Uncertainty is certain in the world of uncertainty.This study revisits an economic production quantity(EPQ)model with shortages for stock-dependent demand of the items with reworking and disposing of the imperfect one...Uncertainty is certain in the world of uncertainty.This study revisits an economic production quantity(EPQ)model with shortages for stock-dependent demand of the items with reworking and disposing of the imperfect ones over a random planning horizon under the joint effect of inflation and time value of money,where the expected time length is imprecise in nature.Transmission of learning effect has been incorporated to reduce the defective production.The total expected profit over the random planning horizon is maximized subject to the imprecise space constraint.The possibility,necessity and credibility measures have been introduced to defuzzify the model.The simulation-based genetic algorithm is used to make decision for the above EPQ model in different measures of uncertainty.The model is illustrated through an example.Sensitivity analysis shows the impacts of different parameters on the objective function in the model.展开更多
Safe and effective autonomous navigation in dynamic environments is challenging for four-wheel independently driven steered mobile robots(FWIDSMRs)due to the flexible allocation of multiple maneuver modes.To address t...Safe and effective autonomous navigation in dynamic environments is challenging for four-wheel independently driven steered mobile robots(FWIDSMRs)due to the flexible allocation of multiple maneuver modes.To address this problem,this study proposes a novel multiple mode-based navigation system,which can achieve efficient motion planning and accurate tracking control.To reduce the calculation burden and obtain a comprehensive optimized global path,a kinodynamic interior-exterior cell exploration planning method,which leverages the hybrid space of available modes with an incorporated exploration guiding algorithm,is designed.By utilizing the sampled subgoals and the constructed global path,local planning is then performed to avoid unexpected obstacles and potential collisions.With the desired profile curvature and preselected mode,a fuzzy adaptive receding horizon control is proposed such that the online updating of the predictive horizon is realized to enhance the trajectory-following precision.The tracking controller design is achieved using the quadratic programming(QP)technique,and the primal-dual neural network optimization technique is used to solve the QP problem.Experimental results on a real-time FWIDSMR validate that the proposed method shows superior features over some existing methods in terms of efficiency and accuracy.展开更多
To reduce vehicle emissions in road networks, a new signal coordination algorithm based on approximate dynamic programming （ADP） is developed for two intersections. Taking the Jetta car as an experimental vehicle, f...To reduce vehicle emissions in road networks, a new signal coordination algorithm based on approximate dynamic programming （ADP） is developed for two intersections. Taking the Jetta car as an experimental vehicle, field tests are conducted in Changchun Street of Changchun city and vehicle emission factors in complete stop and uniform speed states are collected. Queue lengths and signal light colors of approach lanes are selected as state variables, and green switch plans are selected as decision variables of the system. Then the calculation model of the optimization index during the planning horizon is developed based on the basis function method of the ADP. The temporal-difference algorithm is employed to update the weighting factor vector of the approximate function. Simulations are conducted in Matlab and the results show that the established algorithm outperforms the conventional coordination algorithm in reducing vehicle emissions by 8.2%. Sensitive analysis of the planning horizon length on the evaluation index is also conducted and the statistical results show that the optimal length of the planning horizon is directly proportional to the traffic load.展开更多
Taxiing aircraft and towed aircraft with drawbar are two typical dispatch modes on the flight deck of aircraft carriers. In this paper, a novel hierarchical solution strategy, named as the Homogenization-Planning-Trac...Taxiing aircraft and towed aircraft with drawbar are two typical dispatch modes on the flight deck of aircraft carriers. In this paper, a novel hierarchical solution strategy, named as the Homogenization-Planning-Tracking(HPT) method, to solve cooperative autonomous motion control for heterogeneous carrier dispatch systems is developed. In the homogenization layer, any towed aircraft system involved in the sortie task is abstracted into a virtual taxiing aircraft. This layer transforms the heterogeneous systems into a homogeneous configuration. Then in the planning layer, a centralized optimal control problem is formulated for the homogeneous system. Compared with conducting the path planning directly with the original heterogeneous system, the homogenization layer contributes to reduce the dimension and nonlinearity of the formulated optimal control problem in the planning layer and consequently improves the robustness and efficiency of the solution process. Finally, in the tracking layer, a receding horizon controller is developed to track the reference trajectory obtained in the planning layer. To improve the tracking performance,multi-objective optimization techniques are implemented offline in advance to determine optimal weight parameters used in the tracking layer. Simulations demonstrate that smooth and collision-free cooperative trajectory can be generated efficiently in the planning phase. And robust trajectory tracking can be realized in the presence of external disturbances in the tracking phase.The developed HPT method provides a promising solution to the autonomous deck dispatch for unmanned carrier aircraft in the future.展开更多
The authors analyze a finite horizon,single product,period review model in which pricingand inventory decisions are made simultaneously.Demands in different periods are random variablesthat are independent of each oth...The authors analyze a finite horizon,single product,period review model in which pricingand inventory decisions are made simultaneously.Demands in different periods are random variablesthat are independent of each other and their distributions depend on the product price.Pricing andordering decisions are made at the beginning of each period and all shortage are backlogged.Orderingcost is a convex function of the amount ordered.The objective is to find an inventory and pricing policymaximizing expected discounted profit over the finite horizon.The authors characterize the structure ofthe optimal combined pricing and inventory strategy for this model.Moreover,the authors demonstratehow the profit-to-go function,order up to level,reorder point and optimal price change with respectto state and time.展开更多
This paper presents a computationally efficient real-time trajectory planning framework for typical unmanned combat aerial vehicle （UCAV） performing autonomous air-to-surface （A/S） attack. It combines the benefits...This paper presents a computationally efficient real-time trajectory planning framework for typical unmanned combat aerial vehicle （UCAV） performing autonomous air-to-surface （A/S） attack. It combines the benefits of inverse dynamics optimization method and receding horizon optimal control technique. Firstly, the ground attack trajectory planning problem is mathematically formulated as a receding horizon optimal control problem （RHC-OCP）. In particular, an approximate elliptic launch acceptable region （LAR） model is proposed to model the critical weapon delivery constraints. Secondly, a planning algorithm based on inverse dynamics optimization, which has high computational efficiency and good convergence properties, is developed to solve the RHCOCP in real-time. Thirdly, in order to improve robustness and adaptivity in a dynamic and uncer- tain environment, a two-degree-of-freedom （2-DOF） receding horizon control architecture is introduced and a regular real-time update strategy is proposed as well, and the real-time feedback can be achieved and the not-converged situations can be handled. Finally, numerical simulations demon- strate the efficiency of this framework, and the results also show that the presented technique is well suited for real-time implementation in dynamic and uncertain environment.展开更多
文摘Uncertainty is certain in the world of uncertainty.This study revisits an economic production quantity(EPQ)model with shortages for stock-dependent demand of the items with reworking and disposing of the imperfect ones over a random planning horizon under the joint effect of inflation and time value of money,where the expected time length is imprecise in nature.Transmission of learning effect has been incorporated to reduce the defective production.The total expected profit over the random planning horizon is maximized subject to the imprecise space constraint.The possibility,necessity and credibility measures have been introduced to defuzzify the model.The simulation-based genetic algorithm is used to make decision for the above EPQ model in different measures of uncertainty.The model is illustrated through an example.Sensitivity analysis shows the impacts of different parameters on the objective function in the model.
基金The work was funded in part by the Guangdong Major Science and Technology Project,China(Grant Nos.2019B090919003 and 2017B090913001)in part by the China Postdoctoral Science Foundation(Grant No.2019M650179)+2 种基金in part by the Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2019ZT08Z780)in part by the Dongguan Innovative Research Team Program,China(Grant No.201536000100031)in part by the Guangdong HUST Industrial Technology Research Institute,Guangdong Provincial Key Laboratory of Manufacturing Equipment Digitization,China(Grant No.2020B1212060014).
文摘Safe and effective autonomous navigation in dynamic environments is challenging for four-wheel independently driven steered mobile robots(FWIDSMRs)due to the flexible allocation of multiple maneuver modes.To address this problem,this study proposes a novel multiple mode-based navigation system,which can achieve efficient motion planning and accurate tracking control.To reduce the calculation burden and obtain a comprehensive optimized global path,a kinodynamic interior-exterior cell exploration planning method,which leverages the hybrid space of available modes with an incorporated exploration guiding algorithm,is designed.By utilizing the sampled subgoals and the constructed global path,local planning is then performed to avoid unexpected obstacles and potential collisions.With the desired profile curvature and preselected mode,a fuzzy adaptive receding horizon control is proposed such that the online updating of the predictive horizon is realized to enhance the trajectory-following precision.The tracking controller design is achieved using the quadratic programming(QP)technique,and the primal-dual neural network optimization technique is used to solve the QP problem.Experimental results on a real-time FWIDSMR validate that the proposed method shows superior features over some existing methods in terms of efficiency and accuracy.
基金The National High Technology Research and Development Program of China (863 Program ) (No. 2011AA110304 )the National Natural Science Foundation of China (No. 50908100)
文摘To reduce vehicle emissions in road networks, a new signal coordination algorithm based on approximate dynamic programming （ADP） is developed for two intersections. Taking the Jetta car as an experimental vehicle, field tests are conducted in Changchun Street of Changchun city and vehicle emission factors in complete stop and uniform speed states are collected. Queue lengths and signal light colors of approach lanes are selected as state variables, and green switch plans are selected as decision variables of the system. Then the calculation model of the optimization index during the planning horizon is developed based on the basis function method of the ADP. The temporal-difference algorithm is employed to update the weighting factor vector of the approximate function. Simulations are conducted in Matlab and the results show that the established algorithm outperforms the conventional coordination algorithm in reducing vehicle emissions by 8.2%. Sensitive analysis of the planning horizon length on the evaluation index is also conducted and the statistical results show that the optimal length of the planning horizon is directly proportional to the traffic load.
基金the National Key Research and Development Plan,China(No.2019YFB1706502)the National Natural Science Foundation of China(Nos.62003366,12102077,12072059)+1 种基金the China Postdoctoral Science Foundation(No.2020M670744)the Natural Science Foundation of Liaoning Province,China(No.2010-ZD-0021)。
文摘Taxiing aircraft and towed aircraft with drawbar are two typical dispatch modes on the flight deck of aircraft carriers. In this paper, a novel hierarchical solution strategy, named as the Homogenization-Planning-Tracking(HPT) method, to solve cooperative autonomous motion control for heterogeneous carrier dispatch systems is developed. In the homogenization layer, any towed aircraft system involved in the sortie task is abstracted into a virtual taxiing aircraft. This layer transforms the heterogeneous systems into a homogeneous configuration. Then in the planning layer, a centralized optimal control problem is formulated for the homogeneous system. Compared with conducting the path planning directly with the original heterogeneous system, the homogenization layer contributes to reduce the dimension and nonlinearity of the formulated optimal control problem in the planning layer and consequently improves the robustness and efficiency of the solution process. Finally, in the tracking layer, a receding horizon controller is developed to track the reference trajectory obtained in the planning layer. To improve the tracking performance,multi-objective optimization techniques are implemented offline in advance to determine optimal weight parameters used in the tracking layer. Simulations demonstrate that smooth and collision-free cooperative trajectory can be generated efficiently in the planning phase. And robust trajectory tracking can be realized in the presence of external disturbances in the tracking phase.The developed HPT method provides a promising solution to the autonomous deck dispatch for unmanned carrier aircraft in the future.
基金supported by the National Natural Science Foundation of China under Grant Nos.70621061,70671100,70501014Beijing Philosophy and Social Science, Research Center for Beijing Transportation Development
文摘The authors analyze a finite horizon,single product,period review model in which pricingand inventory decisions are made simultaneously.Demands in different periods are random variablesthat are independent of each other and their distributions depend on the product price.Pricing andordering decisions are made at the beginning of each period and all shortage are backlogged.Orderingcost is a convex function of the amount ordered.The objective is to find an inventory and pricing policymaximizing expected discounted profit over the finite horizon.The authors characterize the structure ofthe optimal combined pricing and inventory strategy for this model.Moreover,the authors demonstratehow the profit-to-go function,order up to level,reorder point and optimal price change with respectto state and time.
基金supported by the National Defense Foundation of China(No.403060103)
文摘This paper presents a computationally efficient real-time trajectory planning framework for typical unmanned combat aerial vehicle （UCAV） performing autonomous air-to-surface （A/S） attack. It combines the benefits of inverse dynamics optimization method and receding horizon optimal control technique. Firstly, the ground attack trajectory planning problem is mathematically formulated as a receding horizon optimal control problem （RHC-OCP）. In particular, an approximate elliptic launch acceptable region （LAR） model is proposed to model the critical weapon delivery constraints. Secondly, a planning algorithm based on inverse dynamics optimization, which has high computational efficiency and good convergence properties, is developed to solve the RHCOCP in real-time. Thirdly, in order to improve robustness and adaptivity in a dynamic and uncer- tain environment, a two-degree-of-freedom （2-DOF） receding horizon control architecture is introduced and a regular real-time update strategy is proposed as well, and the real-time feedback can be achieved and the not-converged situations can be handled. Finally, numerical simulations demon- strate the efficiency of this framework, and the results also show that the presented technique is well suited for real-time implementation in dynamic and uncertain environment.
基金Supported by National Basic Research Program of China （973 Program） （2010CB731800）, Key Project of Natural Science Fouudation of China （60934003）, National Natural Science Foundation of China （61074065, 60974018）, Natural Science Foundation of Hebei Province（F2012203119）, and the Science Foundation of Yanshan University for the Excellent Ph. D. Students （201204） The authors thank Chen Cai-Lian of the Shanghai Jiao Tong University for her comments on English polishing and problem formulation.
