| 1. |
- 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 ; 2019-May, 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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| 2. |
- Li, Yuchao, et al.
(författare)
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A cascade control approach to active suspension using pneumatic actuators
- 2019
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Ingår i: Asian Journal of Control. - : Wiley. - 1561-8625 .- 1934-6093. ; , s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Operators of forest machinery suffer from intensive whole body vibrations, which are big threats to their health. Therefore, it is important to investigate effective seat undercarriages and control methods for vibration reduction. This paper addresses the control problem of a novel seat undercarriage with pneu-matic actuators customized for forest machinery. A two-layer cascade controlstructure is developed, where the top layer consists of a group of proportional controllers to regulate the position of pneumatic actuators and the bottom layeris a sliding mode controller for force and stiffness tracking. The advantage ofthe sliding mode control is to achieve robust control performance with coarse system models. The paper demonstrates that the proposed control structure is better than a traditional PID controller. The robust stability of the sliding mode controller is proved by the Lyapunov's method. Experiments show its capability of reducing at least 20% amplitude of seat vibrations from 0.5 to 1 Hz.
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| 3. |
- Li, Yuchao, et al.
(författare)
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A hierarchical control system for smart parking lots with automated vehicles : Improve efficiency by leveraging prediction of human drivers
- 2019
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Ingår i: Proceedings 2019 18TH EUROPEAN CONTROL CONFERENCE (ECC). - : IEEE. ; , s. 2675-2681
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Konferensbidrag (refereegranskat)abstract
- In this work, we introduce a hierarchical architecture for management of multiple automated vehicles in a parking lot provided the existence of human-driven vehicles. The proposed architecture consists of three layers: behavior prediction, vehicle coordination and maneuver control, with the first two sitting in the infrastructure and the third one equipped on individual vehicles. We assume all three layers share a consistent view of the environment by considering it as a grid world. The grid occupancy is modeled by the prediction layer via collecting information from automated vehicles and predicting human-driven vehicles. The coordination layer assigns parking spots and grants permissions for vehicles to move. The vehicle control embraces the distributed model predictive control (MPC) technique to resolve local conflicts occurred due to the simplified vehicle models used in the design of the prediction and coordination layers. Numerical evaluation shows the effectiveness of the proposed control system.
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