Horizontal Maneuvers Research Articles

A free surface corrected lumped parameter model for near-surface horizontal maneuvers of underwater vehicles in waves

We provide theory and results obtained from the application of a 6-degree of freedom lumped parameter maneuvering model (LPMM) able to predict the maneuvering motions of underwater vehicles navigating at shallow depth below free surface waves. The parameters of the maneuvering model are identified using a combination of steady and unsteady captive maneuvers, simulated with high fidelity computational fluid dynamic (CFD) methods. This work focuses on correcting the LPMM, which is accurate for deep water motions, to account for free surface effects. A frequency domain strip theory method is used to account for changes in the added mass due to free surface proximity, to calculate memory forces, and to estimate wave excitation forces while a 3D time domain boundary element method is used to predict steady-state wave making forces. The result is a combined maneuvering and seakeeping model for underwater vehicles operating at shallow depths below the free surface. Near-surface horizontal zig-zag motion predictions in both calm water and under waves reveal the importance of including the free surface as vehicle trajectories at shallow depths differ substantially from those at deeper submergences for identical maneuvering inputs.

Numerical investigation on the effect of interceptor mechanism on maneuvering derivatives

ABSTRACT The effect of the interceptor mechanism on maneuvering motion is still unstudied while its positive effect on the total resistance and dynamic trim angle is well-known. Therefore, in the present study, the effect of the interceptor mechanism on the maneuvering derivatives is investigated numerically. Firstly, the calm water validation is performed for the bare hull and equipped with the interceptor. Then, the horizontal Planar Motion Mechanism simulations are conducted to calculate the maneuvering derivatives via computational fluid dynamics analyses. The results show that for the selected forward velocity the existence of the interceptor increases the amplitudes of the yaw moments and the sway forces. In addition to this, it has a remarkable effect on the sway force phases while the effect of yaw moment phases can be negligible. Since it changes phases and amplitudes, it causes a considerable increase in each linear horizontal maneuvering derivative for the selected case.

Numerical investigation of the scale effect on the horizontal maneuvering derivatives of an underwater vehicle

This paper presents the effects of different scales on non-dimensional horizontal hydrodynamic derivatives of a generic underwater vehicle, DARPA Suboff. Thus, three different scales are created for fully appended submarine form. A numerical viscous solver is utilized to model the Planar Motion Mechanism (PMM) technique, numerically. Before presenting the scale effect, the numerical model is verified and validated with an appropriate method and available experimental data. Firstly, the sway forces and yaw moments are obtained under different scenarios, then the linear horizontal maneuvering derivatives of each scale are calculated and compared with each other. It is found that the sway forces obtained from pure yaw analyses are remarkably affected by the scale, while sway forces obtained from pure sway analyses are not affected reasonably. Yaw moment values are affected remarkably in neither pure sway nor pure yaw analyses. The scale effect appears also in a similar way in the linear maneuvering coefficients.

Envelopes and waves: safe multivehicle collision avoidance for horizontal non-deterministic turns

We present an approach to analyzing the safety of asynchronous, independent, non-deterministic, turn-to-bearing horizontal maneuvers for two vehicles. Future turn rates, final bearings, and continuously varying ground speeds throughout the encounter are unknown but restricted to known ranges. We develop a library of formal proofs about turning kinematics, and apply the library to create a formally verified timing computation. Additionally, we create a technique that evaluates future collision possibilities that is based on waves of position possibilities and relies on the timing computation. The result either determines that the encounter will be collision-free, or computes a safe overapproximation for when and where collisions may occur.

Deformation Analysis of the Multiplanar Conformal Off-Axis Four-Mirror in an Aerospace Environment

The effect of maneuver overload on a new type of the multiplanar conformal off-axis four-mirror is studied under the noninertial environment of aerospace. Two kinds of maneuvering flight, horizontal maneuvering and vertical maneuvering, are taken as examples, and the force analysis of the aircraft in the noninertial environment is considered. And the force analysis of the aircraft and the multiplanar conformal off-axis four-mirror is connected by the overload coefficient. Finally, the finite element simulation analysis of the multiplanar conformal off-axis four-mirror is carried out. The results show that the influence of maneuver overload on the multiplanar conformal off-axis four-mirror cannot be ignored. Large overload will result in large deformation of the multiplanar conformal off-axis four-mirror. The deformation is closely related to the structure of the multiplanar conformal off-axis four-mirror. Under the action of lateral force, nonuniform deformation is more likely to occur on the surface of the multiplanar conformal off-axis four-mirror.

Quality evaluation model of unmanned aerial vehicle's horizontal flight maneuver based on flight data

Quality evaluation model of unmanned aerial vehicle's horizontal flight maneuver based on flight data

Horizontal Maneuver Coordination for Aircraft Collision-Avoidance Systems

The safe integration of unmanned aircraft into the airspace requires reliable systems to keep aircraft separated. Unmanned aircraft will likely use primarily horizontal maneuvers, in contrast with manned aircraft collision-avoidance systems, which use only vertical maneuvers. Horizontal maneuvers are much less straightforward to coordinate than vertical maneuvers. In some situations, it is better for both aircraft to maneuver in the same direction; in other situations, it is better to maneuver in opposite directions. In addition, unlike manned aircraft, unmanned aircraft will likely carry different collision-avoidance systems. This paper introduces the idea of using a universal coordination table to ensure complementary maneuvers between different kinds of collision-avoidance systems. The coordination table is generated using dynamic programming. Empirical results demonstrate the benefit of coordination tables in terms of safety and efficiency.

Remotely piloted aircraft system with optimum avoidance maneuvers

In order for remotely piloted aircraft systems (RPAS) to operate in unsegregated airspace, one of the most important risks to mitigate is that of the mid-air collision. The RPAS must be capable of detecting the potential for a mid-air collision and performing avoidance maneuvers at normal flight conditions and under contingency or emergency conditions. In particular, when the link is severed the RPAS will become “uncontrolled” by the remote pilot, but the loss of link does not imply the loss of the remotely piloted aircraft. A D&A system is required for safe operations of RPAS in airspace shared with other aircraft, including manned aircraft. The onboard system of an unmanned aircraft has to be equipped with an efficient detection and early risk analysis system, as well as a system assisting the pilot in making a decision or an autonomous control system able to perform a maneuver to avoid collision. Collision avoidance maneuvers should be planned by taking into account the operational specificities of the RPAS. The resolution advisory’s strength and direction could be adapted to the capabilities of the RPAS. For example, horizontal resolution advisories could be introduced for RPAS unable of reaching the vertical acceleration/speeds required for vertical resolution advisories. The selection of types of sensors, their sensitivity and range can be made by taking into account RPAS maneuverability. The traffic advisory and resolution advisory regions could be defined by the same circumstances, among others. The aim of this work is to determine an optimal trajectory of horizontal avoidance maneuver of a mini remotely piloted aircraft, minimizing the time of performing a maneuver when avoiding a manned aircraft flying at a much higher speed, guaranteeing a minimally required distance between the passing objects.

Horizontal-vertical guidance of Quadrotor for obstacle shape mapping

A real-time guidance algorithm for obstacle shape mapping is proposed. A stereo vision system and an ultrasonic sensor are assumed to be mounted on a quadrotor to obtain the shape information of an obstacle. The depth map acquired by the stereo vision system is utilized to detect and map the obstacle. Mapping the obstacle is performed by utilizing obstacle data points acquired from the depth map. States of the quadrotor are used to generate a path for obstacle mapping in real time. The quadrotor moves around the obstacle to map the overall shape of the obstacle while avoiding collisions. The quadrotor also performs vertical maneuvers if the image plane of the vision system cannot cover the entire obstacle. The horizontal and vertical maneuvers are performed in sequence to develop a systematic scheme to efficiently map the obstacle. Finally, numerical simulations are performed to demonstrate the performance of the proposed guidance algorithm.

Сравнение методов управления квазигоризонтальными маневрами гиперзвукового летательного аппарата

Сравнение методов управления квазигоризонтальными маневрами гиперзвукового летательного аппарата

An exact multi-objective mixed integer nonlinear optimization approach for aircraft conflict resolution

An exact mixed integer nonlinear optimization (MINO) model is presented for tackling the aircraft conflict detection and resolution problem in air traffic management. Given a set of flights and their configurations, the aim of the problem was to provide new configurations such that all conflict situations are avoided, with conflict situation understood to mean an event in which two or more aircraft violate the minimum safety distances that must be maintained in flight. The proposed model solves the problem using both horizontal (velocity and angle turn change) and vertical (altitude level change) maneuvers. As a special case, another model is presented in which only horizontal maneuvers are used. The models proposed are based on a geometric construction which involves trigonometric functions, so the constraint system is included via a large set of trigonometric and nonconvex inequalities. A multicriteria approach is presented to provide useful information to air traffic control officers about the maneuvers to be performed. The main results of an extensive computational experiment are reported in which the performance of the state-of-the-art nonconvex MINO solver Minotaur is studied.

Observability analysis of inertial navigation errors from optical flow subspace constraint

Fusion of inertial and vision sensors is an effective aid to inertial navigation systems (INS) during GPS outage. Optical flow-aided inertial navigation circumvents feature tracking, landmark mapping, and state vector augmentation typical of simultaneous localization and mapping (SLAM). This paper focuses on the observability analysis of INS errors from implicit measurements of the optical flow subspace constraint, and derives how observable and unobservable directions are affected by the motion of a camera rigidly coupled to an inertial measurement unit (IMU). Straight motion and piecewise constant (PWC) attitude segments yield the random constant IMU errors observable. The unobservable directions are the three-dimensional (3D) position error, the velocity error along the ground velocity, and the combination of angular misalignment about the local vertical and the velocity error along the horizontal direction orthogonal to the ground velocity. The velocity error along the ground velocity becomes observable with horizontal maneuvering. A Monte Carlo simulation validates the observability analysis, and reveals the feasibility of IMU calibration and the mitigation of navigation error growth with the aid of the optical flow subspace constraint compared with the unaided INS.

Submarine Maneuvers Using Direct Overset Simulation of Appendages and Propeller and Coupled CFD/Potential Flow Propeller Solver

This article presents two approaches to simulate maneuvers of a model radio-controlled submarine. In the direct simulation approach, rudders, stern planes, and propellers are gridded and treated as moving objects using dynamic overset technology. The second approach couples the overset computational fluid dynamics (CFD) solver and a potential flow propeller code, with both codes exchanging velocities at the propeller plane and wake, body forces, and propeller forces and moments, whereas rudders and stern planes are still explicitly resolved. It is shown that during the maneuvers, the range of advance coefficients does not deviate much from the design point, making a coupled approach a valid choice for standard maneuvering simulations. By allowing time steps about an order of magnitude larger than for the direct simulation approach, the coupled approach can run about five times faster. The drawback is a loss of resolution in the wake as the direct propeller simulation can resolve blade vortical structures. Open water propeller curves were simulated with both the direct propeller approach and the coupled approach, showing that the coupled approach can match the direct approach performance curves for a wide range of advance coefficients. Simulations of a horizontal overshoot maneuver at two approach speeds were performed, as well as vertical overshoot and controlled turn maneuvers at high speed. Results show that both CFD approaches can reproduce the experimental results for all parameters, with errors typically within 10%.

Overset simulation of a submarine and propeller in towed, self-propelled and maneuvering conditions

Simulations of the free running submarine model DARPA Suboff in a horizontal overshoot maneuver are presented. To perform the simulations, the fully appended hull was fitted with the conceptual submarine propeller E1619. The overset flow solver CFDShip-Iowa v4.5 was used to perform the computations, including coupling with the propeller code PUF-14. Propeller open water curves were obtained for two grids over a wide range of advance coefficients covering high to moderately low loads, with results compared to available experimental data. The open water curves were also simulated with the coupled CFDShip-Iowa/PUF-14 approach. While computations are performed with delayed detached-eddy simulation (DDES), simulations with Reynolds-averaged Navier–Stokes (RANS), detached-eddy simulation (DES) and with no turbulence model were also performed. Results show that RANS overly dissipates the wake while the solution with no turbulence model shows unphysical instability in the tip vortices. Overall, open water curves are predicted well by the discretized propeller and by the coupled CFDShip-Iowa/PUF-14 approach. The towed DARPA Suboff hull fitted with sail, rudders and stern planes was simulated and results were compared against experimental data, showing satisfactory results. Self-propulsion computations of the DARPA Suboff fitted with the E1619 propeller were performed and the resulting propeller performance analyzed, both using a rotating gridded propeller and the CFDShip-Iowa/PUF-14 approach. A 20/10 overshoot maneuver is demonstrated with both approaches, showing that the results are similar when the propeller remains close to straight-ahead conditions, but trends between approaches tend to diverge for large wake distortions and low advance ratios. A more complex simulation of a surfacing maneuver of the submarine in waves is demonstrated showing the potential of the approach to tackle simulations including massive free surface deformations in a realistic environment.

A theoretical approach to observability analysis of the SDINS/GPS in maneuvering with horizontal constant velocity

A theoretical method for analyzing the observability of a strapdown inertial navigation system (SDINS) integrated with the global positioning system (GPS) is proposed. The analysis is performed based on two types of maneuvers for a vehicle on a horizontal trajectory: level flight with constant north velocity and level flight with constant east velocity. The observability also is analyzed using the convergence theorem, stationary state observability analysis results, and Kalman filter measurement information to rearrange the SDINS error model equation. The state variables are divided into observable and unobservable parts, and determine which state variables are observable and estimable with some errors from the relationship of observable and unobservable state variables. Our results have shown that the north and east axes accelerometer bias errors were unobservable, and that attitude errors, and east and down axes gyro bias errors were estimable with some unknown bias errors. It has been shown that horizontal maneuvering improves the observability of down axis gyro bias error compared with the stationary state, and the estimation errors of the heading error state and east axis gyro bias error are dependent on the magnitude of north velocity. The results of the theoretical observability analysis are confirmed through computer simulation.

Evaluation of Tactical Conflict Resolution Algorithms for Enroute Airspace

Algorithms for resolving air traffic conflicts are tested on archived tracking data from 102 actual operational errors (violations of minimum required separation due to controller error). The algorithms compute horizontal or vertical resolution maneuvers for tactical conflicts in which the minimum required separation is predicted to be lost within approximately two minutes. The horizontal maneuvers are issued as heading vectors, and the vertical maneuvers are issued as standard altitude clearances. Algorithms for the vertical resolutions were presented in an earlier paper, and algorithms for the horizontal resolutions are described in this paper. Simulation results show that these resolution algorithms could have prevented most of the archived operational errors. In some cases, the controller failed to enter an altitude amendment consistent with the voice clearance, and in eight such cases the conflict was not detected early enough to be resolved in the simulation. The correct altitude amendments were added to the recorded data for those cases (to simulate the correct entry by the controller), and successful resolution was then achieved for all cases.

On the Use of $Q^{2}$ Abstractions to Lower the Computational Cost of Derivation of Conflict Resolution Advisories in Air Traffic Control

This paper addresses the high computational complexity of generating multistep conflict resolution advisories (RAs) in air traffic control. Because this problem is known to be NP-hard, one cannot expect algorithms that will solve every instance of the problem independent of its size. Thus, the goal is to develop more efficient algorithms that can analyze a wider space of possible RAs, for instance, horizontal maneuvers. This paper presents a study of the use of abstraction to such a problem. However, abstractions can lead to wrong decisions, e.g., to maneuvers that result in unsafe states. Such abstractions are referred to as inconsistent. To avoid these kinds of problems, we use the so-called Q <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> abstractions, which are derived from the specifications of a problem and are guaranteed to be consistent. To assess the usability of the Q <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> approach to computing horizontal RAs, we analyze the impact of such abstractions on the computational cost of an exhaustive search algorithm and on the quality of RAs found. The results show that the use of the Q <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> approach lowers the conflict-resolution computation time without losing much of the quality of solutions.

RIB형 표적정의 수평면 조종운동 간략모델

A Rigid Inflatable Boat (RIB) is now widely used for commercial and military purpose. In this paper, it is supposed that seven-meter-class RIB be used as an unmanned target ship for naval training. In order to develop many tactical maneuvering patterns of a target ship, a simple horizontal maneuvering model of a RIB is needed. Therefore, models of speed and yaw rate are constructed as the first-order differential equations based on Lewandowski#s empirical formula for steady turning circle diameter of a conventional planning hull. Some parameters in the models are determined using the results of sea trial tests. Finally, proposed models are validated through the comparison of the simulation result with the sea trial result for a specific scenario. Even though a simple model does not represent the horizontal motion of a RIB precisely, however, it can be used enough to develop tactical trajectory patterns.

Aircraft collision avoidance with potential gradient—ground‐based avoidance for horizontal maneuvers

AbstractThis paper describes ground‐based avoidance for horizontal maneuvers using a concept of potential as a collision avoidance aircraft procedure. First, mathematical formulation is introduced by using potential as a way to systematically represent the conditions contributing to collision avoidance such as a threat of collision with other aircraft and degrees of deviation from the original course.The flight course with a lower potential is considered safer. In the choice of a specific avoidance course, an avoidance pattern generation method by means of potential gradient is shown. the future location of the aircraft is sampled at a certain time interval. the shift of the sampling point corresponding to the potential gradient at each sampling point or the force applied to each sampling point (attractive or repulsive) is repeated.It was confirmed that by means of this method, avoidance patterns without danger of collision can be obtained with only horizontal avoidance except for special cases. However, when the sampling points are symmetric or when more than three aircraft are involved, the procedure is not adequate and some provisions are needed. to this end, the sampling point arrangement in the initial stage before the avoidance pattern is formed and the three‐dimensional avoidance including vertical avoidance can be considered.