Finite-time adaptive fuzzy control for a class of output constrained nonlinear systems with dead-zone

The article investigates the finite-time adaptive fuzzy control for a class of nonlinear systems with output constraint and input dead-zone. First, by skillfully combining the barrier Lyapunov function, backstepping design method, and finite-time control theory, a novel adaptive state-feedback tracking controller is constructed, and the output constraint of the nonlinear system is not violated. Second, the fuzzy logic system is used to approximate unknown function in the nonlinear system. Third, the finite-time command filter is introduced to avoid the problem of “complexity explosion” caused by repeated differentiations of the virtual control signal in conventional backstepping control schemes. Meanwhile, a new saturation function is added in the compensating signal for filter error to improve control accuracy. Finally, based on Lyapunov stability analysis, all the signals of the closed-loop are proved to be semi-globally uniformly ultimately bounded, and the tracking error converges to a small neighborhood region of the origin in a finite time. A simulation example is presented to demonstrate the effectiveness for the proposed control scheme.     

利用贫软锰矿制备锰盐的研究

用二氧化硫法处理贫软锰矿，得到含硫酸锰和连二硫酸锰的溶液，继而将该溶液进行净化，除杂，浓缩，结晶处理即得工业级硫酸锰，结晶母液用碳铵沉淀即得碳酸锰产品     

杭州下沙土壤Pb、Zn、Cu的环境质量评价

对杭州下沙区土壤中酸碱度和铅、锌、铜进行监测分析,并使用单因子污染指数法与内梅罗综合污染指数法评价该区土壤环境质量状况。结果表明下沙区土壤偏碱性,重金属含量超过该区本底值,各区域土壤重金属含量关系从高到低依次为工业区、绿地、商业区、高教区。     

On Detectability and Observability of Discrete‐Time Stochastic Markov Jump Systems with State‐Dependent Noise

This paper mainly studies the notions of detectability and observability for discrete‐time stochastic Markov jump systems with state‐dependent noise. Two concepts, called “W‐detectability” and “W‐observability,” for such systems are introduced, and are shown to coincide with the other concepts on detectability and observability reported recently in literature. Moreover, some criteria and interesting properties for both W‐detectability and W‐observability are obtained.     

A large-range compliant micropositioning stage with remote-center-of-motion characteristic for parallel alignment

Micro-/nanopositioning stage with remote-center-of-motion (RCM) plays a key role in precision out-of-plane aligning since it can eliminate harmful lateral displacement generated at the output platform. This paper presents the design, modeling and test of a novel large-range flexure-based micropositioning stage with RCM characteristic. The stage is composed of an outer RCM guiding mechanism and a inner output-stiffness enhanced lever amplifier (OELA). The outer RCM guiding mechanism is constructed by a symmetric double parallelogram mechanism which can guide the stage to perform a RCM movement with high rotational precision. The inner OELA is designed to amplify the output displacement of the adopted piezoelectric stack actuator (PSA). Compared with conventional lever amplifier, the proposed OELA possesses twice the output stiffness, which makes it more appropriate for actuating the outer mechanism and therefore, a large rotational range can be obtained. Based on the pseudo-rigid-body-model (PRBM) method, the analytical models predicting kinematics, statics, and dynamics of the RCM stage have been established. Besides, the dimensional optimization is conducted in order to maximize the first resonance frequency of the stage. After that, finite element analysis is carried out to validate the established models and the prototype of the stage is fabricated for performance tests. The experimental results show that the developed RCM stage has a rotational range of 6.96 mrad while the maximum center shift of the RCM point is as low as \(9.2\,{\upmu } \text {m}\), which validate the effectiveness of the proposed scheme.     

Robust Stochastic Stability and Control for Uncertain Singular Markovian Jump Systems with Multiplicative Noise

This paper focuses on the problems of robust stability and stabilization and robust control for uncertain singular Markovian jump systems with (x,v)‐dependent noise. The parameter uncertainties appearing in state, input, disturbance as well as diffusion terms are assumed to be time‐varying but norm‐bounded. Based on the approach of generalized quadratic stability, the memoryless state feedback controller is designed for the robust stabilization problem, which ensures that the resulting closed‐loop system has an impulse‐free solution and is asymptotically stable in the mean square. Furthermore, the results of robust control problem are derived. The desired state feedback controller is presented, which not only meets the requirement of robust stabilization but also satisfies a prescribed performance level. The obtained results are formulated in terms of strict LMIs. What we have obtained can be viewed as corresponding extensions of existing results on uncertain singular systems. A numerical example is finally given to demonstrate the application of the proposed method.     

用程序代码控制热启动的原理与实现

本文介绍了微机启动的原理,给出了用程序代码控制热启动的两种方法。     

Smooth transition between different gaits of a hexapod robot via a central pattern generators algorithm

This paper focuses on the topic of smooth gait transition of a hexapod robot by a proposed central pattern generator (CPG) algorithm. Through analyzing the movement characteristics of the real insects, it is easy to generate kinds of gait patterns and achieve their smooth transition if we employ a series of oscillations with adjustable phase lag. Based on this concept, a CPG model is proposed, which is constructed by an isochronous oscillators and several first-order low-pass filters. As an application, a hexapod robot and its locomotion control are introduced by converting the CPG signal to robot’s joint space. Simulation and real world experiment are completed to demonstrate the validity of the proposed CPG model. Through measuring the position of the body center and the distance between footpoints and ground, the smooth gait transition can be achieved so that the effectiveness of the proposed method is verified.