Zhaoyue Zhang^{1, *}, Jing Zhang², Peng Wang¹, Lei Chen³

CMC-Computers, Materials & Continua, Vol.57, No.1, pp. 151-166, 2018, DOI:10.32604/cmc.2018.02890

Abstract In order to explore the safe operation of UAVs in non-segregated airspace, a collision risk model for cylindrical UAVs based on conflict areas was constructed and the risk of conflict between manned and unmanned aerial vehicles was researched. According to the results of risk analysis, a strategy for solving the conflict of aircraft is proposed, and the risk assessment experiment of unmanned aerial vehicle (UAV) in non-isolated airspace conflict is carried out. The results show that under the experimental conditions, large unmanned aerial vehicles equipped with ADS-B, TCAS and other airborne sensing systems will indeed More >

Valera-Montero LL, PJ Muñoz-Rodríguez, H Silos-Espino, S Flores-Benítez

Phyton-International Journal of Experimental Botany, Vol.85, pp. 176-183, 2016, DOI:10.32604/phyton.2016.85.176

Abstract Guava fruit produced in Calvillo, Aguascalientes (Mexico) is considered to be of the best quality in this country. Nevertheless, growers from this place empirically know that there is a noticeable variation among individual trees within the same orchard, and variation among individuals from different orchards. In order to have a clear evidence of this, morphology analysis of guava was performed taking data from seventy nine individuals out of thirty six orchards, while RAPD was performed on a subset of twenty six individuals. Similarity was found for morphology data ranging from 87-100%, while similarity from RAPD More >

Liu Duo-Neng^1,2, Hou Zhong-Xi¹, Guo Zheng¹, Yang Xi-Xiang¹, Gao Xian-Zhong¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.6, pp. 531-565, 2016, DOI:10.3970/cmes.2016.111.531 - 01 March 2022

Abstract Dynamic soaring is a flight maneuver to exploit gradient wind field to extend endurance and traveling distance. Optimal trajectories for permissible wind conditions are generated for loitering dynamic soaring as well as for traveling patterns with a small unmanned aerial vehicle. The efficient direct collection approach based on the Runge-Kutta integrator is used to solve the optimization problem. The fast convergence of the optimization process leads to the potential for real-time applications. Based on the results of trajectory optimizations, the general permissible wind conditions which involve the allowable power law exponents and feasible reference wind… More >

B. J. Zhu^1,2, Z. X. Hou¹, X. Z. Wang³, Q. Y. Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.5, pp. 357-377, 2015, DOI:10.3970/cmes.2015.106.357

Abstract The paper presents a comprehensive study on the performance of long endurance and long distance trajectory optimization of engineless UAV in dynamic soaring. A dynamic model of engineless UAV in gradient wind field is developed. Long endurance and long distance trajectory optimization problems are modelled by non-linear optimal control equations. Two different boundary conditions are considered and results are compared: (i) open long endurance pattern, (ii) closed long endurance pattern, (iii) open long distance pattern. In patterns of (i) and (ii), the UAV return to original position with the maximum flying time in pattern (ii) More >

B. J. Zhu^1,2, Z. X. Hou¹, Y. F. Lu¹, S. Q. Shan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.6, pp. 467-490, 2015, DOI:10.3970/cmes.2015.105.467

Abstract This paper mainly analyzes the dynamic soaring of UAV utilizing gradient wind. Dynamic soaring is an efficient path in which UAV absorbs energy from environment to enhance its flight endurance. A set of three-dimensional point dynamic equations for a soaring aircraft in three degrees of freedom is used in calculations. To simplify the calculation, the gradient wind’s direction is taken into decomposition. The notion of trajectory subsection analysis is applied to account for the energy transformation mechanism during the dynamic soaring, and the zone of direction is converted into cutting-in angle, which is regarded as More >