Vasilios Tsourapas

A New Predictive Lateral Load Transfer Ratio for Rollover Prevention Systems

In rollover prevention systems, a real-time lateral load transfer ratio (LTR) is typically computed to predict the likelihood of a vehicle to rollover and, hence, initiate rollover prevention measures. A traditional LTR largely relies on a lateral accelerometer signal to calculate rollover propensity. A new predictive LTR (PLTR) is developed in this paper, which utilizes a drivers steering input and several other sensor signals available from the vehicles electronic stability control system. The new PLTR index can provide a time-advanced measure of rollover propensity and, therefore, offers significant benefits for closed-loop rollover prevention. Simulation results are presented using the industry-standard software CarSim to demonstrate the benefits of the new PLTR index. Experimental results of open-loop comparisons between LTR and PLTR indexes are presented, followed by experimental results on the closed-loop implementation of a PLTR-based rollover prevention system. The results in this paper document how a predictive rollover index can be developed and the advantages of such a system in rollover prevention.

New method of identifying real-time Predictive Lateral load Transfer Ratio for rollover prevention systems

Vehicle rollover accounts for a significant percentage of fatal accidents in the USA and worldwide. In this paper, two rollover indexes are proposed and analyzed. The first rollover index estimates the actual Lateral Transfer Ratio (LTR) while the second, referred to as ‘Predictive Lateral Transfer Ratio’ (PLTR), incorporates the predictive influence of the drivers steering input, thus allowing the actuator to respond faster to the rollover scenario. Both algorithms are compared in open loop and closed loop simulation environment using a baseline control system. The PLTR is shown to be superior in preventing rollover under a number of different cornering maneuvers. The vehicle used for simulation is a large SUV with a top-loaded condition. Preliminary experimental results comparing the two algorithms are also presented.

A Coordinated Boost Control in a Twincharged Spark Ignition Engine With High External Dilution

This paper proposes a novel master-slave control strategy for coordination of throttle, wastegate and supercharger actuators in an electrically twincharged engine in order to guarantee efficient boost control during transients, while at steady state a throttle-wastegate coordination provides minimum engine backpressure hence engine efficiency elevation. The benefits and challenges associated with Low Pressure Exhaust Gas Recirculation (LP-EGR) in a baseline turbocharged engine, including improved engine efficiency, mainly due to better combustion phasing, and sluggish engine response to a torque demand due to slowed down air path dynamics were studied and quantified in [1]. Hence in this paper an electrical Eaton TVS roots type supercharger at high pressure side of the turbocharger compressor (TC compressor) is added to the baseline turbocharged engine and the performance of the proposed controller in the presence of LP-EGR, which is a more demanding condition, is evaluated and compared to the turbocharged engine. One dimensional (1D) crankangle resolved engine simulations show that the proposed master-slave control strategy can effectively improve the transient response of the twincharged engine, making it comparable to naturally aspirated engines, while the consumed electrical energy during transients can be recovered from the decreased fuel consumption due to LP-EGR conditions at steady state in approximately 1 second. Finally, a simple controller is developed to bypass the TC compressor and maximize the engine feeding charge during the transients in order to avoid TC compressor choking and achieve faster response. INTRODUCTION Nowadays turbocharging is the most prevalent mean of boosting the engine feeding charge. Unfortunately turbocharged engines can suffer from drivability issues such as insufficient boost pressure at low engine speeds and slower torque response known as ”turbo-lag”. Supercharging is the next popular method of boosting the engines, which does not possess the drivabilComp. bypass valve Throttle TC Compressor Turbine Wastegate EGR cooler EGR valve Exhaust manifold CAC Intake Manifold 80 180 180 Supercharger CAC FIGURE 1. Schematic of twincharged SIDI engine Proceedings of the ASME 2016 Dynamic Systems and Control Conference DSCC2016 October 12-14, 2016, Minneapolis, Minnesota, USA

From neural state-space description of marine powerplants to reduced-order Volterra models

The problem of reduced nonlinear input-output models for marine propulsion powerplants is visited by starting from the neural state-space description of the system, the neural networks of which can be trained by using steady-state data of the powerplant collected either from measurements or derived by use of conventional thermodynamic models. The analysis proposed is based on the Taylor expansion of the logistic sigmoid function, appearing in the neural torque approximators of the neural plant description, yielding a finite polynomial Volterra expression, approximating the dynamic behavior of the plant with desired accuracy. The reduced nonlinear model obtains finally the form of a sum of homogenous Volterra operators, and can be used for frequency domain characterization of the system and the design of nonlinear feedforward controllers.