| 1. |
|
|
| 2. |
- Asl, Reza Mohammadi, et al.
(författare)
-
Fuzzy-Based Parameter Optimization of Adaptive Unscented Kalman Filter : Methodology and Experimental Validation
- 2020
-
Ingår i: IEEE Access. - : IEEE. - 2169-3536. ; 8, s. 54887-54904
-
Tidskriftsartikel (refereegranskat)abstract
- This study introduces a fuzzy based optimal state estimation approach. The new method is based on two principles: Adaptive Unscented Kalman filter, and Fuzzy Adaptive Grasshopper Optimization Algorithm. The approach is designed for the optimization of an adaptive Unscented Kalman Filter. To find the optimal parameters for the filter, a fuzzy based evolutionary algorithm, named Fuzzy Adaptive Grasshopper Optimization Algorithm, is developed where its efficiency is verified by application to different benchmark functions. The proposed optimal adaptive unscented Kalman filter is applied to two nonlinear systems: a robotic manipulator, and a servo-hydraulic system. Different simulation tests are conducted to verify the performance of the filter. The results of simulations are presented and compared with a previous version of the unscented Kalman filter. For a realistic test, the proposed filter is applied on the practical servo-hydraulic system. Practical results are discussed, and presented results approve the capability of the presented method for practical applications.
|
|
| 3. |
- Asl, Reza Mohammadi, et al.
(författare)
-
Integral Non-Singular Terminal Sliding Mode Controller for nth-Order Nonlinear Systems
- 2019
-
Ingår i: IEEE Access. - : Institute of Electrical and Electronics Engineers (IEEE). - 2169-3536. ; 7, s. 102792-102802
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, a new integral non-singular terminal sliding mode control method for nonlinear systems is introduced. The proposed controller is designed by defining a new sliding surface with an additional integral part. This new manifold is first introduced into the second-order system and then expanded to nth-order systems. The stability of the control system is demonstrated for both second-order and nth-order systems by using the Lyapunov stability theory. The proposed controller is applied to a robotic manipulator as a case study for second-order systems, and a servo-hydraulic system as a case study for third-order systems. The results are presented and discussed.
|
|
| 4. |
- Berglund, Erik, et al.
(författare)
-
Mapping between different kinematic structures without absolute positioning during operation
- 2012
-
Ingår i: Electronics Letters. - : Institution of Engineering and Technology (IET). - 0013-5194 .- 1350-911X. ; 48:18, s. 1110-1112
-
Tidskriftsartikel (refereegranskat)abstract
- When creating datasets for modelling of human skills based on training examples from human motion, one can encounter the problem that the kinematics of the robot does not match the human kinematics. Presented is a simple method of bypassing the explicit modelling of the human kinematics based on a variant of the self-organising map (SOM) algorithm. While the literature contains instances of SOM-type algorithms used for dimension reduction, this reported work deals with the inverse problem: dimension increase, as we are going from 4 to 5 degrees of freedom.
|
|
| 5. |
- Bergsten, Pontus, 1971-, et al.
(författare)
-
Fuzzy Observers
- 2001
-
Ingår i: The 10th IEEE International Conference on Fuzzy Systems (Volym:3). - New York, USA : IEEE conference proceedings. - 078037293X ; , s. 700-703
-
Konferensbidrag (refereegranskat)abstract
- We consider the analysis and design of three different types of nonlinear observers for dynamic Takagi-Sugeno fuzzy systems. Our approach is based on extending existing nonlinear observer schemes, namely Thau-Luenberger and sliding mode observers, to the case of interpolated multiple local affine linear models. Then linear matrix inequality based techniques are used for observer analysis and design.
|
|
| 6. |
- Bergsten, Pontus, 1971-, et al.
(författare)
-
Observers for Takagi-Sugeno fuzzy systems
- 2002
-
Ingår i: IEEE transactions on systems, man and cybernetics. Part B. Cybernetics. - : IEEE Journals & Magazines. - 1083-4419 .- 1941-0492. ; 32:1, s. 114-121
-
Tidskriftsartikel (refereegranskat)abstract
- We focus on the analysis and design of two different sliding mode observers for dynamic Takagi-Sugeno (TS) fuzzy systems. A nonlinear system of this class is composed of multiple affine local linear models that are smoothly interpolated by weighting functions resulting from a fuzzy partitioning of the state space of a given nonlinear system subject to observation. The Takagi-Sugeno fuzzy system is then an accurate approximation of the original nonlinear system. Our approach to the analysis and design of observers for Takagi-Sugeno fuzzy systems is based on extending sliding mode observer schemes to the case of interpolated multiple local affine linear models. Thus, our main contribution is nonlinear observer analysis and design methods that can effectively deal with model/plant mismatches. Furthermore, we consider the difficult case when the weighting functions in the Takagi-Sugeno fuzzy system depend on the estimated state
|
|
| 7. |
- Chadalavada, Ravi Teja, 1989-, et al.
(författare)
-
Accessing your navigation plans! Human-Robot Intention Transfer using Eye-Tracking Glasses
- 2018
-
Ingår i: Advances in Manufacturing Technology XXXII. - Amsterdam, Netherlands : IOS Press. - 9781614999010 - 9781614999027 ; , s. 253-258
-
Konferensbidrag (refereegranskat)abstract
- Robots in human co-habited environments need human-aware task and motion planning, ideally responding to people’s motion intentions as soon as they can be inferred from human cues. Eye gaze can convey information about intentions beyond trajectory and head pose of a person. Hence, we propose eye-tracking glasses as safety equipment in industrial environments shared by humans and robots. This paper investigates the possibility of human-to-robot implicit intention transference solely from eye gaze data. We present experiments in which humans wearing eye-tracking glasses encountered a small forklift truck under various conditions. We evaluate how the observed eye gaze patterns of the participants related to their navigation decisions. Our analysis shows that people primarily gazed on that side of the robot they ultimately decided to pass by. We discuss implications of these results and relate to a control approach that uses human eye gaze for early obstacle avoidance.
|
|
| 8. |
- Chadalavada, Ravi Teja, 1989-, et al.
(författare)
-
Bi-directional navigation intent communication using spatial augmented reality and eye-tracking glasses for improved safety in human-robot interaction
- 2020
-
Ingår i: Robotics and Computer-Integrated Manufacturing. - : Elsevier. - 0736-5845 .- 1879-2537. ; 61
-
Tidskriftsartikel (refereegranskat)abstract
- Safety, legibility and efficiency are essential for autonomous mobile robots that interact with humans. A key factor in this respect is bi-directional communication of navigation intent, which we focus on in this article with a particular view on industrial logistic applications. In the direction robot-to-human, we study how a robot can communicate its navigation intent using Spatial Augmented Reality (SAR) such that humans can intuitively understand the robot's intention and feel safe in the vicinity of robots. We conducted experiments with an autonomous forklift that projects various patterns on the shared floor space to convey its navigation intentions. We analyzed trajectories and eye gaze patterns of humans while interacting with an autonomous forklift and carried out stimulated recall interviews (SRI) in order to identify desirable features for projection of robot intentions. In the direction human-to-robot, we argue that robots in human co-habited environments need human-aware task and motion planning to support safety and efficiency, ideally responding to people's motion intentions as soon as they can be inferred from human cues. Eye gaze can convey information about intentions beyond what can be inferred from the trajectory and head pose of a person. Hence, we propose eye-tracking glasses as safety equipment in industrial environments shared by humans and robots. In this work, we investigate the possibility of human-to-robot implicit intention transference solely from eye gaze data and evaluate how the observed eye gaze patterns of the participants relate to their navigation decisions. We again analyzed trajectories and eye gaze patterns of humans while interacting with an autonomous forklift for clues that could reveal direction intent. Our analysis shows that people primarily gazed on that side of the robot they ultimately decided to pass by. We discuss implications of these results and relate to a control approach that uses human gaze for early obstacle avoidance.
|
|
| 9. |
- Currie, Bronwen, et al.
(författare)
-
Living dangerously: implications of hydrogen sulphide events for marine life along the Namibian coast : A.G.V. Salvanes6, R. Bahlo5
- 2008
-
Ingår i: International Symposium on Eastern Boundary Upwelling Ecosystems: Spain.
-
Konferensbidrag (populärvet., debatt m.m.)abstract
- Hypoxia, anoxia and free hydrogen sulphide in the water column are characteristic of the inner shelf coastal upwelling system off central Namibia. Biogeochemical monitoring of the diatomaceous sediments along the central coast over a 3-year period, coupled with acoustic studies and ROV video coverage, indicated a major role played by the seafloor in the generation and control of H2S into the water column. We determined the sedimentary processes resulting in the generation and dispersal of hydrogen sulphide, and its effect on some of the locally important fishes and invertebrates.Marked interannual variability with no obvious seasonal trends was apparent in methane contents of sediments even over the short three-year period, whilst sulphate reduction rates in the sediment showed little change. The large sulphur bacteria Thiomargarita namibiensis and Beggiatoa spp. form dense mats over extensive areas of mud and oxidize sulphide at the sediment-water interface, thereby regulating its flux into the overlying water. During episodic events however, hydrogen sulphide pervades the entire water column, followed by severe hypoxia. Under experimental conditions, the survival of juvenile horse mackerel Trachurus trachurus capensis was limited to less than two hours in water containing <0.7ml.l-1 dissolved oxygen. If sulphide was also present survival time was reduced to less than 30 minutes. In contrast, pelagic gobies Sufflogobius bibarbatus survive exposure to extended periods of anoxia and water containing sulphide. Gobies are found abundantly on the muddy seafloor where they evidently possess both physiological and behavioural strategies to survive sulphide and anoxia, accounting for the success of this species in Namibian waters and its importance as a key diet species for predatory fish, seabirds and marine mammals.
|
|
| 10. |
- Driankov, Dimiter, 1952-, et al.
(författare)
-
A Takagi-Sugeno fuzzy gain-scheduler
- 1996
-
Ingår i: Proceedings of the Fifth IEEE International Conference on Fuzzy Systems. - New York, USA : IEEE conference proceedings. - 0780336453 ; , s. 1053-1059
-
Konferensbidrag (refereegranskat)abstract
- In the present paper we describe the design of a fuzzy gain scheduler for tracking a reference trajectory of a nonlinear autonomous system. The proposed fuzzy gain scheduling method has two major advantages over the existing crisp gain scheduling methods. First, it provides a general and formally motivated method for the interpolation of available local control laws into a global gain scheduling control law. Second, the method for determining the weights of the local control laws in the global gain scheduling control law is general and computationally efficient. It is shown that a fuzzy gain scheduler can be designed such that robust asymptotic stability is met. Finally, an LQR control design based method is presented
|
|
