This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat fl...This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat flux density,and analyzes the overall heat dissipation pathways of the bearings.By changing parameters such as input current,rotor speed,and inlet oil flow rate,the study applies a multi-physics field coupling method to investigate the influence of different parameters on the temper-ature field and heat dissipation patterns of the bearings,which is then validated through experi-ments.This research provides a theoretical basis for the optimal design of magnetic fluid bearing sys-tems.展开更多
实现智能网联汽车换道的安全决策是改善交通安全、提高道路机动性的关键任务。本文探究了智能网联汽车换道的安全性问题,从驾驶安全的角度出发,分析了极端换道行为和紧急换道行为给交通安全带来的不利影响,强调风险评估的重要性,并梳理...实现智能网联汽车换道的安全决策是改善交通安全、提高道路机动性的关键任务。本文探究了智能网联汽车换道的安全性问题,从驾驶安全的角度出发,分析了极端换道行为和紧急换道行为给交通安全带来的不利影响,强调风险评估的重要性,并梳理了利用环境传感器、交通冲突指标、车辆微观轨迹数据等换道风险评估方法。通过风险评估识别风险,并采取相应的措施,能够显著减少危险换道行为导致的交通事故。阐述了智能网联汽车在传统环境以及车联万物(vehicle to everything,V2X)场景下,通过获取环境信息完成换道决策的方法;重点剖析了智能网联汽车在V2X环境下,通过周围环境的感知和识别、目标检测、数据处理进行决策,并对未来智能网联汽车在V2X环境下实现安全决策提出合理建议。然后分析了现有换道决策模型方法,归纳为4类:即规则模型、离散选择模型、人工智能模型、博弈论模型;系统地总结了决策模型在国内外道路行车安全领域的研究和应用现状、存在的问题,以及应用展望。综上所述,尽管智能网联汽车的换道技术已取得重大研究成果,但未来仍存在很多挑战。针对现有研究中存在的问题:低等级自动驾驶环境情况下如何安全可靠地进行决策、智能网联汽车在低渗透率情况下如何做出更为高效和智能的驾驶决策、信息不完全情况下如何实现安全决策、在换道决策模型算法的可优化性方面如何改进,提出可行的解决方案。展开更多
In order to adapt to the specific task, the six-axis dynamic contact force between end-effectors of intelligent robots and working condition needs to be perceived. Therefore, the dynamic property of six-axis force sen...In order to adapt to the specific task, the six-axis dynamic contact force between end-effectors of intelligent robots and working condition needs to be perceived. Therefore, the dynamic property of six-axis force sensor which is installed on the end-effectors of intelligent robots will have influence on the veracity of detection and judgment to working environment contact force by intelligent robots directly. In this paper, dynamic analysis to double-layer and pre-stressed multi-limb six-axis force sensor is conducted. First, the structure of the sensor is introduced, and the limb number is confirmed by introducing the related definitions of convex analysis. Then, based on vibration of multiple-degree-of-freedom system, a mechanical vibration simplified model of double-layer and pre-stressed multiple limb six-axis force sensor is set up. After that, movement differential equations of sensor and the response of analytical expression are deduced, and the movement differential equations is solved. Finally, taking the double-layer and pre-stressed seven limb six-axis force sensor as an example, numerical calculation and simulation of deriving result is conducted, which verify the correctness and feasibility of the theoretical analysis.展开更多
A novel orthogonal-parallel six-axis force/torque sensor is studied based on a modified Stewart platform architecture,and the optimal design and experiment research of the sensor are discussed.Firstly,the model of ort...A novel orthogonal-parallel six-axis force/torque sensor is studied based on a modified Stewart platform architecture,and the optimal design and experiment research of the sensor are discussed.Firstly,the model of orthogonal parallel six-axis force/torque sensor based on improved Stewart platform architecture and its static mathematical model are proposed.Secondly,according to the actual working condition of the sensor,the sensor is optimized and the optimal solution is obtained.Then,the experimental prototype and calibration system is developed.Finally,the superiority of the sensor structure and the effectiveness of the optimization method are verified by calibration experiments.The results of the proposed method are useful for the further research and application of the orthogonal-parallel six-axis force/torque sensor.展开更多
基金the National Natural Science Foundation of China(No.52075468)the Natural Science Foundation of Hebei Province(No.E2020203052)+1 种基金the Key Scientific Research Projects of North China University of Technology(No.ZD-YG-202306-23)the Tangshan Science and Technology Project(No.23130201E).
文摘This paper analyzes the sources of heat losses in magnetic fluid bearings,proposes various cou-pling relationships of physical fields,divides the coupled heat transfer surfaces while ensuring the continuity of heat flux density,and analyzes the overall heat dissipation pathways of the bearings.By changing parameters such as input current,rotor speed,and inlet oil flow rate,the study applies a multi-physics field coupling method to investigate the influence of different parameters on the temper-ature field and heat dissipation patterns of the bearings,which is then validated through experi-ments.This research provides a theoretical basis for the optimal design of magnetic fluid bearing sys-tems.
文摘实现智能网联汽车换道的安全决策是改善交通安全、提高道路机动性的关键任务。本文探究了智能网联汽车换道的安全性问题,从驾驶安全的角度出发,分析了极端换道行为和紧急换道行为给交通安全带来的不利影响,强调风险评估的重要性,并梳理了利用环境传感器、交通冲突指标、车辆微观轨迹数据等换道风险评估方法。通过风险评估识别风险,并采取相应的措施,能够显著减少危险换道行为导致的交通事故。阐述了智能网联汽车在传统环境以及车联万物(vehicle to everything,V2X)场景下,通过获取环境信息完成换道决策的方法;重点剖析了智能网联汽车在V2X环境下,通过周围环境的感知和识别、目标检测、数据处理进行决策,并对未来智能网联汽车在V2X环境下实现安全决策提出合理建议。然后分析了现有换道决策模型方法,归纳为4类:即规则模型、离散选择模型、人工智能模型、博弈论模型;系统地总结了决策模型在国内外道路行车安全领域的研究和应用现状、存在的问题,以及应用展望。综上所述,尽管智能网联汽车的换道技术已取得重大研究成果,但未来仍存在很多挑战。针对现有研究中存在的问题:低等级自动驾驶环境情况下如何安全可靠地进行决策、智能网联汽车在低渗透率情况下如何做出更为高效和智能的驾驶决策、信息不完全情况下如何实现安全决策、在换道决策模型算法的可优化性方面如何改进,提出可行的解决方案。
基金Supported by the National Natural Science Foundation of China(No.51505124)the Natural Science Foundation of Hebei Province(No.E2016209312)the Foster Fund Projects of North China University of Science and Technology(No.JP201505)
文摘In order to adapt to the specific task, the six-axis dynamic contact force between end-effectors of intelligent robots and working condition needs to be perceived. Therefore, the dynamic property of six-axis force sensor which is installed on the end-effectors of intelligent robots will have influence on the veracity of detection and judgment to working environment contact force by intelligent robots directly. In this paper, dynamic analysis to double-layer and pre-stressed multi-limb six-axis force sensor is conducted. First, the structure of the sensor is introduced, and the limb number is confirmed by introducing the related definitions of convex analysis. Then, based on vibration of multiple-degree-of-freedom system, a mechanical vibration simplified model of double-layer and pre-stressed multiple limb six-axis force sensor is set up. After that, movement differential equations of sensor and the response of analytical expression are deduced, and the movement differential equations is solved. Finally, taking the double-layer and pre-stressed seven limb six-axis force sensor as an example, numerical calculation and simulation of deriving result is conducted, which verify the correctness and feasibility of the theoretical analysis.
基金Supported by the National Natural Science Foundation of China(No.51505124)Foster Fund Projects of North China University of Science and Technology(No.JP201505)the Science and Technology Research Project of Hebei Province(No.ZD2020151).
文摘A novel orthogonal-parallel six-axis force/torque sensor is studied based on a modified Stewart platform architecture,and the optimal design and experiment research of the sensor are discussed.Firstly,the model of orthogonal parallel six-axis force/torque sensor based on improved Stewart platform architecture and its static mathematical model are proposed.Secondly,according to the actual working condition of the sensor,the sensor is optimized and the optimal solution is obtained.Then,the experimental prototype and calibration system is developed.Finally,the superiority of the sensor structure and the effectiveness of the optimization method are verified by calibration experiments.The results of the proposed method are useful for the further research and application of the orthogonal-parallel six-axis force/torque sensor.