This paper proposes a novel collision post structure designed to improve the crashworthiness of subway cab cars.The structure provides two innovative features:1)a simpler connection between the post and the car roof,w...This paper proposes a novel collision post structure designed to improve the crashworthiness of subway cab cars.The structure provides two innovative features:1)a simpler connection between the post and the car roof,which gives a more reasonable load transfer path to reduce the stress concentration at the joint;and 2)a stiffness induction design that provides an ideal deformation model to protect the safe space of the cab cars.The novel collision post structure was evaluated with finite element analysis,and a prototype cab car was mechanically tested.The results demonstrate that the deformation response was stable and agreed well with the expected ideal mode.The maximum load was 874.17 kN and the responses remained well above the elastic design load of 334 kN as required by the design specification.In addition,there was no significant tearing failure during the whole test process.Therefore,the novel collision post structure proposed has met the requirements specified in new standard to improve the crashworthiness of subway cab cars.Finally,the energy absorption efficiency and light weight design highlights were also summarized and discussed.展开更多
This paper proposes two novel rescue robots,including a cutter robot and a jack robot,which are aimed to contribute to rescue activities such as to cut through obstacles and to jack up debris in dangerous sites and na...This paper proposes two novel rescue robots,including a cutter robot and a jack robot,which are aimed to contribute to rescue activities such as to cut through obstacles and to jack up debris in dangerous sites and narrow spaces,where a rescue team can not work or approach.Firstly,a multilinked tracked rescue robot platform composed of connected crawler vehicles is developed,which has high mobility on irregular terrain and ability to move into narrow collapsed structures.Then,the cutter robot and jack robot are designed on the basis of rescue robot platform equipped with a cutter or a jack mechanism and corresponding manipulators in the front segment.The cutter refitted by an angle grinder is able to cut through 10 mm diameter steel bars.The electric jack mechanism designed based on multiple layers screw sleeves structure can lift up 300 kg load from 70 mm to 400 mm.Experimental results validate the capability of the two rescue robots.展开更多
A new kind of eight-wheel lunar rover is developed, which is a complex closed-chain system and has good capabilities of climbing slope, surmounting obstacles and adapting to uneven terrain. In this paper, the mechanic...A new kind of eight-wheel lunar rover is developed, which is a complex closed-chain system and has good capabilities of climbing slope, surmounting obstacles and adapting to uneven terrain. In this paper, the mechanical structure of the novel eight-wheel lunar rover is introduced, forward and inverse kinematic models of the rover are established according to the closed-chain coordinate transformation and instantaneous coincidence coordinate. Based on structural characteristics, its kinetic characteristics are analyzed. Wheel slippages are separated and calculated, and a method for closed-loop control modification using wheel slip estimation during the model establishment is proposed. The results can be applied to the motion control of lunar rover.展开更多
Random vertical track irregularities are one of essential vibration sources in bridge, track structure and high-speed train systems. The common model of such irregularities is a stationary and ergodic Gaussian process...Random vertical track irregularities are one of essential vibration sources in bridge, track structure and high-speed train systems. The common model of such irregularities is a stationary and ergodic Gaussian process. The study presents the results of numerical dynamic analysis of advanced virtual models of composite BTT （bridge/ballasted track structure/high-speed train） systems. The analysis has been conducted for a series of types of single-span simply-supported railway composite （steel-concrete） bridges, with a symmetric platform, located on lines with ballasted track structure adapted for high-speed trains. The bridges are designed according to Polish bridge standards. A new methodology of numerical modeling and simulation of dynamic processes in BTT systems has been applied. The methodology takes into consideration viscoelastic suspensions of rail-vehicles, nonlinear Hertz wheel-rail contact stiffness and one-side wheel-rail contact, physically nonlinear elastic-damping properties of the track structure, random vertical track irregularities, approach slabs and other features. Computer algorithms of FE （finite element） modeling and simulation were programmed in Delphi. Both static and dynamic numerical investigations of the bridges forming the series of types have been carried out. It has been proved that in the case of common structural solutions of bridges and ballasted track structures, it is necessary to put certain limitations on operating speeds, macadam ballast and vertical track roughness.展开更多
Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is...Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is based on wheel-rail method, but it enables to overcome the speed limitation by adhesion because it is operated through a non-contact method using a linear motor as a propulsion system and reduce the overall construction costs by its compatibility with the conventional railway systems. Therefore, a comparative analysis on electromagnetic characteristics according to the structural combinations on the stator-mover of LSM （linear synchronous motor） for VHST （very high speed train） maintaining the conventional wheel-rail method is conducted, and the structure of coreless superconducting LSM suitable for 600 km/h VHST is finally proposed in this paper.展开更多
Heavy-duty legged robots have been regarded as one of the important developments in the field of legged robots because of their high payload-total mass ratio,terrain adaptability,and multitasking.The problems associat...Heavy-duty legged robots have been regarded as one of the important developments in the field of legged robots because of their high payload-total mass ratio,terrain adaptability,and multitasking.The problems associated with the development and use of heavy-duty legged robots have motivated researchers to conduct many important studies,covering topics related to the mechanical structure,force distribution,control strategy,energy efficiency,etc.Overall,heavy-duty legged robots have three main characteristics:greater body masses,larger body sizes,and higher payload-total mass ratios.Thus,various heavy-duty legged robots and their performances are reviewed here.This review presents the current developments with regard to heavy-duty legged robots.Also,the main characteristics of high-performance heavy-duty legged robots are determined and conclusions are drawn.Furthermore,the current research of key techniques of heavy-duty legged robots,including the mechanical structure,force distribution,control method,and power source,is described.To assess the transportation capacity of heavy-duty legged robots,performance evaluation parameters are proposed.Finally,problems that need further research are addressed.展开更多
To extend electric vehicle (EV) running distance, the vehicle energy regeneration (ER) method and vehicle control strategy were designed based on the original vehicle braking system. The ER principle of direct current...To extend electric vehicle (EV) running distance, the vehicle energy regeneration (ER) method and vehicle control strategy were designed based on the original vehicle braking system. The ER principle of direct current (DC) brushless motor was studied, the motor mathematical model and PI control method with torque close-loop were built. This control method was applied to pure EV and the real road tests were evaluated. The ER control does not make any significant uncomfortable influence brake feeling and can save about 10% battery energy based on 3 times economic commission for Europe (ECE) driving cycles.展开更多
In this paper, the structured trajectory planning of lane change in collision-free road environment is studied and validated using the vehicle-driver integration data, and a new trajectory planning model for lane chan...In this paper, the structured trajectory planning of lane change in collision-free road environment is studied and validated using the vehicle-driver integration data, and a new trajectory planning model for lane change is proposed based on linear offset and sine function to balance driver comfort and vehicle dynamics. The trajectory curvature of the proposed model is continuous without mutation, and the zero-based curvature at the starting and end points during lane change assures the motion direction of end points in parallel with the lane line. The field experiment are designed to collect the vehicle-driver integration data, such as steering angle, brake pedal angel and accelerator pedal angel. The correction Correlation analysis of lane-changing maneuver and influencing variables is conducted to obtain the significant variables that can be used to calibrate and test the proposed model. The results demonstrate that vehicle velocity and Y-axis acceleration have significant effects on the lane-changing maneuver, so that the model recalibrated by the samples of different velocity ranges and Y-axis accelerations has better fitted performance compared with the model calibrated by the sample trajectory. In addition, the proposed model presents a decreasing tendency of the lane change trajectory fitted MAE with the increase of time span of calibrating samples at the starting stage.展开更多
基金Project(2016YFB1200505-016)supported by the National Key Research and Development Program of ChinaProject(51675537)supported by the National Natural Science Foundation of ChinaProject(2018zzts161)supported by the Independent Exploration and Innovation Project of Central South University,China。
文摘This paper proposes a novel collision post structure designed to improve the crashworthiness of subway cab cars.The structure provides two innovative features:1)a simpler connection between the post and the car roof,which gives a more reasonable load transfer path to reduce the stress concentration at the joint;and 2)a stiffness induction design that provides an ideal deformation model to protect the safe space of the cab cars.The novel collision post structure was evaluated with finite element analysis,and a prototype cab car was mechanically tested.The results demonstrate that the deformation response was stable and agreed well with the expected ideal mode.The maximum load was 874.17 kN and the responses remained well above the elastic design load of 334 kN as required by the design specification.In addition,there was no significant tearing failure during the whole test process.Therefore,the novel collision post structure proposed has met the requirements specified in new standard to improve the crashworthiness of subway cab cars.Finally,the energy absorption efficiency and light weight design highlights were also summarized and discussed.
基金Supported by the National High Technology Research and Development Programme of China(No.#2012AA041505)
文摘This paper proposes two novel rescue robots,including a cutter robot and a jack robot,which are aimed to contribute to rescue activities such as to cut through obstacles and to jack up debris in dangerous sites and narrow spaces,where a rescue team can not work or approach.Firstly,a multilinked tracked rescue robot platform composed of connected crawler vehicles is developed,which has high mobility on irregular terrain and ability to move into narrow collapsed structures.Then,the cutter robot and jack robot are designed on the basis of rescue robot platform equipped with a cutter or a jack mechanism and corresponding manipulators in the front segment.The cutter refitted by an angle grinder is able to cut through 10 mm diameter steel bars.The electric jack mechanism designed based on multiple layers screw sleeves structure can lift up 300 kg load from 70 mm to 400 mm.Experimental results validate the capability of the two rescue robots.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50975059)the National High-Tech Research and Development Program of China(863 Program)(Grant No.2006AA04Z231)+1 种基金the College Discipline Innovation Wisdom Plan(Grant No.B07018)Development Program of the Excellent Youth Scholars of Harbin Institute of Technology(Grant No.CACZ98504837)
文摘A new kind of eight-wheel lunar rover is developed, which is a complex closed-chain system and has good capabilities of climbing slope, surmounting obstacles and adapting to uneven terrain. In this paper, the mechanical structure of the novel eight-wheel lunar rover is introduced, forward and inverse kinematic models of the rover are established according to the closed-chain coordinate transformation and instantaneous coincidence coordinate. Based on structural characteristics, its kinetic characteristics are analyzed. Wheel slippages are separated and calculated, and a method for closed-loop control modification using wheel slip estimation during the model establishment is proposed. The results can be applied to the motion control of lunar rover.
文摘Random vertical track irregularities are one of essential vibration sources in bridge, track structure and high-speed train systems. The common model of such irregularities is a stationary and ergodic Gaussian process. The study presents the results of numerical dynamic analysis of advanced virtual models of composite BTT （bridge/ballasted track structure/high-speed train） systems. The analysis has been conducted for a series of types of single-span simply-supported railway composite （steel-concrete） bridges, with a symmetric platform, located on lines with ballasted track structure adapted for high-speed trains. The bridges are designed according to Polish bridge standards. A new methodology of numerical modeling and simulation of dynamic processes in BTT systems has been applied. The methodology takes into consideration viscoelastic suspensions of rail-vehicles, nonlinear Hertz wheel-rail contact stiffness and one-side wheel-rail contact, physically nonlinear elastic-damping properties of the track structure, random vertical track irregularities, approach slabs and other features. Computer algorithms of FE （finite element） modeling and simulation were programmed in Delphi. Both static and dynamic numerical investigations of the bridges forming the series of types have been carried out. It has been proved that in the case of common structural solutions of bridges and ballasted track structures, it is necessary to put certain limitations on operating speeds, macadam ballast and vertical track roughness.
文摘Recently, an interest in a hybrid system combining only the merits of the conventional wheel-rail system and Maglev propulsion system is growing as an alternative to high-speed maglev train. This hybrid-type system is based on wheel-rail method, but it enables to overcome the speed limitation by adhesion because it is operated through a non-contact method using a linear motor as a propulsion system and reduce the overall construction costs by its compatibility with the conventional railway systems. Therefore, a comparative analysis on electromagnetic characteristics according to the structural combinations on the stator-mover of LSM （linear synchronous motor） for VHST （very high speed train） maintaining the conventional wheel-rail method is conducted, and the structure of coreless superconducting LSM suitable for 600 km/h VHST is finally proposed in this paper.
基金supported by the National Basic Research Program of China("973" Program)(Grant No.2013CB035502)the International Sci-ence and Technology Cooperation Project with Russia(Grant No.2010DFR70270)+2 种基金the National Natural Science Foundation of China(Grant No.51275106)the"111" Project(Grant No.B07018)the Key Laboratory Opening Funding of Aerospace Mechanism and Control(Grant No.HIT.KLOF.2010057)
文摘Heavy-duty legged robots have been regarded as one of the important developments in the field of legged robots because of their high payload-total mass ratio,terrain adaptability,and multitasking.The problems associated with the development and use of heavy-duty legged robots have motivated researchers to conduct many important studies,covering topics related to the mechanical structure,force distribution,control strategy,energy efficiency,etc.Overall,heavy-duty legged robots have three main characteristics:greater body masses,larger body sizes,and higher payload-total mass ratios.Thus,various heavy-duty legged robots and their performances are reviewed here.This review presents the current developments with regard to heavy-duty legged robots.Also,the main characteristics of high-performance heavy-duty legged robots are determined and conclusions are drawn.Furthermore,the current research of key techniques of heavy-duty legged robots,including the mechanical structure,force distribution,control method,and power source,is described.To assess the transportation capacity of heavy-duty legged robots,performance evaluation parameters are proposed.Finally,problems that need further research are addressed.
基金the National High Technology Research and Development Program (863) of China (No.2002AA501700)
文摘To extend electric vehicle (EV) running distance, the vehicle energy regeneration (ER) method and vehicle control strategy were designed based on the original vehicle braking system. The ER principle of direct current (DC) brushless motor was studied, the motor mathematical model and PI control method with torque close-loop were built. This control method was applied to pure EV and the real road tests were evaluated. The ER control does not make any significant uncomfortable influence brake feeling and can save about 10% battery energy based on 3 times economic commission for Europe (ECE) driving cycles.
基金supported by the National Natural Science Foundation of China(Grant No.61473028)the National Basic Research Program of China("973" Program)(Grant No.2012CB725403)the National High Technology Research and Development Program of China("863" Program)(Grant No.2015AA124103)
文摘In this paper, the structured trajectory planning of lane change in collision-free road environment is studied and validated using the vehicle-driver integration data, and a new trajectory planning model for lane change is proposed based on linear offset and sine function to balance driver comfort and vehicle dynamics. The trajectory curvature of the proposed model is continuous without mutation, and the zero-based curvature at the starting and end points during lane change assures the motion direction of end points in parallel with the lane line. The field experiment are designed to collect the vehicle-driver integration data, such as steering angle, brake pedal angel and accelerator pedal angel. The correction Correlation analysis of lane-changing maneuver and influencing variables is conducted to obtain the significant variables that can be used to calibrate and test the proposed model. The results demonstrate that vehicle velocity and Y-axis acceleration have significant effects on the lane-changing maneuver, so that the model recalibrated by the samples of different velocity ranges and Y-axis accelerations has better fitted performance compared with the model calibrated by the sample trajectory. In addition, the proposed model presents a decreasing tendency of the lane change trajectory fitted MAE with the increase of time span of calibrating samples at the starting stage.
