A Lyapunov-based three-axis attitude intelligent control approach for unmanned aerial vehicle

A novel Lyapunov-based three-axis attitude intelligent control approach via allocation scheme is considered in the proposed research to deal with kinematics and dynamics regarding the unmanned aerial vehicle systems.There is a consensus among experts of this field that the new outcomes in the present complicated systems modeling and control are highly appreciated with respect to state-of-the-art.The control scheme presented here is organized in line with a new integration of the linear-nonlinear control approaches,as long as the angular velocities in the three axes of the system are accurately dealt with in the inner closed loop control.And the corresponding rotation angles are dealt with in the outer closed loop control.It should be noted that the linear control in the present outer loop is first designed through proportional based linear quadratic regulator(PD based LQR) approach under optimum coefficients,while the nonlinear control in the corresponding inner loop is then realized through Lyapunov-based approach in the presence of uncertainties and disturbances.In order to complete the inner closed loop control,there is a pulse-width pulse-frequency(PWPF) modulator to be able to handle on-off thrusters.Furthermore,the number of these on-off thrusters may be increased with respect to the investigated control efforts to provide the overall accurate performance of the system,where the control allocation scheme is realized in the proposed strategy.It may be shown that the dynamics and kinematics of the unmanned aerial vehicle systems have to be investigated through the quaternion matrix and its corresponding vector to avoid presenting singularity of the results.At the end,the investigated outcomes are presented in comparison with a number of potential benchmarks to verify the approach performance.

Application of hybrid robust three-axis attitude control approach to overactuated spacecraft——A quaternion based model

A novel hybrid robust three-axis attitude control approach, namely HRTAC, is considered along with the well-known developments in the area of space systems, since there is a consensus among the related experts that the new insights may be taken into account as decision points to outperform the available materials. It is to note that the traditional control approaches may generally be upgraded, as long as a number of modifications are made with respect to state-of-the-art, in order to propose high-precision outcomes. Regarding the investigated issues, the robust sliding mode finite-time control approach is first designed to handle three-axis angular rates in the inner control loop, which consists of the pulse width pulse frequency modulations in line with the control allocation scheme and the system dynamics. The main subject to employ these modulations that is realizing in association with the control allocation scheme is to be able to handle a class of overactuated systems, in particular. The proportional derivative based linear quadratic regulator approach is then designed to handle three-axis rotational angles in the outer control loop, which consists of the system kinematics that is correspondingly concentrated to deal with the quaternion based model. The utilization of the linear and its nonlinear terms, simultaneously, are taken into real consideration as the research motivation, while the performance results are of the significance as the improved version in comparison with the recent investigated outcomes. Subsequently, there is a stability analysis to verify and guarantee the closed loop system performance in coping with the whole of nominal referenced commands. At the end, the effectiveness of the approach considered here is highlighted in line with a number of potential recent benchmarks.

Nonlinear autopilot design for interceptors with tail fins and pulse thrusters via θ–D approach

The missile autopilot for an interceptor with tail fins and pulse thrusters is designed via the θ-D approach. The nonlin- ear dynamic model of the pitch and yaw motion of the missile is transformed into a linear-like structure with state-dependent coef- ficient （SDC） matrices. Based on the linear-like structure, a θ-D feedback controller is designed to steer the missile to track refer- ence acceleration commands. A sufficient condition that ensures the asymptotic stability of the tracking system is given based on Lyapunov＇s theorem. Numerical results show that the proposed autopilot achieves good tracking performance and the closed-loop tracking system is asymptotically stable.

Control Approaches to Soil Pollution from Heavy Metals

With the continuous development of human society and economy and the continuous progress of industrial technology,more and more pollutants are discharged into the natural environment,and soil environment is also affected at the same time. Among pollutants leading to soil pollution,heavy metals have resulted in most serious soil pollution. Here,many control and restoration approaches to soil pollution from heavy metals are proposed,and characteristics and applicable conditions of various methods are compared,so as to provide theoretical references for the control and restoration of soil pollution from heavy metals in future.

Systematic evaluation of the clinical nursing pathway with the GRADE approach applied to functional exercise in patients with hip replacements before and after surgery

Objective： To evaluate the effect of the clinical nursing pathway applied to functional exercise in patients with hip replacements before and after the operation. Methods： The China National Knowledge Infrastructure （CNKI）, WanFang Data, Chinese science and technology journal database （VIP）, PubMed, Web of Science, EMBASE, CBM and the Cochrane Library （2015-5） were searched for randomized controlled trials （RCTs） on clinical nursing pathways for func- tional exercise in patients with hip replacements before and after surgery from June 2015 to January 2010. The references included in the literature were also retrieved. To meet the literature standard, 2 reviewers independently selected and extracted data according to the inclusion criteria and assessed the risks of bias. RevMan 5.3 software was used in this meta-analysis. The quality of evidence was evaluated using grade profiler3.6 software, the level recommended for grading. Results： A total of 15 RCTs and 1248 patients were included. The meta-analysis showed that, in the clinical nursing path group, the Harris score of hip function [SMD = 3.35, 95%CI （2.53, 4.16）, P 〈 0.00001 ] and incidence of thrombosis embolism [RR - 0.28, 95%0 （0.15, 0.53）, P 〈 0.0001 ], pulmonary infection [RR = 0.33, 95%CI （0.14, 0.82）, P = 0.02], urinary retention [RR - 0.22, 95%CI （0.09, 0.52）, P = 0.0005], constipation [RR = 0.20, 95%0 （0.10, 0.40）, P 〈 0.00001 ], patients＇ satisfaction for nursing care [RR -- 1.26, 95%0 （1.17, 1.36）, P 〈 0.00001 ] and shortened hospitalization times [5MD = -1.91, 95%C! （ 2.39, -1.43）, P 〈 0.0001 ]were statistically significantly better than those in the control group. However, in reducing joint dislocations [Rig = 0.25, 95%C1 （0.05, 1.15）, P - 0.08], pressure ulcers [RR = 0.25, 95%0 （0.03, 2.19）, P = 0.21], and incidence of complications [RR = 0.42, 95%0 （0.15, 1.12）, P = 0.08], there was no statis- tically significant difference between the two groups. Funnel plot analysis of the average length of stay showed that there might be some publication bias in the literature. The GRADE evaluation results showed that the level of Harris scores for hip function was moderate and the incidence of thrombosis, urinary retention and satisfaction of patients regarding nursing were low, and the rest of the factors analyzed were very low. Conclusions： The effect of the clinical nursing pathway applied to functional exercises in patients with hip replacements before and after surgery was significantly better than that of routine nursing. However, it was restricted by the evaluation grade of the research results and the standardization and uniformity of the research. The results of the above study need to be verified by more high-quality RCTs.

Monte-Carlo based cascade control approach with focus on real overactuated space systems

The present research relies on a cascade control approach through the Monte-Carlo based method in the presence of uncertainties to evaluate the performance of the real overactuated space systems.A number of potential investigations in this area are first considered to prepare an idea with respect to state-of-the-art.The insight proposed here is organized to present attitude cascade control approach including the low thrust in connection with the high thrust to be implemented,while the aforementioned Monte-Carlo based method is carried out to guarantee the approach performance.It is noted that the investigated outcomes are efficient to handle a class of space systems presented via the center of mass and the moments of inertial.And also a number of profiles for the thrust vector and the misalignments as the disturbances all vary in its span of nominal variations.The acquired results are finally analyzed in line with some well-known benchmarks to verify the approach efficiency.The key core of finding in the research is to propose a novel 3-axis control approach to deal with all the mentioned uncertainties of space systems under control,in a synchronous manner,as long as the appropriate models in the low-high thrusts are realized.

Robust parametric approach for tracking control of an air-breathing hypersonic cruise vehicle

To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furthermore, the flight control problem is formulated as a robust model tracking control problem. And then, based on the robust parametric approach, eigenstructure assignment and reference model tracking theory, a parametric optimization method for robust controller design is presented. The simulation results show the effectiveness of the proposed approach.

Distribution Characteristics of Soil Salinity in Absorbing Carbon Forest

[Objective] The paper was to analyze the soil salinity characteristics in Xinjiang region, and develop salinization characteristic research, so as to provide reference for salinization research in arid region. [Method] With different land types of soil vertical profiles in Karamay absorbing carbon forest as research object, soil salinity and water soluble ions were determined and analyzed using statistical characteristic value and trend surface, and the distribution characteristic of soil salinity in the region was explored.[Result] The salinity in survey area of absorbing carbon forest mainly were sulfate-chloride type and chloride type, of which cations were mainly Na＋, K＋ and Ca2＋, anions were CO32-, Cl- and SO42-, the variation coefficient of CO32 - was as high as 292.91, while the variation coefficient of Cl- was 265.56. The variation of soil total soluble salts in the soil layer of 0-100 cm was not significant, indicating that the content in each soil layer was relatively stable. [Conclusion] The study provided basis for speeding up dynamic monitoring for soil salinization and finding the effective control approach against salinization

Mathematical Study of A Memory Induced Biochemical System

In this work, to study the effect of memory on a bi-substrate enzyme kinetic reaction, we have introduced an approach to fractionalize the system, considering it as a threecompartmental model. Solutions of the fractionalized system are compared with the corresponding integer-order model. The equilibrium points of the fractionalized system are derived analytically. Their stability properties are discussed from numerical aspect. We determine the changes of the substances due to the changes of "memory effect". The effect is discussed critically from the perspective of product formation. We have also analyzed the memory induced system with a control measure in view of optimizing the product. Our numerical result reveals that the solutions of the fractionalized system, when it is free from memory, are in good agreement with the integer-order system.It is noticed that the effect of memory influences the reaction in the forward direction and assists in yielding the product more quickly. However, an extensive use of memory makes the system slower, but introduction of a control input makes the reaction faster. It is possible to overcome the slowness of the reaction due to the undue effect of memory by appropriate use of a control measure.

On Advanced Control Methods toward Power Capture and Load Mitigation in Wind Turbines

This article provides a survey of recently emerged methods for wind turbine control. Multivariate control approaches to the optimization of power capture and the reduction of loads in components under time-varying turbulent wind fields have been under extensive investigation in recent years. We divide the related research activities into three categories： modeling and dynamics of wind turbines, active control of wind turbines, and passive control of wind turbines. Regarding turbine dynamics, we discuss the physical fundamentals and present the aeroelastic analysis tools. Regarding active control, we review pitch control, torque control, and yaw control strategies encompassing mathematical formulations as well as their applications toward different objectives. Our survey mostly focuses on blade pitch control, which is considered one of the key elements in facilitating load reduction while maintaining power capture performance. Regarding passive control, we review techniques such as tuned mass dampers, smart rotors, and microtabs. Possible future directions are suggested.

Cascade adaptive control of uncertain unified chaotic systems

The chaos control of uncertain unified chaotic systems is considered. Cascade adaptive control approach with only one control input is presented to stabilize states of the uncertain unified chaotic system at the zero equilibrium point. Since an adaptive controller based on dynamic compensation mechanism is employed, the exact model of the unified chaotic system is not necessarily required. By choosing appropriate controller parameters, chaotic phenomenon can be suppressed and the response speed is tunable. Sufficient condition for the asymptotic stability of the approach is derived. Numerical simulation results confirm that the cascade adaptive control approach with only one control signal is valid in chaos control of uncertain unified chaotic systems.

STUDIES ON FOREST WATER CYCLING

Principal ideas, research approaches and installations in both Liangshui and Maoershan Ecological Stations were diseussed. Significance of comparability and synchronous detennination in research methods were stressed. Comparison analysis was done on the results gained from diferent methods. Adaptive mechanisms of Mongolian oak (Quercus mongolica) to drought and unproductive sites wer expounded through hydrological cycling studies. Surface runoff and flood peak were decreased and the developing processes of flood peak were postponed or delayed because of the presence of huge forest canopy and forest floor. However, the conclusions of forest influences on total runoff,especially in spring and in the dry season t are significant to agricultul practices in notheast China and turned out contrary for satershed sizes or different approaches, which should be studied further.

Coupled Conductive-Convective-Radiative Heat Transfer in Hollow Blocks with Two Air Cells in the Vertical Direction Subjected to an Incident Solar Flux

This work presents the results of a set of steady-state numerical simulations about heat transfer in hollow blocks in the presence of coupled natural convection,conduction and radiation.Blocks with two air cells deep in the vertical direction and three identical cavities in the horizontal direction are considered(typically used for building ceilings).Moreover,their outside horizontal surface is subjected to an incident solar flux and outdoor environment temperature while the inside surface is exposed to typical indoor environment conditions.The flows are considered laminar and two-dimensional over the whole range of parameters examined.The conservation equations are solved by means of a finite difference method based on the control volumes approach,relying on the SIMPLE algorithm for what concerns the coupling of pressure and velocity.The effects of the number of cells in the horizontal direction and the thermal conductivity on the heat transfer through the alveolar structure have been investigated.The results show that the number of holes has a significant impact on the value of the overall heat flux through the considered structure.

An Optimal FASA Approach for UAV Trajectory Tracking Control

In this paper,a fully actuated system approach(FASA)-based control scheme is proposed for the trajectory tracking of a quadrotor unmanned aerial vehicle(UAV).System uncertainty,external disturbance and actuator constraint are all considered,which make the problem challenging.Inspired by the active disturbance rejection control(ADRC),tracking di®erentiator(TD)and extended state observer(ESO)are introduced for handling the uncertainties and generating the feedback signals.With the proposed feedback control law,the performance of the resulted closed loop system is related to its eigenstructure-eigenvalue and eigenvectors.Based on a type of control parametrization method,the parametrized eigenstructure of the closed loop system are optimized.A better performance is observed by comparative numerical simulation.

Common Fixed Point Theorems and Q-property for Quasi-contractive Mappings under c-distance on TVS-valued Cone Metric Spaces without the Normality

In this paper, we derive the stochastic maximum principle for optimal control problems of the forward-backward Markovian regime-switching system. The control system is described by an anticipated forward-backward stochastic pantograph equation and modulated by a continuous-time finite-state Markov chain. By virtue of classical variational approach, duality method, and convex analysis, we obtain a stochastic maximum principle for the optimal control.

Sex determination mechanisms and sex control approaches in aquaculture animals

Aquaculture is one of the most efficient modes of animal protein production and plays an important role in global food security.Aquaculture animals exhibit extraordinarily diverse sexual phenotypes and underlying mechanisms,providing an ideal system to perform sex determination research,one of the important areas in life science.Moreover,sex is also one of the most valuable traits because sexual dimorphism in growth,size,and other economic characteristics commonly exist in aquaculture animals.Here,we synthesize current knowledge of sex determination mechanisms,sex chromosome evolution,reproduction strategies,and sexual dimorphism,and also review several approaches for sex control in aquaculture animals,including artificial gynogenesis,application of sex-specific or sex chromosome-linked markers,artificial sex reversal,as well as gene editing.We anticipate that better understanding of sex determination mechanisms and innovation of sex control approaches will facilitate sustainable development of aquaculture.

Vehicle height and leveling control of electronically controlled air suspension using mixed logical dynamical approach

Vehicle height and leveling control of electronically controlled air suspension(ECAS) still poses theoretical challenges for researchers that have not been adequately addressed in prior research. This paper investigates the design and verification of a new controller to adjust the vehicle height and to regulate the roll and pitch angles of the vehicle body(leveling control) during the height adjustment procedures. A nonlinear mechanism model of the vehicle height adjustment system is formulated to describe the dynamic behaviors of the system. By using mixed logical dynamical(MLD) approach, a novel control strategy is proposed to adjust the vehicle height by controlling the on-off statuses of the solenoid valves directly. On this basis, a correction algorithm is also designed to regulate the durations of the on-off statuses of the solenoid valves based on pulse width modulated(PWM) technology, thus the effective leveling control of the vehicle body can be guaranteed. Finally, simulations and vehicle tests results are presented to demonstrate the effectiveness and applicability of the proposed control methodology.

The Controlled Approach in City Planning:Technique and Practice---Take,as an example,the control type of planning for the developing area of Chigang in Guangzhou

On the basis of the practice in Guangzhou in recent years,this article proposes the tech-nique of the“control”approach in city planning,and presents its specific application and ex-plorations with the example of the planning for the developing area of Chigang inGuangzhou.With the reform of the urban economic-political system and the advancement of theopen-door policy,significant changes are evolving in the ideas and the ways of city planningand design.To meet the demand of these developments,the new“control”approach in cityplanning and design is thus adopted.

Lines cluster approaching mode control for air-breathing hypersonic vehicle under disturbances and uncertainties

This paper investigates the velocity and altitude tracking control problem for airbreathing hypersonic vehicle(AHV)in the presence of external disturbances and parameter uncertainties.A composite controller containing improved lines cluster approaching mode control(LCAMC)and nonlinear disturbance observer(NDO)is developed to guarantee the tracking errors converge to zero and enhance the robustness of control system.Meanwhile,considering the multiple uncertain parameters,a genetic algorithm(GA)based Pareto uncertainty estimation is employed to predict the parameter uncertainties of the AHV dynamics.Besides,the mathematical proofs of proposed method are analyzed by utilizing Lyapunov theory.Simulation results demonstrate the effective tracking performance,excellent disturbance estimation and uncertainty estimation ability of the composite method.

Controlled synthesis of CO_2-diol from renewable starter by reducing acid value through preactivation approach

Synthesis of polyols from carbon dioxide（CO2） is attractive from the viewpoint of sustainable development of polyurethane industry;it is also interesting to adjust the structure of the CO2-polyols for versatile requirement of polyurethane.However,when renewable malonic acid was used as a starter,the copolymerization reaction of CO2 and propylene oxide（PO） was uncontrollable,since it proceeded slowly（13 h） and produced 40.4 wt%of byproduct propylene carbonate（PC） with a low productivity of 0.34kg/g.A careful analysis disclosed that the acid value of the copolymerization medium was the key factor for controlling the copolymerization reaction.Therefore,a preactivation approach was developed to dramatically reduce the acid value to 0.6mg（KOH）/gby homopolymerization of PO into oligo-ether-diol under the initiation of malonic acid,which ensured the controllable copolymerization,where the copolymerization time could be shortened by 77%from 13 to 3 h,the PC content was reduced by 76%from 40.4 wt%to 9.4 wt%,and the productivity increased by 61%from 0.34 to 0.55 kg/g.Moreover,by means of preactivation approach,the molecular weight as well as the carbonate unit content in the CO2-diol was also controllable.