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  • Trajectory generation of heat load test based on gauss pseudospectral method

    • 摘要:

      A new trajectory generation for heat load test is proposed based on gauss pseudospectral method within limit range. Firstly, with multiple path constraints and flight task requirements taken into consideration, heat load parameters are introduced into the dynamics equations. In order to solve the problem of generating such a trajectory within limit range rapidly, the dynamics equations have been normalized by Earth related parameters. Secondly, since the gauss pseudospectral method is just employed to solve the discrete nonlinear programming problem, transformations are developed, which can relate the Lagrange multipliers of the discrete nonlinear programming problem to the costates of the continuous optimal control problem. In addtion, another approach of trajectory generation by tracking the given heat rate is also presented. Finally, simulation results with common aero vehicle (CAV-H) show that the trajectories obtained by both methods can well perform the heat load test with high stagnation heating rate and the large total aeroheating amount; meanwhile, gauss pseudospectral method is better than the compared one in the given range. Furthermore, the 3-D trajectory states and control variables, angle of attack and bank, which are generated by gauss pseudospectral method, can change smoothly.

    • 作者:

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

    • 刊名:

      Science China Technological Sciences

    • 在线出版时间:

      2018-2-1

  • Second-Order Dynamic Sliding-Mode Control for Nonminimum Phase Underactuated Hypersonic Vehicles

    • 摘要:

      This paper deals with the second-order dynamic sliding-mode control (SODSMC) problem for nonminimum phase underactuated hypersonic vehicles. First, the underactuated hypersonic vehicle attitude control model is introduced. The normal form and the nonminimum phase nature for the vehicle are discussed. Thus, the nonminimum phase system is divided into the minimum phase subsystem and the nonminimum phase subsystem via the system decomposition approach. Second, the SODSMC scheme is developed. The conventional sliding-mode controller and the second-order dynamic sliding-mode controller are designed for the two subsystems. Besides, the dynamic sliding manifold is provided for the nonminimum phase subsystem. Simulation results for the nonminimum phase underactuated hypersonic vehicle are presented to demonstrate the effectiveness and robustness of the proposed control scheme.

    • 作者:

      Zhi Wang;为民 包;Huifeng Li

    • 刊名:

      IEEE Transactions on Industrial Electronics

    • 在线出版时间:

      2017-4

  • Adaptive tracking guidance method in injection phase for hypersonic glide vehicles

    • 摘要:

      According to the trajectory tracking problem of hypersonic glide vehicle under great deviation conditions, a new adaptive tracking guidance method in the injection phase was put forward based on the adaptively revised weighting matrix. The main control mode and standard trajectory characteristics were analyzed. The simplified longitudinal motion equations were linearized near the standard trajectory. An improved adaptive tracking guidance method was designed by introducing the error term in linear quadratic performance index. The simulation results of CAV-H indicate that this method can achieve a great performance in adaptive tracking guidance in the injection phase, and has a good robustness to the initial and process deviation.

    • 作者:

      Ruizhi He;Luhua Liu;Guojian Tang;为民 包

    • 刊名:

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

    • 在线出版时间:

      2016-10-28

  • An Interacting-Multiple-Model Method for Tracking a Hypersonic Glide Target

    • 摘要:

      In terms of tracking a hypersonic glide target (HGT), a tracking method is proposed based on interacting-multiple-model (IMM). Target tracking mainly contains two missions: system modeling and choosing filtering algorithm. First, a tracking system is established composed of state and measurement equations on basis of ground-based radar measuring. The Singer model is used to represent the unknown aerodynamic acceleration. Then, to enhance model adaptation of the tracking method, three-model interacting filter is constructed with maneuver-frequency adaption based on unscented Kalman filter (UKF). Through tracking a flight trajectory generated by Gauss Pseudospectral Method, the effectiveness of the proposed method is validated and the multiple-model is superior to the single-model.

    • 作者:

      Jingshuai Huang;Hongbo Zhang;Shang Wu;Guojian Tang;为民 包

    • 刊名:

    • 在线出版时间:

      2020-8

  • Entry trajectory generation based on quasi-three-dimensional acceleration guidance

    • 摘要:

      A new entry trajectory planning approach based on quasi-three-dimensional acceleration guidance for hypersonic glide vehicles is proposed. In order to improve the maneuvering capability of entry vehicles, the planner proposed in this paper leave both angle of attack and bank be free, which means the traditional Shuttle type planner will not work. To settle the problem, the planner plans a quasi-three-dimensional acceleration profile, satisfying all path constraints from initial to the target firstly. In this paper, the generation of reference profile is divided into scheming two sub-profiles, longitudinal drag profile and lateral acceleration profile in series and the key is how to obtain the lateral profile with planned drag profile. Secondly, a reduced order dynamics is obtained with the extraction longitudinal motion parameters from drag profile. Based on the reduced order dynamics, a Newton iteration scheme is employed to generate the reference profile with initial drag and lateral acceleration profile. Corresponding to the reference profile, the standard trajectory and control variables can be extracted. Finally, to track the standard profile, a PD feedback law is developed. And Simulations with CAV-H model show that both the standard and actual 3-D trajectory generated by tracker can meet the path constraints and flight task requirements.

    • 作者:

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

    • 刊名:

    • 在线出版时间:

      2016-8-26

  • High sensitivity flexible electronic skin based on graphene film

    • 摘要:

      Electronic skin with high sensitivity, rapid response, and long-term stability has great value in robotics, biomedicine, and in other fields. However, electronic skin still has challenges in terms of sensitivity and response time. In order to solve this problem, flexible electronic skin with high sensitivity and the fast response was proposed, based on piezoresistive graphene films. The electronic skin was a pressure sensor array, composed of a 4 × 4 tactile sensing unit. Each sensing unit contained three layers: The underlying substrate (polyimide substrate), the middle layer (graphene/polyethylene terephthalate film), and the upper substrate bump (polydimethylsiloxane). The results of the measurement and analysis experiments, designed in this paper, indicated that the flexible electronic skin achieved a positive resistance characteristic in the range of 0 kPa–600 kPa, a sensitivity of 10.80 Ω/kPa in the range of 0 kPa–4 kPa, a loading response time of 10 ms, and a spatial resolution of 5 mm. In addition, the electronic skin realized shape detection on a regular-shaped object, based on the change in the resistance value of each unit. The high sensitivity flexible electronic skin designed in this paper has important application prospects in medical diagnosis, artificial intelligence, and other fields.

    • 作者:

      Xiaozhou Lü;Jiayi Yang;Liang Qi;为民 包;Liang Zhao;人杰 陈

    • 刊名:

      Sensors

    • 在线出版时间:

      2019-2-2

  • Rapid generation of multi-target entry trajectory for hypersonic glide vehicles

    • 摘要:

      An entry trajectory planning algorithm that generates multi-target trajectories satisfying path and terminal constraints is investigated in this paper. The entry trajectory is divided into the initial and glide phase, and a switch condition is used to ensure a smooth connection of these two phases. A nominal angle of attack is used in the whole trajectory and then the bank angle is the main control variable which is under design. In the initial phase, a constant bank angle is used to generate the trajectory to match a fix terminal height of transition condition. In the glide phase, a planner consists of the longitudinal and lateral sub-planner is developed based on the drag acceleration guidance logic. The drag acceleration profile is designed as a second order curve of velocity, its initial and terminal points are fixed and the middle value of the drag acceleration is calculated onboard according to the distance to go. The magnitude of the bank angle is solved from the longitudinal sub-planner, whereas the sign of the bank angle is determines by the lateral sub-planner. Then, a tracker is employed to follow the reference drag acceleration profile. The algorithm converts the highly constrained multi-target entry trajectory planning problem into a two parameters searching problem. Finally, the approach is tested using Common Aero Vehicle-H model, and the results demonstrate that the algorithm can generate multi-target entry trajectories rapidly while satisfying all the path and terminal constraints.

    • 作者:

      Ruizhi He;Luhua Liu;Guojian Tang;为民 包

    • 刊名:

    • 在线出版时间:

      2016-8-26

  • Computational challenge of fractional differential equations and the potential solutions

    • 摘要:

      We present a survey of fractional differential equations and in particular of the computational cost for their numerical solutions from the view of computer science. The computational complexities of time fractional, space fractional, and space-time fractional equations are O(N2M), O(NM2), and O(NM(M + N)) compared with O(MN) for the classical partial differential equations with finite difference methods, where M, N are the number of space grid points and time steps. The potential solutions for this challenge include, but are not limited to, parallel computing, memory access optimization (fractional precomputing operator), short memory principle, fast Fourier transform (FFT) based solutions, alternating direction implicit method, multigrid method, and preconditioner technology. The relationships of these solutions for both space fractional derivative and time fractional derivative are discussed. The authors pointed out that the technologies of parallel computing should be regarded as a basic method to overcome this challenge, and some attention should be paid to the fractional killer applications, high performance iteration methods, high order schemes, and Monte Carlo methods. Since the computation of fractional equations with high dimension and variable order is even heavier, the researchers from the area of mathematics and computer science have opportunity to invent cornerstones in the area of fractional calculus.

    • 作者:

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

    • 刊名:

      Mathematical Problems in Engineering

    • 在线出版时间:

      2015

  • Fast simulation of X-ray pulsar signals at a spacecraft

    • 摘要:

      Existing methods for simulating pulsar signals at a spacecraft are inapplicable for large flux or high frequency because of their low efficiency, hindering research on X-ray pulsar-based navigation. To solve the problem, we propose a fast method based on the relation derivation between the photon arrival time and corresponding photon phase at the spacecraft. The absolute differences of searched frequencies between simulated data and observational data for the Crab pulsar are less than10−4, which sufficiently validates the method. Furthermore, the proposed method is up to 3 orders of magnitude faster than other methods, which shows that it is more efficient and better satisfies the needs of real-time navigation verification.

    • 作者:

      Jianyu Su;Haiyan Fang;为民 包;Haifeng Sun;Lirong Shen;Liang Zhao

    • 刊名:

      Acta Astronautica

    • 在线出版时间:

      2020-1

  • Design of extended reduced controller of the system with uncertainties

    • 摘要:

      To avoid the control failure caused by system parameter uncertainty, we analyze the performance index of a reduced controller mixed with parts of the fast modes. We use a sixth-order roll autopilot system as an example to illustrate the timescale characteristic change caused by system parameter uncertainty. Then, we simulate and analyze the states needed to design a reduced controller and the highest order of the controller. The extended reduced controller using all potential slow modes is designed, and its control performance is verified through simulation. Results show that the control performance of the extended reduced controller is equivalent to that of the traditional reduced controller, and the proposed controller shows good adaptability for a system with uncertainties.

    • 作者:

      Wendong Liu;Huabin Li;为民 包;Sheng Sun

    • 刊名:

      Information and Control

    • 在线出版时间:

      2017-4-20

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