| 1. |
- Akhmetov, Yerlan, et al.
(författare)
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Predictive Driver Interpreter by using Inverse Model for Heavy Vehicles
- 2010
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Ingår i: 13th International IEEE, Annual Conference on Intelligent Transportation Systems, Madeira Island, Portugal, September 19-22, 2010. ; , s. 174-179
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Konferensbidrag (refereegranskat)abstract
- This paper evaluates predictive control and necessary time horizon for heavy vehicle's active safety functionality by using an inverse model as predictor. The predictive driver interpreter provides the anticipating signals for limiting the forward velocity which can guarantee a manoeuvre's safe realization without loss of control. It has been integrated in a control allocation structure. The controller has been tested for an open-loop avoidance manoeuvre which is given by a sine with dwell steering input. Simulations showed for the studied manoeuvre and truck configuration that the passive vehicle is stable up to amplitude of 105 deg of steering wheel angle. When no predictive horizon was applied in the control allocation, the amplitude could be increased to 150 deg. When a predictive horizon of 1.5 s was used the amplitude could be doubled and still be stable.
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| 2. |
- Ihlberg, Leo, et al.
(författare)
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Early clinical outcome of aortic transcatheter valve-in-valve implantation in the Nordic countries
- 2013
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier. - 0022-5223 .- 1097-685X. ; 146:5, s. 1047-1054
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Transcatheter valve-in-valve implantation has emerged as an option, in addition to reoperative surgical aortic valve replacement, to treat failed biologic heart valve substitutes. However, the clinical experience with this approach is still limited. We report the comprehensive experience of transcatheter valve-in-valve implantation in the Nordic countries from May 2008 to January 2012. less thanbrgreater than less thanbrgreater thanMethods: A total of 45 transcatheter aortic valve-in-valve implantations were performed during the study period in 11 centers. The mean age of the patients was 80.6 years (range, 61-91), 26 were male and 19 were female, and the mean EuroSCORE, EuroSCORE II, and Society of Thoracic Surgeons score was 35.4, 16.3, and 14.6, respectively. The type of failure was stenosis and combined in 58% (mean and peak aortic valve gradient, 77 and 45 mm Hg, respectively) and regurgitation in 42% of cases. The SAPIEN/XT (Edwards LifeSciences, Irvine, Calif) and CoreValve (Medtronic Inc, Minneapolis, Minn) system was used in 33 and 12 cases, respectively. The access route was transapical in 25, transfemoral in 17, transaortic in 2, and subclavian in 1 case. The mean follow-up was 14.4 months. The periprocedural and postoperative outcomes were assessed using the Valve Academic Research Consortium criteria. less thanbrgreater than less thanbrgreater thanResults: No intraprocedural mortality occurred. The technical success rate was 95.6% (1 second valve implantation, 1 conversion to open surgery). The all-cause 30-day mortality was 4.4% (1 cardiac-related and 1 aspiration pneumonia). The major complications within 30 days included stroke in 2.2%, periprocedural myocardial infarction in 4.4%, and major vascular complication in 2.2% of patients. At 1 month, all but 1 patient had either no or mild paravalvular leakage, with a mean and peak valve gradient of 17 mm Hg (range, 4-38) and 30 mm Hg (range, 7-68), respectively. The mean gradient was greater than 20 mm Hg in 17% of patients and remained unchanged at 12 months. The 1-year survival was 88.1%. less thanbrgreater than less thanbrgreater thanConclusions: Transcatheter valve-in-valve implantation is widely performed, albeit in small numbers, in most centers in the Nordic countries. The short-termresults were excellent in this high-risk patient population, demonstrating a low incidence of device-or procedure-related complications. However, a considerable number of patients were left with suboptimal systolic valve performance with unknown long-term effects, warranting close surveillance after transcatheter valve-in-valve implantation.
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| 3. |
- Nilsson, Peter, 1976, et al.
(författare)
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A Driver Model Using Optic Information for Longitudinal and Lateral Control of a Long Vehicle Combination
- 2014
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Ingår i: IEEE 17th International Conference on Intelligent Transportation Systems (ITSC), October 8-11, 2014. Qingdao, China. - 9781479960774 ; , s. 1456-1461
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Konferensbidrag (refereegranskat)abstract
- High driver acceptance is believed to be an important aspect when introducing automated driving functionalities for prospective long vehicle combinations. The main hypothesis of this paper is that high driver acceptance can be realized by utilizing driver models inspired by human cognition as an integrated part of such functions. It is envisioned that the human driver will more easily understand, and trust, a system that behaves in a human-like manner.In the study of a combined retardation and lane-change scenario, a driver model based on optic information was used, together with a single track vehicle model, to control the steering and retardation of a simulated vehicle. The parameters of the driver model’s lateral behavior were estimated using driving data measured from an A-double combination during actual lane-changes.Numerical simulations showed that the driver model was able to generate safe and conservative deceleration and steering for the studied scenario. In future work for automated functionalities, the combined driver and vehicle model could be used when evaluating different tentative plans for lane changes, in real time.
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| 4. |
- Nilsson, Peter, 1976, et al.
(författare)
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Performance characteristics for automated driving of long heavy vehicle combinations evaluated in motion simulator
- 2014
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Ingår i: 25th IEEE Intelligent Vehicles Symposium, IV 2014; Dearborn, MI; United States; 8 June 2014 through 11 June 2014. - 9781479936380 ; , s. 362-369
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Konferensbidrag (refereegranskat)abstract
- This paper presents a driving simulator experiment in which manual and automated driving of a prospective long vehicle combination has been studied. Based on post analysis of manual and automated driving trajectories, characteristic measures reflecting the manual drivers behavior have been proposed. It was observed that the drivers had a round shape of the utilized accelerations while negotiating the curves. A similar shape was found when using an objective function which included minimizing the resultant jerk vector.
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| 5. |
- Sadeghi Kati, Maliheh, 1979, et al.
(författare)
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Evaluation of Dynamical Behaviour of Long Heavy Vehicles Using Performance Based Characterstics
- 2014
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Ingår i: FISITA 2014 World Automotive Congress - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Long Heavy Vehicle Combinations (LHVCs) are an attractive alternative to Conventional Heavy Vehicle Combinations (CHVCs) in goods transportation because of reduction in fuel consumption, reduced costs and emissions. One major issue concerning LHVCs is their potential impacts on traffic safety that is the most controversial issue of LHVCs. Road safety performance of LHVCs depends on their technical features such as power train and braking systems capability, lateral dynamical stability, manoeuvrability and etc. By introducing LHVCs as a part of future transportation, there is a need to ensure that they are performing within specific boundary conditions. Defining proper technical characteristics, denoted as Performance Based Characteristics (PBCs) for LHVCs would assist to create operational requirements by which LHVCs will be allowed to operate in the road network with less negative road safety impacts. A comprehensive list of safety related PBCs is defined in (1). In this paper the test conditions and methods for each characteristic are specified and a set of heavy vehicle combinations (including European vehicle combinations, modular vehicle combinations and perspective modular vehicle combinations) are assessed and compared by using computer simulations. In addition, it is shown that by design parameter changes it is possible to improve the performance of a truck with double centre-axle trailers to perform almost similar as existing European conventional vehicle combinations like a truck and centre-axle trailer combination.
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| 6. |
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| 7. |
- Sundström, Peter, et al.
(författare)
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Vectorized single-track model in Modelica for articulated vehicles with arbitrary number of units and axles
- 2014
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Ingår i: Modelica conference 2014, Lund, Sweden, March 10-12, 2014.
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Konferensbidrag (refereegranskat)abstract
- A linear single-track model for articulated vehicles hasbeen implemented. The model can represent an articulatedvehicle with an arbitrary number of units eachwith an arbitrary number of axles. Lateral and yawdynamics are in focus but longitudinal effects in couplingsare also included. In the model, tire forces arelinear with respect to slip angle. The couplings betweenunits are represented as non-linear kinematicconstraints which are valid for small and large articulationangles.Four use cases are presented: Inverse dynamics forfeedforward control, frequency responses when varyingparameters, steady-state evaluations and dynamicsimulation. For these use cases, four parametrizationsof the model are used corresponding to a tractor with asemitrailer a truck with a dolly and a semitrailer, an Adouble(tractor+semitrailer+dolly+semitrailer) and anapproximate version of an airport baggage carrier withfive full trailers.
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| 8. |
- Tagesson, Kristoffer K D, 1985, et al.
(författare)
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Driver response at tyre blow-out in heavy vehicles & the importance of scrub radius
- 2014
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Ingår i: 25th IEEE Intelligent Vehicles Symposium, IV 2014; Dearborn, MI; United States; 8 June 2014 through 11 June 2014. - 9781479936380 ; , s. 1157-1162
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Konferensbidrag (refereegranskat)abstract
- Front tyre blow-outs lead to several fatal accidents involving heavy vehicles. Common for most heavy vehicles is a positive scrub radius. This can result in a destabilising steering wheel torque at front tyre blow-out. In this study the safety improvement achieved when reducing scrub radius is quantified. By using a heavy truck equipped with a modified electric power steering system it was possible to change the scrub radius virtually. Brakes were configured to emulate front tyre blow-out which appeared as a sudden disturbance on one of the front tyres. In total 20 drivers took part in the study which was run on a test track at 50 km/h. Results show that the produced average lateral deviation from the original direction was 23 cm, when scrub radius was 12 cm, compared to 16 cm, when scrub radius was 0 cm. The main cause of the observed difference was a small, yet significant, initial overshoot in steering wheel angle which can be derived from the destabilising steering wheel torque.
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| 9. |
- Tagesson, Kristoffer K D, 1985, et al.
(författare)
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Driver Response to Automatic Braking under Split Friction Conditions
- 2014
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Ingår i: 12th International Symposium on Advanced Vehicle Control (AVEC '14), Tokyo Japan. ; , s. 666-671
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Konferensbidrag (refereegranskat)abstract
- At normal pedal braking on split-μ a driver can actively steer or adjust brake level to control lateral drift. The same driver response and thus lateral deviation cannot be assumed when brakes are automatically triggered by a collision mitigation system, since the driver can be expected as less attentive. To quantify lateral deviation in this scenario a test was run at 50 km/h with 12 unaware drivers in a heavy truck. Brakes were configured to emulate automatic braking on split-μ. Results show that the produced maximum lateral deviation from the original direction was 0.25 m on average. Two drivers deviated by 0.5 m. This can be compared to 2.2 m which was reached when steering was held fixed.
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| 10. |
- Tagesson, Kristoffer K D, 1985, et al.
(författare)
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The influence of steering wheel size when tuning power assistance
- 2014
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Ingår i: International Journal of Heavy Vehicle Systems. - 1741-5152 .- 1744-232X. ; 21:4, s. 295-309
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes how steering assistance should scale with steering wheel size. A method has been developed to scale complete torque felt by the driver, both for continuous and discontinuous feedback. This was used in an experiment with 17 subjects all driving a truck with three differently sized steering wheels. The test took place on a handling track at 45–90 km/h. Continuous feedback was evaluated subjectively; discontinuous feedback by measuring angular response. Results show that torque feedback should decrease as steering wheel size decreases. A rule of thumb is to keep driver force level constant to maintain perceived handling and comfort. This also maintained the average steering wheel angle change response to discontinuous assistance. Furthermore large variance in angular response was observed. The direction, measured 0.25 s after start of a pulse, was the same as that of the pulse applied in 88% of the recordings.
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