Real-Time Landing Point Redesignation (LPR) Algorithm

2008 ◽  
Author(s):  
Babak Cohanim ◽  
Brian Collins
Keyword(s):  
Real Time ◽  
Landing Point

Real-Time Trajectory Generation and Reachability Determination in Autorotative Flare

2020 ◽  
Vol 65 (3) ◽  
pp. 1-17
Author(s):  
Brian F. Eberle ◽  
Jonathan D. Rogers
Keyword(s):  
Real Time ◽  
Trajectory Generation ◽  
Contact Theory ◽  
Simulation Environment ◽  
Order Model ◽  
Landing Point ◽  
Overall Performance ◽  
Simulation Results ◽  
Six Degree Of Freedom ◽  
Trajectory Generator

Autorotation maneuvers inherently offer little margin for error in execution and induce high pilot workload, particularly as the aircraft nears the ground in an autorotative flare. Control augmentation systems may potentially reduce pilot workload while simultaneously improving the likelihood of a successful landing by offering the pilot appropriate cues. This paper presents an initial investigation of a real-time trajectory generation scheme for autorotative flare based on time-to-contact theory. The algorithm exhibits deterministic runtime performance and provides a speed trajectory that can be tracked by a pilot or inner-loop controller to bring the vehicle to a desired landing point at the time of touchdown. A low-order model of the helicopter dynamics in autorotation is used to evaluate dynamic feasibility of the generated trajectories. By generating and evaluating trajectories to an array of candidate landing points, the set of reachable landing points in front of the aircraft is determined. Simulation results are presented in which the trajectory generator is coupled with a previously derived autorotation controller. Example cases and trade studies are conducted in a six degree-of-freedom simulation environment to demonstrate overall performance as well as robustness of the algorithm to variations in target landing point, helicopter gross weight, and winds. The robustness of the reachability determination portion of the algorithm is likewise evaluated through trade studies examining off-nominal flare entry conditions and the effects of winds.

Ground-Based Videometric Method and System for the Real-Time Measurement of Aircraft Landing Track

2014 ◽  
Vol 635-637 ◽  
pp. 824-831 ◽  
Author(s):  
Xiang Zhou ◽  
Zhi Hui Lei ◽  
Dan Fu ◽  
Xiao Hu Zhang
Keyword(s):  
Real Time ◽  
Global Positioning System ◽  
Large Scale ◽  
Time Measurement ◽  
Landing Point ◽  
The Real ◽  
Aircraft Landing ◽  
Real Time Measurement ◽  
Global Positioning ◽  
New Type

This paper proposes a ground-based videometric method and system for measuring the glide track of landing aircraft in real time. The proposed method is applicable for large-scale measurement via regional relays with multiple cameras. Its measurement ranges from kilometers away to the landing point, and it simultaneously fulfills the real-time measurement of the position and trajectory of aircraft. The real-time measurement result of the actual aircraft landing process shows a deviation from DGPS(Difference Global Positioning System) as small as 20 cm in the measuring region of 1 km. The proposed measurement method for aircraft landing track based on videometrics can establish a new type of landing aid system removed from radar and GPS.

Landing Point Predicting Method in Target Re-Entry Measurement

2014 ◽  
Vol 596 ◽  
pp. 463-467
Author(s):  
Xiao Yong Li ◽  
Wei Kang Zhu ◽  
Jin Biao Zhou ◽  
Gui Ming Chen ◽  
Lei Yang ◽  
...  
Keyword(s):  
Real Time ◽  
Engineering Application ◽  
Integration Step ◽  
Atmospheric Models ◽  
Step Size ◽  
Processing Methods ◽  
Landing Point ◽  
Broad Applicability ◽  
Forward Engineering

By introducing some atmospheric models and selecting methods for minimum integration step size and optimum initial integration value, a program of real time and near real time landing point predicting together with weighted processing methods of many groups of landing point parameters were put forward. Engineering application showed: the above methods and program improved real time and near real time landing point predicting precision more greatly compared with previously used methods, which had proved their broad applicability.

scholarly journals Biped Walking Based on Stiffness Optimization and Hierarchical Quadratic Programming

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1696
Author(s):  
Xuanyang Shi ◽  
Junyao Gao ◽  
Yizhou Lu ◽  
Dingkui Tian ◽  
Yi Liu
Keyword(s):  
Quadratic Programming ◽  
Real Time ◽  
Inverse Dynamics ◽  
Reaction Force ◽  
Feedback Controller ◽  
Whole Body ◽  
Real Time Control ◽  
Velocity Feedback ◽  
Landing Point ◽  
Multiple Variables

The spring-loaded inverted pendulum model is similar to human walking in terms of the center of mass (CoM) trajectory and the ground reaction force. It is thus widely used in humanoid robot motion planning. A method that uses a velocity feedback controller to adjust the landing point of a robot leg is inaccurate in the presence of disturbances and a nonlinear optimization method with multiple variables is complicated and thus unsuitable for real-time control. In this paper, to achieve real-time optimization, a CoM-velocity feedback controller is used to calculate the virtual landing point. We construct a touchdown return map based on a virtual landing point and use nonlinear least squares to optimize spring stiffness. For robot whole-body control, hierarchical quadratic programming optimization is used to achieve strict task priority. The dynamic equation is given the highest priority and inverse dynamics are directly used to solve it, reducing the number of optimizations. Simulation and experimental results show that a force-controlled biped robot with the proposed method can stably walk on unknown uneven ground with a maximum obstacle height of 5 cm. The robot can recover from a 5 Nm disturbance during walking without falling.

Anti-Collision Study for the Wells from New Artificial Islands Across Gigantic Mature Oil Field in Middle East Area

2021 ◽  
Author(s):  
Ryota Fujinaga ◽  
Mohamed Abdulrahman Alzaabi ◽  
Takahiro Toki ◽  
Motohiro Toma ◽  
Kerron Kerman Andrews
Keyword(s):  
Middle East ◽  
Real Time ◽  
Oil Field ◽  
Slot Allocation ◽  
Landing Point ◽  
The Past ◽  
Company Policy ◽  
Geological Models ◽  
Jack Up

Abstract 107 new wells are planned to be drilled primarily from two new Artificial Islands during the period of one project from 2023 to 2029. The number of existing wells in the oil field has reached 1,068 Mother bores, 2,178 wellbores @16,453,666ft total well length as of December 2019. Trajectories, especially from existing Artificial Islands, are getting more complex so as to avoid collision issues, and it is becoming increasingly difficult to drill accordingly. It is of great importance to assure that it is possible to drill the planned wells without serious collision issues before the execution of the project. Trajectories for planned wells were drafted one-by-one utilizing "DecisionSpace Well Planning" based on the predetermined slot allocation with the planned drilling pad design. Geological models are incorporated into DecisionSpace Well Planning. Therefore, formation tops were taken into account in order to make the trajectories more realistic. After that, trajectories were exported to "COMPASS" and anti-collision scan was performed on well-by-well basis. Anti-collision scan was performed among planned wells as well as actual wells. In case that one well has such serious collision issues that the well cannot/should not be planned based on company policy as a result of Anti-collision scan, trajectory or Landing Point (LP)/Total Depth (TD) location were adjusted. Then, Anti-collision scan was carried out again. If it was confirmed that there is no serious Anti-collision issues, trajectory was considered as final. It has been found that all the wells during the period from 2023 to 2029 can be drilled without serious collision issues by slightly adjusting LP/TD while satisfying several practical drilling requirements. Through the Anti-collision study, following recommendations for the avoidance of collision were obtained:Multi Station Analysis (MSA)+In-Field Referencing (IFR)+SAG correction should be applied in all the Jack up operations as well as Island operationsApplication of real-time MSA should be considered on a case-by-case basisMWD survey for the past wells should be corrected with IFR+MSA to reduce EOU sizeRe-Gyro jobs for low-quality survey wells should be enhanced around the project's development areaKick off point (KOP) should be deeper in the center of the drilling pad and shallower in the edge of the drilling pad

Some Recent Results in Quiescent Prominence Spectrometry

1979 ◽  
Vol 44 ◽  
pp. 41-47
Author(s):  
Donald A. Landman
Keyword(s):  
Real Time ◽  
Computer System ◽  
Spectral Response ◽  
Absolute Intensity ◽  
Solar Observatory ◽  
Target Size ◽  
Small Target ◽  
Signal Averaging ◽  
Quiescent Prominence

This paper describes some recent results of our quiescent prominence spectrometry program at the Mees Solar Observatory on Haleakala. The observations were made with the 25 cm coronagraph/coudé spectrograph system using a silicon vidicon detector. This detector consists of 500 contiguous channels covering approximately 6 or 80 Å, depending on the grating used. The instrument is interfaced to the Observatory’s PDP 11/45 computer system, and has the important advantages of wide spectral response, linearity and signal-averaging with real-time display. Its principal drawback is the relatively small target size. For the present work, the aperture was about 3″ × 5″. Absolute intensity calibrations were made by measuring quiet regions near sun center.

Video real-time imaging of artificial membranes during freeze-drying by cryo-electron microscopy

1988 ◽  
Vol 46 ◽  
pp. 16-17
Author(s):  
Alan S. Rudolph ◽  
Ronald R. Price
Keyword(s):  
Real Time ◽  
Self Assembly ◽  
Freeze Drying ◽  
Video Capture ◽  
Drying Process ◽  
Artificial Membranes ◽  
The Past ◽  
Cryo Electron Microscopy ◽  
Spherical Structures ◽  
Capture Techniques

We have employed cryoelectron microscopy to visualize events that occur during the freeze-drying of artificial membranes by employing real time video capture techniques. Artificial membranes or liposomes which are spherical structures within internal aqueous space are stabilized by water which provides the driving force for spontaneous self-assembly of these structures. Previous assays of damage to these structures which are induced by freeze drying reveal that the two principal deleterious events that occur are 1) fusion of liposomes and 2) leakage of contents trapped within the liposome [1]. In the past the only way to access these events was to examine the liposomes following the dehydration event. This technique allows the event to be monitored in real time as the liposomes destabilize and as water is sublimed at cryo temperatures in the vacuum of the microscope. The method by which liposomes are compromised by freeze-drying are largely unknown. This technique has shown that cryo-protectants such as glycerol and carbohydrates are able to maintain liposomal structure throughout the drying process.

An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

1976 ◽  
Vol 34 ◽  
pp. 542-543
Author(s):  
R.P. Goehner ◽  
W.T. Hatfield ◽  
Prakash Rao
Keyword(s):  
Electron Diffraction ◽  
Real Time ◽  
Pattern Analysis ◽  
Flow Diagram ◽  
Hard Copy ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Transmission Electron ◽  
One Step ◽  
Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

Microstructural investigation of surface roughness in MBE-grown AlAs

1995 ◽  
Vol 53 ◽  
pp. 454-455
Author(s):  
R. Rajesh ◽  
R. Droopad ◽  
C. H. Kuo ◽  
R. W. Carpenter ◽  
G. N. Maracas
Keyword(s):  
Thin Film ◽  
Real Time ◽  
Growth Control ◽  
Native Oxide ◽  
Effusion Cell ◽  
Surface Oxide Layer ◽  
Microstructural Investigation ◽  
Mbe Growth ◽  
Film Substrate ◽  
And Control

Knowledge of material pseudodielectric functions at MBE growth temperatures is essential for achieving in-situ, real time growth control. This allows us to accurately monitor and control thicknesses of the layers during growth. Undesired effusion cell temperature fluctuations during growth can thus be compensated for in real-time by spectroscopic ellipsometry. The accuracy in determining pseudodielectric functions is increased if one does not require applying a structure model to correct for the presence of an unknown surface layer such as a native oxide. Performing these measurements in an MBE reactor on as-grown material gives us this advantage. Thus, a simple three phase model (vacuum/thin film/substrate) can be used to obtain thin film data without uncertainties arising from a surface oxide layer of unknown composition and temperature dependence.In this study, we obtain the pseudodielectric functions of MBE-grown AlAs from growth temperature (650°C) to room temperature (30°C). The profile of the wavelength-dependent function from the ellipsometry data indicated a rough surface after growth of 0.5 μm of AlAs at a substrate temperature of 600°C, which is typical for MBE-growth of GaAs.

Real-time observation of vortex lattices in a superconductor

1993 ◽  
Vol 51 ◽  
pp. 1050-1051
Author(s):  
K. Harada ◽  
T. Matsuda ◽  
J.E. Bonevich ◽  
M. Igarashi ◽  
S. Kondo ◽  
...  
Keyword(s):  
Real Time ◽  
Flux Line ◽  
Electron Holography ◽  
Lorentz Microscopy ◽  
Vortex Lattices ◽  
Flux Lines ◽  
Magnetic Flux Lines ◽  
Time Observation ◽  
Thin Superconductor ◽  
Real Time Observation

Previous observations of magnetic flux-lines (vortex lattices) in superconductors, such as the field distribution of a flux-line, and flux-line dynamics activated by heat and current, have employed the high spatial resolution and magnetic sensitivity of electron holography. And recently, the 2-D static distribution of vortices was also observed by this technique. However, real-time observations of the vortex lattice, in spite of scientific and technological interest, have not been possible due to experimental difficulties. Here, we report the real-time observation of vortex lattices in a thin superconductor, by means of Lorentz microscopy using a 300 kV field emission electron microscope. This technique allows us to observe the dynamic motion of individual vortices and record the events on a VTR system.The experimental arrangement is shown in Fig. 1. A Nb thin film for transmission observation was prepared by chemical etching. The grain size of the film was increased by annealing, and single crystals were observed with a thickness of 50∼90 nm.

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