For enhancing the control effectiveness,we firstly design a fuzzy logic based sliding mode controller(FSMC)for nonlinear crane systems.On basis of overhead crane dynamic characteristic,the sliding mode function with r...For enhancing the control effectiveness,we firstly design a fuzzy logic based sliding mode controller(FSMC)for nonlinear crane systems.On basis of overhead crane dynamic characteristic,the sliding mode function with regard to trolley position and payload angle.Additionally,in order to eliminate the chattering problem of sliding mode control,the fuzzy logic theory is adopted to soften the control performance.Moreover,aiming at the FSMC parameter setting problem,a DE algorithm based optimization scheme is proposed for enhancing the control performance.Finally,by implementing the computer simulation,the DE based FSMC can effectively tackle the overhead crane sway problem and avoid unexpected accident greatly.展开更多
Due to the importance and role of systems engineering in space mission developments, optimization of Omid's systems engineering as a milestone to its current and future generations is focused. In this regard systems ...Due to the importance and role of systems engineering in space mission developments, optimization of Omid's systems engineering as a milestone to its current and future generations is focused. In this regard systems engineering management organization as the basis of optimization work flow in the conceptual design phase is proposed for improvement. To improve the systems engineering management, an agile enhanced organization chart is developed that defines various system duties. This is a type of concurrent engineering approach that promotes direct communication and data interchange between the team members. Due to the importance of decision making in the conceptual design phase, two design matrices are constructed that portray merits of various design options in terms of improved satellite life as well as specific choices of remote sensing capability for the Omid second generation(Omid-2). Conceptual design optimization is explored considering several structural objectives as well as optimal solar energy absorption utilizing a multiple criteria decision making approach. The Eigenvector method is utilized to formulate the objective function via expert judgment. This approach is robust with respect to designer probable miss-judgment. The optimized version of Omid-2 turned out to be a passive Z-axis spin stabilized satellite made of hexagonal honeycomb configuration with carbon-epoxy side panels and Aluminum bottom plate.展开更多
I.I NTRODUCTION W ITH the advent of low-carbon economy,there has been a growing interest in harnessing renewable energy resources particularly for electricity generation.Renewable energy resources are advocated for th...I.I NTRODUCTION W ITH the advent of low-carbon economy,there has been a growing interest in harnessing renewable energy resources particularly for electricity generation.Renewable energy resources are advocated for the economic and environ-展开更多
This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is...This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.展开更多
Under complex currents, the motion governing equations of marine cables are complex and nonlinear, and the calculations of cable configuration and tension become difficult compared with those under the uniform or simp...Under complex currents, the motion governing equations of marine cables are complex and nonlinear, and the calculations of cable configuration and tension become difficult compared with those under the uniform or simple currents. To obtain the numerical results, the usual Newton-Raphson iteration is often adopted, but its stability depends on the initial guessed solution to the governing equations. To improve the stability of numerical calculation, this paper proposed separated the particle swarm optimization, in which the variables are separated into several groups, and the dimension of search space is reduced to facilitate the particle swarm optimization. Via the separated particle swarm optimization, these governing nonlinear equations can be solved successfully with any initial solution, and the process of numerical calculation is very stable. For the calculations of cable configuration and tension of marine cables under complex currents, the proposed separated swarm particle optimization is more effective than the other particle swarm optimizations.展开更多
The structure of the optimal solution set is derived for linear fractional programming with the representation theorem of polyhedral sets. Based on an adaptation of the convex simplex method credited to Gilmore and Go...The structure of the optimal solution set is derived for linear fractional programming with the representation theorem of polyhedral sets. Based on an adaptation of the convex simplex method credited to Gilmore and Gomory, we give the uniqueness condition of optimal solution and the computational procedures to find all optimal solutions if the uniqueness condition is not satisfied. Finally, an illustrative example is also given.展开更多
An optimal guidance law based on missile-target line-of-sight (LOS) angular rate is presented for intercepting a nonmaneuvering target. It is then integrated with sliding-mode control theory by using reaching-law of s...An optimal guidance law based on missile-target line-of-sight (LOS) angular rate is presented for intercepting a nonmaneuvering target. It is then integrated with sliding-mode control theory by using reaching-law of sliding-mode, in order to derive an optimal sliding-mode guidance law for intercepting a maneuvering target. The new guidance method's robustness against target maneuvers and good miss distance performance are proved by the second method of Lyapunov and simulation results. The presented guidance law is simple to implement in practical applications.展开更多
Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar park...Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar parking orbit. Once the landing area has been selected and it is time to deorbit for landing, a ΔV burn of 19.4 m/s is performed to establish a 100×15 km elliptical orbit. At perilune, the landing jets are ignited, and a propulsive landing is performed. A guidance and control scheme for lunar soft landing is proposed in the paper, which combines optimal theory with nonlinear neuro-control. Basically, an optimal nonlinear control law based on artificial neural network is presented, on the basis of the optimum trajectory from perilune to lunar surface in terms of Pontryagin's maximum principle according to the terminal boundary conditions and performance index. Therefore some optimal control laws can be carried out in the soft landing system due to the nonlinear mapping function of the neural network. The feasibility and validity of the control laws are verified in a simulation experiment.展开更多
This paper deals with the problem of planned lead time calculation in a Material Requirement Planning (MRP) environment under stochastic lead times. The objective is to minimize the sum of holding and backlogging co...This paper deals with the problem of planned lead time calculation in a Material Requirement Planning (MRP) environment under stochastic lead times. The objective is to minimize the sum of holding and backlogging costs. The proposed approach is based on discrete time inventory control where the decision variables are integer. Two types of systems are considered: multi-level serial-production and assembly systems. For the serial production systems (one type of component at each level), a mathematical model is suggested. Then, it is proven that this model is equivalent to the well known discrete Newsboy Model. This directly provides the optimal values for the planned lead times. For multilevel assembly systems, a dedicated model is proposed and some properties of the decision variables and objective function are proven. These properties are used to calculate lower and upper limits on the decision variables and lower and upper bounds on the objective function. The obtained limits and bounds open the possibility to develop an efficient optimization algorithm using, for example, a Branch and Bound approach. The paper presents the proposed models in detail with corresponding proofs and se'~eral numerical examples. Some advantages of the suggested models and perspectives of this research are discussed.展开更多
We systemically investigate the interchannel four-wave mixing (FWM) in dispersion-managed WDM systems with arbitrary launch position. We optimize the number of fiber sections, and the dispersion ratio for the system p...We systemically investigate the interchannel four-wave mixing (FWM) in dispersion-managed WDM systems with arbitrary launch position. We optimize the number of fiber sections, and the dispersion ratio for the system performance.展开更多
In this paper, the matrix algebraic equations involved in the optimal control problem of time-invariant linear Ito stochastic systems, named Riccati- Ito equations in the paper, are investigated. The necessary and suf...In this paper, the matrix algebraic equations involved in the optimal control problem of time-invariant linear Ito stochastic systems, named Riccati- Ito equations in the paper, are investigated. The necessary and sufficient condition for the existence of positive definite solutions of the Riccati- Ito equations is obtained and an iterative solution to the Riccati- Ito equations is also given in the paper thus a complete solution to the basic problem of optimal control of time-invariant linear Ito stochastic systems is then obtained. An example is given at the end of the paper to illustrate the application of the result of the paper.展开更多
Based on the uncertainty theory, this paper is devoted to the redundancy allocation problem in repairable parallel-series systems with uncertain factors, where the failure rate, repair rate and other relative coeffici...Based on the uncertainty theory, this paper is devoted to the redundancy allocation problem in repairable parallel-series systems with uncertain factors, where the failure rate, repair rate and other relative coefficients involved are considered as uncertain variables. The availability of the system and the corresponding designing cost are considered as two optimization objectives. A crisp multiobjective optimization formulation is presented on the basis of uncertainty theory to solve this resultant problem. For solving this problem efficiently, a new multiobjective artificial bee colony algorithm is proposed to search the Pareto efficient set, which introduces rank value and crowding distance in the greedy selection strategy, applies fast non-dominated sort procedure in the exploitation search and inserts tournament selection in the onlooker bee phase. It shows that the proposed algorithm outperforms NSGA-II greatly and can solve multiobjective redundancy allocation problem efficiently. Finally, a numerical example is provided to illustrate this approach.展开更多
For the missile with blended aero-fin and lateral impulsive thrust, a blended control autopilot is designed, which comprises an optimal controller and a control allocation module. The combined optimal/classical approa...For the missile with blended aero-fin and lateral impulsive thrust, a blended control autopilot is designed, which comprises an optimal controller and a control allocation module. The combined optimal/classical approach is applied to designing the optimal controller to determine the virtual controls, and the control allocation module is used to distribute the desired vitlual controls onto the redundant control effectors. The autopilot holds some attractive characteristics, such as simple structure, good tracking performance and robustness; moreover the actual constraints of the control effectors can be taken into account. Based on this blended control autopilot, it is found that the conflict between stability and fast tracking performance is serious when using the total acceleration as feedback. In order to avoid this problem, the transient factors in total acceleration are eliminated, so the acceleration caused only by angle of attack is used as feedback, and obvious improvement is shown. Finally, how to get reasonable acceleration feedback is discussed, and conclusion is presented that after passing the low-pass filter, the total acceleration can also be used as feedback, and satisfied tracking performance can be obtained.展开更多
For the purpose of practical application in traffic engineering, especially in automatic control of traffic systems, in this paper a numerical model for the dynamic simulation of traffic flow was presented, involving ...For the purpose of practical application in traffic engineering, especially in automatic control of traffic systems, in this paper a numerical model for the dynamic simulation of traffic flow was presented, involving difference schemes, boundary conditions and their discrete forms, expressions of traffic behavior parameters and technique of modelling parameter identification. The analysis of numerical simulation for several realistic examples shows the usefulness and advantages of the model.展开更多
Method of optimal hydraulic design and CAD application of runner blades of axial-flow hydraulic turbines are discussed on the basis of optimization principle and CAD technique in this paper. Based on the theory of flu...Method of optimal hydraulic design and CAD application of runner blades of axial-flow hydraulic turbines are discussed on the basis of optimization principle and CAD technique in this paper. Based on the theory of fluid dynamics, the blade's main geometrical parameter, working parameters and performances index of the blades and the relationship between them are analysed, and the mathematical model of optimal hydraulic design of axial-flow runners has been established. Through nonlinear programming, the problems can be solved. By making use of the calculation geometry and computer graphics, the distribution method of the singular points, and an CAD applied software, an optimal hydraulic design are presented.展开更多
Nonlinear evolution equations(NLEEs)are primarily relevant to nonlinear complex physical systems in a wide range of fields,including ocean physics,plasma physics,chemical physics,optical fibers,fluid dy-namics,biology...Nonlinear evolution equations(NLEEs)are primarily relevant to nonlinear complex physical systems in a wide range of fields,including ocean physics,plasma physics,chemical physics,optical fibers,fluid dy-namics,biology physics,solid-state physics,and marine engineering.This paper investigates the Lie sym-metry analysis of a generalized(3+1)-dimensional breaking soliton equation depending on five nonzero real parameters.We derive the Lie infinitesimal generators,one-dimensional optimal system,and geo-metric vector fields via the Lie symmetry technique.First,using the three stages of symmetry reductions,we converted the generalized breaking soliton(GBS)equation into various nonlinear ordinary differential equations(NLODEs),which have the advantage of yielding a large number of exact closed-form solu-tions.All established closed-form wave solutions include special functional parameter solutions,as well as hyperbolic trigonometric function solutions,trigonometric function solutions,dark-bright solitons,bell-shaped profiles,periodic oscillating wave profiles,combo solitons,singular solitons,wave-wave interac-tion profiles,and various dynamical wave structures,which we present for the first time in this research.Eventually,the dynamical analysis of some established solutions is revealed through three-dimensional sketches via numerical simulations.Some of the new solutions are often useful and helpful for study-ing the nonlinear wave propagation and wave-wave interactions of shallow water waves in many new high-dimensional nonlinear evolution equations.展开更多
基金This work is supported by the Natural Science Foundation of Jiangsu Province(No.BK20160913)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.18KJB520035)+4 种基金the High Level Teacher Research Foundation of Nanjing University of Posts and Telecommunications(No.NY2016021)the Incubation Foundation of Nanjing University of Posts and Telecommunications(No.NY217055)Postdoctoral Foundation of Jiangsu Province(No.1701016A)Natural Science Foundation of China(No.61602259,No.61373135 and No.61672299)National Engineering Laboratory for Logistics Information Technology,YuanTong Express Co.LTD.
文摘For enhancing the control effectiveness,we firstly design a fuzzy logic based sliding mode controller(FSMC)for nonlinear crane systems.On basis of overhead crane dynamic characteristic,the sliding mode function with regard to trolley position and payload angle.Additionally,in order to eliminate the chattering problem of sliding mode control,the fuzzy logic theory is adopted to soften the control performance.Moreover,aiming at the FSMC parameter setting problem,a DE algorithm based optimization scheme is proposed for enhancing the control performance.Finally,by implementing the computer simulation,the DE based FSMC can effectively tackle the overhead crane sway problem and avoid unexpected accident greatly.
文摘Due to the importance and role of systems engineering in space mission developments, optimization of Omid's systems engineering as a milestone to its current and future generations is focused. In this regard systems engineering management organization as the basis of optimization work flow in the conceptual design phase is proposed for improvement. To improve the systems engineering management, an agile enhanced organization chart is developed that defines various system duties. This is a type of concurrent engineering approach that promotes direct communication and data interchange between the team members. Due to the importance of decision making in the conceptual design phase, two design matrices are constructed that portray merits of various design options in terms of improved satellite life as well as specific choices of remote sensing capability for the Omid second generation(Omid-2). Conceptual design optimization is explored considering several structural objectives as well as optimal solar energy absorption utilizing a multiple criteria decision making approach. The Eigenvector method is utilized to formulate the objective function via expert judgment. This approach is robust with respect to designer probable miss-judgment. The optimized version of Omid-2 turned out to be a passive Z-axis spin stabilized satellite made of hexagonal honeycomb configuration with carbon-epoxy side panels and Aluminum bottom plate.
文摘I.I NTRODUCTION W ITH the advent of low-carbon economy,there has been a growing interest in harnessing renewable energy resources particularly for electricity generation.Renewable energy resources are advocated for the economic and environ-
文摘This paper focuses on the simulation and test of the switched reluctance starter/generator systems. Through the emulational analysis of the initial starting torque, the optimal turn-on section of the power switches is discovered. The fundamental theory of the generating operation is analyzed with the linearity model, and a new method is presented based on voltage pulse width modulation for the generating mode control. Through the steady-state and optimized emulation of the output power and system efficiency, the optimizational control approach for the generating mode over a wide speed range is introduced. At last, the test of the 3KW prototype system shows that the dynamic and static performance of this system is fine.
基金supported by the National Natural Science Foundation of China(Grant Nos.51009092 and 51279107)the Scientific Research Foundation of State Education Ministry for the Returned Overseas Chinese Scholars
文摘Under complex currents, the motion governing equations of marine cables are complex and nonlinear, and the calculations of cable configuration and tension become difficult compared with those under the uniform or simple currents. To obtain the numerical results, the usual Newton-Raphson iteration is often adopted, but its stability depends on the initial guessed solution to the governing equations. To improve the stability of numerical calculation, this paper proposed separated the particle swarm optimization, in which the variables are separated into several groups, and the dimension of search space is reduced to facilitate the particle swarm optimization. Via the separated particle swarm optimization, these governing nonlinear equations can be solved successfully with any initial solution, and the process of numerical calculation is very stable. For the calculations of cable configuration and tension of marine cables under complex currents, the proposed separated swarm particle optimization is more effective than the other particle swarm optimizations.
文摘The structure of the optimal solution set is derived for linear fractional programming with the representation theorem of polyhedral sets. Based on an adaptation of the convex simplex method credited to Gilmore and Gomory, we give the uniqueness condition of optimal solution and the computational procedures to find all optimal solutions if the uniqueness condition is not satisfied. Finally, an illustrative example is also given.
文摘An optimal guidance law based on missile-target line-of-sight (LOS) angular rate is presented for intercepting a nonmaneuvering target. It is then integrated with sliding-mode control theory by using reaching-law of sliding-mode, in order to derive an optimal sliding-mode guidance law for intercepting a maneuvering target. The new guidance method's robustness against target maneuvers and good miss distance performance are proved by the second method of Lyapunov and simulation results. The presented guidance law is simple to implement in practical applications.
文摘Returning to moon has become a top topic recently. Many studies have shown that soft landing is a challenging problem in lunar exploration. The lunar soft landing in this paper begins from a 100 km circular lunar parking orbit. Once the landing area has been selected and it is time to deorbit for landing, a ΔV burn of 19.4 m/s is performed to establish a 100×15 km elliptical orbit. At perilune, the landing jets are ignited, and a propulsive landing is performed. A guidance and control scheme for lunar soft landing is proposed in the paper, which combines optimal theory with nonlinear neuro-control. Basically, an optimal nonlinear control law based on artificial neural network is presented, on the basis of the optimum trajectory from perilune to lunar surface in terms of Pontryagin's maximum principle according to the terminal boundary conditions and performance index. Therefore some optimal control laws can be carried out in the soft landing system due to the nonlinear mapping function of the neural network. The feasibility and validity of the control laws are verified in a simulation experiment.
文摘This paper deals with the problem of planned lead time calculation in a Material Requirement Planning (MRP) environment under stochastic lead times. The objective is to minimize the sum of holding and backlogging costs. The proposed approach is based on discrete time inventory control where the decision variables are integer. Two types of systems are considered: multi-level serial-production and assembly systems. For the serial production systems (one type of component at each level), a mathematical model is suggested. Then, it is proven that this model is equivalent to the well known discrete Newsboy Model. This directly provides the optimal values for the planned lead times. For multilevel assembly systems, a dedicated model is proposed and some properties of the decision variables and objective function are proven. These properties are used to calculate lower and upper limits on the decision variables and lower and upper bounds on the objective function. The obtained limits and bounds open the possibility to develop an efficient optimization algorithm using, for example, a Branch and Bound approach. The paper presents the proposed models in detail with corresponding proofs and se'~eral numerical examples. Some advantages of the suggested models and perspectives of this research are discussed.
文摘We systemically investigate the interchannel four-wave mixing (FWM) in dispersion-managed WDM systems with arbitrary launch position. We optimize the number of fiber sections, and the dispersion ratio for the system performance.
文摘In this paper, the matrix algebraic equations involved in the optimal control problem of time-invariant linear Ito stochastic systems, named Riccati- Ito equations in the paper, are investigated. The necessary and sufficient condition for the existence of positive definite solutions of the Riccati- Ito equations is obtained and an iterative solution to the Riccati- Ito equations is also given in the paper thus a complete solution to the basic problem of optimal control of time-invariant linear Ito stochastic systems is then obtained. An example is given at the end of the paper to illustrate the application of the result of the paper.
基金supported by National Natural Science Foundation of China (No. 71171199)Natural Science Foundation of Shaanxi Province of China (No. 2013JM1003)
文摘Based on the uncertainty theory, this paper is devoted to the redundancy allocation problem in repairable parallel-series systems with uncertain factors, where the failure rate, repair rate and other relative coefficients involved are considered as uncertain variables. The availability of the system and the corresponding designing cost are considered as two optimization objectives. A crisp multiobjective optimization formulation is presented on the basis of uncertainty theory to solve this resultant problem. For solving this problem efficiently, a new multiobjective artificial bee colony algorithm is proposed to search the Pareto efficient set, which introduces rank value and crowding distance in the greedy selection strategy, applies fast non-dominated sort procedure in the exploitation search and inserts tournament selection in the onlooker bee phase. It shows that the proposed algorithm outperforms NSGA-II greatly and can solve multiobjective redundancy allocation problem efficiently. Finally, a numerical example is provided to illustrate this approach.
文摘For the missile with blended aero-fin and lateral impulsive thrust, a blended control autopilot is designed, which comprises an optimal controller and a control allocation module. The combined optimal/classical approach is applied to designing the optimal controller to determine the virtual controls, and the control allocation module is used to distribute the desired vitlual controls onto the redundant control effectors. The autopilot holds some attractive characteristics, such as simple structure, good tracking performance and robustness; moreover the actual constraints of the control effectors can be taken into account. Based on this blended control autopilot, it is found that the conflict between stability and fast tracking performance is serious when using the total acceleration as feedback. In order to avoid this problem, the transient factors in total acceleration are eliminated, so the acceleration caused only by angle of attack is used as feedback, and obvious improvement is shown. Finally, how to get reasonable acceleration feedback is discussed, and conclusion is presented that after passing the low-pass filter, the total acceleration can also be used as feedback, and satisfied tracking performance can be obtained.
文摘For the purpose of practical application in traffic engineering, especially in automatic control of traffic systems, in this paper a numerical model for the dynamic simulation of traffic flow was presented, involving difference schemes, boundary conditions and their discrete forms, expressions of traffic behavior parameters and technique of modelling parameter identification. The analysis of numerical simulation for several realistic examples shows the usefulness and advantages of the model.
文摘Method of optimal hydraulic design and CAD application of runner blades of axial-flow hydraulic turbines are discussed on the basis of optimization principle and CAD technique in this paper. Based on the theory of fluid dynamics, the blade's main geometrical parameter, working parameters and performances index of the blades and the relationship between them are analysed, and the mathematical model of optimal hydraulic design of axial-flow runners has been established. Through nonlinear programming, the problems can be solved. By making use of the calculation geometry and computer graphics, the distribution method of the singular points, and an CAD applied software, an optimal hydraulic design are presented.
基金The author,Sachin Kumar,is grateful to the Science and Engi-neering Research Board(SERB),DST,India under project scheme Empowerment and Equity Opportunities for Excellence in Science(EEQ/2020/000238)for the financial support in carrying out this research.
文摘Nonlinear evolution equations(NLEEs)are primarily relevant to nonlinear complex physical systems in a wide range of fields,including ocean physics,plasma physics,chemical physics,optical fibers,fluid dy-namics,biology physics,solid-state physics,and marine engineering.This paper investigates the Lie sym-metry analysis of a generalized(3+1)-dimensional breaking soliton equation depending on five nonzero real parameters.We derive the Lie infinitesimal generators,one-dimensional optimal system,and geo-metric vector fields via the Lie symmetry technique.First,using the three stages of symmetry reductions,we converted the generalized breaking soliton(GBS)equation into various nonlinear ordinary differential equations(NLODEs),which have the advantage of yielding a large number of exact closed-form solu-tions.All established closed-form wave solutions include special functional parameter solutions,as well as hyperbolic trigonometric function solutions,trigonometric function solutions,dark-bright solitons,bell-shaped profiles,periodic oscillating wave profiles,combo solitons,singular solitons,wave-wave interac-tion profiles,and various dynamical wave structures,which we present for the first time in this research.Eventually,the dynamical analysis of some established solutions is revealed through three-dimensional sketches via numerical simulations.Some of the new solutions are often useful and helpful for study-ing the nonlinear wave propagation and wave-wave interactions of shallow water waves in many new high-dimensional nonlinear evolution equations.