Purpose In this paper, an online convex optimization method for the exoatmospheric ascent trajectory of space interceptors is proposed. The purpose of this paper is to transform the original trajectory optimization pr...
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Purpose In this paper, an online convex optimization method for the exoatmospheric ascent trajectory of space interceptors is proposed. The purpose of this paper is to transform the original trajectory optimization problem into a sequence of convex optimization subproblems. Design/methodology/approach For convenience in calculating accuracy and efficiency, the complex nonlinear terminal orbital elements constraints are converted into several quadratic equality constraints, which can be better computed by a two-step correction method during the iteration. First, the nonconvex thrust magnitude constraint is convexified by the lossless convexification technique. Then, discretization and successive linearization are introduced to transform the original problem into a sequence of one convex optimization subproblem, considering different flight phases. Parameters of trust-region and penalty are also applied to improve the computation performance. To correct the deviation in real time, the iterative guidance method is applied before orbit injection. Findings Numerical experiments show that the algorithm proposed in this paper has good convergence and accuracy. The successive progress can converge in a few steps and 3-4 s of CPU time. Even under engine failure or mission change, the algorithm can yield satisfactory results. Practical implications The convex optimization method presented in this paper is expected to generate a reliable optimal trajectory rapidly in different situations and has great potential for onboard applications of space interceptors. Originality/value The originality of this paper lies in the proposed online trajectory optimization method and guidance algorithm of the space inceptors, especially for onboard applications in emergency situations.
In this manuscript, a multi-stage cooperative interception problem is investigated in which the flight vehicles are launched successively to intercept a high maneuvering target cooperatively. We first provide the form...
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ISBN:
(纸本)9789881563972
In this manuscript, a multi-stage cooperative interception problem is investigated in which the flight vehicles are launched successively to intercept a high maneuvering target cooperatively. We first provide the formulation of the multi-stage cooperative interception problem. Then, a coverage-based guidance algorithm is developed to obtain the expected locations of the flight vehicles by maximizing the interception probability. Moreover, the interception probability is analyzed which is related to the number of the flight vehicle and the information accuracy of the target.
In this manuscript, a multi-stage cooperative interception problem is investigated in which the flight vehicles are launched successively to intercept a high maneuvering target cooperatively. We first provide the form...
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In this manuscript, a multi-stage cooperative interception problem is investigated in which the flight vehicles are launched successively to intercept a high maneuvering target cooperatively. We first provide the formulation of the multi-stage cooperative interception problem. Then, a coverage-based guidance algorithm is developed to obtain the expected locations of the flight vehicles by maximizing the interception probability. Moreover, the interception probability is analyzed which is related to the number of the flight vehicle and the information accuracy of the target.
The development of a novel type of hybrid underwater glider (HUG) that combines the advantages of buoyancy-driven underwater glider and propeller-driven autonomous underwater vehicle (AUV) has recently received consid...
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The development of a novel type of hybrid underwater glider (HUG) that combines the advantages of buoyancy-driven underwater glider and propeller-driven autonomous underwater vehicle (AUV) has recently received considerable interest. HUG is designed with a rotatable thruster to ensure the enough maneuverability of the vehicle for underwater docking. Unlike the fixed funnel-type dock, the dock proposed here can rotate actively to allow the vehicle to approach the docking station from most range of directions providing better accessibility for the vehicle. Considering that the ocean current may have a significant impact on the HUG, a pursuit guidance algorithm with current compensation is presented. The performance of the guidance algorithm is compared with other existing guidance algorithms, such as pure pursuit guidance and proportional navigation guidance by simulation based on the dynamic model of HUG. Moreover, underwater docking experiments are conducted to validate the feasibility of the docking system and the effectiveness of the proposed guidance algorithm. The experimental results indicate that the proposed algorithm compensates well for the current disturbances on HUG docking mission and the HUG can dock with the rotatable dock entrance successfully. (C) 2016 Elsevier Ltd. All rights reserved.
This manuscript investigates a multi-stage cooperative interception problem in which the flight vehicles are launched successively to intercept a high maneuvering target cooperatively. We first give the formulation of...
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ISBN:
(纸本)9789881563910
This manuscript investigates a multi-stage cooperative interception problem in which the flight vehicles are launched successively to intercept a high maneuvering target cooperatively. We first give the formulation of the multi-stage cooperative interception problem. Then, a coverage-based guidance algorithm is developed to obtain the expected locations of the flight vehicles by maximizing the interception probability. Moreover, the interception probability is analyzed and compared with the simultaneous cooperative interception approach. The numerical simulation examples are given to show the effectiveness of the proposed approach.
This manuscript investigates a multi-stage cooperative interception problem in which the flight vehicles are launched successively to intercept a high maneuvering target *** first give the formulation of the multi-sta...
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ISBN:
(纸本)9781509009107
This manuscript investigates a multi-stage cooperative interception problem in which the flight vehicles are launched successively to intercept a high maneuvering target *** first give the formulation of the multi-stage cooperative interception ***,a coverage-based guidance algorithm is developed to obtain the expected locations of the flight vehicles by maximizing the interception ***,the interception probability is analyzed and compared with the simultaneous cooperative interception *** numerical simulation examples are given to show the effectiveness of the proposed approach.
Spacecraft formation flight is increasingly pivotal in the design of new space missions. This demands an high level of autonomy to optimize science time, and the development of advanced mission concepts to surpass cur...
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Spacecraft formation flight is increasingly pivotal in the design of new space missions. This demands an high level of autonomy to optimize science time, and the development of advanced mission concepts to surpass current technological limitations. Recently, Low Earth Orbit (LEO) has been explored as solution for experimental validation of novel formation flight technologies. LEO is related to proximity formation flight missions, which require active guidance algorithms to ensure mission success and safe operations. An efficient guidance algorithm is proposed to enhance the autonomy of proximity formation flight missions, enabling variable formations and reconfiguration while ensuring safety. The optimal formation trajectory problem, conceptualized as Circular Relative Orbit, addresses the relative motion with respect to a reference orbit. Rigorous Lyapunov design is proposed to ensure convergence to the desired trajectory, guaranteeing closed-loop system stability. It incorporates an Artificial Potential Field function to deal with the formation flight problem. Initial simulations are conducted to assess the effectiveness of the proposed approach within the restricted Two-Body dynamics framework. The algorithm is applied to accomplish a space interferometer deploying mission in LEO, demonstrating its efficacy through a compact implementation. Finally, the algorithm's general and wider effectiveness is validated with elliptical and L2 Halo reference orbits.
Snake robots under environments with avoidance constraints hardly track routes such that traditional guidance approaches become infeasible. Motivated by it, this work presents a line-of-sight-guidance virtual-snake-ro...
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Snake robots under environments with avoidance constraints hardly track routes such that traditional guidance approaches become infeasible. Motivated by it, this work presents a line-of-sight-guidance virtual-snake-robot integrated scheme for snake robots to track paths and obey collision avoidance regulations. Main contributions include the avoidance regulation-compliant kinematics guidance law and finite-time-converged adaptive dynamic controller. In kinematics, a virtual leader is used to optimize nondifferentiable inflection into smooth to provide a jitter-free direction. Considering avoidance constraints, corresponding guidance strategies are innovatively designed for head-on, overtaking, and crossing scenarios to ensure the safety and autonomy of path tracking. In terms of dynamics, maneuvering control is executed by a finite-time disturbance observer-based event-triggered terminal sliding-mode controller. The unmeasured errors and uncertainties are accurately compensated, and input event-triggering rules can reduce the actuator burden. Finally, the stability analysis proves system errors' finite-time convergence, and result validations confirm the performance superiority and feasibility of this method.
Navigating through environments replete with obstacles while adhering to dynamic constraints poses a formidable challenge for fixed-wing Unmanned Aerial Vehicles (UAVs), as they remain vulnerable to collision threats....
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Navigating through environments replete with obstacles while adhering to dynamic constraints poses a formidable challenge for fixed-wing Unmanned Aerial Vehicles (UAVs), as they remain vulnerable to collision threats. Moreover, in scenarios involving multiple dynamic obstacles, a quick and reactive maneuver is needed. To address this challenge, this paper introduces a collision avoidance algorithm tailored for fixed-wing UAVs operating within dynamic constraints amidst a multi-obstacle environment. Leveraging a geometric approach with low computational load, this algorithm offers a pragmatic solution for ensuring UAV safety and maneuverability in complex airspace scenarios. The algorithm uses a discrete Kalman filter to predict obstacle trajectories and generates a two-dimensional plane containing the minimum of the obstacle trajectory. A target point for collision avoidance is computed according to the resulting two-dimensional plane considering the movement trajectory of the obstacle and dynamic constraints of the unmanned aerial vehicle. Moreover, the collision times are predicted for scenarios with multiple obstacles. Numerical simulations are performed to demonstrate the effectiveness of the proposed algorithm.
This article presents an improved guidance law for underactuated marine vessels that compensates cross-track error caused by external disturbances through its sideslip. The proposed guidance law demonstrates improved ...
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This article presents an improved guidance law for underactuated marine vessels that compensates cross-track error caused by external disturbances through its sideslip. The proposed guidance law demonstrates improved path-following performance regardless of disturbances, such as waves, winds, and ocean currents. This article also presents an adaptive neural-network (NN) control law for the partially known vessel dynamics with state constraints. For satisfying the state constraints, this control scheme adopts an integral barrier Lyapunov function (iBLF)-based backstepping control technique. It is shown that the closed-loop system remains bounded, and state constraints are always satisfied. Finally, the efficacy of the improved guidance law and iBLF-based adaptive control strategy was verified in simulation and experiments using an autonomous surface vessel.
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