摘要
为了建立更加准确的接触碰撞力模型,提高空间指向机构指向精度和稳定性;提出了一种考虑摩擦因素的改进的非线性法向接触刚度模型,基于修正的L-N模型,建立了更加准确的新的接触碰撞力模型,与已有模型进行了对比分析,并对新的接触碰撞力模型的准确性进行了试验验证;采用牛顿-欧拉法、"接触-分离"两状态模型、修正的Coulomb模型及新的法向接触碰撞力刚度模型,以空间指向机构为研究对象,建立了其动力学方程,研究了不同工况环境对空间指向机构动态特性的影响。研究结果表明:考虑摩擦因素的新的接触碰撞力模型能够更加精确地描述关节铰的接触碰撞效应,并且新模型的适用范围更加广泛;间隙导致空间指向机构动态性能出现明显的振荡,并随着间隙的增大,振荡加剧;关节铰结合面处的表面粗糙度越小,初始碰撞力越大;转速越大对机构产生的冲击力越大,机构的振动频率越高,机构的运行越不稳定。研究结果丰富了接触碰撞力建模方法,为高精度指向机构的设计与应用提供理论依据。
In order to establish a more accurate contact force model and improve the pointing accuracy and stability of the spatial pointing mechanism, an improved nonlinear normal contact stiffness model considering the friction factor is proposed. Compared with the existing contact force model, a more accurate model based on the modified L-N model is established, and the accuracy of the new contact force model is verified by experiments. Using Newton-Euler method, contact-separation two-state model, modified Coulomb model and new normal contact force stiffness model, the spatial pointing mechanism is taken as the research object, and its dynamic equation is established, and the influences of different working conditions on the dynamic characteristics of spatial pointing mechanism are studied. The research shows that the new contact force model considering the friction factor can describe the contact collision effect of the joint more accurately, and the new model has wider application range;the gap causes a significant oscillation in the dynamic performance of the spatial pointing mechanism, and with the increase of the gap, the oscillation is intensified;the smaller the surface roughness of joint, the larger the initial collision force;the greater the rotational speed, the greater the impact force on the mechanism, and the higher the vibration frequency of the mechanism, the more unstable the operation of the mechanism. The research results enrich the contact force modeling method and provide a theoretical basis for the design and application of high-precision pointing mechanism.
作者
韩雪艳
李富娟
高振辉
李仕华
HANXueyan;LI Fujuan;GAO Zhenhui;LI Shihua(Laboratory of Parallel Robot and Mechatronic System of Hebei Province,Yanshan University,Qinhuangdao 066004;College of Mechanical Engineering,Yanshan University,Qinhuangdao 066004)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2020年第15期170-180,共11页
Journal of Mechanical Engineering
基金
国家自然科学基金(51775475)
河北省自然科学基金(E2016203463)资助项目。
关键词
非线性碰撞力
指向机构
动力学
表面粗糙度
摩擦
nonlinear collision force
pointing mechanism
dynamics
surface roughness
friction
