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20th Chinese Intelligent Systems Conference

作者： Liu, Zhiming Song, Shaoqian Song, Zhiguo Dong, Tian Chen, Xinmin China Acad Launch Vehicle Technol Beijing 100076 Peoples R China Chinese Acad Sci Ningbo Inst Mat Technol & Engn Ningbo 315201 Peoples R China

ISBN: (纸本)9789819786602;9789819786589;9789819786572

The terminal guidance flight process of aircraft is influenced by complex constraints. To address the operational requirements of active radar and infrared seekers, a specialized guidance law has been developed. This guidance law is designed to meet the constraints related to the terminal landing angle, the Synthetic Aperture Radar (SAR) imaging motion, and the field angle of the composite seeker simultaneously. The proposed method is based on a two-channel optimal guidance law that incorporates the terminal landing angle constraint. In the lateral channel, a forward bevel angle command tracking guidance law is introduced, and a field boundary correction term is added in the terminal guidance phase to satisfy the field angle constraint. Numerical simulation results demonstrate that the guidance law effectively meets the SAR imaging constraints and performs well in maintaining the field of view constraints of the seeker, even in the presence of disturbances.

关键词： Composite seeker Field angle SAR imaging guidance law terminal guidance

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Fast fixed-time three-dimensional terminal guidance with non-concave trajectory constraint

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Chinese Journal of Aeronautics 2024年第3期37卷 208-218页

作者： Youmin GONG Yanning GUO Yueyong LYU Dongyu LI Guangfu MA Department of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Cyber Science and Technology Beihang UniversityBeijing 100191China

Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft rendezvous and docking terminal phase with external disturbance is investigated in this ***,a fixed-time observer based on real-time differentiator is developed to compensate for the external disturbance,whose estimation error can converge to zero after a time independent of the initial ***,a sliding surface ensuring fixed-time convergence is *** sliding surface can guarantee that the vehicle achieves a non-concave trajectory,which is better for avoiding collision and maintaining the visibility of the landing site or docking ***,the nonsingular guidance ensuring the fixed-time convergence of the sliding surface is proposed,which is continuous and chatter *** last,three numerical simulations of Mars landing are performed to validate the effectiveness and correctness of the designed scheme.

关键词： Three-dimensional terminal guidance Non-concave trajectory constraint Fast fixed-time control Sliding mode control

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Neural-Network-Based Nonlinear Optimal terminal guidance With Impact Angle Constraints

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2024年第1期60卷 819-830页

作者： Cheng, Lin Wang, Han Gong, Shengping Huang, Xu Beihang Univ Sch Astronaut Beijing 102206 Peoples R China

The terminal guidance problem considering nonlinearity, optimality, and impact angle constraints is investigated. First, the conditions for optimal guidance in the longitudinal plane are derived based on the Pontryagin's maximum principle, and then the to-be-solved two-point boundary value problem is equivalent to a backward integration problem. Then, analytical boundaries are given to initialize the states for backward integration. Based on the easily accessible dataset, a neural network is trained to approximate the optimal guidance commands. Lastly, an optimal terminal guidance scheme combined with the neural network and a biased proportional navigation guidance is proposed. Compared with the existing terminal guidance methods, the proposed guidance strategy balances the performances about flight optimality, on-board implementation capability, and impact angle satisfaction when high dynamical nonlinearity is considered. Simulations are given to validate the effectiveness of the proposed techniques, and demonstrate the advantages of the algorithm on optimality, real-time performance, and impact angle satisfaction in nonlinear cases.

关键词： Neural networks Navigation Missiles Indexes Gravity Trajectory Real-time systems Deep neural networks impact angle constraint optimal control optimal guidance terminal guidance

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Automatic terminal guidance for small fixed-wing unmanned aerial vehicles

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JOURNAL OF FIELD ROBOTICS 2023年第1期40卷 3-29页

作者： Yang, Yachao Li, Jie Liu, Chang Yang, Yu Li, Juan Wang, Zhenbei Wu, Xueyong Fu, Lei Xu, Xiao Beijing Inst Technol Sch Mechatron & Elect Engn 5 South St Beijing 100081 Peoples R China

The research presented in this article focuses on expanding and deepening the prior research of a low-cost terminal guidance system in a previous paper entitled "Design, implementation and verification of a low-cost terminal guidance system for small fixed-wing UAVs." An automatic terminal guidance workflow is specially designed for an individual in a small fixed-wing unmanned aerial vehicle (SUAV) swarm. The extended work around the proposed workflow primarily involves upgrading onboard hardware modules to improve sensor accuracy and environmental adaptability, the imaging performance of the seeker, as well as the computational capability of the image processor, applying object detection to replace the human-in-the-loop function and adopting the integral proportional guidance law in the vertical direction to reduce the required overload and obtain a larger impact angle. Furthermore, we conducted several field tests on two types of SUAV against a stationary target on the ground in a field scenario. The experiments have generated valuable onboard image data and SUAV status information, all of which are aligned in the time domain. The only remaining data sets that support the findings of this study are available from the corresponding author. Our study into automatic terminal guidance has yielded a solution of the automatic strap-down monocular terminal guidance problem of individual SUAVs. The field trials of a single SUAV demonstrate the robustness and efficiency of the proposed automatic terminal guidance methodology and lays a foundation for the future SUAVs' cooperative attack test.

关键词： autonomous SUAV systems design terminal guidance

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Pseudo-Spectral MPSP-Based Unified Midcourse and terminal guidance for Reentry Targets

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2023年第4期59卷 3982-3994页

作者： Sharma, Prayag Kumar, Prem Padhi, Radhakant Indian Inst Sci Dept Aerosp Engn Bangalore 560012 Karnataka India Programme Air Def DRDO Hyderabad 500058 Telangana India

A unified optimal guidance scheme is presented in this article for both midcourse and terminal phases combined. It minimizes the total deceleration resulting in enhanced range and/or higher impact velocity, while satisfying the terminal constraints on impact angle and miss distance. State-dependent terms are included in the cost function of the recently proposed generalized quasi-spectral-model predictive static programming (MPSP) and, because of its similarity with the pseudo-spectral philosophy, it is renamed as "pseudo-spectral MPSP." Extensive simulation studies with different engagement scenarios illustrate the effectiveness of the proposed guidance to engage with incoming high-speed ballistic targets.

关键词： Force Drag Aerodynamics Three-dimensional displays Solid modeling Philosophical considerations Missiles Angle-constrained guidance model predictive static programming (MPSP) guidance midcourse guidance minimum acceleration guidance optimal guidance terminal guidance

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Design, implementation, and verification of a low-cost terminal guidance system for small fixed-wing UAVs

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JOURNAL OF FIELD ROBOTICS 2021年第5期38卷 801-827页

作者： Yang, Yachao Liu, Chang Li, Jie Yang, Yu Li, Juan Zhang, Zhidong Ye, Bobo Beijing Inst Technol Sch Mechatron Engn Intelligent Unmanned Syst Grp Beijing 100081 Peoples R China

A terminal guidance control system for small fixed-wing unmanned aerial vehicles (SUAV, with a wingspan of around 1.5 m) is proposed in this paper based on a visible light strap-down seeker. The system is implemented using low-cost, open-source components with a cost less than $2000 and proved to be feasible, transplantable and effective for different types of SUAVs, achieving a good terminal guidance accuracy (circular error probable = 1.5 m) against a nonmaneuvering target on the ground. Impacts of low-cost and low-precision electrical modules mainly include influence on terminal guidance information, measurement of SUAV state values and the presented system's time-delay. We examine the practical median flow algorithm for target tracking, the attitude pursuit guidance law for terminal guidance control and the pursuit image frame method for large delay interception to eliminate adverse effects. Furthermore, the performance and robustness are evaluated by laboratory tests as well as field flight trials on two different SUAV platforms. This paper provides a robust, effective and proven reference for the development of the aggressive SUAV for SUAV swarms.

关键词： small fixed-wing unmanned aerial vehicle terminal guidance visible optical strap-down seeker

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CTG-Net: an efficient cascaded framework driven by terminal guidance mechanism for dilated pancreatic duct segmentation

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PHYSICS IN MEDICINE AND BIOLOGY 2023年第21期68卷 215006-215006页

作者： Zou, Liwen Cai, Zhenghua Qiu, Yudong Gui, Luying Mao, Liang Yang, Xiaoping Nanjing Univ Dept Math Nanjing 210093 Peoples R China Nanjing Univ Med Sch Nanjing 210007 Peoples R China Nanjing Drum Tower Hosp Dept Gen Surg Nanjing 210008 Peoples R China Nanjing Univ Sci & Technol Sch Math & Stat Nanjing 210094 Peoples R China

Pancreatic duct dilation indicates a high risk of various pancreatic diseases. Segmentation for dilated pancreatic duct (DPD) on computed tomography (CT) image shows the potential to assist the early diagnosis, surgical planning and prognosis. Because of the DPD's tiny size, slender tubular structure and the surrounding distractions, most current researches on DPD segmentation achieve low accuracy and always have segmentation errors on the terminal DPD regions. To address these problems, we propose a cascaded terminal guidance network to efficiently improve the DPD segmentation performance. Firstly, a basic cascaded segmentation architecture is established to get the pancreas and coarse DPD segmentation, a DPD graph structure is build on the coarse DPD segmentation to locate the terminal DPD regions. Then, a terminal anatomy attention module is introduced for jointly learning the local intensity from the CT images, feature cues from the coarse DPD segmentation and global anatomy information from the designed pancreas anatomy-aware maps. Finally, a terminal distraction attention module which explicitly learns the distribution of the terminal distraction regions is proposed to reduce the false positive and false negative predictions. We also propose a new metric called tDice to measure the terminal segmentation accuracy for targets with tubular structures and two other metrics for segmentation error evaluation. We collect our dilated pancreatic duct segmentation dataset with 150 CT scans from patients with five types of pancreatic tumors. Experimental results on our dataset show that our proposed approach boosts DPD segmentation accuracy by nearly 20% compared with the existing results, and achieves more than 9% improvement for the terminal segmentation accuracy compared with the state-of-the-art methods.

关键词： pancreatic duct dilation terminal guidance cascaded strategy distance transform distraction attention medical image segmentation

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terminal guidance Based on Bezier Curve for Climb-and-Dive Maneuvering Trajectory With Impact Angle Constraint

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IEEE ACCESS 2019年 7卷 2969-2977页

作者： Qin, Zhen Qi, Xiaoye Fu, Yongling Beihang Univ Sch Mech Engn & Automat Beijing 10083 Peoples R China

To improve the penetration capability and the damage effectiveness of cruise missiles, maneuvering trajectory with specific impact angle is applied in terminal guidance. In this paper, an innovative online method for terminal guidance is presented, which can guide the cruise missile to a stationary target along a climb-and-dive maneuvering trajectory while meeting the expected impact angle. The basic principles of the proposed guidance method are the Bezier curve theory and the missile inverse dynamics. The maneuvering trajectory is shaped by a third-order Bezier curve based on the missile current state, the target position, and the impact angle constraint. The real-time guidance command represented by attack angle alpha is obtained based on the missile inverse dynamics. The shape of flight trajectory can be modified by regulating the Bezier parameters b(1) and b(2) to satisfy different tactical requirements without changing the boundary conditions. Simulation results demonstrate the effectiveness of the proposed method applied in cruise missile terminal guidance.

关键词： Cruise missile terminal guidance maneuvering trajectory impact angle Bezier curve

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A terminal guidance algorithm based on ant colony optimization

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COMPUTERS & ELECTRICAL ENGINEERING 2019年 77卷 128-146页

作者： Nobahari, Hadi Nasrollahi, Saeed Sharif Univ Technol Dept Aerosp Engn Tehran *** Iran

In this paper, terminal engagement of a maneuvering target and a pursuer is investigated. A heuristic nonlinear model predictive guidance algorithm is presented. Nonlinear kinematics of the pursuer and the target is utilized to formulate the guidance problem. Also, the target maneuver is assumed to be unknown. The proposed heuristic guidance algorithm uses an ant-based optimization algorithm to estimate simultaneously the states of the pursuer, the maneuver of the target, and the optimal guidance commands. Performance of the new guidance algorithm against maneuvering and non-maneuvering targets is evaluated using numerical simulations. Also, the results of the guidance algorithm are compared to the true proportional navigation, a guidance law based on backstepping, augmented proportional navigation, switched bias proportional navigation, linear quadratic differential game, state dependent Riccati equation-differential game, and proportional navigation-improved particle swarm optimization guidance. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： terminal guidance Ant colony optimization State estimation Target maneuver estimation Autopilot dynamic Nonlinear model predictive control

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terminal guidance for a Hypersonic Vehicle with Impact Time Control

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JOURNAL OF guidance CONTROL AND DYNAMICS 2018年第8期41卷 1790-1798页

作者： Wang, Jiawei Zhang, Ran Beihang Univ Sch Astronaut Beijing 100191 Peoples R China

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