Goal-Oriented Control Systems(GOCS):From HOW to WHAT

Brief:New control theory is required to underpin safe design and deployment of future highly automated systems to deal with uncertain environments and complicated tasks,enabled by AI and other advanced technologies.Goal-Oriented Control Systems offer potential to transform the control system design from currently instructing a control system how to perform a task to specifying what is to be achieved.

Grinding Chatter Detection and Identication Based on BEMD and LSSVM

Grinding chatter is a self?induced vibration which is unfavorable to precision machining processes. This paper proposes a forecasting method for grinding state identification based on bivarition empirical mode decomposition(BEMD) and least squares support vector machine(LSSVM), which allows the monitoring of grinding chatter over time. BEMD is a promising technique in signal processing research which involves the decomposition of two?dimen?sional signals into a series of bivarition intrinsic mode functions(BIMFs). BEMD and the extraction criterion of its true BIMFs are investigated by processing a complex?value simulation chatter signal. Then the feature vectors which are employed as an amplification for the chatter premonition are discussed. Furthermore, the methodology is tested and validated by experimental data collected from a CNC guideway grinder KD4020 X16 in Hangzhou Hangji Machine Tool Co., Ltd. The results illustrate that the BEMD is a superior method in terms of processing non?stationary and nonlinear signals. Meanwhile, the peak to peak, real?time standard deviation and instantaneous energy are proven to be e ec?tive feature vectors which reflect the di erent grinding states. Finally, a LSSVM model is established for grinding status classification based on feature vectors, giving a prediction accuracy rate of 96%.

Model Predictive Control of Nonlinear Systems: Stability Region and Feasible Initial Control

This paper proposes a new method for model predictive control （MPC） of nonlinear systems to calculate stability region and feasible initial control profile/sequence, which are important to the implementations of MPC. Different from many existing methods, this paper distinguishes stability region from conservative terminal region. With global linearization, linear differential inclusion （LDI） and linear matrix inequality （LMI） techniques, a nonlinear system is transformed into a convex set of linear systems, and then the vertices of the set are used off-line to design the controller, to estimate stability region, and also to determine a feasible initial control profile/sequence. The advantages of the proposed method are demonstrated by simulation study.

Composite Nonlinear Bilateral Control for Teleoperation Systems With External Disturbances

This paper presents a new composite nonlinear bilateral control method based on the nonlinear disturbance observer(NDOB) for teleoperation systems with external disturbances. By introducing the estimations of NDOB and systems' nominal nonlinear dynamics into controller design, a NDOB based composite nonlinear bilateral controller is constructed to attenuate the influence of disturbance and uncertain nonlinearities. As compared with the existing bilateral control methods which usually achieve force haptic(i.e., contact force tracking)through a passive way, the newly proposed method has two major merits: 1) asymptotical convergence of both position and force tracking errors is guaranteed;2) disturbance influence on force tracking error dynamics is rejected through the direct feedforward compensation of disturbance estimation. Simulations on a nonlinear teleoperation system are carried out and the results validate the effectiveness of the proposed controller.

Design of Accelerated Life Test Plans——Overview and Prospect

Accelerated life test(ALT) is currently the main method of assessing product reliability rapidly, and the design of efficient test plans is a critical step to ensure that ALTs can assess the product reliability accurately, quickly, and economically. With the promotion of the national strategy of civil-military integration, ALT will be widely used in the research and development(R&D) of various types of products, and the ALT plan design theory will face further challenges. To aid engineers in selecting appropriate theories and to stimulate researchers to develop the theories required in engineering, with focus on the demands for theory research that arise from the implementation of ALT, this paper reviews and summarizes the development of ALT plan design theory. The development of the theory and method for planning optimal ALT for location-scale distribution, which is the most applied and mature theory of designing the optimal ALT plan, are described in detail. Taking this as the center of radiation, some problems that ALT now faces, such as the verification of the statistical model, limitation of sample size, solutions of resource limits, optimization of the test arrangement, and management of product complexity, are discussed, and the general ideas and methods of solving these problems are analyzed. Suggestions for selecting appropriate ALT plan design theories are proposed, and the urgent solved theory problems and opinions of their solutions are proposed. Based on the principle of convenience for engineers to select appropriate methods according to the problems found in practice, this paper reviews the development of optimal ALT plan design theory by taking the engineering problems arising from the ALT implementation as the main thread, provides guidelines on selecting appropriate theories for engineers, and proposes opinions about the urgent solved theory problems for researchers.

Octreotide-induced acute life-threatening gallstones after vicarious contrast medium excretion:A case report

BACKGROUND Octreotide is widely used for the treatment of acromegaly,neuroendocrine tumors,and secretory diarrhea.However,long-term octreotide treatment can increase the incidence of gallstones.Vicarious contrast medium excretion(VCME)through the hepatobiliary system is well known.However,few studies have reported octreotide-induced acute gallstones following VCME.CASE SUMMARY A 69-year-old man presented with left lower back pain and hematuria caused by a fall.The patient had a history of polycystic kidney disease.VCME occurred following renal artery embolization for a ruptured polycystic kidney.After 5 d of treatment with octreotide,the patient developed acute gallstones and intrahepatic cholestasis which further induced pancreatitis and cholangitis.He was discharged after hemodialysis,antibiotics,and supportive treatments.CONCLUSION For patients with a high-risk of VCME,octreotide should be cautiously administered and carefully monitored.

Novel Accelerating Life Test Method and Its Application by Combining Constan Stress and Progressive Stress

Constant stress accelerated life tests(ALTs) can be applied to obtain a high estimation accuracy of reliability measure?ments, but these are time?consuming tests. Progressive stress ALTs can yield failures more quickly but cannot guaran tee the estimation accuracy of reliability measurements. In this paper, a progressive?constant combination stress ALT is proposed to combine the merits of both tests. The optimal plan, in which the design variables are the initial pro?gressive stress level, the progressive stress ramp rate, the sample allocation proportion of the progressive stress and the constant stress level, is determined using the principle of minimizing the asymptotic variance of the maximum likelihood estimator of the natural log reliable life for the connectors. A comparison between the optimal PCCSALT plan and the CSALT plan with the same sample size and estimation accuracy shows that the test time is reduced by 13.59% by applying the PCCSALT.

A Modified Model Predictive Control Scheme

In implementations of MPC (Model Predictive Control) schemes, two issues need to be addressed. One is how to enlarge the stability region as much as possible. The other is how to guarantee stability when a computational time limitation exists. In this paper, a modified MPC scheme for constrained linear systems is described. An offline LMI-based iteration process is introduced to expand the stability region. At the same time, a database of feasible control sequences is generated offline so that stability can still be guaranteed in the case of computational time limitations. Simulation results illustrate the effectiveness of this new approach. Keywords Model predictive control - linear matrix inequality - stability region - terminal region - feasibility Xiao-Bing Hu received the B.S. degree in Aviation Electronic Engineering at Civil Aviation Institute of China, Tianjin, China, in 1998, the M.S. degree in Automatic Control Engineering at Nanjing University of Aeronautics & Astronautics, Nanjing, China, in 2001, and the Ph.D. degree in Aeronautical and Automotive Engineering at Loughborough University, UK, in 2005.He is currently a Research Fellow in Department of Informatics at Sussex University, UK. His major field of research includes predictive control, artificial intelligence, air traffic management, and flight control. Wen-Hua Chen received his MSc and Ph.D. degrees from Department of Automatic Control at Northeast University, China, in 1989 and 1991, respectively.From 1991 to 1996, he was a Lecturer in Department of Automatic Control at Nanjing University of Aeronautics & Astronautics, China. He held a research position and then a Lectureship in Control Engineering in Center for Systems and Control at University of Glasgow, UK, from 1997 to 2000. He holds a Lectureship in Flight Control Systems in Department of Aeronautical and Automotive Engineering at Loughborough University, UK. He has published one book and more than 60 papers on journals and conferences. His research interests are the development of advanced control strategies and their applications in aerospace engineering.

Experimental Tests of Autonomous Ground Vehicles with Preview

This paper describes the design and experimental tests of a path planning and reference tracking algorithm for autonomous ground vehicles. The ground vehicles under consideration are equipped with forward looking sensors that provide a preview capability over a certain horizon. A two-level control framework is proposed for real-time implementation of the model predictive control （MPC） algorithm, where the high-level performs on-line optimization to generate the best possible local reference respect to various constraints and the low-level commands the vehicle to follow realistic trajectories generated by the high-level controller. The proposed control scheme is implemented on an indoor testbed through networks with satisfactory performance.

Process development for producing a food-grade glucose solution from rice straws

In this paper, processes for producing a food-grade glucose solution through enzymatic hydrolysis of celluloserich solids obtained from rice straws are presented. The rice straws were pretreated by acid-catalyzed steam explosion, and the reaction efficiency, toxicity control, and process economic feasibility were studied. Mass transfer resistance to the hydrolysis reaction was reduced by grinding with glass beads. A higher glucose concentration could be obtained by feeding more cellulose in the hydrolysis reaction; however, this also resulted in the production of undesired byproducts. Thus, a soaking process for the cellulose solids in water was developed to effectively reduce the generation of byproducts in the hydrolysis reaction. The resulting food-grade glucose solution can provide 414 kilocalories per liter, and could be used during a food-shortage crisis in the future.The current production cost is estimated to be 0.82 USD·L^(-1).

Potential Bands of Sentinel-2A Satellite for Classification Problems in Precision Agriculture

Various indices are used for assessing vegetation and soil properties in satellite remote sensing applications. Some indices,such as normalized difference vegetation index(NDVI) and normalized difference water index(NDWI), are capable of simply differentiating crop vitality and water stress. Nowadays, remote sensing capabilities with high spectral, spatial and temporal resolution are available to analyse classification problems in precision agriculture. Many challenges in precision agriculture can be addressed by supervised classification, such as crop type classification, disease and stress(e.g., grass, water and nitrogen) monitoring. Instead of performing classification based on designated indices, this paper explores direct classification using different bands information as features. Land cover classification by using the recently launched Sentinel-2A image is adopted as a case study to validate our method. Four approaches of featured band selection are compared to classify five classes(crop, tree, soil, water and road) with the support vector machines(SVMs)algorithm, where the first approach utilizes traditional empirical indices as features and the latter three approaches adopt specific bands(red, near infrared and short wave infrared) related to indices, specific bands after ranking by mutual information(MI), and full bands of on-board sensors as features, respectively. It is shown that a better classification performance can be achieved by directly using the selected bands after MI ranking compared with the one using empirical indices and specific bands related to indices, while the use of all 13 bands can marginally improve the classification accuracy than MI based one. Therefore, it is recommended that this approach can be applied for specific Sentinel-2A image classification problems in precision agriculture.

Robust Assignment of Airport Gates with Operational Safety Constraints

This paper reviews existing approaches to the airport gate assignment problem （AGAP） and presents an optimization model for the problem considering operational safety constraints. The main objective is to minimize the dispersion of gate idle time periods （to get robust optimization） while ensuring appropriate matching between the size of each aircraft and its assigned gate type and avoiding the potential hazard caused by gate apron operational conflict. Genetic algorithm is adopted to solve the problem, An illustrative example is given to show the effectiveness and efficiency of the algorithm. The algorithm performance is further demonstrated using data of a terminal from Beijing Capital International Airport （PEK）.

Energy-efficient power amplifiers and linearization techniques for massive MIMO transmitters: a review

Highly efficient power amplifiers(PAs)and associated linearization techniques have been developed to accommodate the explosive growth in the data transmission rate and application of massive multiple input multiple output(mMIMO)systems.In this paper,energy-efficient integrated Doherty PA monolithic microwave integrated circuits(MMICs)and linearization techniques are reviewed for both the sub-6 GHz and millimeter-wave(mm-Wave)fifth-generation(5G)mMIMO systems;different semiconductor processes and architectures are compared and analyzed.Since the 5G protocols have not yet been finalized and PA specifications for mMIMO are still under consideration,it is worth investigating novel design methods to further improve their efficiency and linearity performance.Digital predistortion techniques need to evolve to be adapted in mMIMO systems,and some creative linearity enhancement techniques are needed to simultaneously improve the compensation accuracy and reduce the power consumption.

Development of nonlinear disturbance observer based control and nonlinear PID： A personal note

This paper gives an overview of early development of nonlinear disturbance observer design technique and the disturbance observer based control （DOBC） design. Some critical points raised in the development of the methods have been reviewed and discussed which are still relevant for many researchers or practitioners who are interested in this method. The review is followed by the development of a new type of nonlinear PID controller for a robotic manipulator and its experimental tests. It is shown that, under a number of assumptions, the DOBC consisting of a predictive control method and a nonlinear disturbance observer could reduce to a nonlinear PID with special features. Experimental results show that, compared with the predictive control method, the developed controller significantly improves performance robustness against uncertainty and friction. This paper may trigger further research and interests in the development of DOBC and related methods, and building up more understanding between this group of control methods with comparable ones （particularly control methods with integral action）.

Chattering-free sliding mode control with unidirectional auxiliary surfaces for miniature helicopters

Purpose-This article proposes a chattering-free sliding mode control scheme with unidirectional auxiliary surfaces(UAS-SMC)for small miniature autonomous helicopters(Trex 250).Design/methodology/approach-The proposed UAS-SMC scheme consists of a nested sequence of rotor dynamics,angular rate,Euler angle,velocity and position loops.Findings-It is demonstrated that the UAS-SMC strategy can eliminate the chattering phenomenon exhibiting in the convenient SMC method and achieve a better approaching speed.Originality/value-The proposed control strategy is implemented on the helicopter and flight tests clearly demonstrate that a much better performance could be achieved,compared with convenient SMC schemes.

Recursive Filter with Partial Knowledge on Inputs and Outputs

This paper investigates the problem of state estimation for discrete-time stochastic linear systems, where additional knowledge on the unknown inputs is available at an aggregate level and the knowledge on the missing measurements can be described by a known stochastic distribution. Firstly, the available knowledge on the unknown inputs and the state equation is used to form the prior distribution of the state vector at each time step. Secondly, to obtain an analytically tractable likelihood function, the effect of missing measurements is broken down into a systematic part and a random part, and the latter is modeled as part of the observation noise. Then, a recursive filter is obtained based on Bayesian inference. Finally, a numerical example is provided to evaluate the performance of the proposed methods.

无人机污染源自主搜寻算法综述

自主搜寻在环境保护、灾后搜救和工业监控等方面有重要作用.无人机传感平台凭借其灵活的机动性成为实现自主搜寻的有效途径之一.针对自主搜寻中两个关键任务,即污染源定位和污染边界跟踪,本文分别梳理了相关算法体系,并揭示了其设计思想的本质.对于污染物溯源,控制驱动和信息驱动两类算法是目前的研究主流,但两者的结合却鲜有报道.在边界跟踪方面,本文从单平台和多平台协作两方面总结了现有文献的控制和估计方法.根据双重控制思想,本文分析了相关算法的设计思路,并展望了下一步的研究重点.

Curvature-regulated transmembrane anion transport by a trifluoromethylated bisbenzimidazole

In this paper,we demonstrate that modification of anion-transport:active l,3-bis(benzimidazol-2-yl)benzene with strongly electron-withdrawing trifluoromethyl and nitro groups leads to a dramatic increase in the anionophoric activity,and the activity may be greatly regulated by the curvatures of the liposomes used.

Anion-Responsive Manganese Porphyrin Facilitates Chloride Transport and Induces Immunogenic Cell Death

Chloride is the most abundant anion in living systems.Most natural or synthetic chloride anionophores function via hydrogen-bonding interactions.However,dynamic metal-anion coordination can also be an efficient way of transporting chloride across membranes.Here,we investigate anion transport by manganese(Ⅲ)meso-tetraphenylporphyrin chloride{[Mn(TPP)Cl],TPP=meso-tetraphenylporphyrin}complex that exhibits labile axial coordination.[Mn(TPP)Cl]showed high chloride transport activity in a bilayer vesicle model with an EC_(50) value of 4.42×10^(−3) mol%.In living cells,[Mn(TPP)Cl]induced rapid chloride influx and autophagy.The release of Ca^(2+)and adenosine 5′-triphosphate(ATP),as well as the relocation of calreticulin,revealed that[Mn(TPP)Cl]caused immunogenic cell death.Proteomic analysis indicated that[Mn(TPP)Cl]impaired several physiological processes,including DNA synthesis,transcription,mitochondrial respiration,RNA translation,and immune response.Our study suggests that dynamic metal-anion interactions across membranes might provide a practical strategy for the interference of chloride homeostasis.