A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to...A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to poor performance.The method combines a fault-tolerant fault location method based on long-term and short-term memory networks to accurately locate the fault section.Then,an operation control method for relay protection based on adaptive weight and whale optimization algorithm(WOA)is used to construct an objective function considering the shortest relay protection action time and the smallest impulse current.The adaptive weight and WOA are employed to obtain the optimal strategy for relay protection operation control,reducing the action time and impulse current.Experimental results demonstrate the effectiveness of the proposed method in accurately locating faults and improving relay protection performance.The longest operation time is reduced by 4.7023 s,and the maximum impulse current is limited to 0.3 A,effectively controlling the impact of large impulse currents and enhancing control efficiency.展开更多
The dynamics of spatial parallel manipulator with rigid and flexible links is explored. Firstly, a spatial beam element model for finite element analysis is established. Then, the differential equation of motion of be...The dynamics of spatial parallel manipulator with rigid and flexible links is explored. Firstly, a spatial beam element model for finite element analysis is established. Then, the differential equation of motion of beam element is derived based on finite element method. The kinematic constraints of parallel manipulator with rigid and flexible links are obtained by analyzing the motive parameters of moving platform and the relationships of movements of kinematic chains, and the overall kinetic equation of the parallel mechanism with rigid and flexible links is derived by assembling the differential equations of motion of components. On the basis of abovementioned analyses, the dynamic mechanical analysis of the spatial parallel manipulator with rigid and flexible links is conducted. After obtaining the method for force analysis and expressions for the calculation of dynamic stress of flexible components, the dynamic analysis and simulation of spatial parallel manipulator with rigid and flexible links is performed. The result shows that because of the elastic deformation of flexible components in the parallel mechanism with rigid and flexible links, the force on each component in the mechanism fluctuates sharply, and the change of normal stress at the root of drive components is also remarkable. This study provides references for further studies on the dynamic characteristics of parallel mechanisms with rigid and flexible links and for the optimization of the design of the mechanism.展开更多
The dynamic modeling and solution of the 3-■RS spatial parallel manipulators with flexible links were investigated.Firstly,a new model of spatial flexible beam element was proposed,and the dynamic equations of elemen...The dynamic modeling and solution of the 3-■RS spatial parallel manipulators with flexible links were investigated.Firstly,a new model of spatial flexible beam element was proposed,and the dynamic equations of elements and branches of the parallel manipulator were derived.Secondly,according to the kinematic coupling relationship between the moving platform and flexible links,the kinematic constraints of the flexible parallel manipulator were proposed.Thirdly,using the kinematic constraint equations and dynamic model of the moving platform,the overall system dynamic equations of the parallel manipulator were obtained by assembling the dynamic equations of branches.Furthermore,a few commonly used effective solutions of second-order differential equation system with variable coefficients were discussed.Newmark numerical method was used to solve the dynamic equations of the flexible parallel manipulator.Finally,the dynamic responses of the moving platform and driving torques of the 3-■RS parallel mechanism with flexible links were analyzed through numerical simulation.The results provide important information for analysis of dynamic performance,dynamics optimization design,dynamic simulation and control of the 3-■RS flexible parallel manipulator.展开更多
The object of study is about dynamic modeling and control for a 2 degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic and dynamic equations are established according to the charac...The object of study is about dynamic modeling and control for a 2 degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic and dynamic equations are established according to the characteristics of mixed rigid and flexible structure. By using the singular perturbation approach (SPA), the model of the mechanism can be separated into slow and fast subsystems. Based on the feedback linearization theory and input shaping technique, the large scale rigid motion controller and the flexible link vibration controller can be designed separately to achieve fast and accurate positioning of the PM.展开更多
This paper considers a hybrid two-stage flow-shop scheduling problem with m identical parallel machines on one stage and a batch processor on the other stage. The processing time of job Jj on any of m identical parall...This paper considers a hybrid two-stage flow-shop scheduling problem with m identical parallel machines on one stage and a batch processor on the other stage. The processing time of job Jj on any of m identical parallel machines is aj≡ a (j∈N), and the processing time of job Jj is bj(j∈N) on a batch processor M. We take makespan (Cmax) as our minimization objective. In this paper, for the problem of FSMP-BI (m identical parallel machines on the first stage and a batch processor on the second stage), based on the algorithm given by Sung and Choung for the problem of 1| rj, BI | Cmax under the constraint of the given processing sequence, we develop an optimal dynamic programming Algorithm H1 for it in max{O(nlogn), O(nB)} time. A max{O(nlogn), O(nB)} time symmetric Algorithm H2 is given then for the problem of BI-FSMP (a batch processor on the first stage and m identical parallel machines on the second stage).展开更多
Sewage source heat pump unit operates under partial load most of the time, and study on the law of coefficient of performance (COP) of the unit varying with load ratio can provide basis for the heat pump units running...Sewage source heat pump unit operates under partial load most of the time, and study on the law of coefficient of performance (COP) of the unit varying with load ratio can provide basis for the heat pump units running in high efficiency. A mathematical model determining COP, evaporation temperature and condensation temperature of a single unit was proposed. Under the condition of uniform load distribution, the model was established according to different ways of bearing partial load with the same type multiple units but different parallel operation models, and the operation characteristics of units were analyzed as well. Results show that the single screw water-source heat pump can maintain high COP only at 60%—100% load ratio, COP decreases sharply with the decrease of load ratio, and the units with parallel operation are controlled by the load ratio of a single unit according to the reduction of total load which can keep the average COP at high level within a wide load range.展开更多
A prototype of a novel hybrid hand is developed by combing a parallel wrist with three flexible fingers.Its dynamics model is established,its grabbed forces are measured,and its grabbing performances are analyzed.Firs...A prototype of a novel hybrid hand is developed by combing a parallel wrist with three flexible fingers.Its dynamics model is established,its grabbed forces are measured,and its grabbing performances are analyzed.First,Jacobian and Hessian matrices of the moving platform in the parallel wrist are derived,the kinematics formulas for solving the general velocity and the general acceleration of the moving platform are derived.Second its dynamics model is established for solving the dynamic actuation forces,the dynamic constrained forces of the developed hybrid hand.Third,its simulation mechanism is constructed in Matlab,and the theoretical solutions of the kinematics and the dynamics of the developed hybrid hand are verified to be correct using its simulation mechanism.Finally,when objects with different mass are grabbed by prototype of hybrid hand in different poses,the grabbed forces are measured,and the grabbing performances are discovered and analyzed to verify its merits.展开更多
In order to solve the problem that previous relation researches in operational task-resource matching are hard to flexible computing for generating a new matching scheme from the existing scheme under the condition of...In order to solve the problem that previous relation researches in operational task-resource matching are hard to flexible computing for generating a new matching scheme from the existing scheme under the condition of operational tasks or resources adjusted in uncertainty cases, role-based approaches to operational task-resource flexible matching model and algorithm are proposed in the paper for flexible matching operational tasks with resources.Firstly, through introducing the concept of roles, the role-based calculation framework of operational task-resource flexible matching is constructed. Secondly, two aspect indexes about resource utilization ratio(RUR) and time utilization ratio(TUR) are given to reflect operational task-resource matching quality(TRMQ), which can be regarded as the objective function for modeling role-based operational task-resource flexible matching mathematical formulation. On the basis of this, the role-based artificial bee colony(RABC) algorithm, including five specific calculating operators, is put forward for solving the flexible matching problem with double encoding on operational tasks and resources by roles. Finally, via comparing with the previous methods in application cases, it can be validated that role-based model and proposed algorithm are more effective, which can be used to obtain a new incremental scheme from the existing matching scheme for adopting the operational tasks or resources adjustment. Moreover, there are flexible computation advantages of the approaches proposed in this paper to solve the problem about operational task-resource matching in large-scale.展开更多
In the view of staff shortages and the huge inventory of products in the current market, we put forward a personnel scheduling model in the target of closing to the delivery date considering the parallelism. Then we d...In the view of staff shortages and the huge inventory of products in the current market, we put forward a personnel scheduling model in the target of closing to the delivery date considering the parallelism. Then we designed a scheduling algorithm based on genetic algorithm and proposed a flexible parallel decoding method which take full use of the personal capacity. Case study results indicate that the flexible personnel scheduling considering the order-shop scheduling, machine automatic capabilities and personnel flexible in the target of closing to the delivery date optimize the allocation of human resources, then maximize the efficiency.展开更多
A series-parallel hydraulic hybrid system applied to public buses is put forward,and parameters of key components are analyzed and determined.Energy management strategy based on logic threshold is designed which is ai...A series-parallel hydraulic hybrid system applied to public buses is put forward,and parameters of key components are analyzed and determined.Energy management strategy based on logic threshold is designed which is aimed at efficient operation of the overall system considering the operational characteristic of the components and taking the curves of engine,hydraulic pump/motor and hydraulic pump as the main design basis;regenerative control strategy which makes regenerative brake system and frictional brake system work harmoniously is designed to raise recovery rate of regenerative brake energy.System dynamic modeling and simulation results show that the energy control strategy designed here is able to adapt system to changes of working condition and switch the operating mode reasonably.The regenerative braking control strategy is effective in raising the utilization of energy and improving fuel economy.展开更多
To improve the inference efficiency of convolutional neural networks(CNN),the existing neural networks mainly adopt heuristic and dynamic programming algorithms to realize parallel scheduling among operators.Heuristic...To improve the inference efficiency of convolutional neural networks(CNN),the existing neural networks mainly adopt heuristic and dynamic programming algorithms to realize parallel scheduling among operators.Heuristic scheduling algorithms can generate local optima easily,while the dynamic programming algorithm has a long convergence time for complex structural models.This paper mainly studies the parallel scheduling between operators and proposes an inter-operator parallelism schedule(IOPS)scheduling algorithm that guarantees the minimum similar execution delay.Firstly,a graph partitioning algorithm based on the largest block is designed to split the neural network model into multiple subgraphs.Then,the operators that meet the conditions is replaced according to the defined operator replacement rules.Finally,the optimal scheduling method based on backtracking is used to schedule the computational graph.Network models such as Inception-v3,ResNet-50,and RandWire are selected for testing.The experimental results show that the algorithm designed in this paper can achieve a 1.6×speedup compared with the existing sequential execution methods.展开更多
文摘A novel operation control method for relay protection in flexible DC distribution networks with distributed power supply is proposed to address the issue of inaccurate fault location during relay protection,leading to poor performance.The method combines a fault-tolerant fault location method based on long-term and short-term memory networks to accurately locate the fault section.Then,an operation control method for relay protection based on adaptive weight and whale optimization algorithm(WOA)is used to construct an objective function considering the shortest relay protection action time and the smallest impulse current.The adaptive weight and WOA are employed to obtain the optimal strategy for relay protection operation control,reducing the action time and impulse current.Experimental results demonstrate the effectiveness of the proposed method in accurately locating faults and improving relay protection performance.The longest operation time is reduced by 4.7023 s,and the maximum impulse current is limited to 0.3 A,effectively controlling the impact of large impulse currents and enhancing control efficiency.
基金Projects(2014QNB18,2015XKMS022)supported by the Fundamental Research Funds for the Central Universities of ChinaProjects(51475456,51575511)supported by the National Natural Science Foundation of China+1 种基金Project supported by the Priority Academic Programme Development of Jiangsu Higher Education InstitutionsProject supported by the Visiting Scholar Foundation of China Scholarship Council
文摘The dynamics of spatial parallel manipulator with rigid and flexible links is explored. Firstly, a spatial beam element model for finite element analysis is established. Then, the differential equation of motion of beam element is derived based on finite element method. The kinematic constraints of parallel manipulator with rigid and flexible links are obtained by analyzing the motive parameters of moving platform and the relationships of movements of kinematic chains, and the overall kinetic equation of the parallel mechanism with rigid and flexible links is derived by assembling the differential equations of motion of components. On the basis of abovementioned analyses, the dynamic mechanical analysis of the spatial parallel manipulator with rigid and flexible links is conducted. After obtaining the method for force analysis and expressions for the calculation of dynamic stress of flexible components, the dynamic analysis and simulation of spatial parallel manipulator with rigid and flexible links is performed. The result shows that because of the elastic deformation of flexible components in the parallel mechanism with rigid and flexible links, the force on each component in the mechanism fluctuates sharply, and the change of normal stress at the root of drive components is also remarkable. This study provides references for further studies on the dynamic characteristics of parallel mechanisms with rigid and flexible links and for the optimization of the design of the mechanism.
基金Projects(50875002, 60705036) supported by the National Natural Science Foundation of ChinaProject(3062004) supported by Beijing Natural Science Foundation, China+1 种基金Project(20070104) supported by the Key Laboratory of Complex Systems and Intelligence Science, Institute of Automation, Chinese Academy of SciencesProject(2009AA04Z415) supported by the National High-Tech Research and Development Program of China
文摘The dynamic modeling and solution of the 3-■RS spatial parallel manipulators with flexible links were investigated.Firstly,a new model of spatial flexible beam element was proposed,and the dynamic equations of elements and branches of the parallel manipulator were derived.Secondly,according to the kinematic coupling relationship between the moving platform and flexible links,the kinematic constraints of the flexible parallel manipulator were proposed.Thirdly,using the kinematic constraint equations and dynamic model of the moving platform,the overall system dynamic equations of the parallel manipulator were obtained by assembling the dynamic equations of branches.Furthermore,a few commonly used effective solutions of second-order differential equation system with variable coefficients were discussed.Newmark numerical method was used to solve the dynamic equations of the flexible parallel manipulator.Finally,the dynamic responses of the moving platform and driving torques of the 3-■RS parallel mechanism with flexible links were analyzed through numerical simulation.The results provide important information for analysis of dynamic performance,dynamics optimization design,dynamic simulation and control of the 3-■RS flexible parallel manipulator.
基金This project is supported by National Natural Science Foundation of China (No.50390064, No.50375099) Doctorate Foundation of Ministry of Education of China(No.20020248048).
文摘The object of study is about dynamic modeling and control for a 2 degree-of-freedom (DOF) planar parallel mechanism (PM) with flexible links. The kinematic and dynamic equations are established according to the characteristics of mixed rigid and flexible structure. By using the singular perturbation approach (SPA), the model of the mechanism can be separated into slow and fast subsystems. Based on the feedback linearization theory and input shaping technique, the large scale rigid motion controller and the flexible link vibration controller can be designed separately to achieve fast and accurate positioning of the PM.
基金Sponsored by the Innovation Foundation of Shanghai University(Grant No.A.10-0101-07 -406)NNSF of China(Grant No.60874039)
文摘This paper considers a hybrid two-stage flow-shop scheduling problem with m identical parallel machines on one stage and a batch processor on the other stage. The processing time of job Jj on any of m identical parallel machines is aj≡ a (j∈N), and the processing time of job Jj is bj(j∈N) on a batch processor M. We take makespan (Cmax) as our minimization objective. In this paper, for the problem of FSMP-BI (m identical parallel machines on the first stage and a batch processor on the second stage), based on the algorithm given by Sung and Choung for the problem of 1| rj, BI | Cmax under the constraint of the given processing sequence, we develop an optimal dynamic programming Algorithm H1 for it in max{O(nlogn), O(nB)} time. A max{O(nlogn), O(nB)} time symmetric Algorithm H2 is given then for the problem of BI-FSMP (a batch processor on the first stage and m identical parallel machines on the second stage).
基金Supported by National Natural Science Foundation of China (No. 50578048)"Heating, Gas, Ventilation and Air Conditioning" Key Laboratory Open Subject in Beijing (No. KF200710)the Postdoctoral Researcher Science Foundation of China (No. 20090450986)
文摘Sewage source heat pump unit operates under partial load most of the time, and study on the law of coefficient of performance (COP) of the unit varying with load ratio can provide basis for the heat pump units running in high efficiency. A mathematical model determining COP, evaporation temperature and condensation temperature of a single unit was proposed. Under the condition of uniform load distribution, the model was established according to different ways of bearing partial load with the same type multiple units but different parallel operation models, and the operation characteristics of units were analyzed as well. Results show that the single screw water-source heat pump can maintain high COP only at 60%—100% load ratio, COP decreases sharply with the decrease of load ratio, and the units with parallel operation are controlled by the load ratio of a single unit according to the reduction of total load which can keep the average COP at high level within a wide load range.
基金This study was funded by MajorResearch Project of National Natural ScienceFoundationof China(Grant number 91748125)Natural Science Foundation of Hebei,China(Grant number E2020203010).
文摘A prototype of a novel hybrid hand is developed by combing a parallel wrist with three flexible fingers.Its dynamics model is established,its grabbed forces are measured,and its grabbing performances are analyzed.First,Jacobian and Hessian matrices of the moving platform in the parallel wrist are derived,the kinematics formulas for solving the general velocity and the general acceleration of the moving platform are derived.Second its dynamics model is established for solving the dynamic actuation forces,the dynamic constrained forces of the developed hybrid hand.Third,its simulation mechanism is constructed in Matlab,and the theoretical solutions of the kinematics and the dynamics of the developed hybrid hand are verified to be correct using its simulation mechanism.Finally,when objects with different mass are grabbed by prototype of hybrid hand in different poses,the grabbed forces are measured,and the grabbing performances are discovered and analyzed to verify its merits.
基金supported by the Advance Research Foundation of Chinese General Equipment Department(9140C880101140C88367)Major Program of the National Natural Science Foundation of China(U1435218)
文摘In order to solve the problem that previous relation researches in operational task-resource matching are hard to flexible computing for generating a new matching scheme from the existing scheme under the condition of operational tasks or resources adjusted in uncertainty cases, role-based approaches to operational task-resource flexible matching model and algorithm are proposed in the paper for flexible matching operational tasks with resources.Firstly, through introducing the concept of roles, the role-based calculation framework of operational task-resource flexible matching is constructed. Secondly, two aspect indexes about resource utilization ratio(RUR) and time utilization ratio(TUR) are given to reflect operational task-resource matching quality(TRMQ), which can be regarded as the objective function for modeling role-based operational task-resource flexible matching mathematical formulation. On the basis of this, the role-based artificial bee colony(RABC) algorithm, including five specific calculating operators, is put forward for solving the flexible matching problem with double encoding on operational tasks and resources by roles. Finally, via comparing with the previous methods in application cases, it can be validated that role-based model and proposed algorithm are more effective, which can be used to obtain a new incremental scheme from the existing matching scheme for adopting the operational tasks or resources adjustment. Moreover, there are flexible computation advantages of the approaches proposed in this paper to solve the problem about operational task-resource matching in large-scale.
基金Supported by Anhui Provincial Natural Science Foundation (1308085MF102)Fundamental Research Funds for the Central Universities(2012HGBZ0195)
文摘In the view of staff shortages and the huge inventory of products in the current market, we put forward a personnel scheduling model in the target of closing to the delivery date considering the parallelism. Then we designed a scheduling algorithm based on genetic algorithm and proposed a flexible parallel decoding method which take full use of the personal capacity. Case study results indicate that the flexible personnel scheduling considering the order-shop scheduling, machine automatic capabilities and personnel flexible in the target of closing to the delivery date optimize the allocation of human resources, then maximize the efficiency.
基金Supported by the National Natural Science Foundation of China(No.50875054)Weihai Science and Technology Development Plan Project(No.2012DXGJ13)
文摘A series-parallel hydraulic hybrid system applied to public buses is put forward,and parameters of key components are analyzed and determined.Energy management strategy based on logic threshold is designed which is aimed at efficient operation of the overall system considering the operational characteristic of the components and taking the curves of engine,hydraulic pump/motor and hydraulic pump as the main design basis;regenerative control strategy which makes regenerative brake system and frictional brake system work harmoniously is designed to raise recovery rate of regenerative brake energy.System dynamic modeling and simulation results show that the energy control strategy designed here is able to adapt system to changes of working condition and switch the operating mode reasonably.The regenerative braking control strategy is effective in raising the utilization of energy and improving fuel economy.
基金Supported by the National Key Research and Development Project of China(No.2020AAA0104603)the National Natural Science Foundation of China(No.61834005,61772417)the Shaanxi Province Key R&D Plan(No.2021GY-029).
文摘To improve the inference efficiency of convolutional neural networks(CNN),the existing neural networks mainly adopt heuristic and dynamic programming algorithms to realize parallel scheduling among operators.Heuristic scheduling algorithms can generate local optima easily,while the dynamic programming algorithm has a long convergence time for complex structural models.This paper mainly studies the parallel scheduling between operators and proposes an inter-operator parallelism schedule(IOPS)scheduling algorithm that guarantees the minimum similar execution delay.Firstly,a graph partitioning algorithm based on the largest block is designed to split the neural network model into multiple subgraphs.Then,the operators that meet the conditions is replaced according to the defined operator replacement rules.Finally,the optimal scheduling method based on backtracking is used to schedule the computational graph.Network models such as Inception-v3,ResNet-50,and RandWire are selected for testing.The experimental results show that the algorithm designed in this paper can achieve a 1.6×speedup compared with the existing sequential execution methods.
