Renyong Zhang¹, Caisheng Wei^{2, *}, Zeyang Yin^{3, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.1, pp. 89-107, 2020, DOI:10.32604/cmes.2020.07985 - 01 January 2020

Abstract This paper investigates a novel quasi fixed-time orbit tracking control method for spacecraft around an asteroid in the presence of uncertain dynamics and unknown uncertainties. To quantitatively characterize the transient and steady-state responses of orbit tracking error system, a continuous performance function is devised via using a quartic polynomial. Then, integrating backstepping control technique and barrier Lyapunov function leads to a quasi fixed-time convergent orbit tracking controller without using any fractional state information and symbolic functions. Finally, two groups of illustrative examples are employed to test the effectiveness of the proposed orbit control method. More >

Xin Wang^{1, 2, *}, Xiaokui Yue^{1, 2}, Haowei Wen^{1, 2}, Jianping Yuan^{1, 2}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.1, pp. 61-87, 2020, DOI:10.32604/cmes.2020.06871 - 01 January 2020

Abstract In this paper, a hybrid passive/active vibration (HPAV) controller of a loosely connected spacecraft consisting of a servicing satellite, a target and an X-shape structure isolator is first proposed to suppress vibrations of the system when subjected to the impulsive external excitations during the on-orbit missions. The passive dynamic response of the combined system can be adjusted appropriately to achieve the desired vibration isolation performance by tuning the structural parameters of the bio-inspired X-shape structure. Moreover, the adaptive control design through dynamic scaling technique is selected as the active component to maintain high vibration isolation More >

Wenyan Guo^{1, *}, Ting Liu¹, Fang Dai¹, Peng Xu¹

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 337-354, 2020, DOI:10.32604/cmc.2020.06411

Abstract Whale optimization algorithm (WOA) is a new population-based metaheuristic algorithm. WOA uses shrinking encircling mechanism, spiral rise, and random learning strategies to update whale’s positions. WOA has merit in terms of simple calculation and high computational accuracy, but its convergence speed is slow and it is easy to fall into the local optimal solution. In order to overcome the shortcomings, this paper integrates adaptive neighborhood and hybrid mutation strategies into whale optimization algorithms, designs the average distance from itself to other whales as an adaptive neighborhood radius, and chooses to learn from the optimal solution… More >

Qidan Zhu^a, Zhibo Yang^a,*

Computer Systems Science and Engineering, Vol.34, No.4, pp. 179-189, 2019, DOI:10.32604/csse.2019.34.179

Abstract The approach power compensator system (APCS) plays a role in the automatic carrier landing system (ACLS), and the performance of the APCS is affected by the carrier air-wake in the final-approach . In this paper, the importance of the APCS is verified through the analysis of the signal flow chart of the ACLS. Hence, it is necessary to suppress the carrier air-wake in order to improve the anti-interference ability. The adaptive sliding mode control (ASMC) not only has better dynamic tracking performance compared to the nonlinear mode, but also can efficiently resist the disturbance caused More >

N. Mohanapriya¹, Dr. B. Kalaavathi²

Intelligent Automation & Soft Computing, Vol.25, No.4, pp. 663-672, 2019, DOI:10.31209/2018.100000041

Abstract Medical images are obtained straight from the medical acquisition devices so that, the image quality becomes poor and may contain noises. Low contrast and poor quality are the major issues in the production of medical images. Medical imaging enhancement technology gives way to solve these issues; it helps the doctors to see the interior portions of the body for early diagnosis, also it improves the features the visual aspects of an image for a right diagnosis. This paper proposes a new blend of Particle Swarm Optimization (PSO) and Accelerated Particle Swarm Optimization (APSO) called Hybrid… More >

Rana Javed Masood¹, DaoBo Wang¹, Zain Anwar Ali², Muhammad Anwar²

Intelligent Automation & Soft Computing, Vol.25, No.2, pp. 295-304, 2019, DOI:10.31209/2018.100000009

Abstract In this article, adaptive hybrid control scheme is proposed for controlling the position of a coaxial tri-rotor unmanned aerial system (UAS) in the presence of input saturation and external wind disturbance. The adaptive hybrid controller consists of model reference adaptive control with integral feedback (MRACI) and proportional integral derivative (PID) controller. The adaptive controller deals with the flight dynamics uncertainties and PID controller is used for tuning the gains of MRACI whereas the stability of system is verified by Lyapunov stability criterion. The integrator improves the order of the system thereby improving the convergence rate… More >

Awais Qasim^a, Syed Asad Raza Kazmi^b

Intelligent Automation & Soft Computing, Vol.25, No.1, pp. 49-63, 2019, DOI:10.31209/2018.100000012

Abstract The paradigm of multi-agent systems is very expressive to model distributed real-time systems. These real-time multi-agent systems by their working nature have temporal constraints as they need to operate in pervasive, dynamic and unpredictable environments. To achieve better fault-tolerance, they need to have the ability of self-adaptivity making them adaptable to the failures. Presently there is a lack of vocabulary for the formal modelling of real-time multi-agent systems with self-adaptive ability. In this research we proposed a framework named SMARTS for the formal modelling of self-adaptive real-time multi-agent systems. Our framework integrates MAPE-K interfaces, reflection More >

Xia Wang¹, Hongming Shen¹, Huawei Tao², Ruiyu Liang³, Xing Deng^4,5, Haijian Shao⁵, Li Zhao^6,*, Cairong Zou⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.2, pp. 551-567, 2019, DOI:10.32604/cmes.2019.06314

Abstract To make full use of the residual audible frequency band of hearing-loss patients and improve the intelligibility of speech, an adaptive nonlinear frequency compression (NFC) algorithm is proposed, which amplifies signals below the cutoff frequency while compresses signals above the cutoff frequency. Firstly, high-frequency signals are decomposed to critical band signals according to the BARK scale. Secondly, the global compression ratio is determined according to the patient's cutoff frequency and maximum audible frequency. Thirdly, the sub-band compression ratio is adaptively determined based on the global compression ratio and normalized average energy of subband signals. Finally, More >

Ying Song^1,2, Jiale Yan^1,2, Shaofan Li^2,*, Zhuang Kang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.2, pp. 465-492, 2019, DOI:10.32604/cmes.2019.07190

Abstract In the present work, a state-based peridynamics with adaptive particle refinement is proposed to simulate water ice crater formation due to impact loads. A modified Drucker-Prager constitutive model was adopted to model ice and was implemented in the state-based peridynamic equations to analyze the elastic-plastic deformation of ice. In simulations, we use the fracture toughness failure criterion in peridynamics to simulate the quasi-brittle failure of ice. An adaptive particle refinement method in peridynamics was proposed to improve computational efficiency. The results obtained using the peridynamic model were compared with the experiments in previous literatures. It More >

Yongwei Wang¹, Fei Han^2,*, Gilles Lubineau^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.121, No.2, pp. 399-423, 2019, DOI:10.32604/cmes.2019.07192

Abstract Classical continuum mechanics which leads to a local continuum model, encounters challenges when the discontinuity appears, while peridynamics that falls into the category of nonlocal continuum mechanics suffers from a high computational cost. A hybrid model coupling classical continuum mechanics with peridynamics can avoid both disadvantages. This paper describes the hybrid model and its adaptive coupling approach which dynamically updates the coupling domains according to crack propagations for brittle materials. Then this hybrid local/nonlocal continuum model is applied to fracture simulation. Some numerical examples like a plate with a hole, Brazilian disk, notched plate and More >