-IT Communication-Architecture: Network switch design guidelines

Rising communication needs in transportation systems due to meshed control circuits and complex sensor technology like lidar, radar and cameras lead to increasing wiring harness and system complexity. To solve this, we made an approach for a unified car-IT communication-architecture based on IEEE 802.3 switched Ethernet for use in the vehicular environment. In this paper, we present the requirements for and realization of the core-network components to enable deterministic communication and the corresponding real-time calculus for system verification.

Topology and Design Optimization of a 14 V Automotive Power Net Using a Modified Discrete PSO in a Physical Simulation

In the last years, hydraulic powered chassis control systems have been replaced by electrical systems due to efficiency reasons. Additionally, more and more comfort electronics have been integrated. These circumstances have lead to a high power demand in todays automotive power nets. For this reason, voltage stability has become an important design criterion of the power net. This paper describes a simulation based method to optimize the power net topology and the dimensioning of components with regard to voltage stability requirements. A Modified Discrete Particle Swarm Optimization is used in combination with a physical power net simulation. In order to optimize the topology itself, a tool flow for an automated change of the simulation model is presented. To achieve best possible performance, the influence of the configuration parameters on the algorithm performance is evaluated and appropriate parameters are chosen for the given problem. Finally, exemplary optimization results are shown by pointing out optimal topologies for different constraints of the minimum terminal voltage.

Automotive network planning - A genetic approach

While talking of future communication architectures in transportation systems a lot, only few show a realization and expected efforts to build such a network. In this paper, we present a network planning process and metrics to estimate the costs of a next generation Car-IT Communication-Architecture based on data of a real, luxury class car. We utilize a virtual cost function and a genetic search algorithm and show the results in our real-life scenario.

Experimental Investigations on an Autonomous Load Shutdown Mechanism in Respect to Voltage Stability in Automotive Power Nets

The power demand in 14V automotive power nets has steadily increased in recent years. On the one hand, more and more comfort electronics have been integrated. On the other hand, previously hydraulically driven chassis control systems have been replaced by electrically powered systems in order to increase efficiency. This trend has led to a drastic increase of the loads combined peak power. For this reason, voltage stability has become an important design criterion of automotive power nets. This paper experimentally investigates the influence of an autonomous load shutdown mechanism on voltage stability. The mechanism temporarily shuts down non-safety-critical heating systems with high continuous power consumption, e.g. seat heaters. This mechanism is implemented on a generic ECU hardware. In order to achieve the most realistic behavior of the system, the hardware is integrated into a 14V power net test bench, consisting of a car chassis and the wiring harness. Concluding measurements reveal that this mechanism is able to increase the terminal voltage at the most critical positions of the power net by about 1V.

Modeling of an electromechanical actuator in respect to voltage stability in automotive power nets

Due to efficiency reasons, more and more previously mechanically driven systems have been electrified in recent years. While this development reduces fuel consumption in conventional drive trains, it is essential in electric vehicles due to the omission of the combustion engine. The transient peak power of these systems has a negative influence on voltage stability in automotive power buses. For this reason, voltage stability has become an important criterion in the design process of a power net. Beside the electrical power steering, the electro hydraulic breaking systems is one of the critical systems regarding peak power consumption. In this paper, a dynamic model of an electromechanical actuator for an automotive breaking system is presented. The model is validated by comparison of simulation and measurement from a real car. Furthermore, a sensitivity analysis examines the influence of parameters on the occurring peak current during the startup process. It is shown, that temperature and correlating armature resistance have an significant influence on the peak starting current.

Design optimization of a 14 V automotive power net using a parallelized DIRECT algorithm in a physical simulation

The high power demand of electrical components in cars and the associated complexity of the 14 V power net have steadily increased in recent years. An important design criterion of the power net is the voltage stability during peak loads. This paper describes a simulation-based optimization method to fulfill the voltage stability requirements in a minimum-weight configuration of the power net. The method is applied to different power net topologies which are configured using a mixture of discrete and continuous parameters. Finally, the performance of the optimization algorithm as well as the optimization results are presented and evaluated.

Multicore Enablement for Automotive Cyber Physical Systems

Abstract Smart mobility addresses ecological, safe and flexible transportation needs of individuals and the general public. Smart mobility draws synergies from integrating traditionally disjoint domains like automotive, railway, avionics and geography-/business-specific location based services. Cyber physical systems (CPS), built around multicore processor technology, provision powerful platforms to realize smart mobility applications. However, multicore processors require adequate enablement in order to tackle their inherent complexities related to efficient exploitation of parallel resources under safety, security and real-time constraints. This paper addresses two topics: First, we discuss the different notions CPS may adopt in the automotive domain and outline their potentials. Second, we propose a holistic virtualization approach consisting of Hypervisor/VMM middleware for processor virtualization in combination with hardware-assisted communication virtualization. This will allow providing high-bitrate, dependable and QoS conform interconnect services among compute, memory and I/O resources of automotive ECU systems. Zusammenfassung Smart Mobility bietet Lösungen für die Bedürfnisse des Einzelnen sowie der Öffentlichkeit nach einer ökologisch nachhaltigen, sicheren und flexiblen Verkehrsinfrastruktur. Es vereint traditionell getrennte Verkehrsdomänen wie Straße, Schiene und Flugzeug sowie ortsbezogene Dienste und Dienstleistungen zu einem zusammenwirkenden Gesamtkonzept. Cyber-Physical Systems (CPS), basierend auf Mehrkernprozessoren, stellen die erforderlichen leistungsfähigen IT-Plattformen für Smart Mobility Anwendungen zur Verfügung. Beim Einsatz von Mehrkernprozessoren bedarf es jedoch geeigneter Methoden, die es erlauben, die inhärente Komplexität bei der effizienten Nutzung der parallelen Ressourcen zu beherrschen und dabei gleichzeitig spezifische Anforderungen wie Safety, Sicherheit und Realzeit zu erfüllen. Dieser Artikel behandelt zwei Themenkomplexe. Zum einen erläutern wir die verschiedenen Aspekte von CPS in der Fahrzeugdomäne und zeigen deren Potentiale auf. Zum anderen schlagen wir einen ganzheitlichen Virtualisierungsansatz vor, bestehend aus Hypervisor/VMM Middleware für Prozessorvirtualisierung und Hardware-unterstützter Kommmunikationsvirtualisierung. Dieser Ansatz ermöglicht hochbitratige, zuverlässige und QoS-konforme Verbindungen zwischen Rechner-, Speicher- und I/O-Ressourcen in Fahrzeugsteuergeräten.

An architecture for power management in automotive systems

This paper presents an architectural model for power management in automotive systems. It is based on recent advances in cyber physical and cybernetic control systems. Based upon a previous model of power management, formal interactions in between a hierarchical structure are characterized. In the architecture, strategic decisions allow coordinated adjusting of power management plans as well as local autonomy in subsystem scope.