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I.O.M.A.E.E. Hassanain

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String-stable automated steering in cooperative driving applications

Master thesis - I.O.M.A.E.E. Hassanain, N. van de Wouw, Mohsen Alirezaei, Jeroen Ploeg, J.W. van Wingerden

The ever-increasing road transport demand in the developing and the developed world has resulted in road-traffic networks nearing maximum capacity. Traditional approaches to this problem, such as increasing road capacity, do not offer long-term solutions. Combined with rising environmental concerns, the demand for smarter solutions has never been higher. One such solution, which has gained significant ground in the past decades, is automated vehicle platooning. A vehicle platoon is an interconnected dynamical system consisting of automated vehicles driving in close proximity, coordinating their movement through measurements and sometimes inter-vehicular communication. By allowing driving in close proximity, platoons have the potential to increase road capacity, whilst reducing fuel consumption. Platoons are subject to safety and performance requirements. In order to meet these requirements the vehicle platoon needs be string stable, such that effects of disturbances are not amplified in the upstream direction of the string of vehicles. String-stable platoons also help preventing ghost traffic jams, typically caused by human driver behaviour. Advancements in vehicle platooning research have mostly been concerned with longitudinal automation, and consequently with longitudinal string stability. However, driving at small inter-vehicular gaps also requires lateral automation. Naturally, this means that string stability in the lateral sense is required. Therefore, the objective of this MSc thesis is to develop a lateral control method for automated vehicle platoons that yield string-stable behaviour. In the first part, an error model based on a vehicle-following control strategy, which uses vehicle path following, is derived. This model is then used to describe the path-following problem within a platoon. In the second part, a control strategy is proposed using the H∞ framework, such that path following and lateral string stability are guaranteed a-priori. The robustness properties and the performance of the designed controller are analysed by means of frequency-domain analysis and time-domain simulations. Finally, path following and the string-stability properties of the controller have been validated experimentally. The experiments performed confirm the theoretical analysis, thereby showing that lateral string stability is obtainable using the proposed method.

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Validation of a Moving Base Driving Simulator for Motion Sickness Research

Master thesis - T.M.W. Talsma, K.N. de Winkel, I.O.M.A.E.E. Hassanain, R. Happee, D.M. Pool

Higher levels of automation in driving may allow drivers to engage in other activities, but may also increase the likelihood of Motion Sickness (MS). The exact causes of MS are not well understood, and various susceptibility factors(e.g. age, gender, ethnicity) can cause large individual differences. To better understand and predict MS, it is ideally studied in a safe and controlled environment, such as a driving simulator. However, the validity of driving simulator studies on MS as a proxy for on-road studies with real vehicles has not been properly evaluated. We conducted an experiment where the temporal aspects and symptom profiles of MS in a real-road driving scenario are compared to Simulator Sickness (SS) in a reproduction of this scenario in a motion-base driving simulator. A cohort of 25 participants was exposed to both the car and the simulator conditions. The scenarios consisted of sections of provocative(slaloming, stop-and-go) and normal driving. Sickening stimuli of the simulator were similar to the car accelerations in design (r = 0.51) but different in outcome (r = 0.27) as a result of motion cueing. MIsery Scale (MISC) scores on a 30 s interval, post-experiment Motion Sickness Assessment Questionnaire (MSAQ) scores, Galvanic Skin Response(GSR) and Electrogastrography (EGG) data were collected. Results showed significant correlations between the car and simulator conditions for 3 out of 4 MSAQ symptom categories (0.48 < r < 0.73, p < 0.02) and a relation (r = 0.57,p = 0.004) for individual sensitivity to sickness. Sickness onset times did not differ between the car and the simulator[F(1,308) = 4.80, p = 0.029], after Bonferroni corrections had been applied. Both MS and SS increased and decreased as a result of the driving style, with the effect being larger in the car condition, than in the simulator (for MISC [F(1,248)= 19.15, p = 0.000] and for GSR [F(1,230) = 5.55, p = 0.019]). Results from all four measures indicate that the severity of sickness was higher in the car as compared to in the simulator. EEG responses did not fully show expected outcomes. However, the signal quality was limited and dedicated EGG equipment may yield different results. Because individual sensitivity and temporal aspects of SS and MS were similar between the car and simulator but different in magnitude, we conclude relative validity for the simulator. As the human vestibular system, a prominent contributor in causing sickness, is solely sensitive to accelerations, we attribute the difference in magnitude due to downscaling of the vehicle motion in the simulator. In order to obtain absolute validity, either extensive training or considerable technological advances may be necessary.