科创中国

According to the analysis of the composite LQR design method proposed by Kokotovic, whether the standard two-scale model established during controller design meets the inherent system time scale characteristic is judged based on the difference between the performance index of composite and optimal control. The defect of system decomposition according to open-loop characteristic is presented and the influence of the system parameter change to closed-loop time scale characteristic is also analyzed. A method to convert the general linear dynamic equations to a standard two-scale model is proposed based on the closed-loop time scale characteristic analysis. The influence of the small parameter μ on the composite control design is also analyzed. Finally, according to the standard two-scale model, the controller can be sensitive to the change of the time scale characteristics caused by the change of system parameters or feedback control, and can get satisfactory control effect.

Wen Dong Liu;Shi Peng Fan;Hua Bin Li;为民 包

Kongzhi yu Juece/Control and Decision

2017-4-1

The three-dimensional multiple constrained guidance problem for a hypersonic gliding vehicle (HGV) against a stationary ground target in dive phase is investigated. A coupled nonlinear dynamic model is established on account of the bank-to-turn control scheme adopted by the HGV, which formulates the relation between line-of-sight angles and trajectory control variables. On this basis, a finite-time nonlinear disturbance observer is introduced to estimate the lumped uncertainty. Utilizing the estimation as feedforward compensation, a guidance law based on the adaptive multivariable super-twisting sliding mode control is designed to realize precise strike with designated impact angles. The finite-time stability of closed-loop guidance system is proven through the Lyapunov technique. Numerical simulations are executed to validate the mission adaptiveness and the robustness of the presented guidance scheme.

Yuxin Liao;Huifeng Li;为民 包

IEEE Transactions on Industrial Electronics

2018-3

Landing footprint is critical to generate a feasible trajectory onboard for entry vehicles. In this paper, a new landing footprint calculation based on geometry-predicted trajectory is proposed. First, the lateral motion states, turning radius and angle, are analytically solved based on a planned drag acceleration vs. energy (D-E) profile. Through some simple coordinate and geometrical triangle transformation, all the trajectory states are extracted. Second, by calculating the maximum longitudinal range point, the furthest reachable boundary for planned D-E profile is obtained with proposed geometry-predicted trajectory. Finally, the landing footprint can be generated by repeatedly computing the reachable boundaries for all D-E profiles in the entry corridor. Simulation results with Common Aero Vehicle (CAV) model validate the accuracy of the geometry-predicted trajectory. Furthermore, detailed comparison of footprint generation results between the traditional and the proposed are presented at last.

Yuan Long Zhang;Ke Jun Chen;Lu Hua Liu;Guo Jian Tang;为民 包

Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering

2017-8-1

The plasma sheath can be regarded as a model of a phenomenon of spacecraft reentry or hypersonic vehicles and causes so called radio blackout, which interferes with radio signals. This paper gives a survey on several aspects of plasma sheath, including the characteristic of plasma sheath, experiments to deal with the blackout and numerical solutions. The numerical methods includes WKB, finite-difference time-domain method, particle-in-cell method, CFD based method and Monte Carlo method. Some discussions are also presented.

Liang Zhao;为民 包;Chun Ye Gong

2014

A multiple constrained diving guidance law which can satisfy terminal angle and velocity constraints for hypersonic vehicle is studied in this paper. The relative motion equations between a vehicle and a moving target are constructed, and pseudo control strategy is introduced to simplify the original nonlinear equations. In addition, it employs optimal control with minimum energy consumption to design diving guidance law with terminal angle constraint and improves the robustness through revising the line-of-sight angle error based on sliding mode control. Finally, an ideal velocity curve is designed and the corresponding parameter is also obtained automatically to control the velocity magnitude. The results of CAV-H vehicle test show that this method can guide the vehicle to satisfy terminal multiple constraints even if the outside disturbances exist, and can offer reference for high precision and strong robustness guidance of hypersonic vehicle in dive phase.

Jianwen Zhu;Luhua Liu;Guojian Tang;为民 包

2017-1-20

For the terminal guidance problem of a missile intercepting a maneuvering target, a profile-tracking-based adaptive guidance law is proposed with inherent continuity in this paper. To flexibly and quantitatively control the convergence rate of the line-of-sight rate, a standard tracking profile is designed where the convergence rate is analytically given. Then, a nonsingular fast terminal sliding-mode control approach is used to track the profile. By estimating the square of the upper bound of target maneuver, an adaptive term is constructed to compensate the maneuver. Therefore, no information of target acceleration is required in the derived law. Stability analysis shows that the tracking error can converge to a small neighborhood of zero in finite time. Furthermore, a guidance-command-conversion scheme is presented to convert the law into the one appropriate for endoatmospheric interceptions. Simulation results indicate that the proposed law is effective and outperforms existing guidance laws.

Jingshuai Huang;Hongbo Zhang;Guojian Tang;为民 包

International Journal of Aerospace Engineering

2019

A novel three-dimensional robust guidance law based on H _∞ filter and H _∞ control is proposed to meet the constraints of the impact accuracy and the flight direction under process disturbances for the dive phase of hypersonic vehicle. Complete three-dimensional coupling relative motion equations are established and decoupled into linear ones by feedback linearization to simplify the design process of the further guidance law. Based on the linearized equations, H _∞ filter is introduced to eliminate the measurement noises of line-of-sight angles and estimate the angular rates. Furthermore, H _∞ robust control is well employed to design guidance law, and the filtered information is used to generate guidance commands to meet the guidance goal accurately and robustly. The simulation results of CAV-H indicate that the proposed three-dimensional equations can describe the coupling character more clearly than the traditional decoupling guidance, and the proposed guidance strategy can guide the vehicle to satisfy different multiple constraints with high accuracy and robustness.

Jianwen Zhu;Luhua Liu;Guojian Tang;为民 包

Advances in Space Research

2016-1-15

The computational complexity of one-dimensional time fractional reaction-diffusion equation is O (N²M) compared with O (N M) for classical integer reaction-diffusion equation. Parallel computing is used to overcome this challenge. Domain decomposition method (DDM) embodies large potential for parallelization of the numerical solution for fractional equations and serves as a basis for distributed, parallel computations. A domain decomposition algorithm for time fractional reaction-diffusion equation with implicit finite difference method is proposed. The domain decomposition algorithm keeps the same parallelism but needs much fewer iterations, compared with Jacobi iteration in each time step. Numerical experiments are used to verify the efficiency of the obtained algorithm.

Chunye Gong;为民 包;Guojian Tang;Yuewen Jiang;Jie Liu

The Scientific World Journal

2014

An optimal maneuver strategy considering terminal guidance accuracy for hypersonic vehicle in dive phase is investigated in this paper. First, it derives the complete three-dimensional nonlinear coupled motion equation without any approximations based on diving relative motion relationship directly, and converts it into linear decoupled state space equation with the same relative degree by feedback linearization. Second, the diving guidance law is designed based on the decoupled equation to meet the terminal impact point and falling angle constraints. In order to further improve the interception capability, it constructs maneuver control model through adding maneuver control item to the guidance law. Then, an integrated performance index consisting of maximum line-of-sight angle rate and minimum energy consumption is designed, and optimal control is employed to obtain optimal maneuver strategy when the encounter time is determined and undetermined, respectively. Furthermore, the performance index and suboptimal strategy are reconstructed to deal with the control capability constraint and the serous influence on terminal guidance accuracy caused by maneuvering flight. Finally, the approach is tested using the Common Aero Vehicle-H model. Simulation results demonstrate that the proposed strategy can achieve high precision guidance and effective maneuver at the same time, and the indices are also optimized.

Jianwen Zhu;Luhua Liu;Guojian Tang;为民 包

Acta Astronautica

2014-11

To solve precise guidance and maneuver penetration problems for hypersonic vehicle in dive phase, the optimal guidance method with maneuver was proposed. Considering that the traditional guidance law based on zero-LOS angle rate can debase penetrative ability, it designed reference motion for the rate in diving-plane and turning-plane. Besides, in order to enhance penetrative ability farther and realize precise guidance, it took advantage of optimal control with the optimal index of maximum terminal velocity to track the LOS angle rate, and pseudo control variable was introduced to simplify the resolution of optimal control problem. Finally, it analyzed the guidance capability and stability of this method. The results of CAV-H vehicle test show that the algorithm can realize maneuvering flight, and can satisfy terminal impact point and falling angle constraints. Therefore, the method can offer reference for high precision guidance and maneuver penetration for hypersonic vehicle in dive phase.

Jianwen Zhu;Luhua Liu;Guojian Tang;为民 包

Guofang Keji Daxue Xuebao/Journal of National University of Defense Technology

2013-12