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With the publication of ISO26262 [1] and the concept of Functional Safety, being able to identify the required safety integrity level for software components and defining the respective development steps has become increasingly important. A number of Tier 1 automotive suppliers, including Robert Bosch LLC, have been developing software for safety relevant systems, and have experience with a number of methods and tools for software analysis. This paper will focus on the pros and cons of the Criticality Analysis method. Criticality Analysis (CA) is a method that rates outputs, sub-components and inputs to a function based on the ASIL rating of the function. Faller [2] proposed the use of CA in conjunction with IEC 61508 safety standard, and this author proposes that the CA can also be used in conjunction with ISO 26262. CA allows taking a function with any ASIL rating and breaking down the signal chain to develop safety requirements at each stage (see [2, 3]).

This paper describes an investigation about the efficiency of safety-related non-functional software unit tests (NFSWUT). Well defined design, implementation and test processes are widely used in the respective industry. In order to fulfill the ISO 26262[1] requirement, additional effort is necessary to execute the NFSWUT. However, the efficiency of these tests is still not confirmed. This paper will provide an overview about an investigation of the effort-benefit ratio of the NFSWUT.

This paper describes an approach to estimate the sideslip angle of a vehicle based on a commercial Domain Control Unit (DCU) with integrated sensors for all 6 degrees of freedom of the vehicle body. The main advantage of the derived algorithms is the absence of vehicle and tire model equations and consequently the robustness with respect to model validity ranges, parameters and uncertainties. Computer simulations and driving tests show a high accuracy for the estimated Bryant angles, lateral and longitudinal velocities and the sideslip angle even during high-dynamic maneuvers. The authors will also focus on potential applications like vehicle stabilization by means of steering and braking interventions.

This paper describes an integrated safety concept for Vehicle Dynamics Management (VDM) - the control integration of an electronic stability brake control system (ESC) and with other active chassis systems. The partner system considered is an active front steering system (AFS) which permits steering angle super-position. The VDM steering algorithms and the associated monitoring and reconfiguration functions are integrated into the ESC-ECU. The AFS-ECU houses actuator control and comfort functionalities. This paper focuses on the functional safety concept and the development activities required to achieve the necessary high integrity level.

Active Front Steering (AFS) provides an electronically controlled superposition of an angle to the steering wheel angle. This additional degree of freedom enables a continuous and driving-situation dependent adaptation of the steering characteristics. Features like steering comfort, effort and steering dynamics are optimized and stabilizing steering interventions can be performed. After the successful introduction of the AFS System together with the new BMW 5-series into the international market, ZF Lenksysteme focuses on a modular system concept with new and improved functionalities. Currently, the variable steering ratio (VSR) provides the most evident benefit for the driver. This function represents an adaptation of the static steering characteristics by adjusting the steering ratio between the steering wheel angle and an average road wheel angle to the driving situation as a function of the vehicle velocity.

Active Front Steering (AFS) provides an electronically controlled superposition of an angle to the steering wheel angle. This additional degree of freedom enables a continuous and driving-situation dependent adaptation of the steering characteristics. Features like steering comfort, effort and steering dynamics are optimized and stabilizing steering interventions can be performed. After the successful introduction of AFS (or active steering) together with the new BMW 5-series into the international market, ZF Lenksysteme focuses on aspects like system modularization and integration. For that reason the system bounds, its functionality, and the required system interface are defined to provide a compatibility to several overall chassis control concepts. This paper focuses on a modular system concept and its respective advantages and requirements.

Active Front Steering (AFS) provides an electronically controlled superposition of an active angle to the steering wheel angle. This steering system developed by ZF Lenksysteme and BMW AG enables driver dependent as well as automatic steering interventions. The permanent mechanical connection between steering wheel and road wheels remains. Since the AFS system was recently introduced together with the new BMW 5 series, the most of the investigations of steering systems do not include the dynamic behavior of such mechatronic actuators. On the other hand, these kind of models are required to design control algorithms and model based monitoring functions that provide the desired accuracy and real-time algorithms that run on a series electronical control unit. This paper summarizes a validated mathematical model of the AFS actuator including 8 rigid bodies, 46 constraint relations and a synchronus motor.

Active Front Steering (AFS) is a newly developed technology for passenger cars that realises an electronically controlled superposition of an angle to the hand steering wheel angle that is prescribed by the driver. It enables functionalities such as (vehicle velocity) variable steering ratio, steering lead, as well as it provides an interface to support vehicle dynamics control systems. This paper focuses on application dependent safety functions and steering assistance functions. All functions described are model based, their accuracy is demonstrated.