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Technique of approximate optimal vibration control and simulation for vehicle active suspension systems are developed. Considered the nonlinear damping of springs, mechanical model and a nonlinear dynamic system for a class of tracked vehicle suspension vibration control are established and the corresponding system of state space form is described. To prolong the working life of suspension system and improve ride comfort, based on the active suspension vibration control devices and using optimal control approach, an approximate optimal vibration controller is designed, and an algorithm is presented for the vibration controller. Numerical simulation results illustrate the effectiveness of the proposed technique.

The electric vehicle circular charging device is a kind of large, high-power, DC, box charging equipment, which has the characteristics of power sharing and flexible charging. In order to make the circular charging device work and operate normally, a remote mobile monitoring and fault diagnosis system is designed based on cloud platform. The system is composed of server and mobile terminal. The server is developed based on Web Service platform, providing large data interaction for mobile terminals. The mobile terminal is based on the Android platform to design the mobile monitoring function for the charging pile and to handle the fault. The analysis and diagnosis method based on fault tree and fault processing flow of charging equipment is given in detail. The application of the system shows that the intelligent management, intelligent operation monitoring and intelligent after-sale service of the equipment are realized, and the management efficiency is improved.

To realize the robust control of underactuated Autonomous Underwater Vehicle (AUV) with uncertainties of un-modeled dynamics, parameter perturbations and random disturbances, a robust optimal sliding mode control approach is proposed based on Linear quadratic optimal regulator (LQR) and sliding mode control. Firstly, the AUV model in vertical plane is given. Secondly, based on the State Dependent Riccati Equation (SDRE), the optimal controller is designed for the AUV nominal system without uncertainties, which makes the quadratic performance index optimal. Then, considering the uncertainty of the system, the robust optimal integral sliding mode control law is designed based on SDRE nominal controller, which makes the AUV system satisfy the requirement of the performance index, and it is robust to the parameter perturbations and random disturbances. Finally, the validity and robustness of the presented control approach is demonstrated by a dynamic model of the Remote Environmental Unit (REMUS) AUV.

Technique of optimal vibration control and simulation for vehicle active suspension systems is developed. Considered the nonlinear damping of springs, mechanical model and nonlinear dynamic system for a class of tracked vehicle half-car suspensions vibration control are established and the corresponding system of state space form is described. In order to prolong the working life of suspension system and improve ride comfort, based on the active suspension vibration control devices and used optimal control approach, an optimal vibration controller is designed, and an algorithm is presented for the vibration controller. Numerical simulation results illustrate the effectiveness of the proposed technique.

This paper considers the optimal trajectory tracking control (OTTC) problem for autonomous underwater vehicles (AUVs) with delays in actuator and measurement affected by shallow wave disturbances. Firstly, we construct the models of AUVs with delays, shallow wave disturbances and the desired trajectory respectively. Secondly, through a particular transformation, the original AUV system with delays is reduced into a non-delay free system. Then the coupled two-point boundary value (TPBV) problems are derived from the optimal control theory; and using a recently developed successive approximation approach to construct sequences, the coupled TPBV problem is transformed into two decoupled linear differential sequences in state vectors and adjoint vectors. By iterative solving the two differential sequences, the approximate OTTC law is obtained. Finally, the effectiveness and feasibility of the OTTC law is demonstrated by a dynamic model of the Remote Environmental Unit (REMUS) AUVs.

Nonlinear optimal vibration control (NOVC) for autonomous underwater vehicles (AUVs) with input delay affected by wave disturbances is considered. Firstly, the AUVs model with input delay in vertical plane is obtained, and an exosystem to generate the irregular wave disturbances is constructed. Secondly, through a particular transformation, the original system with input delay is reduced into a delay free system. Then, the coupled two-point boundary value (TPBV) problem for the AUVs system without delay is derived from the optimal control theory. By using a recently developed successive approximation approach to construct sequences, the coupled TPBV problem is transformed into solving two decoupled linear differential sequences in state vectors and adjoint vectors. By iterative solving the two equation sequences, the approximate NOVC law is obtained. Finally, the effectiveness and feasibility of the presented control law is demonstrated by a numerical example of the Remote Environmental Unit (REMUS) AUVs.

The trends of and relationships among the plant community, soil nutrients, and four soil enzymes were investigated after being abandoned for 10, 15, 20, 30, and 45 years to reveal the soil properties during the restoration in the Loess Hilly Region. The results indicate the following ranking of dominant plant community species

We investigated the species composition and diversity of four grassland communities with different slope aspects in the loess hilly area of China. The power law was used to analyze spatial heterogeneity of the community and spatial pattern of the population. The results showed that Artemisia sacrorum was the dominant species and occurred in each site. Other species had different status and contributed differently to the spatial pattern of communities. Moreover, the spatial patterns of communities responded differently to various slope aspects, with the degree of aggregation ranked as sunnyhalf-sunnyhalf-shadyshady. The spatial heterogeneity index of community was positively correlated with the Simpson diversity index, but was negatively correlated with Margalef richness, Shannon diversity and Pielou evenness. The relative spatial heterogeneity index of the dominant species (A. sacrorum), sub-dominant species (Lespedeza dahurica and Stipa bungeana), and a few associated species (Artemisia scoparia, Melica scabrosa) were larger than that of the community, which resulted in cluster distribution. However, the relative spatial heterogeneity index of most associated species (Phragmites communis, Sonchus arvensis, and Bothriochloa flaccidum) showed the similar trends with the distribution of the community. In contrast, the relative spatial heterogeneity index of Cephalanoplos segetum, Gueldenstaedtia multiflora and Artemisia giraldii was lower than that of the community. These differences reduced the aggregation degree of the community. In summary, the aggregation degree of community was determined by dominant species, sub-dominant species and occasional species. Specifically, the dominant species, sub-dominant species and some associated species could promote the aggregation of the community, but occasional species would reduce the cluster distribution.本研究以黄土丘陵沟壑区4种不同坡向的草地植物群落为研究对象,探讨其物种组成和多样性特征,并运用幂乘方法则分析了群落的空间异质性和种群空间格局.结果表明: 铁杆蒿在不同坡向均有分布,为群落优势种;其他物种在不同坡向群落中的地位及对群落空间格局的贡献不同.不同坡向植物群落的空间分布格局均为集群分布,且聚集程度大小为阳坡＞半阳坡＞半阴坡＞阴坡.群落空间异质性指数与Simpson多样性指数呈显著正相关,与Margalef丰富度指数、Shannon多样性指数和Pielou均匀度指数呈显著负相关.优势种铁杆蒿、亚优势种达乌里胡枝子和长芒草,以及少数伴生种如猪毛蒿、臭草的相对空间异质性指数大于群落整体空间异质性指数,使群落趋于集群分布;多数伴生种如芦苇、苦荬菜、白羊草的相对空间异质性指数与群落整体空间异质性指数相近,它们与群落自身分布状态一致;刺儿菜、米口袋、茭蒿等偶见种的相对空间异质性指数小于群落整体空间异质性指数,降低了群落的聚集程度.综上,群落的聚集程度主要由优势种、亚优势种和偶见种共同决定,其中优势种、亚优势种和部分伴生种促使群落呈聚集分布,偶见种则降低了群落的集群分布.

Fault Tree Analysis (FTA) is a well-established and well-understood technique, widely used for fault diagnosis of a wide range of systems. In this paper, a fault diagnosis system for electric vehicle charging devices is designed and developed based on FTA, in order to accurately locate and quickly solve the fault problems of the charging devices. Firstly, a four-layer structure of the fault diagnosis system framework is constructed concretely, which is made up with client layer, service layer, communication layer and equipment layer. Secondly, the fault tables are set up by analyzing the actual fault of the charging pile and the charging generator. Then, according to the fault tables, we design the fault tree and put forward the flow of fault diagnosis. Finally, the fault diagnosis system is tested in the actual project, which can realize the fast location of the fault and greatly shortened the maintenance time.

The depth issue of underactuated autonomous underwater vehicle (AUV) under wave disturbances is addressed and an approximate optimal disturbance rejection control (ODRC) is proposed. Firstly, a nonlinear control model of AUV in vertical plane is given, and the model of wave disturbances is generated by an exosystem. Secondly, the coupled two-point boundary value (TPBV) problem for AUV is derived from the theory of the quadratic optimal control. Using a recently developed successive approximation approach, the coupled TPBV problem is transformed into solving decoupled a linear state equation sequence and a linear adjoint equation sequence. Then by iterative solving the two equation sequences, the approximate ODRC law is obtained. Finally, simulation is provided to demonstrate the effectiveness.

According to the national standard, an electric vehicle drive-motor test and analysis system is developed based on least square method. Firstly, the system structure is designed, which consists of three layers: monitoring layer, measurement and control layer and equipment layer, and the functions and composition of each part are introduced. Secondly, the control system is designed to be two parts: the test system and the analysis system, and the flow charts of the test system and the analysis system are given. Then, in order to analyze the performance of the motor, the principle of the least square method of curve fitting is used. Finally, the system is applied actually in motor industry, and the effectiveness and practicability are verified.

In order to solve the rotational torque curve fitting problem of three-phase asynchronous motor, an on-line fitting algorithm based on particle swarm optimization is designed. Firstly, the rotational torque model of three-phase asynchronous motor is established by using the Taylor-polynomial model. Secondly, through the particle swarm optimization algorithm and the polynomial evaluation function, the order of optimal fitting is solved and the online fitting is realized. Finally, the algorithm is applied actually in motor industry through Visual Studio platform, and shows that it is effective.

In this paper, a self-adaptive least square method based on data driven is presented, in order to solve the problem of fitting data with severe outliers in motor testing system. Firstly, the mechanical properties of the motor are given, and the model of T-n curve based on the Taylor polynomial expansion approximation is designed. Secondly, the design process of the self-adaptive least-square method is proposed, which uses the gradient descent approximation model and eliminate the influence of outliers by organizing the data. Then, the flow diagram of algorithm is given. Finally, the effectiveness of the presented self-adaptive algorithm is demonstrated in motor testing system.

This paper presents an optimal internal model control (OIMC) algorithm for heading control problem of Autonomous Underwater Vehicle (AUV) affected by irregular wave forces. Firstly, the AUV system model is proposed, and the exosystem of irregular wave forces is obtained based on the Morison equation. Secondly, the disturbances compensator is designed by using internal model. And a new augmented system is constructed, by taking the system and the disturbances compensator in series. Then the optimal control problem of AUV nonlinear system is transformed into the optimal regulator design problem of an augmented system. The OIMC law is designed according to the theory of the quadratic optimal control and stability degree constraint. Finally, the controller is applied to the heading control of AUV with irregular wave forces disturbances, and the results demonstrate the effectiveness and robustness of the controller.

To realize the optimal control of underactuated autonomous underwater vehicle (AUV) in vehicle plane with external disturbances, a optional internal model control (OIMC) is proposed with respect to the quadratic performance indexes. Firstly, the depth control model of underactuated AUV system and the wave model are proposed; then using internal model principle, the disturbances compensator is designed, which exactly offset the impact of external disturbances on the system, and the optional internal model control law is designed according to the different quadratic performance index, which is derived from the Riccati equation. Finally, the controller is applied to the dive plane control of AUV with wave force disturbances, and the results demonstrate the effectiveness and robustness of the controller.

This paper presents an optimal internal model control (OIMC) algorithm for heading control problem of underactuated AUV systems affected by wave disturbances. Firstly, the AUV nonlinear system model is converted to the system model by differential homeomorphism. And the exosystem of wave force disturbances is obtained based on the Morison equation. Secondly, the disturbances compensator is designed by using internal model. And a new augmented system is constructed, by taking the system and the disturbances compensator in series. Then the optimal control problem of AUV nonlinear system is transformed into the optimal regulator design problem of an augmented system. The optimal internal model control law is designed according to the different quadratic performance index. Finally, the controller is applied to the heading control of AUV with wave force disturbances, and the results demonstrate the effectiveness and robustness of the controller.

This paper presents an optimal output tracking control method for a class of typical chemical reaction process of non-isothermal CSTR. Firstly, the model of nonlinear CSTR system is provided. Secondly, by using feedback linearization method, the nonlinear system is converted into a linear system. Then, the output tracking controller is designed, which guarantees that the output signal of the system can track the desired signal asymptotically. At last, the simulation results show the effectiveness of the method.

This paper considers the optimal output tracking control problem for nonlinear systems affected by external disturbances based on stability degree constraint. The objective is to find an optimal output tracking controller, by which the cost function minimum and the state with the optimal having a higher mean-square convergence rate can be obtained. An optimal output tracking law is derived from a Riccati equation and Matrix equations. We give the existence and uniqueness conditions of the control law. Finally, a practical example is given to illustrate the effectiveness of the theory.

This paper considers the optimal rejection with Zero Steady-State Error for nonlinear systems with step and ramp composite disturbances. Firstly, the nonlinear system model with composite disturbances is transformed into linear system with disturbances, then we construct an augmented linear system without disturbances. With respect to the quadratic performance indexes of infinite horizon, consequently, the problem of disturbance rejection with zero steady-state error is transformed into the problem of designing an optimal controller for the augmented plant without disturbances, which can eliminate static error. Thus the disturbances can unfold of the signal through the Taylor series for the form of polynomial function of time, and obtain optimal controller design approach to eliminate the general disturbance. Finally, a practical example is given to illustrate the effectiveness of the theory.

This paper considers an infinite-time optimal damping control problem for a class of nonlinear systems with sinusoidal disturbances. A successive approximation approach (SAA) is applied to design feedforward and feedback optimal controllers. By using the SAA, the original optimal control problem is transformed into a sequence of nonhomogeneous linear two-point boundary value (TPBV) problems. The existence and uniqueness of the optimal control law are proved. The optimal control law is derived from a Riccati equation, matrix equations and an adjoint vector sequence, which consists of accurate linear feedforward and feedback terms and a nonlinear compensation term. And the nonlinear compensation term is the limit of the adjoint vector sequence. By using a finite term of the adjoint vector sequence, we can get an approximate optimal control law. A numerical example shows that the algorithm is effective and robust with respect to sinusoidal disturbances.

Technique of feedforward and feedback optimal vibration control and simulation for long-span cable-bridge coupled systems is developed. Buffeting loading systems of long-span cable-bridge structure are constructed by weighted amplitude wave superposition method. Nonlinear model of cable-bridge coupled vibration control system is established and the corresponding system of state space form is described. In order to reduce buffeting loading influence of the wind-induced vibration for the structure and improve the robust performance of the vibration control, based on semiactive vibration control devices and optimal control approach, a feedforward and feedback optimal vibration controller is designed, and an algorithm is presented for the vibration controller. Numerical simulation results are presented to illustrate the effectiveness of the proposed technique.

We consider an optimal control problem of MIMO systems affected by external disturbances with known dynamic characteristics but unknown initial conditions based on stability degree constraint. The objective is to find an optimal control, by which the cost function minimum and the state with the optimal control having a higher mean-square convergence rate can be obtained. A feedforward and feedback optimal control law is derived from a Riccati equation and a Matrix equation. We give the existence and uniqueness conditions of the feedforward and feedback optimal control law, and present an actualizing algorithm of solving the optimal control law. Finally, a practical example is given to illustrate the effectiveness of the theory.

It is shown in this paper that the successive approximation procedure simplifies computations of the optimal solution of a bilinear-quadratic optimal control problem. For a given bilinear system affected by external periodic disturbances, a sequence of linear problems is constructed, and their solutions are shown to converge to the desired solution. By solving iterative the sequences, the optimal control law is obtained. By comparing the error of quadratic performance indexes, we can obtain an approximate optimal disturbance rejection control law. A simulation example is used to demonstrate the efficiency of the new method.

This paper deals with an optimal control problem for a class of singularly perturbed time-delay large-scale systems. The optimal control laws for the order-reduced slow subsystem with time-delay and fast subsystem are designed, respectively. For the slow subsystem, the sensitivity approach is proposed to solve the coupled two-point boundary value (TPBV) problem with both time delay and advance terms. The TPBV problem is transformed into a decoupled sequence of inhomogeneous linear TPBV problems without time delay and advance terms. By solving the sequence of TPBV problems and Riccati equations, the approximate optimal control law of the original system is obtained. The control law consists of analytic state feedback and a time-delay compensation term which is a series sum of adjoint vectors. The compensation term can be approximately obtained by a recursion formula of adjoint vectors. Numerical examples show that the proposed method is valid.

This paper considers the optimal tracking control (OTC) problem for MIMO systems affected by external disturbances based on stability degree constraint. The objective is to find an OTC, by which the cost function minimum and the state with the OTC having a higher mean-square convergence rate can be obtained. According to the special disturbance form, by supposing the Lagrange operator to solve the two-point boundary value (TPBV) problem, A feedforward and feedback OTC law is derived from a Riccati equation and Matrix equations. We give the existence and uniqueness conditions of the OTC law. Finally, a practical example is given to illustrate the effectiveness of the theory.

The optimal control for CooPerative control of multi-motor drive system is considered. A multi-motor drive model with disturbances is presented. Firstly, the Mathematical model of the cooPerative control of multi-motor drive system is formulated. Then, the finite horizontal feedforward and feedback optimal active control law are designed by introducing a disturbance compensation term, which can be obtained by solving matrix Riccati equation and special matrix equation. The control design method is easy to implement.

This paper considers the optimal tracking control (OTC) problem for Bilinear systems affected by sinusoidal disturbances, and gives a successive approximation approch to solve analogous problems for general bilinear systems. For a given bilinear OTC problem, a sequence of linear problems is constructed, and their solutions are shown to converge to the desired solution. By iteratively solving the sequences of two-point boundary value problem, the OTC law is obtained. By comparing the error of quadratic performance indexes, we can obtain an approximate optimal disturbance rejection tracking control law. Simulations indicate the algorithm is efficient.

This paper implements a hybrid control method combines with Lyapunov switching strategy for a heating system, which is designed both theoretically and practically. Optimal controllers and Proportional-Integral-Derivative (PID) controllers are combined as hybrid controllers. It can be seen that hybrid controllers have good performance on both system transient and steady-state responses. Optimal controllers give fast set-point change responses, PID controllers provide stable control signals and Lyapunov switching theory ensures system stability. Both theoretical designs and experiments achieve satisfying results although inaccuracies happen during hardware implementations.

An approximate optimal tracking control (OTC) algorithm for sinusoidal disturbances rejections of nonlinear systems is developed in this paper. In the proposed control method, the nonlinear two-point boundary value (TPBV) problem, which is derived from the original OTC problem, is rewritten into a new form through a transformation and is transformed into a sequence of linear TPBV problems by using the successive approximation approach. Then the OTC law is obtained from the proposed iterative method successively, which consists of analytic linear feedforward and feedback terms and the limit of a compensation sequence of adjoint vectors. The feedforward term is used to cancel sinusoidal disturbances and the adjoint vectors sequence is the compensation for nonlinearities. A reference input observer is constructed to obtain a physically realizable feedforward controller. And by truncating a finite term of the adjoint vectors sequence, an approximate OTC law is obtained. Numerical simulations are employed to test the effectiveness of the proposed algorithm.

The optimal control problem for nonlinear interconnected large-scale dynamic systems with time-delays is considered. A successive approximation procedure (SAP) designing optimal controller is proposed with respect to a quadratic performance index. By using a successive approximation approach (SAA), the high order, coupled, nonlinear two-point boundary value (TPBV) problem with both time-delay and time-advance terms, which is derived from the necessary condition of the original optimal control problem, is transformed into a sequence of linear decoupled TPBV problems. The optimal control law obtained consists of an accurate linear term and a compensation term which is the limit of the adjoint vector sequence. A suboptimal control law is obtained by truncating a finite iterative result of the adjoint vector sequence as its compensation term. A SAP algorithm to obtain the suboptimal control law is presented. A numerical example illustrates this approach.

This paper develops an approximate design procedure of optimal tracking controllers for a class of nonlinear systems with persistent disturbances in the infinite time domain. By using the successive approximation approach (SAA), the two-point boundary value (TPBV) problem, which is derived from the optimal control theory, is transformed into solving a sequence of linear TPBV problems. The solution sequence of the linear TPBV problems uniformly converges to the solution of the original optimal tracking control (OTC) problem. A feedforward and feedback optimal tracking control (FFOTC) law is derived from a Riccati equation, matrix equations and a sequence of adjoint vectors. The existence and uniqueness conditions of the FFOTC are given. At last, a design algorithm of solving the approximate FFOTC law is proposed, and simulation results demonstrate the validity of the algorithm.

The quadratic optimal control problem for a class of singularly perturbed nonlinear time-delay systems is investigated. Based on successive approximation approach (SAA), the reduced order nonlinear time-delay optimal control law is achieved by solving a decoupled sequence of inhomogeneous linear two-point boundary value (TPBV) problems without time-delay and time-advance terms. The obtained composite control law of the original problem consists of accurate state feedback terms and a nonlinear time-delay compensation term, which is the limit of the adjoint vector sequence. The proposed algorithms not only solve optimal control problems in the singularly perturbed nonlinear time-delay system but also reduce the computation time. Simulation examples are included to illustrate the procedures.