Mode tracking is required in the structural optimization when the frequencies of certain specified modes must be maintained within a suitable range.A simple tracking method employing the mode number is invalid or misl...Mode tracking is required in the structural optimization when the frequencies of certain specified modes must be maintained within a suitable range.A simple tracking method employing the mode number is invalid or misleading when local modes appear or disappear during mesh updating.In this work,a mode tracking scheme combining the nearest neighbor method(NNM)with the modal assurance criterion(MAC)is proposed.Several NNM algorithms are compared,and the k-dimensional tree(kd-tree)NNM is used to transform eigenvectors(mode shapes)from different scales to identical one.A threshold determination method is implemented for the MAC to assess the similarities in all the calculated modes.On the basis of the mode tracking scheme,specified modes can be tracked between different finite element method(FEM)models which have different meshes and optimized shapes.The effectiveness is verified through an example of shape optimization using an electric motor structure.展开更多
In section‘Track decoding’of this article,one of the paragraphs was inadvertently missed out after the text'…shows the flow diagram of the Tr2-1121 track mode.'The missed paragraph is provided below.
Path tracking performed by multiple chassis actuators remains a significant yet challenging issue in intelligent vehicles.This paper presents a robust optimal path tracking control for intelligent vehicles equipped wi...Path tracking performed by multiple chassis actuators remains a significant yet challenging issue in intelligent vehicles.This paper presents a robust optimal path tracking control for intelligent vehicles equipped with a novel wheel module.A wheel module,named corner drive system(CDS),is proposed by integrating drive,brake,steering,and suspension subsystems.In light of the multi-actuator-integrate characteristic of the CDS,a reconfigurable concept is adopted to carry out the vehicle dynamics modeling.To realize an invariance system for both parametric and nonparametric uncertainties,an integral sliding mode control(ISMC)scheme is devised for desired path tracking by combining the advantages of linear quadratic regulator(LQR)in optimization and SMC in robustness.The chattering problem of the ISMC is analyzed and two continuous controllers for chattering elimination are proposed.A control allocation strategy is proposed to dynamically assign the virtual inputs generated by ISMC among four wheels to optimize vehicle stability and minimize energy dissipation.The superiority of the proposed control scheme is demonstrated under different chassis layouts,road friction conditions,and benchmark controllers on a CarSim-based high-fidelity vehicle model with simulation comparison.Subsequently,the Hardware-in-the-Loop(HiL)test is carried out to further evaluate the feasibility and real-time control performance.The quantitative results demonstrate the path tracking performance of the proposed robust optimal controller under both parametric and nonparametric uncertainties.展开更多
This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mod...This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mode,and tracking technology(MTT)is used to avoid frequent alternations of target mode in optimization procedures.An improved planted growth simulation algorithm(IPGSA),which has high search efficiency and quick convergence speed,is proposed to optimize controller parameters coordinately.Based on case study of a large-scale power grid,and by using local and interregional low-frequency oscillation modes as target modes,simulation results verify proposed method in this paper.Furthermore,coordination optimization strategy adapted to multi-operating conditions demonstrates that the proposed approach is robust.展开更多
基金the National Natural Science Foundation of China(No.51775336)the Shanghai Pujiang Program(No.17PJD019)
文摘Mode tracking is required in the structural optimization when the frequencies of certain specified modes must be maintained within a suitable range.A simple tracking method employing the mode number is invalid or misleading when local modes appear or disappear during mesh updating.In this work,a mode tracking scheme combining the nearest neighbor method(NNM)with the modal assurance criterion(MAC)is proposed.Several NNM algorithms are compared,and the k-dimensional tree(kd-tree)NNM is used to transform eigenvectors(mode shapes)from different scales to identical one.A threshold determination method is implemented for the MAC to assess the similarities in all the calculated modes.On the basis of the mode tracking scheme,specified modes can be tracked between different finite element method(FEM)models which have different meshes and optimized shapes.The effectiveness is verified through an example of shape optimization using an electric motor structure.
文摘In section‘Track decoding’of this article,one of the paragraphs was inadvertently missed out after the text'…shows the flow diagram of the Tr2-1121 track mode.'The missed paragraph is provided below.
基金supported by the“Beijing Natural Science Foundation”under Grant L233039“Pioneer and Leading Goose R&D Program of Zhejiang”under Grant 2023C01133“Key R&D Program of Ningbo”under Grant 2023Z014.
文摘Path tracking performed by multiple chassis actuators remains a significant yet challenging issue in intelligent vehicles.This paper presents a robust optimal path tracking control for intelligent vehicles equipped with a novel wheel module.A wheel module,named corner drive system(CDS),is proposed by integrating drive,brake,steering,and suspension subsystems.In light of the multi-actuator-integrate characteristic of the CDS,a reconfigurable concept is adopted to carry out the vehicle dynamics modeling.To realize an invariance system for both parametric and nonparametric uncertainties,an integral sliding mode control(ISMC)scheme is devised for desired path tracking by combining the advantages of linear quadratic regulator(LQR)in optimization and SMC in robustness.The chattering problem of the ISMC is analyzed and two continuous controllers for chattering elimination are proposed.A control allocation strategy is proposed to dynamically assign the virtual inputs generated by ISMC among four wheels to optimize vehicle stability and minimize energy dissipation.The superiority of the proposed control scheme is demonstrated under different chassis layouts,road friction conditions,and benchmark controllers on a CarSim-based high-fidelity vehicle model with simulation comparison.Subsequently,the Hardware-in-the-Loop(HiL)test is carried out to further evaluate the feasibility and real-time control performance.The quantitative results demonstrate the path tracking performance of the proposed robust optimal controller under both parametric and nonparametric uncertainties.
基金This work was supported by the Shanghai Science and Technology Commission Innovation Action Plan(Grant No.18DZ1203200).
文摘This paper presents an approach for designing parameters of power system stabilizer(PSS)and FACTS damping controllers in a large scale practical power system.The objective is maximizing damping ratio of the target mode,and tracking technology(MTT)is used to avoid frequent alternations of target mode in optimization procedures.An improved planted growth simulation algorithm(IPGSA),which has high search efficiency and quick convergence speed,is proposed to optimize controller parameters coordinately.Based on case study of a large-scale power grid,and by using local and interregional low-frequency oscillation modes as target modes,simulation results verify proposed method in this paper.Furthermore,coordination optimization strategy adapted to multi-operating conditions demonstrates that the proposed approach is robust.
