In the engineering database system, multiple versions of a design including engineering drawings should be managed efficiently. The paper proposes an efficient spatial data structure, that is an expansion of the R tre...In the engineering database system, multiple versions of a design including engineering drawings should be managed efficiently. The paper proposes an efficient spatial data structure, that is an expansion of the R tree and HR tree, for version management of engineering drawings. A novel mechanism to manage the difference between drawings is introduced to the HR tree to eliminate redundant duplications and to reduce the amount of storage required for the data structure. Data management mechanism and structural properties of our data structure called the MVR + tree are described.展开更多
[ 篇名 ] Computer aided design of an axial-field PM brushless DC motor for an electric vehicle，[ 篇名 ] Concept of the “KAZ”, the Start of a New Generation in Car Design，[ 篇名 ] Conceptual Design of Hybrid Electr...[ 篇名 ] Computer aided design of an axial-field PM brushless DC motor for an electric vehicle，[ 篇名 ] Concept of the “KAZ”, the Start of a New Generation in Car Design，[ 篇名 ] Conceptual Design of Hybrid Electric Vehicle for Urban Use in China，[ 篇名 ] Consumer Education - An Essential Element in the Acceptance of the Electric Vehicle，[ 篇名 ] Control and Management Strategies for the Delphi High Power Lithium Battery，[ 篇名 ] Control of a Continuously Operated Pole-Changing Induction Machine，[ 篇名 ] Control of compact hybrid drive consisting of PM motor and planetary transmission CVT，[ 篇名 ] Control of independent rear wheel drives for electric and hybrid vehicles using one neuro-fuzzy controller，[ 篇名 ] Controller-induced parasitic torque ripples in a PM synchronous motor，[ 篇名 ] Coordination of Charging Stations for Electric Vehicles，[ 篇名 ] Coupled Electrochemical and Thermal Analysis of Electric-Vehicle Battery Modules，[ 篇名 ] Current Activities of Standardisation in Japan，[ 篇名 ] Current Status Report on U.S. Department of Energy Electric and Hybrid Electric Vehicle Energy Storage R&D Programs，[ 篇名 ] Current-mode control for sensorless BDCM drive with intelligent commutation tuning，[ 篇名 ] DaimlerChrysler EPIC Minivan Powered by Lithium-Ion Batteries，[ 篇名 ] Design and analysis of a new multiphase polygonal-winding permanent-magnet brushless DC machine，[ 篇名 ] Design and development of the 2001 Michigan Tech FutureTruck, a power-split hybrid electric vehicle，[ 篇名 ] Design and development of the 2002 Comell University hybrid electric vehicle，[ 篇名 ] Design and development of the 2002 Michigan Tech FutureTruck, a parallel hybrid electric vehicle，[ 篇名 ] Design and development of the 2002 Penn State University parallel hybrid electric explorer, the Wattmuncher。展开更多
By introducing the homogenous coordinates, degree elevation formulas and combinatorial identities, also by using multiplication of Bernstein polynomials and identity transformation on equations, this paper presents so...By introducing the homogenous coordinates, degree elevation formulas and combinatorial identities, also by using multiplication of Bernstein polynomials and identity transformation on equations, this paper presents some explicit formulas of the first and second derivatives of rational triangular Bézier surface with respect to each variable (including the mixed derivative) and derives some estimations of bound both on the direction and magnitude of the corresponding derivatives. All the results above have value not only in surface theory but also in practice.展开更多
This paper presents a basis for the space of hyperbolic polynomials Гm=span { 1, sht, cht, sh2t, ch2t shmt, chmt} on the interval [0,a] from an extended Tchebyshev system, which is analogous to the Bernstein basis fo...This paper presents a basis for the space of hyperbolic polynomials Гm=span { 1, sht, cht, sh2t, ch2t shmt, chmt} on the interval [0,a] from an extended Tchebyshev system, which is analogous to the Bernstein basis for the space of polynomial used as a kind of well-known tool for free-form curves and surfaces in Computer Aided Geometry Design. Then from this basis, we construct quasi Bézier curves and discuss some of their properties. At last, we give an example and extend the range of the parameter variable t to arbitrary close interval [r, s] （r〈s）.展开更多
This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)c...This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)compensation from DASM can be regulated independently through secondary-excitation controlling.Simulation results by power system computer aided design(PSCAD)show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures.Comparison studies have also been performed between wind turbine pitch control and proposed method.展开更多
The top relief surfaces of an hourglass worm gear hob are ground manually in the traditional manufacturing process,which cannot ensure the width of the land surfaces of the hob.Moreover,each geometric feature of the h...The top relief surfaces of an hourglass worm gear hob are ground manually in the traditional manufacturing process,which cannot ensure the width of the land surfaces of the hob.Moreover,each geometric feature of the hob has been produced through different manufacturing techniques and machine tools,which results in low efficiency.To solve this problem,we propose a semi-automatic computer aided design(CAD)method for hobs.The point clouds of each feature surface of a hob are calculated by combing mathematical equations of the top relief surfaces built by the proposed method with other existing equations of hob surfaces.According to the point clouds,the method can achieve the automatic modeling for the hob in three-dimensional(3D)software by classifying and extracting the parameter information of the feature-hierarchical knowledge of the hob.Based on the generated 3D model,the entire surfaces of the hob can be manufactured on a four-axis computer numerical control(CNC)milling machine through only twice clamping.Verification of the width of the land surface of the hob manufactured by semi-automatic CAD method on a measuring projector proved the precision of the designed width can be ensured.The edge of the contact area on the worm wheel in a meshing experiment is clear and distinct,which means the worm gear drive is meshed well and the hob manufactured by the proposed method has improved machinability.The method simplifies the processing technique,and improves the design efficiency and production accuracy.展开更多
文摘In the engineering database system, multiple versions of a design including engineering drawings should be managed efficiently. The paper proposes an efficient spatial data structure, that is an expansion of the R tree and HR tree, for version management of engineering drawings. A novel mechanism to manage the difference between drawings is introduced to the HR tree to eliminate redundant duplications and to reduce the amount of storage required for the data structure. Data management mechanism and structural properties of our data structure called the MVR + tree are described.
文摘[ 篇名 ] Computer aided design of an axial-field PM brushless DC motor for an electric vehicle，[ 篇名 ] Concept of the “KAZ”, the Start of a New Generation in Car Design，[ 篇名 ] Conceptual Design of Hybrid Electric Vehicle for Urban Use in China，[ 篇名 ] Consumer Education - An Essential Element in the Acceptance of the Electric Vehicle，[ 篇名 ] Control and Management Strategies for the Delphi High Power Lithium Battery，[ 篇名 ] Control of a Continuously Operated Pole-Changing Induction Machine，[ 篇名 ] Control of compact hybrid drive consisting of PM motor and planetary transmission CVT，[ 篇名 ] Control of independent rear wheel drives for electric and hybrid vehicles using one neuro-fuzzy controller，[ 篇名 ] Controller-induced parasitic torque ripples in a PM synchronous motor，[ 篇名 ] Coordination of Charging Stations for Electric Vehicles，[ 篇名 ] Coupled Electrochemical and Thermal Analysis of Electric-Vehicle Battery Modules，[ 篇名 ] Current Activities of Standardisation in Japan，[ 篇名 ] Current Status Report on U.S. Department of Energy Electric and Hybrid Electric Vehicle Energy Storage R&D Programs，[ 篇名 ] Current-mode control for sensorless BDCM drive with intelligent commutation tuning，[ 篇名 ] DaimlerChrysler EPIC Minivan Powered by Lithium-Ion Batteries，[ 篇名 ] Design and analysis of a new multiphase polygonal-winding permanent-magnet brushless DC machine，[ 篇名 ] Design and development of the 2001 Michigan Tech FutureTruck, a power-split hybrid electric vehicle，[ 篇名 ] Design and development of the 2002 Comell University hybrid electric vehicle，[ 篇名 ] Design and development of the 2002 Michigan Tech FutureTruck, a parallel hybrid electric vehicle，[ 篇名 ] Design and development of the 2002 Penn State University parallel hybrid electric explorer, the Wattmuncher。
基金Project supported by the National Natural Science Foundation of China (Nos. 60373033 & 60333010), the National Natural Science Foundation for Innovative Research Groups (No. 60021201), and the National Basic Research Program (973) of China (No. 2002CB312101)
文摘By introducing the homogenous coordinates, degree elevation formulas and combinatorial identities, also by using multiplication of Bernstein polynomials and identity transformation on equations, this paper presents some explicit formulas of the first and second derivatives of rational triangular Bézier surface with respect to each variable (including the mixed derivative) and derives some estimations of bound both on the direction and magnitude of the corresponding derivatives. All the results above have value not only in surface theory but also in practice.
基金Project supported by the National Natural Science Foundation of China (No. 60473130) and the National Basic Research Program (973) of China (No. 2004CB318000)
文摘This paper presents a basis for the space of hyperbolic polynomials Гm=span { 1, sht, cht, sh2t, ch2t shmt, chmt} on the interval [0,a] from an extended Tchebyshev system, which is analogous to the Bernstein basis for the space of polynomial used as a kind of well-known tool for free-form curves and surfaces in Computer Aided Geometry Design. Then from this basis, we construct quasi Bézier curves and discuss some of their properties. At last, we give an example and extend the range of the parameter variable t to arbitrary close interval [r, s] （r〈s）.
文摘This paper investigates the function of doubly-fed asynchronous machine(DASM)with emphasis placed on its ability to the stabilization of the power system including wind generators.P(active power)and Q(reactive power)compensation from DASM can be regulated independently through secondary-excitation controlling.Simulation results by power system computer aided design(PSCAD)show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures.Comparison studies have also been performed between wind turbine pitch control and proposed method.
基金supported by The Development of Design and Manufacturing Technology of Double-Enveloping Worm Pair in High-precision with Little Centre Distance(No.69190135)We would like to thank the Professor Workstation of China Agricultural University in Hebei Baoding Laibo Transmission Machinery Manufacturing Co.LTD(No.20200901).
文摘The top relief surfaces of an hourglass worm gear hob are ground manually in the traditional manufacturing process,which cannot ensure the width of the land surfaces of the hob.Moreover,each geometric feature of the hob has been produced through different manufacturing techniques and machine tools,which results in low efficiency.To solve this problem,we propose a semi-automatic computer aided design(CAD)method for hobs.The point clouds of each feature surface of a hob are calculated by combing mathematical equations of the top relief surfaces built by the proposed method with other existing equations of hob surfaces.According to the point clouds,the method can achieve the automatic modeling for the hob in three-dimensional(3D)software by classifying and extracting the parameter information of the feature-hierarchical knowledge of the hob.Based on the generated 3D model,the entire surfaces of the hob can be manufactured on a four-axis computer numerical control(CNC)milling machine through only twice clamping.Verification of the width of the land surface of the hob manufactured by semi-automatic CAD method on a measuring projector proved the precision of the designed width can be ensured.The edge of the contact area on the worm wheel in a meshing experiment is clear and distinct,which means the worm gear drive is meshed well and the hob manufactured by the proposed method has improved machinability.The method simplifies the processing technique,and improves the design efficiency and production accuracy.
