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Technical Paper

ST-Lib: A Library for Specifying and Classifying Model Behaviors

Test and verification procedures are a vital aspect of the development process for embedded control systems in the automotive domain. Formal requirements can be used in automated procedures to check whether simulation or experimental results adhere to design specifications and even to perform automatic test and formal verification of design models; however, developing formal requirements typically requires significant investment of time and effort for control software designers. We propose Signal Template Library (ST-Lib), a uniform modeling language to encapsulate a number of useful signal patterns in a formal requirement language with the goal of facilitating requirement formulation for automotive control applications. ST-Lib consists of basic modules known as signal templates. Informally, these specify a characteristic signal shape and provide numerical parameters to tune the shape.
Journal Article

A Robust Stability Control System for a Hybrid Electric Vehicle Equipped with Electric Rear Axle Drive

Optimizing/maximizing regen braking in a hybrid electric vehicle (HEV) is one of the key features for increasing fuel economy. However, it is known [1] that maximizing regen braking by braking the rear axle on a low friction surface results in compromising vehicle stability even in a vehicle which is equipped with an ESP (Enhanced Stability Program). In this paper, we develop a strategy to maximize regen braking without compromising vehicle stability. A yaw rate stability control system is designed for a hybrid electric vehicle with electric rear axle drive (ERAD) and a “hang on” center coupling device which can couple the front and rear axles for AWD capabilities. Nonlinear models of the ERAD drivetrain and vehicle are presented using bond graphs while a high fidelity model of the center coupling device is used for simulation.
Technical Paper

Recognizing Manipulated Electronic Control Units

Combatting the modification of automotive control systems is a current and future challenge for OEMs and suppliers. ‘Chip-tuning’ is a manifestation of manipulation of a vehicle's original setup and calibration. With the increase in automotive functions implemented in software and corresponding business models, chip tuning will become a major concern. Recognizing and reporting of tuned control units in a vehicle is required for technical as well as legal reasons. This work approaches the problem by capturing the behavior of relevant control units within a machine learning system called a recognition module. The recognition module continuously monitors vehicle's sensor data. It comprises a set of classifiers that have been trained on the intended behavior of a control unit before the vehicle is delivered. When the vehicle is on the road, the recognition module uses the classifier together with current data to ascertain that the behavior of the vehicle is as intended.
Technical Paper

Controlled Combustion Engines (CCE)

The fact that, in our times, the execution of the exothermic process of combustion (‘heat release”) remains virtually uncontrolled is astonishing. Upon an attempt to rationalize this anomaly on historical grounds, technological means to rectify this astounding state of affairs are presented. They are based on the premise that, in the course of this process, the cylinder-piston enclosure is, in effect, a full-fledged chemical reactor. The salient feature of control is then active intervention into chemical reaction by turbulent jets. Principal elements of the control system are, as in any feedback mechanism, (1) sensors, (2) actuators and (3) a governor. The object of the first is to measure the profile of pressure - the useful output of the process. The second consists of a set of turbulent jet generators for injection of fuel and its mixing with air, as well as for ignition.
Technical Paper

Model and Control of Heat Release in Engines

The concept of the paper stems from the premise that the process of “heat release” in engines involves in essence the evolution and deposition of exothermic energy generated by combustion-events that can be governed promptly by a feedback, adaptive micro-electronic control system. The key to its realization is the principle of DISC (Direct Injection Stratified Charge) engine, implemented by a multi-jet system. The background and the salient features of such a system, referred to as a CCE (Controlled Combustion Engine), have been described in a companion paper (SAE 951961). Presented here are fundamental aspects of the model of the exothermic process and the intrinsic properties of its control system.
Technical Paper

Optimal Design of Reliable Control Systems

In practical applications, failures in the components of the control system can lead to improper, or even unstable, operation of the control loop. These failures can be associated with the process (abrupt change in the process dynamics), the measuring and manipulating devices (sensors, actuators) or the controller itself. It is therefore desired to design control system capable of handling such events in the sense that stability is guaranteed and performance degradation is minimized. The proposed formulation of the reliable performance problem involves the simultaneous minimization of the performance index for all considered failure scenarios. Employing the fractional representation theory, the reliable performance problem is formulated as a quadratically constrained control problem. The solution to this problem is discussed in this paper and an illustrative example is presented.