Cooperation of vehicular systems is the stepping stone towards both road and indoor smart transportation systems. It aims at increasing transportation efficiency and safety compared to the stand-alone vehicular systems. The usage of wireless communication as the foundation of such safety-critical cooperation needs to be embraced with all its benefits and flaws compared to the wired communication. The cooperative functions need to be designed to adapt to the varying reliability of the wireless communication channels such that both the stand-alone vehicles as well as the smart transportation system formed by their cooperation are deemed sufficiently safe. In this paper we build upon a contract-based runtime monitoring architecture and propose a methodology for assuring adaptive behaviour of transportation with respect to the wireless communication channel failures. More specifically, we elaborate how safety analysis of the interaction of the wirelessly connected vehicles can be used as the basis for derivation of the adaptive modes and the corresponding contracts. Furthermore, we discuss how such contracts can be used as the basis for assurance of the adaptive wireless cooperation. We illustrate the proposed methodology on a smart transportation system of a factory.
Autonomous non-military cyber-physical systems are widely studied in research but there are still few applications in industry. One of the reasons relies in the fact that there is still no proof of guarantee for these systems regarding their safety and their ability to behave in a nonhazardous way, mainly because of the induced complexity caused by their learning abilities coupled with the high ability to interact and cooperate of their composing mechatronics elements. More, cyber-physical systems are intended to be merged into socio-technical systems and interact with humans. As a consequence, the study of their ethical behavior translates currently a major stake. Meanwhile, it is clear that this stake is still not address by the scientific community while 1) sci-fi literature and movies have addressed this since a long time 2) some autonomous road vehicles have already injured people, and 3) EU parliament has launched a procedure dealing with the establishment of civil laws for autonomous learning robots. This paper intends then to open the debate on this topic and suggests to extend dependability studies to integrate ethicality as a new dimension. New emerging research fields are identified and an illustration in the autonomous train transportation is presented.
Open access
Safety Systems Engineering in Autonomy
Ethics and Social Impacts of AI
Systems Engineering Methodologies and Applications
Loss of control is a serious problem in aviation that primarily affects General Aviation. Technological advancements can help mitigate the problem, but the FAA certification process makes certain solutions economically unfeasible. This investigation presents the design of a generic adaptive autopilot that could potentially lead to a single certification for use in several makes and models of aircraft. The autopilot consists of a conventional controller connected in series with a robust direct adaptive model reference controller. In this architecture, the conventional controller is tuned once to provide outer-loop guidance and navigation to a reference model. The adaptive controller makes unknown aircraft behave like the reference model, allowing the conventional controller to successfully provide navigation without the need for retuning. A strong theoretical foundation is presented as an argument for the safety and stability of the controller. The stability proof of direct adaptive controllers require that the plant being controlled has no unstable transmission zeros and has a nonzero high frequency gain. Because most conventional aircraft do not readily meet these requirements, a process known as sensor blending was used. Sensor blending consists of using a linear combination of the plant’s outputs that has no unstable transmission zeros and has a nonzero high frequency gain to drive the adaptive controller. Although this method does not present a problem for regulators, it can lead to a steady state error in tracking applications. The sensor blending theory was expanded to take advantage of the system’s dynamics to allow for zero steady state error tracking. This method does not need knowledge of the specific system’s dynamics, but instead uses the structure of the A and B matrices to perform the blending for the general case. The generic adaptive autopilot was tested in two high-fidelity nonlinear simulators of two typical General Aviation aircraft. The results show that the autopilot was able to adapt appropriately to the different aircraft and was able to perform three-dimensional navigation and an ILS approach, without any modification to the controller. The autopilot was tested in moderate atmospheric turbulence, using consumer-grade sensors and actuators currently available in General Aviation aircraft. The generic adaptive autopilot was shown to be robust to atmospheric turbulence and sensor and actuator random noise. In both aircraft simulators, the autopilot adapted successfully to changes in airspeed, altitude, and configuration. This investigation proves the feasibility of a generic autopilot using direct adaptive controller. The autopilot does not need a priori information of the specific aircraft’s dynamics to maintain its safety and stability arguments. Real-time parameter estimation of the aircraft dynamics are not needed. Recommendations for future work are provided.
This technical report presents the design and implementation of a Vehicle Follow Control (VFC) func-tion. The main goal of the project focuses on the Proof-Of-Concept of the functional behavior by Rapid Control Prototyping. First, the problem was analyzed by making a feasibility analysis; taking into account the challenges involved, necessary tools, methods and technology available. Second a requirement elicitation process was carried out using the CAFCR method. The Product Creation Process (PCP) followed at the compa-ny was analyzed and used to obtain the customer wishes related to the function. In addition, the relevant stake-holders were identified and a context diagram was created to define the scope. Use case scenarios were proposed to obtain the desired functionality, which served as an input to formulate the VFC Sys-tem Requirements. Subsequently, the architecture for the design was proposed, where different software components were identified. The controller design consists of four major components: Supervisor con-troller, Governor, Splitter and Hill Holder. The Supervisor controller was designed based on the func-tional requirements, using the company’s heuristic approach to design state-flow charts. The Governor was designed using a combined distance/speed control approach. The design of the Splitter was carried out by splitting the control signals to the respective vehicle actuators. Finally, the design of the Hill Holder was performed using a state-flow chart and a vehicle model. This was done by estimating the amount of force needed to prevent the vehicle from moving when driving on a hill. The controller was designed using Matlab, and implemented in the prototype vehicle using dSPACE HW/SW. A radar target filter algorithm was designed to properly filter the data coming from the radar and to detect the target vehicle to follow. The Verification and Validation phase was carried out according to the V-cycle model. A series of test cases were run with the vehicle to assess whether the functionality meets the requirements, and whether it fulfills the customer wishes. It was concluded that the RCP platform created for this project provides an important contribution for the company, since it can be used for the integration with other functions involving longitudinal control, which is included in the road map for future autonomous driving.