True-temperature inversion algorithm for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization

Herein,a method of true-temperature inversion for a multi-wavelength pyrometer based on fractional-order particle-swarm optimization is proposed for difficult inversion problems with unknown emissivity.Fractional-order calculus has the inherent advantage of easily jumping out of local extreme values;here,it is introduced into the particle-swarm algorithm to invert the true temperature.An improved adaptive-adjustment mechanism is applied to automatically adjust the current velocity order of the particles and update their velocity and position values,increasing the accuracy of the true temperature values.The results of simulations using the proposed algorithm were compared with three algorithms using typical emissivity models:the internal penalty function algorithm,the optimization function(fmincon)algorithm,and the conventional particle-swarm optimization algorithm.The results show that the proposed algorithm has good accuracy for true-temperature inversion.Actual experimental results from a rocket-motor plume were used to demonstrate that the true-temperature inversion results of this algorithm are in good agreement with the theoretical true-temperature values.

Hypersonic reentry trajectory planning by using hybrid fractional-order particle swarm optimization and gravitational search algorithm

This paper proposes a novel hybrid algorithm called Fractional-order Particle Swarm optimization Gravitational Search Algorithm(FPSOGSA)and applies it to the trajectory planning of the hypersonic lifting reentry flight vehicles.The proposed method is used to calculate the control profiles to achieve the two objectives,namely a smoother trajectory and enforcement of the path constraints with terminal accuracy.The smoothness of the trajectory is achieved by scheduling the bank angle with the aid of a modified scheme known as a Quasi-Equilibrium Glide(QEG)scheme.The aerodynamic load factor and the dynamic pressure path constraints are enforced by further planning of the bank angle with the help of a constraint enforcement scheme.The maximum heating rate path constraint is enforced through the angle of attack parameterization.The Common Aero Vehicle(CAV)flight vehicle is used for the simulation purpose to test and compare the proposed method with that of the standard Particle Swarm Optimization(PSO)method and the standard Gravitational Search Algorithm(GSA).The simulation results confirm the efficiency of the proposed FPSOGSA method over the standard PSO and the GSA methods by showing its better convergence and computation efficiency.

求解并联冷机负荷分配问题的改进FODPSO算法

针对并联冷机负荷分配问题,以系统总功率最小为优化目标,建立满足系统末端负荷需求的并联冷机负荷分配优化模型,提出一种改进分数阶达尔文粒子群优化(IFODPSO)算法,以每台冷机的部分负荷率为优化变量进行求解,优化并联冷机系统的运行策略以节能。首先,针对基本分数阶达尔文粒子群优化(FODPSO)算法粒子初始化过于分散的问题,提出利用蒙特卡洛方法结合基本算数运算符生成初始种群;其次,针对其在高维优化中难以同时搜寻到每一维最优解的问题,引入多重优化提高算法稳定性并加快收敛速度;第三,针对易陷入局部最优的问题,通过自适应多策略行为使粒子能够根据其适应度选择合适的更新方式,提高了算法的搜索能力;最后,以2个典型的并联冷机系统作为案例验证所提出算法的性能,并与其他现有优化算法的实验结果进行对比。研究结果表明:相比于其他算法,IFODPSO算法在并联冷机负荷分配问题的求解中能够取得更加显著的节能效果,得到更优的运行策略,同时收敛精度、收敛速度和稳定性都有了显著提高。

基于分数阶达尔文粒子群FODPSO算法的图像分割

图像分割主要用于提取用户感兴趣的目标,是图像分类和识别的基础。采用一种基于分数阶达尔文粒子群算法的图像分割方法,该算法采用分数阶微积分控制系统收敛性,能够对n尺度图像进行n-1个阈值寻优计算。实验结果表明,对比于APSO、CFPSO算法,该算法具有收敛速度快、稳定性强、精度高、全局寻优等特点,有效地克服了传统算法易陷入局部最优和收敛速度慢等缺陷,可满足实际工程需求。