筒型机构的间隙模型和参数辨识研究

【作者】 邓伟；

【导师】 杨国来；

【作者基本信息】 南京理工大学 ， 机械设计及理论， 2012， 硕士

【摘要】 在高速、重载、高精密的机械系统中运动副间隙对系统动力学响应有着重要影响,开展间隙动力学的理论、仿真与实验研究具有重要的工程价值。本文以某国防重点项目为研究背景,采用理论建模、实验测试和参数辨识相结合的研究方法,对含间隙的移动质量-悬臂梁、身管圆柱段-摇架衬套的动力学进行探讨研究。以二状态法的非线性弹簧阻尼模型为间隙铰接触建模方法,利用接触弹塑性力学理论研究了计及间隙、材料属性的微小间隙转动副面-面精细接触模型,得到了静态的接触力与接触变形的非线性关系,并与传统的Hertz模型进行对比分析。使用假设模态法离散Euler梁,建立了含间隙的移动刚体-悬臂梁横向耦合振动方程,编制了数值程序,分析了间隙、速度和接触力参数对动力学响应的影响。在ADAMS平台下使用柔体-刚体接触模型模拟身管圆柱段与摇架衬套之间的相互作用,由最小二乘拟合获取Impact接触力参数,建立了炮身后坐系统的多体动力学模型,进行了不同装配间隙下的数值计算,分析了间隙对接触碰撞和炮口扰动的影响。搭建了测量机构间间隙的实验平台,完成了不同工况下的动态间隙测试。由间隙曲线可以间接地识别机构内碰撞的运动规律、副元素分离和碰撞的历程。数值计算的间隙曲线与测试结果相比一致性较好,验证了理论建模的正确性。在理论计算和间隙实验研究的基础上,通过构建误差函数,使用遗传算法辨识了移动质量-悬臂梁之间的面-面接触的非线性弹簧阻尼系数；使用ADAMS/Insight的DOE优化法,辨识了身管与摇架衬套的配合间隙、动接触刚度等参数。由辨识所得的参数计算的间隙曲线与实验结果更加吻合。更多还原

【Abstract】 Joint clearance has significant influence on system dynamic response especially for the high speed, overload and high precision mechanism. Development of clearance dynamics in theoretical modeling, simulation and experiment will bring intensive practical engineering value. Under the background of a National Defense Project, this dissertation is concerned with sliding contact dynamics for system with clearance by combination of theoretical modeling, experimental testing and parameter identification, including moving rigid body-cantilever beam and cylindrical section of the barrel-cradle bush.Nonlinear spring damper of two-state method was used to build clearance contact model. Based on Contact Elastic/Plastic Mechanics Theory, a more accurate surface-to-surface contact model of revolute joint with small clearance that can take clearance size, material property into consideration was derived. The nonlinear relationship between static contact force and contact deformation was obtained, which was compared with that from traditional Hertz model.Coupled transverse vibration equations of cantilever beam with clearance subjected to a moving rigid body were formulated by discreting Euler beam based on Assumption Mode Method. And numeric computation code was developed. The influences of clearance, velocity and contact force parameters on dynamics response were analyzed. Under the platform of ADAMS, the flexible body-to-rigid body contact model was used to simulate the interaction between cylindrical barrel and cradle bush. Parameters of Impact contact force function were obtained by least square fitting. The multibody dynamics model of barrel recoil system was established. The influence of different assembly clearance on the performance of contact/impact and muzzle disturbance was then investigated via numerical calculation.The test bed for measuring joint clearance was constructed. And dynamic clearance tests were carried out under different working conditions. Via dynamic clearance curve, the interior contact/impact discipline, as well as process of elements’separation and contact can be recognized indirectly. The accuracy of theoretical modeling and calculation was verified by comparison between experimental data and simulated result.Based on theoretical calculation and clearance experiment, the error function was defined. Genetic algorithm is utilized to identify the nonlinear spring damper coefficients of plane-to-plane contact between moving mass and cantilever beam. Also the assembly clearance and continuous contact force parameters between barrel and cradle bush were identified by using DOE optimization method in ADAMS/Insight module. The calculated clearance curve retrieved from computation in light of the identified parameters was more consistent with experimental result.更多还原