Dong Z.,Beihang University |
Dong Z.,Science and Technology on Electronic optic Control Laboratory |
Chen Z.,Beihang University |
Zhou R.,Beihang University |
Zhang R.,Flight Automatic Control Research Institute
Proceedings of the 2011 6th IEEE Conference on Industrial Electronics and Applications, ICIEA 2011 | Year: 2011
This article is concerned with the UAV path re-planning problem to be solved by using a novel approach based on the hybrid of virtual force and A * search algorithm (HVFA). The formulation of the UAV path re-planning is presented, and the hybrid system model of virtual force (VF) is given. The scheme of path re-planning is designed and the corresponding computational complexity is analyzed quantitatively. Simulation results prove the feasibility and usefulness of using HVFA for UAV path re-planning. Performance comparisons between the HVFA method and the fuzzy virtual force (FVF) method demonstrate that the proposed approach is fast enough to meet the real-time requirements of the online path planning problems. © 2011 IEEE.
Zhuoning D.,Beihang University |
Rulin Z.,Flight Automatic Control Research Institute |
Zongji C.,Beihang University |
Rui Z.,Beihang University
Chinese Journal of Aeronautics | Year: 2010
This article proposes a novel fuzzy virtual force (FVF) method for unmanned aerial vehicle (UAV) path planning in complicated environment. An integrated mathematical model of UAV path planning based on virtual force (VF) is constructed and the corresponding optimal solving method under the given indicators is presented. Specifically, a fixed step method is developed to reduce computational cost and the reachable condition of path planning is proved. The Bayesian belief network and fuzzy logic reasoning theories are applied to setting the path planning parameters adaptively, which can reflect the battlefield situation dynamically and precisely. A new way of combining threats is proposed to solve the local minima problem completely. Simulation results prove the feasibility and usefulness of using FVF for UAV path planning. Performance comparisons between the FVF method and the A* search algorithm demonstrate that the proposed approach is fast enough to meet the real-time requirements of the online path planning problems. © 2010 Chinese Journal of Aeronautics.
Zhang G.,University of Chinese Academy of Sciences |
Wang W.,Flight Automatic Control Research Institute
International Journal of Pattern Recognition and Artificial Intelligence | Year: 2016
This paper investigates the design of information theoretic-based fitness function for embedded evolutionary robotics (ERs). Such fitness relies on the assumption that interesting behaviors result in a high sensorimotor (individual) diversity. The current simple entropy as a diversity metric only considers individuals’ difference but ignores their spatial relationship. The sensorimotor stream can be analyzed to construct a simple directed graph that has unique entry and exit nodes. This paper proposes a hierarchic entropy as a diversity metric by incorporating the simple entropy and the spatial relationship based graph entropy. Maximizing the hierarchic entropy, achieved by on-board evolutionary algorithm, thus defines a self-driven fitness function enforcing the controller visiting diverse sensorimotor states. The proposed algorithm achieves better performance than the published results of other entropy-based methods only relying on simple entropy, without requiring additional computational resources. © 2017 World Scientific Publishing Company
Fu Q.-W.,Northwestern Polytechnical University |
Qin Y.-Y.,Northwestern Polytechnical University |
Zhang J.-H.,Flight Automatic Control Research Institute |
Li S.-H.,Northwestern Polytechnical University
Zhongguo Guanxing Jishu Xuebao/Journal of Chinese Inertial Technology | Year: 2012
The classic recursive least-square (RLS) fine alignment method, which uses the horizontal velocity errors as measurements, needs longer time to identify the azimuth error and gyro drift errors. Besides, its convergent speed is affected by the initial value of recursive calculation. An improved method is put forward which directly uses the horizontal specific forces in one second as measurements, and neglects high-order misalignment errors in converting the cubic curve into linear model. On the basis of the simplified model, a low computational complexity RLS algorithm without initial condition is derived to speed up the convergence. The simulation and practicality experiments based on stationary base show that the improved method can identify the misalignment errors and the north gyro drift errors in 120 s, so it greatly shortens the time of initial alignment and gyro drift measurement without affecting alignment accuracy.
Zhou Q.,Northwestern Polytechnical University |
Zhou Q.,Flight Automatic Control Research Institute |
Qin Y.,Northwestern Polytechnical University |
Fu Q.,Northwestern Polytechnical University |
Yue Y.,Flight Automatic Control Research Institute
Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University | Year: 2013
The convergence of geographic meridians at the poles makes steering and positioning extremely difficult if not impossible when utilizing conventional inertial navigation systems(INS) during high latitude flights. The grid coordinate frame mechanization of the inertial navigation system is presented to cope with above problems. The approach allows grid heading to be known directly, without reference to any external sources of information. The Earth-centered Earth-fixed(ECEF) coordinates can be directly applicable to aircraft positioning in the polar regions as an alternative to the use of longitude-latitude coordinates. The grid frame mechanization error equations are derived for integrated navigation systems. The simulation results and their analysis show preliminarily that the error characteristics for grid frame navigation proceed in exactly the same fashion as for the conventional navigation mechanization. The grid frame inertial navigation offers the solution to transpolar aircraft.
Wang J.-A.,Chang'an University |
Liu P.-J.,Flight Automatic Control Research Institute |
Li S.-S.,Chang'an University
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2012
Complex close-in Galileo BOC(1, 1) multipath signals can not be estimated by traditional GPS multipath mitigation algorithms, and therefore a model containing multipath number parameter and using genetic algorithm to estimate the multipath signals was provided. When the actual multipath signal changes little, the last estimated multipath parameters is used, until the multipath model changes largely, then the genetic algorithm is used to estimate the multipath parameter. In urban valley, the multipath signals disappear and appear frequently, and the algorithm estimates all the multipath signals even when it disappears temporarily. Thus when the multipath signals appear again, the multipath parameters could be obtained quickly. The algorithm estimates the multipath signals accurately and reduces the pseudo-range measurement errors, and thereby improves positioning accuracy, and to some extent, reduces the computational complexity.
Xie J.-J.,Xidian University |
Yin Y.-Z.,Xidian University |
Chen Y.,Flight Automatic Control Research Institute
Electronics Letters | Year: 2013
A single-layer wideband printed slot antenna with polarisation diversity is presented using a hybrid feeding technique. The antenna consists of an aperture-coupled feeding element and a coplanar waveguide feeding element. The aperture-coupled microstrip feed line with a 180° phase difference is used to reduce the cross-polarisation level and improve the isolation level. A circular patch is connected to the coplanar waveguide feed line for good impedance matching. By introducing a fan-shaped slot to separate the ground plane of the radiating elements, the measured isolation between the two feeding ports is better than 30 dB in the whole operating band. The measured -10 dB impedance bandwidths are 49% (4.72-7.75 GHz) and 63% (3.96-7.64 GHz) at port 1 and port 2, respectively. Moreover, the proposed antenna has a compact structure and stable gain over the operating band; thus it can be used in the 5.2/5.8 GHz WLAN and 5.5 GHz WiMAX systems. © The Institution of Engineering and Technology 2013.
Xiang Y.,Flight Automatic Control Research Institute |
Ren J.,Flight Automatic Control Research Institute |
Bai M.,Flight Automatic Control Research Institute |
Chen J.,Flight Automatic Control Research Institute |
Zhang J.,Flight Automatic Control Research Institute
Zhongguo Jiguang/Chinese Journal of Lasers | Year: 2014
The process of abrasive machining in lapping is considered as a moving sharp indentor subjected to normal force and tangential force. Based on indentation fracture mechanics theory, the grinding stresses of material, the location of median crack initiation and the direction of median crack propagation beneath an abrasive are analyzed. The calculation formula of median crack propagation length is analyzed by synthetically considering the contribution of elastic stress field, residual stress field and tangential force beneath the abrasive. A theoretical model of relationship between subsurface damage and surface roughness is established. A method of magnetorheological finishing (MRF) spot technique is proposed to the depth of subsurface damage. Predicted results are compared with experimental results, result shows that the error between predicted results and experimental results is less than 5.56%. The theoretical model can be used for prediction the depth of subsurface damage of optical materials in lapping process rapidly, expediently and accurately.
Bai M.-S.,Flight Automatic Control Research Institute |
Li P.,Flight Automatic Control Research Institute |
Zhang J.-K.,Flight Automatic Control Research Institute |
Teng L.,Flight Automatic Control Research Institute
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2013
On the basis of continuous polishing, a new polishing process was developed to meet the special requirements of ring lasers, synchrotron radiation accelerators and optical oscillators for the sphere mirrors with a large radius of curvature. Based on the Preston hypothesis, a mathematical model of material removal was established by analysis on the relative velocity at the radial point of an optical sphere surface in the classic polishing process. Via computer simulation, it explored that the reasons of the nonuniformity in sphere mirrors were that the mirrors cannot stay in the polishing pan during the polishing process and the rotation rate of the polishing pan is asynchronous with the mirrors. Two improvements were enlarging the size of the polishing pan and synchronizing the mirror rotation with the polishing pan. With the proposed process, a spherical mirror with the radius of 6000 mm was polished. Obtained results show that the nonuniformity ΔR/R in a sphere is less than 0.02, the roughness is less than 0.25 nm and the surface defect reaches a zero grade.
Jin L.,Flight Automatic Control Research Institute
Proceedings of the 28th Chinese Control and Decision Conference, CCDC 2016 | Year: 2016
Research on distributed task allocation in multi-unmanned aerial vehicles with multi-tasks. The task is divided into three types: detection, attack and verification tasks. Expertise vector and entropy in information theory are uased to display the commanality and distances of ability on unmanned aerial vehicles and tasks. The relationships between the tasks are also considered. The model of the task allocation for UAVs is established. And the distributed auction algorithm using communication topology is developed to solve the task allocation problem optimally based on the consensus theory. Simulation results show the rationality of the model and the effectiveness of the proposed method. © 2016 IEEE.