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Dynamic Modeling and Analysis of 9-DOF Omnidirectional Legged Vehicle

Chinese Journal of Mechanical Engineering 2011年第4期24卷 515-521页

作者： gao Feng WANG guofu CUI Ying YANG Xinhong School of Transportation Science ＆ Engineering Beihang University Beijing 100191 China

The omnidirectional legged vehicle with steering-rails has a specific mechanism feature, and it can be controlled flexibly and accurately in omnidirectional motion. Currently there lacks further research in this area. In this paper, the mechanical characteristics of independent walking control and steering control and its kinematics principle are introduced, and a vehicle has a composite motion mode of parallel link mechanism and steering mechanism is presented. The motion direction control of the proposed vehicle is only dependant on its steering rails, so its motion is simple and effective to control. When the relative motion between the walking and steering is controlled cooperatively, the vehicle can walk perfectly. By controlling the steering rails, the vehicle can walk along arbitrary trajectory on the ground. To achieve a good result of motion control, an equivalent manipulator model needs to be built. In terms of the mechanism feature and the kinematic principle, the simplified manipulator model consists of a rail in stance phase, a rail in swing phase, and an equivalent leg. Considering the ground surface slope during walking, a parameter of inclination angle is added. Based on such a RPP manipulator model, the equations of motion are derived by means of Lagrangian dynamic approach. To verify the dynamic equations, the motion of the manipulator model is simulated based on linear and nonlinear motion planning. With the same model and motion parameters, the dynamic equations can be solved by Matlab and the calculation data can be gained. Compared with the simulation data, the result confirms the manipulator dynamic equations are correct. As a result of such special characteristics of the legged mechanism with steering rails, it has a potential broad application prospects. The derivation of dynamics equation could benefit the motion control of the mechanism.

关键词： legged vehicle omnidirectional motion steering rails dynamic modeling dynamic simulation

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Prediction of undeformed chip thickness distribution and surface roughness in ultrasonic vibration grinding of inner hole of bearings

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第4期25卷 311-323页

作者： Yanqin LI Daohui XIANG guofu gao Feng JIAO Bo ZHAO School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo 454000China

Ultrasonic vibration grinding differs from traditional grinding in terms of its material removal *** randomness of grain-workpiece interaction in ultrasonic vibration grinding can produce variable chips and impact the surface roughness of ***,previous studies used iterative method to calculate the unformed chip thickness(UCT),which has low computational *** this study,a symbolic difference method is proposed to calculate the *** UCT distributions are obtained to describe the stochastic interaction characteristics of ultrasonic grinding ***,the UCT distribution characteristics under different machining parameters are ***,a surface roughness prediction model is established based on the UCT ***,the correctness of the model is verified by *** study provides a quick and accurate method for predicting surface roughness in longitudinal ultrasonic vibration grinding.

关键词： Ultrasonic vibration grinding Undeformed chip thickness(UCT) Distribution characteristics Surface roughness

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Influence of longitudinal-torsional ultrasonic-assisted vibration on micro-hole drilling Ti-6Al-4V

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Chinese Journal of Aeronautics 2021年第9期34卷 247-260页

作者： guofu gao Ziwen XIA Zhaojie YUAN Daohui XIANG Bo ZHAO School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo 454000China

As Ti-6 Al-4 V is a typical hard to machine material,especially in micro drilling aviation parts,chip breaking difficulty is of increasing interest to explore its further *** this study,Longitudinal-Torsional Ultrasonic Assisted Drilling(LTUAD)was employed to machine Ti-6 Al-4 V,and its feasibility was evaluated by comparing with Conventional Drilling(CD).By combining periodical characteristics and vibration models(the separated or the unseparated ultrasonic elliptical vibration),the influence of ultrasonic frequency on the intersection characteristics of trajectories were *** the intersection characteristics were divided into four categories:even periodicity,odd periodicity,non-odd and even periodicity and composite periodicity,indicating different capability for chip *** applying the longitudinal-torsional compound vibration horn,the micro-hole drilling experiment was carried out on machining *** chip morphology,the thrust force,and the burr height were *** results showed that the morphology of chips presented as smaller and more fragmentary ones in LTUAD compared with continuous helical conical ones and fold-shaped ones in *** with CD,the average values of the thrust force in LTUAD reduced by 1.98%to 24.9%.According to the burr around the hole exit in both LTUAD and CD,the height of the latter was greatly affected by the drilling *** the burr around the exit of the hole were distributed rather evenly with smaller extension in ***,the LTUAD employed in micro-hole drilling was effective.

关键词： Capability for chip breaking Longitudinal-torsional ultrasonic assisted drilling Micro-hole drilling Periodical characters Ti-6Al-4V

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Ultrasonic constitutive model and its application in ultrasonic vibration-assisted milling Ti3Al intermetallics

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Chinese Journal of Aeronautics 2023年第7期36卷 226-243页

作者： guofu gao Zongxia FU Yi WANG Xianrong PAN Daohui XIANG Bo ZHAO School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo 454000China

Ultrasonic vibration-assisted technology is widely utilized in the performance research and manufacturing process of metallic materials owing to its advantages of introducing highfrequency acoustic systems. However, the acoustic plasticity constitutive model and potential mechanism, involving Ti3Al intermetallic compounds, have not yet been clarified. Therefore, the Ultrasonic-K-M hybrid acoustic constitutive model of Ti3Al was established by considering the stress superposition, acoustic thermal softening, acoustic softening and acoustic residual hardening effects according to the dislocation density evolution theory and crystal plasticity theory. Meanwhile, the mechanical behavior of ultrasonic vibration-assisted tension(UVAT) and microstructure of ultrasonic vibration-assisted milling(UVAM) for Ti3Al was investigated. Dislocation density to be overcome from initial deformation to failure of Ti3Al was calculated in UVAT and was verified in UVAM. The results indicated that the Ultrasonic-K-M model showed a good agreement with the experimental data. There was an obviously softening phenomenon after introducing the ultrasonic energy field in the Ti3Al whole deformation region, and the degree of softening was positively correlated with amplitude. Furthermore, the maximum reduction ratio in yield strength of Ti3Al was16 % and the maximum reduction value in ultimate tensile strength was 206.91 MPa. The elongation rose first and then fell as amplitude enlarged, but only as the vibration was applied in the whole deformation region, the elongation was always greater than 14.58 %. In addition, The UVAM process significantly reduced the dislocation density increment to be overcome for Ti3Al material removal by 1.37 times, and promoted dislocation motion and cancellation to make twisted dislocations evolve into parallel dislocations. As the amplitude increased to 4 μm, the depth of the disturbed area of the plastic deformation layer increased by a maximum of 2.5 times.

关键词： Dislocation density Plastic deformation layer Ti3Al intermetallic compounds Ultrasonic-K-M hybrid acoustic constitutive model Ultrasonic vibration-assisted technology

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Microscopic impacts of ultrasonic vibration on interfacial strength of SiCp/Al composites

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CHINESE JOURNAL OF AERONAUTICS 2024年第12期37卷 574-587页

作者： Yuan, Zhaojie Xiang, Daohui Peng, Peicheng Song, Chaosheng Sang, Jinglong Zhang, Yu gao, guofu Zhao, Bo Henan Polytech Univ Sch Mech & Power Engn Jiaozuo 454000 Peoples R China

SiCp/Al composites are used in aerospace and deep-space exploration equipment because of their extremely high strength and thrust-to-weight ratios;however, the differences in the properties of the reinforcement and matrix materials in this type of composites have restricted their applications. The ultrahigh-frequency vibration characteristics of ultrasonic vibration processing technology can effectively solve the above bottlenecks, but the effect of high-frequency vibration on the interfacial properties of SiCp/Al composites is still unclear. The effects of ultrasonic vibration on the interface strength of composites were analyzed from a microscale perspective by means of single particle push-out Molecular Dynamics (MD) simulations and tests under different conditions. The results show that the interface strength is negatively correlated with particle size but positively correlated with ultrasonic amplitude, with a maximum increase of about 51% relative to no ultrasound. Brittle-plastic transition was observed on the surface of particles with high interface strength, and lateral microcracks due to stress concentration were present on the surface of particles with low interface strength. Higher strains and grain refinement were obtained for larger amplitudes, and stacking faults and tangle dislocations appeared on the side of the interface layer close to the Al matrix. The results provide potential insights to improve the micromechanical and mechanical properties of SiCp/Al composites, enhance the longevity of the materials, and realize the sustainable use of resources by expanding the efficient, precise, and clean machining of such materials. (c) 2024 The Author(s). Published by Elsevier Ltd on behalf of Chinese Society of Aeronautics and Astronautics. This is an open access article under the CC BY-NC-ND license (http://***/ licenses/by-nc-nd/4.0/).

关键词： SiCp/Al composites Interface strength Single particle push-out Ultrasonic vibration MD simulations

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Design of large-load ultrasonic vibration grinding system

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Chinese Journal of Acoustics 2022年第2期41卷 154-168页

作者： LI Yanqin ZHAO Bo XIANG Daohui gao guofu JIAO Feng WANG Meng LEI Xiaofei College of Mechanical Engineering Henan Polytechnic UniversityJiaozuo 454000

A large-load ultrasonic vibration grinding system is *** is composed of a transducer,a cylindrical-conical horn,and a spoke-type grinding ***,the spoketype grinding wheel is equivalent to a composite model in which the hub is a cylindrical rod,the spoke and rim are medium-thick ***,the frequency equation of the system is deduced using the continuous boundary conditions of each contact surface,the ultrasonic grinding system design is completed,and the acoustic vibration characteristics of the device are analyzed and *** experimental results show that the proposed model is effective for the design of large-load ultrasonic vibration grinding *** ultrasonic system has a simple structure,stable acoustic vibration characteristics,and uniform displacement amplitude *** is expected to be applied for large-load ultrasonic grinding.

关键词： system cylindrical verified

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基于特征锚杆工作荷载无损检测的巷道围岩稳定性评估初步研究

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岩石力学与工程学报 2004年第z2期23卷 4893-4897页

作者：李义高国付赵阳升太原理工大学矿业工程学院太原030024 太原理工大学采矿工艺研究所太原030024

围岩位移是反映地下结构稳定性的重要参数。而锚杆工作荷载是围岩与锚杆相互作用的集中体现,并且它能够利用动态无损检测方法确定。简要论述了锚杆支护作用原理和锚杆工作荷载的动态测定技术,通过相似模拟试验数据分析,初步探讨了围岩... 详细信息

围岩位移是反映地下结构稳定性的重要参数。而锚杆工作荷载是围岩与锚杆相互作用的集中体现,并且它能够利用动态无损检测方法确定。简要论述了锚杆支护作用原理和锚杆工作荷载的动态测定技术,通过相似模拟试验数据分析,初步探讨了围岩变形和锚杆工作荷载二者的对应关系,由此对巷道围岩稳定性进行了评价。

关键词：岩石力学,围岩稳定性,锚杆,工作荷载,无损检测

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超硬磨料砂轮超声振动修整新进展

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金刚石与磨料磨具工程 2010年第2期30卷 79-82页

作者：赵捷高国富河南理工大学河南焦作454003

硬脆材料精密高效的磨削水平取决于超硬砂轮的修整,随着硬脆材料的广泛使用,超硬磨料砂轮的修整技术也有了新的发展。本文简要叙述了目前一些修整方法的局限性并重点论述了超声波振动修整方法的修整机理以及不同的修整方式,并且对各种... 详细信息

硬脆材料精密高效的磨削水平取决于超硬砂轮的修整,随着硬脆材料的广泛使用,超硬磨料砂轮的修整技术也有了新的发展。本文简要叙述了目前一些修整方法的局限性并重点论述了超声波振动修整方法的修整机理以及不同的修整方式,并且对各种修整方式的特点和效果进行了分析。超声振动修整技术是一种高效的修整方法,修整后的砂轮获得了理想的砂轮形貌。其中,单激励椭圆超声振动修整技术是一种有效而低成本的新型修整方法,可以实现金刚石砂轮的高效修整。

关键词：超硬磨料砂轮超声振动修整砂轮形貌

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超声铣削C/C复合材料铣削力的理论建模

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振动与冲击 2018年第10期37卷 8-13页

作者：高国富胡二娟向道辉赵波河南理工大学机械与动力工程学院河南焦作454000

在平面立铣刀轴向施加纵向超声振动,对超声铣削C/C复合材料的铣削力进行解析。考虑C/C复合材料的层状结构模型和立铣刀的几何模型,以及铣削加工中铣刀旋转为主运动的运动特征,运用斜角切削理论、等效平面和二维正交切削圆的理论对超声... 详细信息

在平面立铣刀轴向施加纵向超声振动,对超声铣削C/C复合材料的铣削力进行解析。考虑C/C复合材料的层状结构模型和立铣刀的几何模型,以及铣削加工中铣刀旋转为主运动的运动特征,运用斜角切削理论、等效平面和二维正交切削圆的理论对超声振动辅助铣削C/C复合材料的铣削力进行建模,获得了超声铣削中的等效平面角的变化规律。并通过数值模拟与实验讨论了超声辅助铣削加工C/C复合材料时随刀具旋转角度变化的铣削力特征。实验结果表明:铣削力的理论曲线的波形变化趋势与实际测得的铣削力的趋势一致。

关键词：超声铣削铣削力斜角切削等效平面

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超声激励薄液膜Faraday波形成机理

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北京航空航天大学学报 2019年第8期45卷 1582-1588页

作者：高国富李康李瑜向道辉赵波河南理工大学机械与动力工程学院

针对35 kHz超声激励薄液膜形成的Faraday波,采用实验和有限元仿真,对Faraday波的形成机理进行探究。建立超声激励下的两相流计算模型,采用计算流体力学(CFD)方法对Faraday波的形成过程进行有限元仿真,通过分析相图和流线图,探讨Faraday... 详细信息

针对35 kHz超声激励薄液膜形成的Faraday波,采用实验和有限元仿真,对Faraday波的形成机理进行探究。建立超声激励下的两相流计算模型,采用计算流体力学(CFD)方法对Faraday波的形成过程进行有限元仿真,通过分析相图和流线图,探讨Faraday波的形成机理,得到Faraday波的振动频率约为超声激励频率的1/2。液体惯性的存在,导致超声激励与液体表面波存在不断变化的相位差,相位差变化周期约等于2个超声激励周期。通过35 k Hz超声激励薄液膜实验,在薄液膜表面观察到排列整齐的Faraday波图案,通过测量Faraday波的波长,得出实验获得的Faraday波频率约为超声激励频率的1/2,与有限元仿真结果一致。

关键词： Faraday波超声激励薄液膜计算流体力学(CFD) 形成机理

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