Navigation Simulation Research Articles

北極海航路航行可能性に関する基礎的研究－航海シミュレーション－

As a fundamental of the navigation simulation to understand the passage possibility through the Northern Sea Route (NSR), the navigation simulation is performed during the sea ice decrease period (2007 to 2011) with the sea ice concentration reanalysis. Under even the strictest sea ice condition, the continuous passage period through the NSR is roughly from the end of August to the beginning of September of each year during 2009 to 2011. The period through the NSR in each year is not fixed. The simulation in this study will evaluate whether ships can pass through the NSR and whether escort ships are needed.

The Study of Fractional Order Controller with SLAM in the Humanoid Robot

We present a fractional order PI controller (FOPI) with SLAM method, and the proposed method is used in the simulation of navigation of NAO humanoid robot from Aldebaran. We can discretize the transfer function by the Al-Alaoui generating function and then get the FOPI controller by Power Series Expansion (PSE). FOPI can be used as a correction part to reduce the accumulated error of SLAM. In the FOPI controller, the parameters (Kp,Ki, and α) need to be tuned to obtain the best performance. Finally, we compare the results of position without controller and with PI controller, FOPI controller. The simulations show that the FOPI controller can reduce the error between the real position and estimated position. The proposed method is efficient and reliable for NAO navigation.

離着岸操船におけるタグボート運用要素の評価

The most important task of harbor tug boats are to support berthing /unberthing of vessels, because marine pilots use those tug boats for safe and efficient ship operation when assisting vessels’ berthing or unberthing. In Japan, the new pilotage low has been active since 2007 and included the third grade pilots which newly established. Unfortunately, they do not have enough experience of tug boat management. They are trying to study about tug boats handling in the harbor for large vessels using ship handling by navigation simulation systems. The senior pilots teach them how to use the tug boats in the ship handling simulator, too. However, the senior pilots have only the experience but do not have standard of the evaluation for management of tug boats handling. In this paper, the authors propose how to evaluate the tug boat handling for ship berthing using the new standard, which is named “Evaluation on elements for tug boat handling.” It is extracted from natural images of ship berthing at actual port named Yokohama. The new standards are consisted of three elements which are propelling power of tug boats, its direction and duration of power. The authors tried to compare the values of the three elements between actual ship handlings and ship handlings by the simulation, then confirmed their effects.

Simulation of Ship Movement after Steering System Failure to Determine the Worst Case Scenario of Grounding

Ship grounding is one of the primary maritime navigation casualties and a result of an error made by the navigating officer, of a technical failure on vital ship equipment or of force majeure. In order to decrease the risk of grounding in such cases, this paper explores the ship movement during navigation when an extraordinary event occurs, such as steering system failure that affects the vessel’s direction directly and speed indirectly. One way to determine the ship movement in such circumstances is by simulating the ship movement on the navigational simulator according to the predefined scenarios, as explained in this paper. A total of 60 scenarios were researched, in the process of which ship type, ship size, ship speed and rudder deflection angle were varied. During the simulation, all relevant data concerning current movement of the ship and a graphical display of the performed simulation were recorded every 30 seconds. On the basis of the simulation results it is possible to determine the worst case scenario which can be used to define the consequence of grounding, one of the parameters necessary for the assessment of the risk of grounding.

Mobile Robot Navigation Using ARTQL Algorithm with Novelty Driven Mechanism

Q-learning algorithm is usually used for traditional mobile robot navigation. The traditional Q-learning methods have the problem of dimension disaster, which may be produced by applying Q-learning to intelligent system of continuous state-space. Besides, the learning activity and efficiency are low. In order to solve these problems, a new method called ARTQL is proposed, which combined ART2 network with the traditional Q-learning algorithm. Then, a learning mechanism called novelty driven is proposed to lead the ARTQL algorithm to learn more actively and efficiently. Through the ARTQL with novelty driven mechanism algorithm, Q-learning Agent in view of the duty which needs to complete to learn an appropriate incremental clustering of state-space model, so Agent can carry out decision-making and a two-tiers online learning of state-space model cluster in unknown environment, without any priori knowledge, through interaction with the environment unceasingly alternately to improve the control strategies, increase the learning accuracy, activity and efficiency. Finally through the mobile robot navigation simulation experiments, we show that, using the proposed algorithm, mobile robot can improve its navigation performance continuously by interactive learning with the environment with high autonomous.

Mathematical model of small water-plane area twin-hull and application in marine simulator

Small water-plane area twin-hull (SWATH) has drawn the attention of many researchers due to its good sea-keeping ability. In this paper, MMG’s idea of separation was used to perform SWATH movement modeling and simulation; respectively the forces and moment of SWATH were divided into bare hull, propeller, rudder at the fluid hydrodynamics, etc. Wake coefficient at the propellers which reduces thrust coefficient, and rudder mutual interference forces among the hull and propeller, for the calculation of SWATH, were all considered. The fourth-order Runge-Kutta method of integration was used by solving differential equations, in order to get SWATH’s movement states. As an example, a turning test at full speed and full starboard rudder of ‘Seagull’ craft is shown. The simulation results show the SWATH’s regular pattern and trend of motion. It verifies the correctness of the mathematical model of the turning movement. The SWATH’s mathematical model is applied to marine simulator in order to train the pilots or seamen, or safety assessment for ocean engineering project. Lastly, the full mission navigation simulating system (FMNSS) was determined to be a successful virtual reality technology application sample in the field of navigation simulation.

Goal conditioning throw mutimodal categorisation in a simulation of rat navigation

Navigation tasks are based on two approaches: place-action directed or goal directed. In the goal directed ones, a reward is generally given to the system when the goal is reached. Many models are able to predict the reward in a simple cases. In this paper, we present an architecture for complex conditioning. The purpose is to present a case where an association is used to predict the reward in the task. In this task, the goal is multimodal, i.e. the presence of one of the components is no longer sufficient. To correctly predict the reward, the correlation between two informations has to be saved. The experiment presents how the system can resolve ambiguities. The hypothesis in our model is that when a hippocampal conditioning is failing, the prefrontal cortex is neuro-modulated to facilitates the categorization of multimodal contexts. The goal is to encode the correlations between the inputs. When the contexts are activated in the future, they will help the conditioning in the hippocampus. The experimental setup is derived from the continuous place navigation task [1,2], where a rat has to find a goal marked by a blue spot, then wait 0.3 s in this location in order to obtain the reward (food). An automated pellet giver producing a sound releases the food. After some time, the sound is linked to the food reward. In the experiment an ambiguity subsists between two locations: two blue spots are present in the environment but only one of them has the sound occurrence. The prediction of the reward is correlated with the correct prediction of the sound, in the sequence place-cell -> blue spot → sound -> food. In this work, we study how failure in the conditioning can be solved by introducing multimodal contexts. Figure 1 Panel A presents the experiment. There are two blue spots in the environment, but the reward is obtained by waiting 0.3s in only one of them. Panel B presents the reward predictions of the rat at the beginning: both of the spots are predicted as a reward. ...

Numerical ship navigation based on weather and ocean simulation

Sea states, such as waves, tidal currents, and wind are important factors for safe and economic ship navigation. In previous papers of Xia et al. (2006a, 2006b) single factor generated by low pressure was studied independently. The objective of this paper is to study how ship navigation is affected by the combined effects of these factors. For clarification, simulations of two representative typhoons were conducted, and the results were compared. Numerical simulations of tidal currents, waves, and wind were applied to provide high-resolution information, which was then used to simulate ship navigation. Estimation of ship position was found effectively by comparing the results from these two cases and using the proposed numerical navigation simulation method.

Research on Mathematical Modeling of Ship Simulation System

With the rapid development of science and technology, mathematical models more and more present in modern production, work and social activities. Must be established to control the production process of mathematical models, use this model on design and calculation of control devices accordingly in order to achieve effective process control. Ship handling Simulator as an advanced teaching method applied in the teaching and training of crews sailing in China have a long history. By driving simulation of ship navigation, training students to train and ship very similar environment.

Motion Planning for Multi-robot Coordination

In this paper, we investigate the problem of task oriented motion planning of multirobot formation. By combining motion planning with task, the representation space model of multi-robot formation is built to characterize the process of formation navigation. Based on that, a hierarchical structure is proposed to ensure so that formation constraint and collision avoidance is maintained during the task realization. The problem of whether a task is feasible is translated to completeness of planning algorithms in representation space. The properties of different planning algorithms are evaluated. The simulation of multi-robot formation navigation in a warehouse environment is presented to prove that the formation constraint and collision avoidance can be maintained with the proposed approach. Moreover, by incorporating the task oriented motion planning framework, it is possible to turn an infeasible task into a feasible one while ensuring that formation can reach the target position.

Research of X-ray pulsar navigation simulation source

As an autonomous navigation method, X-ray pulsar navigation can provide position, timing and attitude information for various spacecrafts. Since the X-rays (1-20 keV) from the pulsar can not penetrate the earth atmosphere, an X-ray source in laboratory needs to be set up to test and calibrate the detector. In this paper an arbitrary X-ray pulse source to simulate the neutron pulsar signal is proposed. The main components of the simulation source are a grid controlled X-ray tube and arbitrary pulse generation electronics. With the arbitrary pulse voltage applied to the tube grid, the X-ray intensity is controlled. Through electron optics design, the tube electrode parameters are optimized. A grid controlled X-ray tube is fabricated and tested. Using a micro-channel plate detector to detect and reconstruct the generated X-ray pulses, the similarity between the accumulated profile and the original pulsar profile is better than 95%. The frequency stability of the pulsar source emulator is about 2×10-11.

An analog modulated simulation source for X-ray pulsar-based navigation

In this paper a high resolution X-ray simulation source is proposed and designed to verify the navigation based on X-ray pulsar in the simulation experience system. The simulation source consists of an arbitrary signal generator and a grid controlled X-ray tube. According to the grid tube's characteristic curve, the data of the pulsar standard pulse template are converted. Then using the method of direct digital frequency synthesis, the converted data are synthesized to waveforms, called the analog modulated grid voltage. In the grid controlled X-ray tube, the grid voltage changes the number of electrons hitting on the target and controls the X-ray intensity. With an analog modulated pulse profile applied on the tube grid electrode, the tube will emit X-rays which will match photons' statistical distribution and simulate the X-ray pulsar profile extremely well. The properties of Crab pulsar simulation source are tested in X-ray pulsar navigation simulation experience system. The results of the test are as follows: Comparing the tested pulse profile with the standard pulsar profile, we have time correlation coefficient is 0.9774, and frequency correlation coefficient is 0.9853. The X-ray photon flux is 1.90 ph·cm-2·s-1, the pulsed fraction is 76.15%, and the half-width half maximum is 1.879 ms. These results show that the X-ray simulation source has several merits, such as: strong ability to simulate the X-ray, low cost and simple operation. So it is an important means for the improvement of X-ray pulsar navigation.

Motor transfer from map ocular exploration to locomotion during spatial navigation from memory

Spatial navigation from memory can rely on two different strategies: a mental simulation of a kinesthetic spatial navigation (egocentric route strategy) or visual-spatial memory using a mental map (allocentric survey strategy). We hypothesized that a previously performed "oculomotor navigation" on a map could be used by the brain to perform a locomotor memory task. Participants were instructed to (1) learn a path on a map through a sequence of vertical and horizontal eyes movements and (2) walk on the slabs of a "magic carpet" to recall this path. The main results showed that the anisotropy of ocular movements (horizontal ones being more efficient than vertical ones) influenced performances of participants when they change direction on the central slab of the magic carpet. These data suggest that, to find their way through locomotor space, subjects mentally repeated their past ocular exploration of the map, and this visuo-motor memory was used as a template for the locomotor performance.

Fiber optic gyroscope vibration error due to fiber tail length asymmetry based on elastic-optic effect

In the assembly of fiber optic gyroscope (FOG), the summation of the fiber tail length of waveguide and fiber ring in two directions cannot be exactly equal (i.e., fiber tail length of FOG in two directions is asymmetry). We analyze and calculate the vibration error of FOG due to this fiber tail length asymmetry based on elastic-optic effect. Inertial navigation simulation is performed to show attitude and positioning errors caused by this vibration error, which clearly shows the importance of reducing fiber-tail length asymmetry in high-accuracy applications.

Vehicle kinematics modeling and design of vehicle trajectory generator system

A trajectory generator based on vehicle kinematics model was presented and an integrated navigation simulation system was designed. Considering that the tight relation between vehicle motion and topography, a new trajectory generator for vehicle was proposed for more actual simulation. Firstly, a vehicle kinematics model was built based on conversion of attitude vector in different coordinate systems. Then, the principle of common trajectory generators was analyzed. Besides, combining the vehicle kinematics model with the principle of dead reckoning, a new vehicle trajectory generator was presented, which can provide process parameters of carrier anytime and achieve simulation of typical actions of running vehicle. Moreover, IMU (inertial measurement unit) elements were simulated, including accelerometer and gyroscope. After setting up the simulation conditions, the integrated navigation simulation system was verified by final performance test. The result proves the validity and flexibility of this design.

항공 산업의 DFSS 적용방법에 관한 연구

Purpose: In this paper, a Design for Six Sigma(DFSS) methodology based on DMADV(Define-Measure-Analyze-Design-Verify) roadmap is presented. Methods: DFSS tools are given for each DMADV phase which is suitable for the aircraft development process. A cost reduction case study of a navigation simulation is demonstrated. Results: DFSS roadmap are presented with implementation tools for each phase. Conclusion: We propose a DFSS methodology which can benefit the design and development personnel to implement DFSS not only in aircraft industry but also in other order-based industries in general.

Simulating ship and buoy motions arising from ocean waves in a ship handling simulator

A ship’s real-time three-dimensional (3D) visualization system, a component of a handling simulator, is one of its most important components, since realistic and intuitive image generation play an essential role in improving the effects of education using ship navigation simulators. Ship handling simulators should have capabilities of calculating ship motions (heave, pitch, and roll) at any given sea state and display the calculated motions through a real-time 3D visualization system. The motion solver of a ship handling simulator calculates those motions in addition to maneuverings for an own ship, the main simulation target, but only provides maneuvering information about traffic ships. Therefore, it is required to simulate traffic ship and buoy motions arising from ocean waves in a ship handling simulator for realistic visualization. In this paper, the authors propose a simple dynamics model by which ship and buoy motions are calculated with the input data of wave height and discuss a method for the implementation of a ship and buoy motion calculation module. The feasibility of the proposed dynamics model and the motion calculation module has been demonstrated through the development of a prototype real-time 3D visualization system based on an open-source 3D graphics engine.

Construct and face validity of a virtual reality–based camera navigation curriculum

IntroductionCamera handling and navigation are essential skills in laparoscopic surgery. Surgeons rely on camera operators, usually the least experienced members of the team, for visualization of the operative field. Essential skills for camera operators include maintaining orientation, an effective horizon, appropriate zoom control, and a clean lens. Virtual reality (VR) simulation may be a useful adjunct to developing camera skills in a novice population. No standardized VR-based camera navigation curriculum is currently available. We developed and implemented a novel curriculum on the LapSim VR simulator platform for our residents and students. We hypothesize that our curriculum will demonstrate construct and face validity in our trainee population, distinguishing levels of laparoscopic experience as part of a realistic training curriculum. MethodsOverall, 41 participants with various levels of laparoscopic training completed the curriculum. Participants included medical students, surgical residents (Postgraduate Years 1–5), fellows, and attendings. We stratified subjects into three groups (novice, intermediate, and advanced) based on previous laparoscopic experience. We assessed face validity with a questionnaire. The proficiency-based curriculum consists of three modules: camera navigation, coordination, and target visualization using 0° and 30° laparoscopes. Metrics include time, target misses, drift, path length, and tissue contact. We analyzed data using analysis of variance and Student's t-test. ResultsWe noted significant differences in repetitions required to complete the curriculum: 41.8 for novices, 21.2 for intermediates, and 11.7 for the advanced group (P < 0.05). In the individual modules, coordination required 13.3 attempts for novices, 4.2 for intermediates, and 1.7 for the advanced group (P < 0.05). Target visualization required 19.3 attempts for novices, 13.2 for intermediates, and 8.2 for the advanced group (P < 0.05). Participants believe that training improves camera handling skills (95%), is relevant to surgery (95%), and is a valid training tool (93%). Graphics (98%) and realism (93%) were highly regarded. ConclusionsThe VR-based camera navigation curriculum demonstrates construct and face validity for our training population. Camera navigation simulation may be a valuable tool that can be integrated into training protocols for residents and medical students during their surgery rotations.

Optimal Path Planning of an Autonomous Mobile Robot Using Genetic Algorithm

An autonomous Mobile Robot (AMR) is a machine able to extract information from its environment and move in a meaningful and purposeful manner. Robot Navigation and Obstacle avoidance are the most important problems in mobile robots. In the past, a number of soft computing algorithms have been designed by many researchers for robot navigation problems but very few are actually implementable because they haven’t considered robot size as parameter. This paper presents software simulation and hardware implementation of navigation of a mobile robot avoiding obstacles and selecting optimal path in a static environment using evolution based Genetic algorithms with robot size as a parameter in fitness function.

Who benefits from simulator training: Personality and heart rate variability in relation to situation awareness during navigation training

ObjectiveThis study tested the relationship between individual differences and Situation Awareness (SA) during training in a navigation simulator. BackgroundSimulators have become an important tool in the training and education of maritime personnel with a view to improving decisions and performance. There are a few, inconclusive empirical studies that have focused on mapping personality characteristics and their link to the ability to generate and maintain SA during simulator training. MethodThirty-six first-year students from the Royal Norwegian Navy Officer Candidate School participated in the study. SA was measured using both subjective and observer ratings. ResultsThe results indicated that low scores on Neuroticism and high scores on Extraversion and Conscientiousness (resilient personality type) predicted both subjective and observer-rated SA. Furthermore, participants with high SA were able to modulate their Heart Rate Variability (HRV), with suppression of HRV during navigation training as well showing recovery of HRV. ApplicationThe potential applications of this research include the assessment of personality differences as a tool in selecting navigators, and the use of HRV as an objective index of adaptability to environmental demands.