Active disturbance rejection control: Applications in aerospace

Control of uncertain dynamical systems has been an area of active research for the past several decades and to this end, various robust control approaches have been proposed in the literature. The active disturbance rejection control (ADRC) represents one prominent approach that has been widely studied and applied for designing robust controllers in diverse areas of engineering applications. In this work, a brief review of the approach and some of its applications in aerospace are discussed. The results show that the approach possesses immense potential to offer viable solution to real life aerospace problems.     

Social Exclusion and the Deconstructed State: Time Perception, Meaninglessness, Lethargy, Lack of Emotion, and Self-Awareness.

The authors hypothesize that socially excluded individuals enter a defensive state of cognitive deconstruction that avoids meaningful thought, emotion, and self-awareness, and is characterized by lethargy and altered time flow. Social rejection led to an overestimation of time intervals, a focus on the present rather than the future, and a failure to delay gratification (Experiment 1). Rejected participants were more likely to agree that "Life is meaningless" (Experiment 2). Excluded participants wrote fewer words and displayed slower reaction times (Experiments 3 and 4). They chose fewer emotion words in an implicit emotion task (Experiment 5), replicating the lack of emotion on explicit measures (Experiments 1-3 and 6). Excluded participants also tried to escape from self-awareness by facing away from a mirror (Experiment 6). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A geometric approach to multivariable control system design of a distillation column

A multivariable control problem of a distillation column is considered, where the object is to maintain two output variables, the compositions of the distillate and the bottom product at some desired values by manipulating the reflux flow rate and the boil-up rate.Based on a linearized model, a geometric approach is applied to the design problem of disturbance rejection control. In other words, a feedback control strategy is desired which enables the complete rejection of the effect of disturbances on both output variables.In obtaining the feedback control, the problem of how many and what state variables are to be measured and fed back has been made clear. In this control strategy, only five state variables are fed back. Thus, only five columns of the feedback gain matrix have non-zero values. Furthermore, two out of these five columns are uniquely determined, and the other three columns can be assigned arbitrary values and used for pole assignment of the controlled system.For the disturbances in composition and flow rate of the feed stream, Δx_F and ΔL_F, the effect of the disturbance Δx_F is completely rejected by the feedback controller, but the effect of the disturbance ΔL_F can only be eliminated from the output Δx_D.A digital simulation of a distillation column composed of nine plates, a condenser and a reboiler was carried out to confirm these results and to show that the linearized model used in this paper is valid for fairly large step changes.     

周期计设计中的分段处理问题

本文通过对反应堆周期计响应时间、过冲量及噪声问题的分析,探论周期测量和周期保护信号分别处理的必要性和可能性,目的在于改善周期信号的品质,提高周期计的使用效果。本文首次报道了差分型周期计的响应函数。     

The Performance of Space-Time Processing for Suppressing Narrowband Interference in CDMA Communications

The requirement to suppress narrowband interferences in CDMA communications stems from the overlay concept, i.e., coexistence of different types of signals in the same frequency band. The conventional approach to rejecting the narrowband interferences has been to whiten the received signal containing the interference, prior to spread spectrum demodulation. In this paper, it is proposed to achieve the interference rejection through spatial processing. The main benefit of this approach is its robustness with respect to the interference bandwidth. Stepping up from single domain spatial processing to space-time processing provides degrees of freedom for both overlay interference cancellation and diversity combining. Two space-time architectures, cascade and joint-domain, are studied and compared to a Rake receiver preceded by a whitening filter. Main contributions of the paper are the development of analytical expressions of (1) the efficiency of each method, (2) the p.d.f.'s of the output SNR in a Rayleigh fading environment, and (3) the error probability associated with each method. The analysis therein demonstrates that the joint-domain architecture outperforms the cascade configuration, which in turn is superior to the whitening filter-Rake combination.     

武钢程潮铁矿预选抛尾工艺流程的研究与改进

在程潮选矿厂改扩建设计时，对预选抛尾流程的设计、生产及改进情况进行了分析和总结，在此基础上，制定了湿式分级全粒级预选抛尾流程，投产后获得了良好的经济效益。     

Some effects of rejection upon attraction to a group.

Adistinction was made between invidious rejection, defined as rejection for reasons that are likely to reflect upon the Ss' self-esteem, and noninvidious rejection. On the basis of the hypothesis that invidious rejection would arouse a need for social reassurance, it was predicted that: (a) for any given degree of rejection, loss of attraction to the group will be smaller when the reason for rejection is invidious than when it is noninvidious, and (b) that the differences in loss of attraction between invidious and noninvidious conditions will be greater after strong than after mild rejection. The results with respect to attraction to the group generally supported Hypothesis 1, but not Hypothesis 2. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

一种高PSRR的无运放带隙基准电路

设计了一种无运放带隙基准电路,该电路采用电压自调节技术来稳定输出基准电压,并实现该带隙基准电路在较宽频率范围内的高PSRR。该基准采用无运放结构,在降低电路复杂性的同时,避免了运算放大器的失调电压对输出基准的温度系数的影响。基于0.18μm BCD工艺,在Cadence环境下仿真得到该电路在10 Hz时,PSRR为-94 dB,在1 MHz时,PSRR为-44 dB;在-40～125℃温度范围内,温度系数为4×10^-6/℃;包含启动电路在内,该电路静态电流约为14μA,片上面积约为0.016 mm²。     

基于改进自抗扰的变流系统直流母线电压波动抑制策略

在直流母线电压波动的情形下,光伏并网变流系统易出现输入输出侧功率传输不平衡、运行不稳等问题,因此提出一种改进线性自抗扰控制策略。首先,建立变流系统物理模型和数学模型,并分析能量传输不平衡原理。然后,设计一阶线性自抗扰控制器取代传统比例积分矢量控制器。进一步,为加强扩张观测器扰动观测能力,引入新型参数解耦方法,形成解耦型改进自抗扰控制,提高系统的快速性和抗扰性。最后,依托频率响应特性曲线和多种模拟工况进行仿真验证。结果表明：相较于传统控制策略,改进线性自抗扰既具备优越的抑制直流侧母线电压波动的能力,又具有良好的扰动抵抗能力与短时暂态故障穿越能力,保证了系统的功率传输平衡与正常平稳运行。