一类不确定双线性广义系统的非脆弱无源控制

研究了一类带有不确定性和时滞的双线性广义系统的无源控制问题,利用Lyapunov泛函方法,通过求解线性矩阵不等式得到了具有非脆弱性的带记忆的状态反馈控制器的显示表达,保证闭环系统广义二次稳定且具有最大耗散率的无源性.给出最大耗散率的计算步骤的同时得到了使系统具有无源性的控制器.最后用数值例子说明了得到定理的有效性.     

一类双线性生态系统的无源控制

研究了一类广义双线性系统的无源控制问题,利用广义Lyapunov函数和线性矩阵不等式,给出了广义双线性系统无源且零解渐近稳定的充分条件,并在一定条件下得到存在状态反馈控制器,使得闭环系统无源且零解渐近稳定的充分条件,同时给出相应的控制器构造方法。     

三种群食物链系统的耗散性控制

利用两种特殊的耗散性控制：H∞－控制和无源化性控制,对三种群食物链系统进行了研究。首先,对三种群食物链系统进行了H∞－控制,获得了使闭环系统在正平衡点处全局渐近稳定的控制律。其次,利用无源化控制,得到了使闭环系统全局渐近稳定的控制律范围。     

线性广义系统的无源控制

研究线性广义系统在有界能量外部输入作用下的无源控制问题,给出广义系统容许且具有严格无源性的充分条件,并且在一定条件下设计一个状态反馈控制器使得闭环系统容许,同时具有严格无源性．     

一类具有加性时滞的神经网络系统的混杂控制

本文研究了具有加性时变时滞的神经网络系统混杂控制.基于混合触发机制构建了神经网络滤波误差系统模型,有效避免了芝诺现象通过求解一类矩阵不等式,给出了使得被控系统具有耗散滤波性能的充分条件,进而得到了基于混合触发机制的H_∞滤波、无源滤波、(Q,S,R)-耗散滤波和L2-L_∞滤波.最后,通过数值例子验证了方法的有效性.     

一个具有突变体的种群模型的变结构控制

基于一个具有突变体的种群模型,提出了相应的控制模型.根据变结构控制原理,针对控制模型,分别设计了变结构控制器和近似变结构控制器,使突变体灭绝.最后通过数值仿真,验证了所得结论的正确性.     

一类离散捕食-食饵模型的混沌跟踪控制

针对一类离散捕食食饵系统,采用Lyapunov指数方法、绘制系统分岔图和混沌吸引子等方式验证了混沌现象的存在.为了消除系统的混沌现象,根据控制理论的轨迹跟踪控制原理,设计混沌跟踪控制器将系统控制到任意给定的期望周期轨道上,达到了稳定种群的目的.仿真分析表明了所设计控制器的有效性.     

一种广义马尔科夫跳变时滞系统的保成本控制

针对广义马尔科夫跳变时滞系统,考虑了保成本控制问题.基于线性矩阵不等式的方法,给出了广义马尔科夫跳变时滞系统在模态独立条件下保成本控制器存在的充分条件.在所得结果基础上,进一步以线性矩阵不等式形式,给出了模态独立控制器增益的求解方法,实现了对广义马尔科夫跳变时滞系统的保成本控制.最后,通过数值例子验证了本文设计方法的有效性.     

毒素在森林各分室循环的广义模型的变结构控制

利用广义系统变结构控制理论,研究了一个毒素在森林各分室循环的广义模型的变结构控制问题.首先,针对毒素在森林生态系统各分室的循环特征,构建了毒素在森林各分室循环的广义模型;其次,利用广义系统理论,对所建模型的平衡点进行了稳定性分析;最后,应用广义系统变结构控制理论设计了变结构控制器,使森林各分室中的毒素最终稳定到零点,使森林生态系统正常发展.     

已烯雌酚在人体各器官转移模型的变结构控制

本文通过线性系统极点配置,李雅普诺夫方法研究了已烯雌酚在人体各器官转移模型的变结构控制问题,得到了使系统尽快达到稳定平衡点的变结构控制器．该问题为生物模型综合控制问题的研究奠定了基础．     

A Switching Controller System for a Wheeled Mobile Robot

A wheeled mobile mechanism with a passive and/or active linkage mechanism for rough terrain environment is developed and evaluated. The wheeled mobile mechanism which has high mobility in rough terrain needs sophisticated system to adapt various environments.We focus on the development of a switching controller system for wheeled mobile robots in rough terrain. This system consists of two sub-systems: an environment recognition system using link angles and an adaptive control system. In the environment recognition system, we introduce a Self-Organizing Map (SOM) for clustering link angles. In the adaptive controllers, we introduce neural networks to calculate the inverse model of the wheeled mobile robot.The environment recognition system can recognize the environment in which the robot travels, and the adjustable controllers are tuned by experimental results for each environment. The dual sub-system switching controller system is experimentally evaluated. The system recognizes its environment and adapts by switching the adjustable controllers. This system demonstrates superior performance to a well-tuned single PID controller.     

A Controller Design Method Based on a Neural Network for an Outdoor Mobile Robot

A wheeled mobile mechanism with a passive and/or active linkage mechanism for travel in rough terrain is developed and evaluated. In our previous research, we developed a switching controller system for wheeled mobile robots in rough terrain. This system consists of two sub-systems: an environment recognition system using a self-organizing map and an adjusted control system using a neural network. In this paper, we propose a new controller design method based on a neural network. The proposed method involves three kinds of controllers: an elementary controller, adjusted controllers, and simplified controllers. In the experiments, our proposed method results in less oscillatory motion in rough terrain and performs better than a well tuned PID controller does.     

Development of passivity in the rat: effect of tranquilizers and antidepressants

Following the views on passivity as one of the features of depression-like behaviour in rats developing as a result of unavoidable painful stimulation an attempt was made to eliminate by antidepressant drugs the passivity manifested in an almost complete absence of motor searching reactions in an "open field" and a maze. However tranquilizing drugs rather than antidepressants to a greater extent induced the effect presupposed. Hence the type of passivity under study corresponds more likely to neurotized behaviour than to a special depression-like. In the second series of experiments the action was studied of multiple injections of antidepressants on similar manifestations of passivity as well as on alimentary instrumental conditioned responses in rats with initially expressed passive character of behaviour. In this case too neither the presupposed increase of motor searching reaction was observed nor any significant changes in the rate of instrumental conditioning nor elimination of its failures of a "refuse" type.     

The enrichment of surface passive film on stainless steel during biofilm development in coastal seawater

The surface passive film on UNS S30400 alloy was characterized before and after biofilm development under different regimes of diurnal lighting in quiescent flowing coastal seawater. As exemplified by atomic force microscopy, the passive film grew under all test conditions with conspicuous variations in morphological features. X-ray photon spectroscopy illustrated an enrichment of the outer film by iron oxide and a progressive increase in the iron oxide/chromium oxide ratio with lighting. Mott-Schottky plots reflected the duplex nature of the film, comprising an outer n-type and an inner p-type configuration. The slopes of the plots showed a strong decrease in donor and acceptor densities with biofilm coverage and lighting, thus confirming passive film growth. These results provide new insights that passive film enrichment is an intrinsic process under practical marine conditions, and show that the evolution of the passive film is a key step to sustained passivity and/or its breakdown by microbial mechanisms.     

Environment Recognition System Based on Multiple Classification Analyses for Mobile Robots

Various mechanisms have recently been developed that combine linkage mechanisms and wheels. In particular, the combination of passive linkage mechanisms and small wheels is a main research trend because standard wheeled mobile mechanisms find it difficult to move on rough terrain. In our previous research, a six-wheel mobile robot employing a passive linkage mechanism has been developed to enhance maneuverability and was able to climb over a 0.20 m bump and stairs. We designed a hybrid velocity and torque controller using a neural network since simple velocity controllers fail to climb up. In this paper, we propose an environment recognition system for a wheeled mobile robot that consists of multiple classification analyses to make the robot more adaptive to various environments by selecting a suitable system such as decision making, navigation and controller using the result of the environment recognition system. We evaluate the recognition performance in operation environments; slopes, bumps and stairs by comparing principle component, k-means and self-organizing map analyses.     

Correlations of pelvis state to foot placement do not imply within-step active control

Experimental studies of human walking have shown that within an individual step, variations in the center of mass (CoM) state can predict corresponding variations in the next foot placement. This has been interpreted by some to indicate the existence of active control in which the nervous system uses the CoM state at or near mid-stance to regulate subsequent foot placement. However, the passive dynamics of the moving body and/or moving limbs also contribute (perhaps strongly) to foot placement, and thus to its variation. The extent to which correlations of CoM state to foot placement reflect the effects of within-step active control, those of passive dynamics, or some combination of both, remains an important and still open question. Here, we used an open-loop-stable 2D walking model to show that this predictive ability cannot by itself be taken as evidence of within-step active control. In our simulations, we too find high correlations between the CoM state and subsequent foot placement, but these correlations are entirely due to passive dynamics as our system has no active control, either within a step or between steps. This demonstrates that any inferences made from such correlations about within-step active control require additional supporting evidence beyond the correlations themselves. Thus, these within-step predictive correlations leave unresolved the relative importance of within-step active control as compared to passive dynamics, meaning that such methods should be used to characterize control in human walking only with caution.     

Winching up heavy loads with a compliant arm: a new local joint controller

A closed kinematic chain, like an arm that operates a crank, has a constrained movement space. A meaningful movement of the chain’s endpoint is only possible along the free movement directions which are given implicitly by the contour of the object that confines the movement of the chain. Many technical solutions for such a movement task, in particular those used in robotics, use central controllers and force–torque sensors in the arm’s wrist or a leg’s ankle to construct a coordinate system (task frame formalism) at the local point of contact the axes of which coincide with the free and constrained movement directions. Motivated by examples from biology, we introduce a new control system that solves a constrained movement task. The control system is inspired by the control architecture that is found in stick insects like Carausius morosus. It consists of decentral joint controllers that work on elastic joints (compliant manipulator). The decentral controllers are based on local positive velocity feedback (LPVF). It has been shown earlier that LPVF enables contour following of a limb in a compliant motion task without a central controller. In this paper we extend LPVF in such a way that it is even able to follow a contour if a considerable counter force drags the limb away along the contour in a direction opposite to the desired. The controller extension is based on the measurement of the local mechanical power generated in the elastic joint and is called power-controlled relaxation LPVF. The new control approach has the following advantages. First, it still uses local joint controllers without knowledge of the kinematics. Second, it does not need a force or torque measurement at the end of the limb. In this paper we test power-controlled relaxation LPVF on a crank turning task in which a weight has to be winched up by a two-joint compliant manipulator.     

Alteration of active and passive Wistar rats adaptive behavior in water-immersion model of depression

Animals with active and passive behavioral strategy were selected among male Wistar rats by testing them in the T-maze. Using the results of rats testing in T-maze index of behavioral activity and index of behavioral passivity were calculated. The development of post-stress psychopathology and ils correlation with initial behavioral strategy were studied under water-immersion stress conditions consiclering individual alteration of adaptive behavior. Two paradigms were used--one time trial (stress) and two times trial (stress-restress). It was found that active and passive rats being subjected to inescapable aversive exposure develop different types of post-stress depression and only passive animals show the signs of posttraumatic stress disorder.     

Individual behavioral and autonomic response to emotional stress in humans

Healthy subjects (n = 53) performed a sound version of the proof-reading test under normal conditions and in the state of emotional stress. Stress resistance was evaluated by the overall number of errors. The propensity to active or passive response to stress was evaluated by the number of "false alarms" and signal omissions. The reaction pattern to emotional stress in stress-resistant subjects, irrespective of their behavioral features, consisted in an increase in sympathetic effects on the cardiac rhythm and a decrease in the reaction time to significant signals. In subjects with low stress resistance, no statistically significant changes in the level of sympathetic tone and reaction time were revealed in the state of stress. Subjects with active behavioral response to stress, irrespective of their level of stress resistance, were characterized by aggressiveness, boldness and independence. Subjects with passive response to stress were inclined to conformism, dependence, and passivity.     

HIV controllers: how these patients control viral replication?

Some patients infected by the HIV are called HIV controllers because viral replication remains undectectable during a prolonged period of time in the absence of any antiretroviral treatment. This state could be considered as a ??functional cure?? in these virally infected patients. Understanding mechanisms underlying this prolonged control of viral replication is key to the development of future vaccinal strategies. French ANRS is exploiting a cohort of HIV controllers since several years, and immunological analysis of these patients has yielded some mechanistic clues that this review will discuss. A striking feature is the very efficient and polyfunctional CD8 T cell response of these patients, which exhibits a high avidity against the gag protein of the virus. Other parameters and questions are studied?: the role of HLA B57, overrepresented in this cohort?; how HIV controllers who do not express a very robust CD8 response control the viral replication?? The long term follow up of these patients will also give important informations on their -immunological, viral and clinical evolution.