154 research outputs found
Robust data assimilation in river flow and stage estimation based on multiple imputation particle filter
In this paper, new method is proposed for a more robust Data Assimilation (DA) design of the
river flow and stage estimation. By using the new sets of data that are derived from the incorporated Multi
Imputation Particle Filter (MIPF) in the DA structure, the proposed method is found to have overcome the
issue of missing observation data and contributed to a better estimation process. The convergence analysis
of the MIPF is discussed and shows that the number of the particles and imputation influence the ability of
this method to perform estimation. The simulation results of the MIPF demonstrated the superiority of the
proposed approach when being compared to the Extended Kalman Filter (EKF) and Particle Filter (PF)
Pemahaman pelajar tingkatan lima katering terhadap bab kaedah memasak dalam mata pelajaran teknologi katering
Bab Kaedah Memasak merupakan salah satu bab yang penting dalam mata
pelajaran Teknologi Katering. Faktor terpenting adalah memastikan pelajar menguasai
serta memahami konsepnya adalah melalui proses pengajaran dan pembelajaran yang
betul. Tinjauan awal di Sekolah Menengah Teknik yang menawarkan Kursus Katering,
menunjukkan bahawa kebanyakan pelajar sukar untuk menguasai dan memahami bab
tersebut. Berdasarkan hasil tinjauan , pengkaji ingin mengenalpasti pemasalahan dalam
memahami bab tersebut. Di samping itu juga, pengkaji ingin mengenalpasti adakah
pencapaian pelajar dalam PMR, minat, motivasi dan gaya pembelajaran mempengaruhi
pemahaman pelajar, Kajian rintis telah dilakukan terhadap 10 orang responden dengan
nilai alpha 0.91. Ini menunjukkan kebolehpercayaan terhadap kajian di jalankan adalah
tinggi. Responden adalah terdiri daripada 30 orang pelajar Tingkatan Lima (ERT)
Sekolah Menengah Teknik Muar, Johor. Keputusan skor min keseluruhan menunjukkan
pelajar berminat dan mempunyai motivasi ynag baik dalam bidang ini. Namun begitu,
gaya pembelajaran yang diamalkan tidak sesuai dan antara pemyebab wujudnya
pemasalahan dalam memahami bab Kaedah Memasak. Ujian kolerasi menunjukkan
bahawa tidak terdapat sebarang hubungan signifikan antara pencapaian PMR pelajar
dengan pemahaman bab tersebut. Sementara minat, motivasi dan gaya pembelajaran
membuktikan ada hubungan signifikan dengan pemahaman pelajar dalam bab Kaedah
Memasak
Improving Seaglider Efficiency: An Analysis of Wing Shapes, Hull Morphologies, and Propulsion Methods
Autonomous underwater gliders are a family of autonomous underwater vehicles used for long-term observation of oceanic environments. These gliders leverage changes in buoyancy and the resulting vertical motion, to generate forward locomotion via hydrodynamic surfaces. In order to function for extended periods, these systems operate in a low-speed, low-drag regime. This research examines factors impacting the operational efficiencies of gliders, including morphological changes, configuration changes, and propulsion. An interesting question arises when considering the operational efficiencies of conventionally propelled systems at the operating speeds typical of gliders. Can a conventional propulsion system match the efficiency of an underwater glider buoyancy engine? A first-principles, energy-based approach to glider operations was derived and verified using real world data. The energy usage for buoyancy driven propulsion was then compared to conventional propulsion types. The results from these calculations indicate that a conventionally propelled autonomous underwater vehicle can compete with and in some cases outperform a buoyancy driven system given the proper propulsive efficiency
Aquatic escape for micro-aerial vehicles
As our world is experiencing climate changes, we are in need of better monitoring technologies.
Most of our planet is covered with water and robots will need to move in aquatic environments.
A mobile robotic platform that possesses efficient locomotion and is capable of operating in
diverse scenarios would give us an advantage in data collection that can validate climate models,
emergency relief and experimental biological research. This field of application is the driving
vector of this robotics research which aims to understand, produce and demonstrate solutions
of aerial-aquatic autonomous vehicles.
However, small robots face major challenges in operating both in water and in air, as well as
transition between those fluids, mainly due to the difference of density of the media.
This thesis presents the developments of new aquatic locomotion strategies at small scales that
further enlarge the operational domain of conventional platforms. This comprises flight, shallow
water locomotion and the transition in-between. Their operating principles, manufacturing
methods and control methods are discussed and evaluated in detail.
I present multiple unique aerial-aquatic robots with various water escape mechanisms, spanning
over different scales. The five robotic platforms showcased share similarities that are compared.
The take-off methods are analysed carefully and the underlying physics principles put into light.
While all presented research fulfils a similar locomotion objective - i.e aerial and aquatic motion
- their relevance depends on the environmental conditions and supposed mission. As such, the
performance of each vehicle is discussed and characterised in real, relevant conditions.
A novel water-reactive fuel thruster is developed for impulsive take-off, allowing consecutive
and multiple jump-gliding from the water surface in rough conditions. At a smaller scale, the
escape of a milligram robotic bee is achieved. In addition, a new robot class is demonstrated,
that employs the same wings for flying as for passive surface sailing. This unique capability
allows the flexibility of flight to be combined with long-duration surface missions, enabling
autonomous prolonged aquatic monitoring.Open Acces
Underwater Robots Part I: Current Systems and Problem Pose
International audienceThis paper constitutes the first part of a general overview of underwater robotics. The second part is titled: Underwater Robots Part II: existing solutions and open issues
Adaptive control simulation for multiagent autonomous underwater cleaning robot
938-943The purpose of this research is to develop an adaptive control system for multiagent autonomous underwater cleaning robots that can handle problems that occur due to large areas of underwater environment cleaning operations, single robot challenges, and ineffective tactics that could cause a system failure. Therefore, the purpose of the research is to develop an adaptive control system for multiagent autonomous underwater cleaning robots that can be used to handle difficulties such as underwater environment cleanliness, single robot issues, and avoiding ineffective approaches that might cause system failure. This research used the MATLAB and Simulink tools to create an adaptive control system and simulate the designed controller with various unknown parameters and disturbances. The results demonstrate the adaptivity, adjustability, and stability of the multiagent underwater cleaning robot’s adaptive control system to cope with the underwater environment’s situations such water current using simulation
Review of Computational Fluid Dynamics Analysis in Biomimetic Applications for Underwater Vehicles
Biomimetics, which draws inspiration from nature, has emerged as a key approach in the development of underwater vehicles. The integration of this approach with computational fluid dynamics (CFD) has further propelled research in this field. CFD, as an effective tool for dynamic analysis, contributes significantly to understanding and resolving complex fluid dynamic problems in underwater vehicles. Biomimetics seeks to harness innovative inspiration from the biological world. Through the imitation of the structure, behavior, and functions of organisms, biomimetics enables the creation of efficient and unique designs. These designs are aimed at enhancing the speed, reliability, and maneuverability of underwater vehicles, as well as reducing drag and noise. CFD technology, which is capable of precisely predicting and simulating fluid flow behaviors, plays a crucial role in optimizing the structural design of underwater vehicles, thereby significantly enhancing their hydrodynamic and kinematic performances. Combining biomimetics and CFD technology introduces a novel approach to underwater vehicle design and unveils broad prospects for research in natural science and engineering applications. Consequently, this paper aims to review the application of CFD technology in the biomimicry of underwater vehicles, with a primary focus on biomimetic propulsion, biomimetic drag reduction, and biomimetic noise reduction. Additionally, it explores the challenges faced in this field and anticipates future advancements
Adaptive control simulation for multiagent autonomous underwater cleaning robot
The purpose of this research is to develop an adaptive control system for multiagent autonomous underwater cleaning robots that can handle problems that occur due to large areas of underwater environment cleaning operations, single robot challenges, and ineffective tactics that could cause a system failure. Therefore, the purpose of the research is to develop an adaptive control system for multiagent autonomous underwater cleaning robots that can be used to handle difficulties such as underwater environment cleanliness, single robot issues, and avoiding ineffective approaches that might cause system failure. This research used the MATLAB and Simulink tools to create an adaptive control system and simulate the designed controller with various unknown parameters and disturbances. The results demonstrate the adaptivity, adjustability, and stability of the multiagent underwater cleaning robot’s adaptive control system to cope with the underwater environment’s situations such water current using simulation
Hovering-mode control of the glider-type unmanned underwater vehicle
Thesis (Master)--Izmir Institute of Technology, Mechanical Engineering, Izmir, 2011Includes bibliographical references (leaves: 104-107)Text in English; Abstract: Turkish and Englishxiii, 109 leavesResearch on the underwater robotics has attracted the interest of many researchers over the years. The primary reasons are the need to perform underwater intervention tasks that are dangerous for a diver and the need to perform underwater survey tasks that last for longer periods of time. Unmanned underwater vehicles can be divided into two categories. Most of the systems, today, that require a certain level of precision and dexterity are built as Remotely Operated Vehicles (ROV). On the other hand, the systems that perform repetitive tasks are configured as Autonomous Underwater Vehicles (AUV). The objective of the thesis is to design a novel, cost-efficient, and fault-tolerant ROV that can hover and be used for shallow water investigation. In order to reduce the cost, the numbers of thrusters are minimized and internal actuators are used for steering the vehicle and stability in hovering mode. Also, the design is planned to be open for modification for further improvements that will enable the use of the vehicle for intervention tasks and studies. In this work, previously developed unmanned underwater vehicles are reviewed. Following this, the conceptual designs are created for the underwater vehicle and internal actuator designs are developed. Designed mechanisms are modeled in SolidWorks© and transferred to MATLAB© Simulink for hovering-mode control studies. Afterwards, to verify the simulation results, experiments are conducted with a seesaw mechanism by using LabVIEW© programming. Finally, results are given, discussed and future works are addressed
3D locomotion biomimetic robot fish with haptic feedback
This thesis developed a biomimetic robot fish and built a novel haptic robot fish system based on the kinematic modelling and three-dimentional computational fluid dynamic (CFD) hydrodynamic analysis. The most important contribution is the successful CFD simulation of the robot fish, supporting users in understanding the hydrodynamic properties around it
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