含间隙转动副冗余约束机构的动力学特性
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摘要
运动副间隙将引起机构运动精度降低,产生振动与噪声,甚至导致机构失效。基于单个平面间隙全文的存在将导致系统增加两个自由度,对含间隙冗余约束平行四边形机构实际自由度进行分析,采用间隙铰接触碰撞模型和拉格朗日方法建立该机构动力学模型,分析了间隙值和间隙位置对机构动力学特性的影响规律。结果表明,随着转动副间隙值的增加,机构运动精度降低,同时平衡力矩的冲击特征减弱;不同位置的转动副两元素接触频率存在差异,因此间隙位置对机构振动存在影响。通过研究含间隙转动副冗余约束机构动力学特性,可以为机构运动副元素尺寸设计及加工过程提供理论指导。
The presence of clearance joints may cause the deterioration of the kinematic accuracy,vibration,noise and even fatigue failure of the system. The number of DOFs is more than the number of independent coordinates in the over-constrained mechanism with multiple clearance joints since two degrees of freedom are introduced when a clearance joint is considered,and the difference is the number of redundant constraints. A common angular coordinate in the clearance of the redundant constraint is eliminated to revise the DOFs and overcome difficulties in dynamic modeling and simulation. The equations of motion for the system is established based on the Impact Ring Model and Lagrange method to study dynamic performance of the planar mechanism. The effects of clearance size and the location of clearance joint on the characteristics of kinematic accuracy,velocity,acceleration,counterbalance moment,and the impact frequency are discussed. The results show that smaller clearance combinations could lead to high kinematic accuracy,obvious vibrations and impact phenomenon. In addition,the components of the revolute joints under smaller clearances experience contact-impact phenomenon more frequently. From the main results obtained in this study,the dynamic model may provide a guidance to the dimension design and machining process of the joint components.
The presence of clearance joints may cause the deterioration of the kinematic accuracy,vibration,noise and even fatigue failure of the system. The number of DOFs is more than the number of independent coordinates in the over-constrained mechanism with multiple clearance joints since two degrees of freedom are introduced when a clearance joint is considered,and the difference is the number of redundant constraints. A common angular coordinate in the clearance of the redundant constraint is eliminated to revise the DOFs and overcome difficulties in dynamic modeling and simulation. The equations of motion for the system is established based on the Impact Ring Model and Lagrange method to study dynamic performance of the planar mechanism. The effects of clearance size and the location of clearance joint on the characteristics of kinematic accuracy,velocity,acceleration,counterbalance moment,and the impact frequency are discussed. The results show that smaller clearance combinations could lead to high kinematic accuracy,obvious vibrations and impact phenomenon. In addition,the components of the revolute joints under smaller clearances experience contact-impact phenomenon more frequently. From the main results obtained in this study,the dynamic model may provide a guidance to the dimension design and machining process of the joint components.
引文
[1]SALAHSHOOR E,EBRAHIMI S,MAASOOMI M.Nonlinear vibration analysis of mechanical systems with multiple joint clearances using the method of multiple scales[J].Mechanism and Machine Theory,2016,105:495-509.
[2]LI P,CHEN W,LI D,et al.Wear Analysis of Two Revolute Joints with Clearance in Multibody Systems[J].Journal of Computational&Nonlinear Dynamics,2015,11(1):1-7.
[3]MUVENGEI O,KIHIU J,IKUA B.Dynamic Analysis of MultiBody Mechanical Systems with Imperfect Kinematic Joints:A Literature Survey and Review[C]//Sustainable Research&Innovation Proceedings,2011,3.
[4]闫绍泽,贾书惠,吴德隆,等.含间隙的变拓扑多体系统动力学建模分析[J].中国机械工程,2000,11(6):624-626.
[5]BAUCHAU O A,RODRIGUEZ J.Modelling of joints with clearance in flexible multibody systems[J].International Journal of Solids and Structures,2002,39(1):41-63.
[6]FLORES P,LANKARANI H M.Dynamic Response of Multibody Systems with Multiple Clearance Joints[J].Journal of Computational Nonlinear Dynamics,2012,7(3):1-13.
[7]BAI Z,TIAN H,ZHAO Y,et al.Dynamics modeling and simulation of mechanism with joint clearance[J].Journal of Harbin Institute of Technology,2010,17(5):706-710.
[8]DUBOWSKY S,DECK J F,COSTELLO H.The dynamic modeling of flexible spatial machine systems with clearance connections[J].Journal of Mechanisms,Transmissions and Automation in design,1987,109(1):87-94.
[9]俞武勇,季林红,闫绍泽,等.含间隙机构运动副的动力学模型[J].机械科学与技术,2001,20(5):665-668.
[10]闫绍泽,陈鹿民,季林红,等.含间隙铰的机械多体系统动力学模型[J].振动工程学报,2003,16(3):290-294.
[11]王庚祥,刘宏昭.考虑球面副间隙的4-SPS/CU并联机构动力学分析[J].机械工程学报,2015,51(1):46-48.
[12]LANKARANI H M,NIKRAVESH P E.A contact force model with hysteresis damping for impact analysis of multibody systems[J].Journal of Mechanical Design,1990,112(3):369-376.
[13]MUVENGEI O,KIHIU J,IKUA B.Dynamic analysis of planar rigid-body mechanical systems with two-revolute clearance joints[J].Nonlinear Dynamics,2013,73(1/2):259-273.
[2]LI P,CHEN W,LI D,et al.Wear Analysis of Two Revolute Joints with Clearance in Multibody Systems[J].Journal of Computational&Nonlinear Dynamics,2015,11(1):1-7.
[3]MUVENGEI O,KIHIU J,IKUA B.Dynamic Analysis of MultiBody Mechanical Systems with Imperfect Kinematic Joints:A Literature Survey and Review[C]//Sustainable Research&Innovation Proceedings,2011,3.
[4]闫绍泽,贾书惠,吴德隆,等.含间隙的变拓扑多体系统动力学建模分析[J].中国机械工程,2000,11(6):624-626.
[5]BAUCHAU O A,RODRIGUEZ J.Modelling of joints with clearance in flexible multibody systems[J].International Journal of Solids and Structures,2002,39(1):41-63.
[6]FLORES P,LANKARANI H M.Dynamic Response of Multibody Systems with Multiple Clearance Joints[J].Journal of Computational Nonlinear Dynamics,2012,7(3):1-13.
[7]BAI Z,TIAN H,ZHAO Y,et al.Dynamics modeling and simulation of mechanism with joint clearance[J].Journal of Harbin Institute of Technology,2010,17(5):706-710.
[8]DUBOWSKY S,DECK J F,COSTELLO H.The dynamic modeling of flexible spatial machine systems with clearance connections[J].Journal of Mechanisms,Transmissions and Automation in design,1987,109(1):87-94.
[9]俞武勇,季林红,闫绍泽,等.含间隙机构运动副的动力学模型[J].机械科学与技术,2001,20(5):665-668.
[10]闫绍泽,陈鹿民,季林红,等.含间隙铰的机械多体系统动力学模型[J].振动工程学报,2003,16(3):290-294.
[11]王庚祥,刘宏昭.考虑球面副间隙的4-SPS/CU并联机构动力学分析[J].机械工程学报,2015,51(1):46-48.
[12]LANKARANI H M,NIKRAVESH P E.A contact force model with hysteresis damping for impact analysis of multibody systems[J].Journal of Mechanical Design,1990,112(3):369-376.
[13]MUVENGEI O,KIHIU J,IKUA B.Dynamic analysis of planar rigid-body mechanical systems with two-revolute clearance joints[J].Nonlinear Dynamics,2013,73(1/2):259-273.