Algorithm for adaptive correction of the ship's movement along the trajectory in the presence of a sea current

2021 ◽  
pp. 115-119
Author(s):  
А.А. Дыда ◽  
К.Н. Чумакова ◽  
А.Ф. Красавина
Keyword(s):  
Auxiliary Function ◽  
Gradient Algorithm ◽  
Gradient Vector ◽  
Correction Algorithm ◽  
Vector Computer ◽  
Line Section ◽  
Straight Line ◽  
Adaptive Correction ◽  
Sea Current ◽  
Virtual Trajectory

В статье предложен алгоритм адаптивной коррекции движения судна по траектории при наличии морского течения. В основе предлагаемого подхода лежит алгоритм градиента вспомогательных функций. Показаны преимущества предложенного алгоритма адаптивной коррекции движения судна по траектории. Сущность предлагаемого подхода заключается в замене прямолинейного участка маршрута судна, новой виртуальной траекторией и использовании ее во вспомогательной функции и при вычислении соответствующего вектора градиента. Компьютерное моделирование подтвердило эффективность предложенного алгоритма адаптивной коррекции. Адаптивные свойства разработанного алгоритма выражаются в том, что он обеспечивает асимптотически точное движение по участкам запланированной траектории, не используя информации о скорости и направлении морского течения. Предполагается использование предложенного адаптивного алгоритма при разработке систем автоматического управления движением судна по маршруту. The article proposes an algorithm for adaptive correction of the ship's movement along the trajectory in the presence of a sea current. The proposed approach is based on the gradient algorithm of auxiliary functions. The advantages of the proposed algorithm for adaptive correction of the ship's motion along the trajectory are shown. The essence of the proposed approach is to replace the straight-line section of the ship's route with a new virtual trajectory and use it in an auxiliary function and in calculating the corresponding gradient vector. Computer simulation has confirmed the effectiveness of the proposed adaptive correction algorithm. The adaptive properties of the developed algorithm are expressed in the fact that it provides asymptotically accurate movement along sections of the planned trajectory, without using information about the speed and direction of the sea current. It is supposed to use the proposed adaptive algorithm in the development of systems for automatic control of the ship's movement along the route.

Determining Average Reservoir Pressure From Pressure Buildup Tests

1974 ◽  
Vol 14 (01) ◽  
pp. 55-62 ◽  
Author(s):  
Hossein Kazemi
Keyword(s):  
Oil Reservoirs ◽  
Reservoir Engineering ◽  
Reservoir Pressure ◽  
Well Test ◽  
Gas Well ◽  
Pressure Buildup ◽  
Line Section ◽  
Straight Line ◽  
Buildup Curve

Abstract Two simple and equivalent procedures are suggested for improving the calculated average reservoir pressure from pressure buildup tests of liquid or gas wells in developed reservoirs. These procedures are particularly useful in gas well test procedures are particularly useful in gas well test analysis, irrespective of gas composition, in reservoirs with pressure-dependent permeability and porosity, and in oil reservoirs where substantial gas porosity, and in oil reservoirs where substantial gas saturation has been developed. A knowledge of the long-term production history is definitely helpful in providing proper insight in the reservoir engineering providing proper insight in the reservoir engineering aspects of a reservoir, but such long-term production histories need not be known in applying the suggested procedures to pressure buildup analysis. Introduction For analyzing pressure buildup data with constant flow rate before shut-in, there are two plotting procedures that are used the most: the procedures that are used the most: the Miller-Dyes-Hutchinson (MDH) plot and the Horner plot. The MDH plot is a plot of p vs log Deltat, whereas the Horner plot is a plot of p vs log [(t + Deltat)/Deltat]. Deltat is the shut-in time and t is a pseudoproduction time equal to the ratio of total produced fluid to last stabilized flow rate before shut-in. This method was first used by Theis in the water industry. Miller-Dyes-Hutchinson presented a method for calculating the average reservoir pressure, T, in in 1950. This method requires pseudosteady state before shut-in and was at first restricted to a circular reservoir with a centrally located well. Pitzer extended the method to include other Pitzer extended the method to include other geometries. Much later, Dietz developed a simpler interpretation scheme using the same MDH plot: p is read on the extrapolated straight-line section of the pressure buildup curve at shut-in time, Deltat,(1) where C is the shape factor for the particular drainage area geometry and the well location; values for C are tabulated in Refs. 5 and 13. For a circular drainage area with a centrally located well, C = 31.6, and for a square, C = 30.9.Horner presented another approach, which depended on the knowledge of the initial reservoir pressure, pi. This method also was first developed pressure, pi. This method also was first developed for a centrally located well in a circular reservoir.Matthews-Brons-Hazebroek (MBH) introduced another average reservoir pressure determination technique, which has been used more often than other methods: first a Horner plot is made; then the proper straight-line section of the buildup curve is proper straight-line section of the buildup curve is extrapolated to [(t + Deltat)/Deltat] = 1 (this intercept is denoted p*); finally, p is calculated from(2) m is the absolute value of the slope of the straightline section of the Horner plot:(3) pDMBH (tDA) is the MBH dimensionless pressure pDMBH (tDA) is the MBH dimensionless pressure at tDA, and tDA is the dimensionless time:(4) tp k a pseudoproduction time in hours:(5) PDMBH tDA) for different geometries and different PDMBH tDA) for different geometries and different well locations are given in Refs. 6 and 13.The second term on the right-hand side of Eq. 2 is a correction term for finite reservoirs that is based on material balance. Thus, for an infinite reservoir, p = pi = p*, where pi is the initial reservoir pressure. SPEJ P. 55

scholarly journals Splitting theorems for Finsler manifolds of nonnegative Ricci curvature

2015 ◽  
Vol 2015 (700) ◽  
Author(s):  
Shin-ichi Ohta
Keyword(s):  
Vector Field ◽  
Ricci Curvature ◽  
Splitting Theorem ◽  
Gradient Vector ◽  
Busemann Function ◽  
Finsler Manifolds ◽  
Nonnegative Ricci Curvature ◽  
Straight Line ◽  
Weighted Ricci Curvature ◽  
Gradient Vector Field

AbstractWe investigate the structure of a Finsler manifold of nonnegative weighted Ricci curvature including a straight line, and extend the classical Cheeger–Gromoll–Lichnerowicz Splitting Theorem. Such a space admits a diffeomorphic, measure-preserving splitting in general. As for a special class of Berwald spaces, we can perform the isometric splitting in the sense that there is a one-parameter family of isometries generated from the gradient vector field of the Busemann function. A Betti number estimate is also given for Berwald spaces.

Accelerated Reduced Gradient Algorithm with Constraint Relaxation in Differential Inverse Kinematics

2021 ◽  
Vol 1 (2) ◽  
pp. 21-32
Author(s):  
Bence Varga ◽  
Hazem Issa ◽  
Richárd Horváth ◽  
József Tar
Keyword(s):  
Kinematic Chain ◽  
Auxiliary Function ◽  
Inverse Kinematic ◽  
Quadratic Functions ◽  
Gradient Algorithm ◽  
Constraint Relaxation ◽  
Hard Constraints ◽  
Reduced Gradient ◽  
Constraint Structure ◽  
The Cost

The Moore-Penrose pseudoinverse-based solution of the differential inverse kinematic task of redundant robots corresponds to the result of a particular optimization underconstraints in which the implementation of Lagrange’s ReducedGradient Algorithm can be evaded simply by considering the zero partial derivatives of the ”Auxiliary Function” associated with this problem. This possibility arises because of the fact that the cost term is built up of quadratic functions of the variable of optimization while the constraint term is linear function of the same variables. Any modification in the cost and/or constraint structure makes it necessary the use of the numerical algorithm. Anyway, the penalty effect of the cost terms is always overridden by the hard constraints that makes practical problems in the vicinity of kinematic singularities where the possible solution stillexists but needs huge joint coordinate time-derivatives. While in the special case the pseudoinverse simply can be deformed, inthe more general one more sophisticated constraint relaxation can be applied. In this paper a formerly proposed acceleratedtreatment of the constraint terms is further developed by the introduction of a simple constraint relaxation. Furthermore, thenumerical results of the algorithm are smoothed by a third order tracking strategy to obtain dynamically implementable solution.The improved method’s operation is exemplified by computation results for a 7 degree of freedom open kinematic chain

An adaptive correction algorithm of non-linear distorted document

2017 ◽  
Vol 16 (4) ◽  
pp. 807-820
Author(s):  
Bo Li ◽  
Jiangqing Wang ◽  
Shengzhou Xu ◽  
Ning Xu ◽  
Fan Li ◽  
...  
Keyword(s):  
Correction Algorithm ◽  
Adaptive Correction ◽  
Non Linear

Ground Target Tracking Guidance Law for Fixed-Wing Unmanned Aerial Vehicle: A Search and Capture Approach

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Min Zhang ◽  
Pengfei Tian ◽  
Xin Chen ◽  
Xin Wang
Keyword(s):  
Guidance Law ◽  
Straight Line ◽  
Tracking Process ◽  
Ground Target ◽  
Virtual Target ◽  
Speed Range ◽  
Aerial Vehicle ◽  
On Line ◽  
Straight Lines ◽  
Virtual Trajectory

One important problem for unmanned aerial vehicles (UAVs) in mission applications is to track ground targets automatically. A major concern is how to keep the tracking process stable and efficient while the motion of the ground targets changes rapidly. In this brief, a new guidance strategy for the ground target “Search and Capture” based on a virtual target is proposed. First, a virtual trajectory, which is composed of straight lines and arcs, is generated based on the motion of the target. The straight lines are used to capture, while the arcs are used to search, and switch between straight line and arc when some condition is met; second, we design a new guidance law based on line-of-sight (LOS) which makes a UAV to track the virtual target automatically. This new method solves the following three problems simultaneously: (1) The UAV always keeps a constant speed to track the target with changing velocity, (2) the generated trajectory meets the flight constraints of the UAV, and (3) the speed range of the ground target can be from the stationary to almost the maximum cruising speed of the UAV. Simulation results show that the proposed guidance strategy can achieve stable tracking for various motions of the ground target.

Design Theory for Speed Control Based on Visual Rhythm for Long Stretches of Freeway

2012 ◽  
Vol 178-181 ◽  
pp. 2586-2590
Author(s):  
Zi Pei Zhang ◽  
Shun Ying Zhu ◽  
Hong Wang ◽  
Bing Liu
Keyword(s):  
Design Theory ◽  
Simulation Experiment ◽  
Speed Control ◽  
Visual Rhythm ◽  
Line Section ◽  
Straight Line ◽  
Demonstration Experiment ◽  
Moving Process ◽  
Made In ◽  
Stimulation Of

This paper analyzed the expressive form and the formation principle of driver’s visual rhythm in the process of driving. Combined with the design model for speed control in straight line section, it proposed the design theory for speed control for long stretches of freeway by using the feature of visual rhythm. Using the 3Ds MAX, the video simulating car moving process on the long stretches of freeway was made in which visual rhythm was a key manipulative parameter. The SSES (Stimulation of Subjectively Equal Speed) was the index of this simulation experiment. Seven males and three females took part in the experiments. The demonstration experiment indicated that the design theory based on visual rhythm can ensure participants regularly maintain a high SSES.

scholarly journals Visual Characteristics of Drivers at Different Sections of an Urban Underpass Tunnel Entrance: An Experimental Study

2021 ◽  
Vol 13 (9) ◽  
pp. 5224
Author(s):  
Fangtong Jiao ◽  
Zhigang Du ◽  
Haoran Zheng ◽  
Shoushuo Wang ◽  
Lei Han ◽  
...  
Keyword(s):  
Experimental Study ◽  
Traffic Accidents ◽  
Fixation Time ◽  
Time Threshold ◽  
Line Section ◽  
Straight Line ◽  
Visual Characteristics ◽  
The Difference ◽  
Real Vehicle ◽  
Tunnel Entrance

The increase in the number of traffic accidents due to the increasing number of urban underpass tunnels necessitate a better investigation of drivers’ visual characteristics when entering the tunnels. A total of 20 drivers were gathered to perform a real vehicle experiment in an urban underpass tunnel. The saccade angle, saccade frequency, and fixation time were selected as the research indexes. The urban underpass tunnel entrance was divided into five sections, namely the external straight line section, the upper half of the ramp, the lower half of the ramp, the shading shed section, and the entrance inner section. The results showed that the saccade angle and frequency of the ramp were significantly smaller than that of the external straight line and the tunnel interior, and the saccade range in front of the entrance was more concentrated. The changes in fixation time and the difference range of 15th-85th fixation time threshold in each section were analyzed. The fixation time of all sections was distributed within the range of 149.476 to 475.414 ms. The driver’s fixation was more and more concentrated when the sidewalls were higher and closer to the portal.

Sign in / Sign up

Export Citation Format

Share Document