| 1. |
- Parseh, Masoumeh, 1989-, et al.
(författare)
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A Data-Driven Method Towards Minimizing Collision Severity for Highly Automated Vehicles
- 2021
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Ingår i: IEEE Transactions on Intelligent Vehicles. - : Institute of Electrical and Electronics Engineers (IEEE). - 2379-8858 .- 2379-8904. ; 6:4, s. 723-735
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Tidskriftsartikel (refereegranskat)abstract
- The deployment of autonomous vehicles on public roads calls for the development of methods that are reliably able to mitigate injury severity in case of unavoidable collisions. This study proposes a data-driven motion planning method capable of minimizing injury severity for vehicle occupants in unavoidable collisions. The method is based on establishing a metric that models the relationship between impact location and injury severity using real accident data, and subsequently including it in the cost function of a motion planning framework. The vehicle dynamics and associated constraints are considered through a precomputed trajectory library, which is generated by solving an optimal control problem. This allows for efficient computation as well as an accurate representation of the vehicle. The proposed motion planning approach is evaluated by simulation, and it is shown that the trajectory associated with the minimum cost mitigates the collision severity for occupants of passenger vehicles involved in the collision.
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| 2. |
- Parseh, Masoumeh, 1989-, et al.
(författare)
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Pre-Crash Vehicle Control and Manoeuvre Planning: A Step Towards Minimizing Collision Severity for Highly Automated Vehicles
- 2019
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Ingår i: 2019 IEEE International Conference of Vehicular Electronics and Safety (ICVES). - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This paper addresses the control of a highly automated vehicle in a traffic scenario, where colliding with other traffic agents is unavoidable. Such a critical situation could be the result of a fault in the vehicle, late obstacle detection or the presence of an aggressive driver. We provide an approach that allows the vehicle’s control system to choose the manoeuvre that is likely to lead to the least severe injuries to vehicle occupants.The approach involves the off-line solving of an optimal control problem to create a set of trajectories based on controlling the steering angle rate and the braking rate at the vehicle’s limits. Occupant injury severity prediction, based on accident data with the focus on impact location, is used by a real-time collision control algorithm to choose a trajectory from the pre-computed optimal set. A simulation set-up is presented to illustrate the idea of the collision control algorithm in a simple scenario involving dynamic traffic agents.
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| 3. |
- Annell, Stefan, et al.
(författare)
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Probabilistic collision estimation system for autonomous vehicles
- 2016
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Ingår i: IEEE Conference on Intelligent Transportation Systems, Proceedings, ITSC. - : IEEE conference proceedings. - 9781509018895 ; , s. 473-478
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Konferensbidrag (refereegranskat)abstract
- Nearly 1.3 million people die each year in traffic-related accidents, whereas an additional 20-50 million peopleare injured. Introducing autonomous vehicles would aim to reduce these numbers by removing the driver from the loop entirely, and thus removing the human error. Intersections are considered a complex traffic situation for autonomous vehicles. Functions which could accurately foresee future events in those situations, mimicking the situation awareness of humans, would improve autonomous systems and increase traffic safety. To address this a system is designed with two main functionalities: estimate the movements of observed vehicles in a general traffic situation and predict the probability of a collision, given the current ego trajectory. This system could either be used as information and feedback for a trajectoryplanner or as support for decision making at higher level system monitoring. The main contributions are the robust system design, that robustly and consistently estimates the likelihood of a collision and thus preventing future collision, and the intention estimation which determines the probability of which route through an intersection an observed vehicle will take through an intersection by using its current state. The system is validated by controlling the ego vehicle’s velocity with a Velocity Planning Controller to avoid colliding. It is shown that in terms of robustness to noise the system successfully avoids collision.
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| 4. |
- Chen, Deyuan, et al.
(författare)
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Optimization based path planning for a two-body articulated vehicle
- 2020
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Ingår i: Optimization based path planning for a two-body articulated vehicle. - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- An articulated vehicle is a two-body design capable of precise maneuvering around obstacles, while carrying heavy loads over rough terrain. In the context of path planning for automated articulated vehicles, it is desirable to fully utilize the maneuverability of the vehicle to enable autonomous operation in confined areas. In this paper we study the impact of model accuracy in an optimization based path planner for an articulated vehicle. For this purpose, we compare the traditional kinematic bicycle model with a two-body articulated model. We evaluate performance in terms of path length, path quality, success rate and computation time through performing test queries in artificial environments and through experiments on a full scale articulated hauler. Results show that for simple, unidirectional maneuvers, performance differences are small, but for more difficult bidirectional maneuvers, the articulated model produces shorter and higher quality paths at a higher success rate. However, the articulated model has 2.75 times longer computation time on average.
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| 5. |
- Giannakopoulos, Stavros, 1989, et al.
(författare)
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Scalable, Modular Feed-Forward Equalizer for Baseband Applications
- 2022
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Ingår i: 2022 17th European Microwave Integrated Circuits Conference, EuMIC 2022. ; , s. 280-283
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Konferensbidrag (refereegranskat)abstract
- This paper presents a modular and scalable fully differential Feed-Forward Equalizer topology suitable for baseband applications. The proposed equalizer topology utilizes Gilbert cell amplifiers as variable gain elements and follows a modular implementation with reuse of identical gain cells. A proof of concept one-tap Feed-Forward Equalizer is designed, characterized in frequency and time domain measurements. The equalizer exhibits a measured single-ended peaking gain control of up to 27 dB at 50 GHz. The equalizer MMIC consumes 370 mW from a -3.3 V supply, measures 0.94\mathrmx0.76mm2, and it was designed in Infineon's 130 nm SiGe BiCMOS process with an f_t of 250 GHz and an f_max of 370 GHz.
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| 6. |
- Johansson, Jesper, 1989, et al.
(författare)
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A Novel Speculative Pseudo-Parallel \Delta\Sigma Modulator
- 2015
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Ingår i: 32rd NORCHIP 2014. ; , s. Article number 7004712-
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Konferensbidrag (refereegranskat)abstract
- We present a novel speculative pseudo-parallel \Delta\Sigma modulator structure, which almost halves the logic depthof the critical path in the pseudo-parallel Hatami structure. Following Hatami, our modulator calculates a block of n consecutive output bits in parallel, and then employs a parallelserial interface to output the bits at n times the modulator clock frequency. We circumvent the block-to-block dependence, which limits the clock speed of the Hatami structure, by speculatively calculating the outputs based on all possible output values of theprevious block, and then selecting the correct one. We present cost and performance estimates for an initial implementation of the modulator, synthesized towards an FPGA and an ASIC technology.
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| 7. |
- Krook, Jonas, 1986, et al.
(författare)
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Design and Formal Verification of a Safe Stop Supervisor for an Automated Vehicle
- 2019
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Ingår i: Proceedings - IEEE International Conference on Robotics and Automation. - : Institute of Electrical and Electronics Engineers (IEEE). - 1050-4729. - 9781538660263 ; , s. 5607-5613
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Konferensbidrag (refereegranskat)abstract
- Autonomous vehicles apply pertinent planning and control algorithms under different driving conditions. The mode switch between these algorithms should also be autonomous. On top of the nominal planners, a safe fallback routine is needed to stop the vehicle at a safe position if nominal operational conditions are violated, such as for a system failure. This paper describes the design and formal verification of a supervisor to manage all requirements for mode switching between nominal planners, and additional requirements for switching to a safe stop trajectory planner that acts as the fallback routine. The supervisor is designed via a model-based approach and its abstraction is formally verified by model checking. The supervisor is implemented and integrated with the Research Concept Vehicle, an experimental research and demonstration vehicle developed at the KTH Royal Institute of Technology. Simulations and experiments show that the vehicle is able to autonomously drive in a safe manner between two parking lots and can successfully come to a safe stop upon GPS sensor failure.
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| 8. |
- Mortazavi Seyedeh, Nooshin, 1986, et al.
(författare)
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Interplay of water and reactive elements in oxidation of alumina-forming alloys
- 2018
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Ingår i: Nature Materials. - : Springer Science and Business Media LLC. - 1476-4660 .- 1476-1122. ; 17:7, s. 610-617
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Tidskriftsartikel (refereegranskat)abstract
- High-temperature alloys are crucial to many important technologies that underpin our civilization. All these materials rely on forming an external oxide layer (scale) for corrosion protection. Despite decades of research on oxide scale growth, many open questions remain, including the crucial role of the so-called reactive elements and water. Here, we reveal the hitherto unknown interplay between reactive elements and water during alumina scale growth, causing a metastable ‘messy’ nano-structured alumina layer to form. We propose that reactive-element-decorated, hydroxylated interfaces between alumina nanograins enable water to access an inner cathode in the bottom of the scale, at odds with the established scale growth scenario. As evidence, hydride-nanodomains and reactive element/hydrogen (deuterium) co-variation are observed in the alumina scale. The defectrich alumina subsequently recrystallizes to form a protective scale. First-principles modelling is also performed to validate the RE effect. Our findings open up promising avenues in oxidation research and suggest ways to improve alloy properties.
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| 9. |
- Mowlavi, Siavash, 1988, et al.
(författare)
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A Review of IC Drivers for VCSELs in Datacom Applications
- 2024
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Ingår i: IEEE Transactions on Very Large Scale Integration (VLSI) Systems. - 1063-8210 .- 1557-9999. ; 32:1, s. 42-54
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Tidskriftsartikel (refereegranskat)abstract
- Vertical-cavity surface-emitting lasers (VCSELs) are an attractive choice for short-range optical interconnects (OIs) in datacom applications. As the limited bandwidth of VCSEL is the major obstacle to achieve higher data rates in these optical systems, significant effort has been made to develop efficient VCSEL drivers to increase data rate while consuming less power. We review the current state of the art in VCSEL driver design, including choices of semiconductor technology, modulation format, VCSEL configuration, and pre-emphasis techniques, with an emphasis on the challenges associated with VCSEL bandwidth limitations, nonlinearities, and thermal behavior. We illustrate the choices with simulations using a physics-based VCSEL model.
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| 10. |
- Mowlavi, Siavash, 1988, et al.
(författare)
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VCSEL Integrated Circuit Drivers: A Review
- 2022
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Ingår i: 2022 IEEE Nordic Circuits and Systems Conference, NORCAS 2022 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Vertical cavity surface emitting lasers (VCSELs) are considered to be an attractive choice for short-range optical interconnects in data acquisition systems. As the limited bandwidth of VCSEL is the major obstacle to achieving higher data rates in these optical systems, significant effort has been made to develop efficient VCSEL drivers in CMOS and SiGe BiCMOS processes to increase data rate while consuming less power. This paper sheds light on the design choices for the technology, modulation format, VCSEL configuration, and pre-emphasis techniques for a targeted performance based on an overview of the popular approaches to implementing low-power high-speed VCSEL drivers, with an emphasis on the challenges associated with designing drivers suitable for working in harsh environments.
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