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- Janardhanan, Sachin, 1983, et al.
(författare)
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Concept design of electric cruise and startability axles for long haul heavy vehicles to maximise driving range
- 2021
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Ingår i: 2021 IEEE Vehicle Power and Propulsion Conference, VPPC 2021 - ProceedingS.
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Konferensbidrag (refereegranskat)abstract
- Electrification of commercial heavy vehicles hasled to the offer of different electric drive-based powertrainarchitectures, most of them with the adaptation of the dieselengine based architecture. Due to the limited driving rangepossible, optimal configuration of the powertrain becomes avital task with the battery as the energy source, which alsotakes a significant portion of payload capacity. A modularand distributed powertrain architecture using separate cruiseand startability axles is introduced in this paper with theaim to maximise driving range. The concept is developed andevaluated using a joint hardware and control design frameworkfor a target vehicle combination of 36 tonnes over a typicalregional long haul drive cycle using simulations. Sensitivitystudy of gear ratios and motor sizes with vehicle targetrequirements is performed to identify the optimal configurationfor the powertrain concept. The simulation results show thatby configuring around50%of the total electric machine powerto the cruise axle and choosing a gear ratio between 12-13, therange capability is maximised, while satisfying startability andcruise mode operations.
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| 4. |
- Jonasson, Mats, 1969, et al.
(författare)
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Simultaneous vehicle dynamics state estimation using pitch-rate sensor
- 2020
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Patent (övrigt vetenskapligt/konstnärligt)abstract
- There is provided a method for estimating friction between a tire of a vehicle and a road surface, the method comprising acquiring, a front wheel axle torque, a rear wheel axle torque, a vehicle longitudinal acceleration, a vehicle pitch rate and wheel rotational velocities. The method further comprises determining a front wheel normal force and a rear wheel normal force, based on a center of gravity of the vehicle and the longitudinal acceleration; determining a longitudinal tire stiffness, jointly determining a vehicle longitudinal velocity, based on the wheel rotational velocities and vehicle longitudinal acceleration, and a vehicle pitch angle relative to the horizontal plane based on the vehicle pitch rate; and determining a friction coefficient between tires and ground based on the front and rear wheel axle torque, the front wheel normal force and the joint estimation of pitch angle and vehicle longitudinal velocity. There is also provided a system for performing the described method.
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| 5. |
- Albinsson, Anton, 1989, et al.
(författare)
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Tire Force Estimation Utilizing Wheel Torque Measurements and Validation in Simulations and Experiments
- 2014
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Ingår i: 12th International Symposium on Advanced Vehicle Control (AVEC '14), Tokyo Japan. ; , s. 294-299
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Konferensbidrag (refereegranskat)abstract
- This study investigates a new tire force estimator based on the recursive least square (RLS) method. Tire force estimation with known driving wheel torque is studied and compared to the case with torque estimation from the internal combustion engine. This is motivated by a future scenario with electric propulsion, which reasonably gives improved wheel torque estimations. Sensitivity to vehicle parameters and challenges with individual lateral tire force estimation are also investigated. The results, experimental and simulation data, show good performance and potential for tire force estimation using the RLS method.
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| 6. |
- Ashok, Nrupathunga, et al.
(författare)
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DEVELOPMENT OF TEST ENVIRONMENTS FOR REVERSE ASSIST FUNCTIONS AS APPLIED TO AN A-DOUBLE VEHICLE COMBINATION
- 2021
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Ingår i: The 16th International Symposium on Heavy Vehicle Transport & Technology.
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Konferensbidrag (refereegranskat)abstract
- High-capacity transport vehicles reduce costs and improve efficiency. Long vehicle combinations such as an A-double combination vehicle (Tractor + semitrailer + dolly + semitrailer) improve transportation efficiency but they are extremely difficult to manoeuvre in tight spaces and in the reverse direction. This document summarizes developing environments to test reverse assist functions as applied to the A-double combination vehicle. These environments create a rapid prototyping platform consisting of a virtual and a scaled environment to test and validate controller concepts. The behaviour of the plant model in the virtual environment, the scaled vehicle model and the plant model in VTM (Volvo Truck Model) are studied and compared. A proportional controller is developed to test the environments and evaluate the process of concept development using the rapid prototype platform. The controller performance is evaluated and a possibility of incorporating integral controller is discussed.
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| 8. |
- Bergman, Frida, Medicine doktor, 1984-, et al.
(författare)
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Walking Time Is associated With Hippocampal Volume in Overweight and Obese Office Workers
- 2020
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Ingår i: Frontiers in Human Neuroscience. - : Frontiers Media S.A.. - 1662-5161. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: To investigate the long-term effects on cognition and brain function after installing treadmill workstations in offices for 13 months.Methods: Eighty healthy overweight or obese office workers aged 40–67 years were individually randomized to an intervention group, receiving a treadmill workstation and encouraging emails, or to a control group, continuing to work as usual. Effects on cognitive function, hippocampal volume, prefrontal cortex (PFC) thickness, and circulating brain-derived neurotrophic factor (BDNF) were analyzed. Further, mediation analyses between changes in walking time and light-intensity physical activity (LPA) on changes in BDNF and hippocampal volume between baseline and 13 months, and multivariate analyses of the baseline data with percentage sitting time as the response variable, were performed.Results: No group by time interactions were observed for any of the outcomes. In the mediation analyses, positive associations between changes in walking time and LPA on changes in hippocampal volume were observed, although not mediated by changes in BDNF levels. In the multivariate analyses, a negative association between percentage sitting time and hippocampal volume was observed, however only among those older than 51 years of age.Conclusion: Although no group by time interactions were observed, our analyses suggest that increased walking and LPA may have positive effects on hippocampal volume and that sedentary behavior is associated with brain structures of importance for memory functions.Trial Registration: www.ClinicalTrials.gov as NCT01997970.
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| 9. |
- Chowdhury, Sohini Roy, et al.
(författare)
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Machine Learning Models for Road Surface and Friction Estimation using Front-Camera Images
- 2018
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Ingår i: 2018 International Joint Conference on Neural Networks (IJCNN). - 2161-4407. - 9781509060146
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Konferensbidrag (refereegranskat)abstract
- Automotive active safety systems can significantly benefit from real-time road friction estimates (RFE) by adapting driving styles, specific to the road conditions. This work presents a 2-stage approach for indirect RFE estimation using front-view camera images captured from vehicles. In stage-1, onvolutional neural network model architectures are implemented to learn region-specific features for road surface condition (RSC) classification. Texture-based features from the drivable surface, sky and surroundings are found to be separate regions of interest for dry, wet/water, slush and now/ice RSC classification. In stage-2, a rule-based model that relies on domain-specific guidelines is implemented to segment the ego-lane drivable surface into [5x3] patches, followed by patch classification and quantization to separate images with high, medium and low RFE. The proposed method achieves average accuracy of 97% for RSC classification in stage-1 and 89% for RFE classification in stage-2, respectively. The 2-stage models are trained using publicly available data sets to enable benchmarking
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| 10. |
- Edrén, Johannes, et al.
(författare)
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Modelica and Dymola for education in vehicle dynamics at KTH
- 2009
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Ingår i: Proceedings from 7th Modelica Conference 2009. - : Linköping University Electronic Press. ; , s. 775-783
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Konferensbidrag (refereegranskat)abstract
- Dymola and Modelica has been used at KTH Vehicle Dynamics (KTHVD) for research work since 2000, see e.g. [1]. With the Vehicle Dynamics Library (VDL) [2], Modelica has become far more accessible for both researchers and students in the field of vehicle dynamics. Therefore a project aiming at introducing it as a tool in education was initiated in order to evaluate the current state of Dymola and Modelica as tools for wider use in education at the division. The work presented in this paper was realized as a part of a PhD course, where one of the tasks were to design dedicated exercises to illustrate fundamentals of vehicle dynamics for students.
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