Real-time Maneuver Research Articles

A maneuvering strategy based on motion camouflage in three-player differential game

In this paper, we consider a three-player differential game in which the defender provides coverage for the evader by maneuvering toward the line of sight between the pursuer and the evader. The TAD game is divided into two pursuit-evasion games to obtain the saddle point strategy for each player. Different from the general solution, the defender uses motion camouflage conditions as its payoff function and gives the real-time maneuvering strategy. This approach ensures that the constraint in the gaming process is met by providing the saddle point solution for each time interval. Additionally, interception strategies are created for each player to get the required heading angle. These strategies and game dynamics can be predicted by examining the current state of the game. Consequently, we establish the advantage region for the pursuer and the defender based on these predictions. Based on the given initial conditions, the advantage region for the defender is presented in its initial velocity vector. Finally, the simulations validate the effectiveness of the proposed strategy and the capture region analysis.

Research on ship navigation strategy in dynamic sea ice environments based on flexibility velocity obstacles algorithm

Sea ice constitutes one of the primary risks in Arctic navigation. Currently, how to maneuver a ship within a sea ice environment relies predominantly on the experience of the pilot. In this paper, based on satellite image data and an improved sea ice target matching approach, a dynamic ship navigation environment within the sea ice zone is established. Subsequently, we developed a sea ice collision risk index (ICRI), which takes into account the relative motion relationship between the sea ice and the ship as well as the sea ice area parameter. Finally, a flexible velocity obstacle (FVO) algorithm is proposed by the Arctic ice navigation proposal, enabling the optimization of ship routes and preventing ships from passing through the central region of large floating ice. The results show that the method proposed in this paper successfully constructs the navigation environment model in the drifting ice region, and can provide real-time maneuvering guidance for ships, effectively reduce the risk of sea ice collision, and optimize the navigation path planning in the ice region. It can improve the safety and pre-planning efficiency of ship navigation in the ice region.

A real-time collision-free maneuver generation algorithm for autonomous driving

In this paper we propose a real-time maneuver generation algorithm for Autonomous Vehicles (AVs). Given a planar road geometry with static and moving obstacles along it, we are interested in finding collision-free maneuvers that satisfied the AV’s dynamics and subject to physical and comfort limits. Based on longitudinal and transverse coordinates, we propose a novel collision avoidance constraint and formulate a suitable maneuver regulation optimal control problem. Maneuver regulation has intrinsic robustness with respect to standard trajectory tracking that stems from the requirement of following a desired path with a desired velocity profile assigned on it. The optimization problem is solved by using a nonlinear optimal control technique that generates (local) optimal trajectories. We demonstrate the efficacy of the proposed algorithm by providing numerical computations on two different scenarios. Finally, experimental results are presented to demonstrate the efficiency of the proposed algorithm both in terms of computational effort and dynamic features captured.

An Intelligent Algorithm for USVs Collision Avoidance Based on Deep Reinforcement Learning Approach with Navigation Characteristics

Many achievements toward unmanned surface vehicles have been made using artificial intelligence theory to assist the decisions of the navigator. In particular, there has been rapid development in autonomous collision avoidance techniques that employ the intelligent algorithm of deep reinforcement learning. A novel USV collision avoidance algorithm based on deep reinforcement learning theory for real-time maneuvering is proposed. Many improvements toward the autonomous learning framework are carried out to improve the performance of USV collision avoidance, including prioritized experience replay, noisy network, double learning, and dueling architecture, which can significantly enhance the training effect. Additionally, considering the characteristics of the USV collision avoidance problem, two effective methods to enhance training efficiency are proposed. For better training, considering the international regulations for preventing collisions at sea and USV maneuverability, a complete and reliable USV collision avoidance training system is established, demonstrating an efficient learning process in complex encounter situations. A reward signal system in line with the USV characteristics is designed. Based on the Unity maritime virtual simulation platform, an abundant simulation environment for training and testing is designed. Through detailed analysis, verification, and comparison, the improved algorithm outperforms the pre-improved algorithm in terms of stability, average reward, rules learning, and collision avoidance effect, reducing 26.60% more accumulated course deviation and saving 1.13% more time.

Space Noncooperative Target Trajectory Tracking Based on Maneuvering Parameter Estimation

The space noncooperative target maneuvering trajectory tracking is essential for the safety of the on-orbit spacecraft. For the noncooperative target, the maneuvering model is complex and changeable. Besides, the maneuvering dynamics model, the operation time, and the maneuvering frequency are previously unknown. It is difficult to achieve high-precision maneuvering trajectory tracking. In this paper, a novel real-time maneuvering trajectory tracking algorithm is developed, in which the maneuvering trajectory of the noncooperative target is discretized first, and then the differential algebra method is utilized to estimate the maneuvering parameter of the noncooperative target in the discretized time. Since the discretized period is very short, the maneuvering parameters of the target in the next discretized time are assumed to be the same as those in the previous discretized time, and the estimated maneuvering parameters are utilized to predict the target’s relative state in the next discretized time to achieve maneuvering trajectory tracking. Compared with the interactive multimodel method (IMM), the proposed method can estimate the maneuvering parameter of the noncooperative target in real time, which greatly reduces the tracking error caused by the mismatching of the target’s maneuvering model. In order to verify the effectiveness of the algorithm, a simulation of a noncooperative target’s maneuvering trajectory tracking is provided. The results demonstrated that the proposed method could track the noncooperative target maneuvering in real time, and the estimation accuracy was improved by about 93.07% compared with the IMM.

BDS near real-time maneuver detection based on triple-differenced phase observations

The BeiDou Navigation Satellite System (BDS) geostationary earth orbit (GEO) and inclined geosynchronous orbit (IGSO) satellites need frequent orbital maneuvers to keep them in position due to various perturbations. However, common users cannot obtain the exact maneuver times, which may yield a decline in the real-time service performance of the BDS. To solve this problem, we presented a near real-time maneuver detection method for BDS based on triple-differenced phase observations, which can automatically detect the exact start and end times of satellite orbital maneuvers. In this method, the carrier-phase triple-differences residuals are firstly computed using the precise station coordinates, broadcast ephemeris and dual-frequency observations of ground tracking stations. Afterward, the residuals are be modeled using linear regression to identify maneuver times. The observations from the BDS Experimental Tracking Stations (BETS) and the reference time announced by the Beijing Satellite Navigation Center (BSNC) from Day of year (DOY) 100 to DOY 300, 2017 are used to evaluate the performance of the proposed method. The detected maneuver periods are consistent with the announced ones, except the detected start times lag 42 min and end times advance 23 min on average. Then, the detected times are further validated by dynamic precise orbit determination (POD) after the maneuver. The phase residuals and 3D RMS of the orbit differences of maneuvered satellites proved that the accuracy of detected maneuver times is better than 5-minute. At last, the kinematic precise point positioning (PPP) validation is implemented to evaluate the effect of more accurate GEO and IGSO satellites to BDS positioning. Results show that both the convergence and accuracy of BDS PPP are improved by adding one satellite that has ended maneuvering.

Real-Time Flight Simulation of Hydrobatic AUVs Over the Full 0$^{\circ}$–360$^{\circ}$ Envelope

Hydrobatic AUVsare very agile, and can perform challenging maneuvers that encompass the full 0 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ}$</tex-math></inline-formula> –360 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ}$</tex-math></inline-formula> flight envelope. Such AUVs can be beneficial in novel use cases in ocean production, environmental sensing, and security, by enabling new capabilities for docking, inspection, or under-ice operations. To further explore their capabilities in such scenarios, it is crucial to be able to model their flight dynamics over the full envelope, which includes strong nonlinear effects and turbulence at high angles of attack. With accurate and efficient simulation models, new hydrobatic maneuvers can be generated and control strategies can be developed. Therefore, this article contributes with a strategy to perform efficient and accurate simulations of hydrobatic maneuvers in real time. A multifidelity hydrodynamic database is synthesized by combining analytical, semiempirical, and numerical methods, thereby capturing fluid forces and moments over the full envelope. A component buildup workflow is used to assemble a nonlinear flight dynamics model using lookup tables generated from the database. This simulation model is used to perform real-time simulations of advanced hydrobatic maneuvers. Simulation results show agreement with literature and experiment, and the simulator shows utility as a development tool in designing new maneuvers and control strategies.

Ranging-Measurements-Based Maneuver Detection Method for Space Target Tracking

Maneuver detection is crucial to improve the performance of space target tracking. A real-time maneuver detection method based on ranging measurements is proposed in this paper. The prediction residual of ranging measurement is selected as the test statistics. Then the maneuver and the outliers can be distinguished by setting multiple hypothesis tests. The traditional strong tracking filters can be improved by applied this detection method. The superiority of the proposed method is verified by a simulation case. Simulation results demonstrate that the new method can provide higher tracking accuracy than the traditional methods when the maneuver and the outliers both exist, and the maneuver and the outliers can be detected exactly.

Modules and Techniques for Motion Planning: An Industrial Perspective.

Research on autonomous cars has become one of the main research paths in the automotive industry, with many critical issues that remain to be explored while considering the overall methodology and its practical applicability. In this paper, we present an industrial experience in which we build a complete autonomous driving system, from the sensor units to the car control equipment, and we describe its adoption and testing phase on the field. We report how we organize data fusion and map manipulation to represent the required reality. We focus on the communication and synchronization issues between the data-fusion device and the path-planner, between the CPU and the GPU units, and among different CUDA kernels implementing the core local planner module. In these frameworks, we propose simple representation strategies and approximation techniques which guarantee almost no penalty in terms of accuracy and large savings in terms of memory occupation and memory transfer times. We show how we adopt a recent implementation on parallel many-core devices, such as CUDA-based GPGPU, to reduce the computational burden of rapidly exploring random trees to explore the state space along with a given reference path. We report on our use of the controller and the vehicle simulator. We run experiments on several real scenarios, and we report the paths generated with the different settings, with their relative errors and computation times. We prove that our approach can generate reasonable paths on a multitude of standard maneuvers in real time.

Integrating Protection Constraints to a MEAN-Based Method for Service Restoration in Radial Distribution Systems

The distribution system service restoration (SR) process implies to change the network topology configuration via a real-time maneuver plan, which in turn results in increased load current and changed short-circuit levels in some adjacent feeders. As a consequence, some protective devices (PD) can operate undesirably. In addition, some network branches may itself become totally unprotected. Therefore, it is essential to consider phase and neutral overcurrent protection in the SR problem, in order to maintain service continuity during emergency situations. A very efficiently approach, named MEAN (Multi-Objective Evolutionary Algorithm with NDE), for solving the SR problem is based on Multi-objective Evolutionary Algorithm (MOEA) that combines subpopulation tables with the Node-Depth Encoding (NDE) technique. This paper proposes to incorporate the phase and neutral overcurrent protection constraints into the MEAN approach for service restoration in radial distribution systems. The approach proposed in this paper, named MEAN-PC (MEAN with Protection Constraints), uses additional subpopulation tables to store the solutions that consider protection constraints. The objective is to show that the overcurrent protection constraints on service restoration problems can be considered in an effective way, correctly indicating feasible solutions of maneuver plan. The proposed overcurrent protection constraints in service restoration are tested and verified on the 135-bus test distribution system.

Design and construction of a prototype bongo to carry out rescue maneuvers as an instruction aid in the Diving and Salvage School of the Colombian Navy

The diving and salvage school of the Colombian Navy offers training in rescue maneuvers, with the purpose that students acquire the skills and abilities required for effective surveillance, protection and attention of people and materials at sea that may involve dangerous situations or threaten human life. Therefore, the teaching and learning skills of student divers have to be improved.&#x0D; The purpose of the project is to design and build a bongo that will allow the students to effectively observe the applicability of the fundamentals of physics such as: Archimedes’ principle, Boyle’s law and Pascal’s principle, as a theoretical and practical tool that serves as effective training on rescue maneuvers in real time for students and under controlled conditions at the facilities of the Diving School of the Navy in the city of Cartagena. For its execution, exploratory research was carried out and a deductive method was applied, which began with the planning study and shipbuilding method used by COTECMAR, followed by the analysis and use of materials as a result of the experience of the Naval Base BN1 “ARC BOLIVAR” in this type of constructions. Construction manuals for rescue equipment of the United States Navy were also used as references. The existing BONGO ARC “CASA”, was used as reference and its information served as an input for naval architecture calculations and finally allowed the construction of the Bongo with the technical specifications required for training in this area of knowledge. The device was put into service for the Diving and Salvage School as a learning tool, maintaining proportional and aesthetic characteristics that provide ease, comfort, safety and efficiency during the instruction and decision-making process at a low cost and minimizing the risk of accidents

Development of Real-Time Maneuver Library Generation Technique for Implementing Tactical Maneuvers of Fixed-Wing Aircraft

This study develops the real-time maneuver library generation technique for performing aggressive maneuvers of fixed-wing aircraft. Firstly, the general maneuver libraries are defined, and then 7th-order polynomials are used to create the maneuver libraries. The attitude command attitude hold (ACAH) system, the rate command rate hold (RCRH) system, and the speed command speed hold (SCSH) system using the proportional-integral-derivative (PID) control technique are designed to minimize the complexity of the flight control system (FCS) and to reduce the weight and volume of the payload. Moreover, the FCS is used for implementing tactical maneuvers. Finally, flight simulations are implemented for the longitudinal loop and Immelmann-turn maneuvers to check the usefulness of the proposed maneuver library generation technique. This study can affect the development of flight techniques for aircraft tactical maneuvers and the modification of air force operational manuals.

Quaternion based linear time-varying model predictive attitude control for satellites with two reaction wheels

Attitude control of a satellite having only two reaction wheels is a challenging issue. To address this problem, previously published researches considered some simplifying assumptions on the satellites such as diagonality of the moment of the inertia matrix. On the other hand, in some works, the total angular momentum of the satellite is assumed to be zero. In this paper, a linear time-variant model predictive control (LTV MPC) is designed to control a satellite with two reaction wheels. This control method can be applied to a satellite with a non-diagonal inertial matrix in the presence of external torques, to rotate the satellite toward the desired directions in the space and orbit. The simulations results show that this method has a small amount of computational cost and enables an under-actuated satellite to perform large real-time maneuvers with acceptable accuracy.

Model Predictive Trajectory Planning for Automated Driving

In order to enable automated driving systems on the road, several key challenges need to be solved. One of these issues is real-time maneuver decision and trajectory planning. This paper introduces a general framework for maneuver and trajectory planning with model predictive methods. It discusses several representations of this framework in distinct complexity levels. In general, sophisticated models require to nonquadratic objective functions with nonlinear constraints, leading to increased computational complexities during calculation. Yet, oversimplified models can neither cope with vehicle dynamics in critical maneuvers nor do they represent complex traffic scenes with several maneuver options appropriately. A scheme to partition the trajectory space into homotopy regions is proposed. In each homotopy class, linearization about a trajectory from this class is applied. Demonstrations by simulation and with experimental vehicles show the capability of the proposed method in selecting optimal maneuvers and trajectories. This is even valid during extreme maneuvers, such as in last moment collision avoidance.

Real-Time Simulation of a Rescue Ship Maneuvering in Short-Crested Irregular Waves

Research on the mathematical model and the real-time simulation of the ship motion is investigated. An equation of three degrees of freedom (DOF) nonlinear maneuvering motion is established by means of the unified model in short-crested irregular waves in deep water. The resistance and propulsion dynamics are modeled by the classical methods as well as forces and moments of the rudder and the viscous crossflow. The three-dimensional boundary element method (BEM) using Green function source is adopted to solve the boundary value problem (BVP) in the frequency domain. The added mass and potential damping coefficients are calculated by Cummins method, and the mean wave drift forces by far-field formulas along with numerical verifications. After that, the turning motions of two ships (a rescue ship NHJ111 and the Mariner) in calm water are performed, and the relative error is approximately 7% by comparing calculated results with the experimental data. The maneuvering motion of the Mariner in short-crested irregular waves is then carried out. The turning trajectory, surge speed, and drift forces agree well with the theoretical results in regular waves. Finally, the synchronous interpolation method with two-thread double-timer is conceived. The real-time maneuvering simulation of NHJ111 using the validated model is then realized. The developed method can lay the foundation for fast computations of predicting the rescue ship motions in waves.

Time-domain simulator for short-term ship manoeuvring prediction: development and applications

ABSTRACTThis paper presents a short-term time-domain algorithm for ship motion simulation. Plane motion was considered, and thus, a three degrees of freedom model was used. The main inputs of the model are: propellers speed, rudder angles and initial conditions (initial position/orientation and linear/rotational velocity). The outputs are final ship position and orientation after a given simulation time. The data available in the Voyage Data Recorder and the results of sea trials performed before the ship delivery were used to estimate the needed parameters, implementing a simple but reliable linear regression scheme. The proposed model was applied to Costa Concordia manoeuvring simulation in order to assess its reliability in terms of trajectory prediction. Finally, as an example of application, the simulator was implemented in a real-time manoeuvring predictor, which is capable of foreseeing the ship position up to 40 s ahead in time, supporting the Commander in emergency operations.

Real-time maneuver optimization of space-based robots in a dynamic environment: Theory and on-orbit experiments

This paper presents the development of a real-time path-planning optimization approach to controlling the motion of space-based robots. The algorithm is capable of planning three dimensional trajectories for a robot to navigate within complex surroundings that include numerous static and dynamic obstacles, path constraints and performance limitations. The methodology employs a unique transformation that enables rapid generation of feasible solutions for complex geometries, making it suitable for application to real-time operations and dynamic environments. This strategy was implemented on the Synchronized Position Hold Engage Reorient Experimental Satellite (SPHERES) test-bed on the International Space Station (ISS), and experimental testing was conducted onboard the ISS during Expedition 17 by the first author. Lessons learned from the on-orbit tests were used to further refine the algorithm for future implementations.

Intraoperative Optical Coherence Tomography - an Overview of Current Clinical Data for the Application in the Anterior and Posterior Segments

Intraoperative optical coherence tomography (iOCT) represents another milestone in ocular imaging technologies. Now, for the first time, high resolution OCT images are available not only pre- or postoperatively, but also intraoperatively. In recent years, there have been significant advances in iOCT technology - from hand-held probes and mounted systems towards iOCT systems which are fully integrated into the surgical microscope and which provide seamless integration into the workflow. These systems offer high-resolution, intraoperative OCT scans in real-time and provide additional information on microstructures of the retina or the cornea. These findings may even lead to a modification of surgical strategies. Like any other new technology, iOCT technology still has some limitations, such as shadowing from instruments and the lack of eye tracking systems. Therefore, the current state of iOCT technology still requires some skill to track surgical maneuvers in real time. Further research and development will help to solve these limitations in the future. However, even if not required for all surgical procedures, iOCT imaging can already improve safety and control in many surgical procedures on the anterior and posterior segments. This has already been shown in several studies and case series. Particularly in the surgery of vitreomacular traction, peeling of epiretinal membranes (ERM peeling) and macular hole surgery, iOCT offers significant added value. It improves the visualisation of transparent structures and helps to avoid the usage of dyes. In addition the success of the surgical maneuvers can be investigated intraoperatively. In lamellar keratoplasty and glaucoma surgery too, iOCT improves precision and safety. Moreover, iOCT technology may help to achieve further insight into ocular pathologies and a better understanding of the impact of surgical maneuvers on visual rehabilitation. Further prospective studies are however required to evaluate the usefulness of iOCT in various surgical procedures on both, the anterior and posterior segments.

Real-Time Onboard Global Nonlinear Aerodynamic Modeling from Flight Data

Flight test and modeling techniques were developed to accurately identify global nonlinear aerodynamic models onboard an aircraft. The techniques were developed and demonstrated during piloted flight testing of an Aermacchi MB-326M Impala jet aircraft. Advanced piloting techniques and nonlinear modeling techniques based on fuzzy logic and multivariate orthogonal function methods were implemented with efficient onboard calculations and flight operations to achieve real-time maneuver monitoring, near-real-time global nonlinear aerodynamic modeling, and prediction validation testing in flight. Results demonstrated that global nonlinear aerodynamic models for a large portion of the flight envelope were identified rapidly and accurately using piloted flight test maneuvers during a single flight, with the final identified and validated models available before the aircraft landed.

Security vulnerabilities of connected vehicle streams and their impact on cooperative driving

Autonomous vehicles capable of navigating unpredictable real-world environments with little human feedback are a reality today. Such systems rely heavily on onboard sensors such as cameras, radar/LIDAR, and GPS as well as capabilities such as 3G/4G connectivity and V2V/V2I communication to make real-time maneuvering decisions. Autonomous vehicle control imposes very strict requirements on the security of the communication channels used by the vehicle to exchange information as well as the control logic that performs complex driving tasks such as adapting vehicle velocity or changing lanes. This study presents a first look at the effects of security attacks on the communication channel as well as sensor tampering of a connected vehicle stream equipped to achieve CACC. Our simulation results show that an insider attack can cause significant instability in the CACC vehicle stream. We also illustrate how different countermeasures, such as downgrading to ACC mode, could potentially be used to improve the security and safety of the connected vehicle streams.