共查询到19条相似文献,搜索用时 156 毫秒
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影响液压锤性能因素的仿真研究 总被引:4,自引:0,他引:4
介绍了一种新型液压锤的工作原理,对液压锤的简化数学模型及考虑所受粘性摩擦力、密封阻力的数学模型进行了仿真研究,并对得出的数据进行了,分析。仿真结果表明:粘性摩擦力降低了BH65液压锤的冲击能,增加了平均输入压力,降低了工作效率,但对冲击频率的影响小大;活塞速度引起的粘性摩擦力比压差引起的粘性摩擦力要大得多,在计算粘性摩擦力时可忽略压差的影响,从而使模型得到简化;密封阻力增加了BH65液压锤的平均输入压力,降低了其冲击能、冲击频率和工作效率。 相似文献
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分析挖掘机工作装置结构及其液压缸摩擦力,根据挖掘机实际结构,建立了挖掘机工作装置结构的简化模型;同时根据实验数据和虚拟样机的静力学和逆动力学计算,得到挖掘机动臂、斗杆及铲斗三组油缸在不同运动状态下的摩擦力曲线,确定其平均摩擦力及摩擦因数的大小;利用仿真软件ADAMS对工作装置虚拟样机模型进行不同工况下的运动学及动力学仿真,仿真结果表明液压缸摩擦力对工作装置运动学参数影响不大,但对其液压缸驱动力的影响较为明显。 相似文献
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在利用电磁作动器对微型盘进行振动主动控制的试验中,发现电磁执行装置中的干摩擦力对控制效果有相当大的影响,为此分析了干摩擦力对隔振系统的影响,得出了基于干摩擦力影响下的振动主动控制系统模型,并结合算例分别对考虑干摩擦影响和不考虑干摩擦影响的情况进行了仿真。仿真结果证实;干摩擦力对振动主动控制的效果有着重要不良影响,如果不能正确考虑其在控制系统模型中的作用,将会导致一些错误的发生,乃至控制系统失控。 相似文献
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采用库仑摩擦力和非库仑摩擦力模型,建立悬臂双盘碰摩转子系统的运动微分方程。利用数值仿真方法,以转速为分叉参数分析了系统运动状态。分析结果表明,采用两种摩擦力模型时,系统产生分叉转速范围和转速带宽均有明显不同,系统通向混沌的道路主要是阵发性分叉和周期分叉。数值仿真结果与碰摩试验结果一致,且在相对速度影响系数B1=0.3和B2=0.06或B1=0.15和B2=0.06的情况下,宜采用非库仑摩擦力模型。 相似文献
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为研究转子压缩机滑片-滑槽运动副的摩擦特性,根据LuGre摩擦模型的建模方法和该运动副的运行特点及工况特点,设计并搭建了滑片-滑槽等效摩擦力测试系统,分析了该系统的摩擦力跃动现象、数据采集区域和摩擦力测量的重复性问题,并进行了摩擦力测试实验。结果表明:该摩擦力测试系统可以根据压缩机的实际工况,对滑片均匀加载相应的正压力FH,并能实现不同匀速直线运动下的摩擦力测量;可以有效消除低速润滑不均匀导致的摩擦力跃动现象;通过润滑初始化可以较准确地获得基于滑片速度变化的摩擦力表达曲线。实验结果与数值计算结果吻合,从而为正确辨识LuGre摩擦模型的参数提供了实验依据。 相似文献
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电液位置伺服系统的摩擦补偿及仿真研究 总被引:1,自引:0,他引:1
对卷取机踏步控制模型液压位置控制系统进行分析并补偿摩擦力,从而提高系统的低速性能。对采用传统PID控制和基于新型摩擦模型建立摩擦观测器进行摩擦补偿,Simulink进行仿真研究。通过仿真结果可以看出,电液位置伺服系统采用PID调节再加上摩擦补偿比单纯采用PID调节时的系统的性能明显改善了,能够实现系统低速运行时的稳定、快速和准确跟踪。 相似文献
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基于振动情况下轧制界面水平-垂直方向摩擦力模型和动态轧制力模型,考虑轧机的结构和工作辊轴承座与牌坊立柱间的摩擦力等因素的影响,建立了热连轧机工作辊水平-垂直系统的非线性振动模型。运用平均法求解得到幅频特性方程,分析外扰力和非线性参数等因素对系统幅频特性的影响,为抑制轧机工作辊水平-垂直振动提供理论指导。通过分析李雅普诺夫指数和位移分岔图,发现系统随外扰力幅值变化表现出周期、倍周期和混沌等不同运动状态。最后,通过分析工作辊轴承座与牌坊立柱间有无衬板间隙这两种情况下的幅频特性及衬板间隙对系统振动的影响规律,提出一种抑制工作辊水平振动和垂直振动的方法,仿真和实验结果均表明该方法有效。 相似文献
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为了提高由直线电机驱动的精密定位系统的定位精度,建立了优化Stribeck摩擦模型,对摩擦力这一影响定位精度的主要因素进行补偿。首先,对于传统的Stribeck摩擦模型进行优化,采用改进的最小二乘算法对模型参数进行辨识。然后,对所建立的摩擦模型补偿算法进行仿真并与扰动观测器的补偿算法进行比较,发现前者速度比后者速度在补偿后提高了4.33%,对摩擦力具有更好的补偿效果。最后,在大行程二维精密定位平台上进行验证,根据平台能够达到的最大速度定义0.005 m/s为低速运动,0.05 m/s为高速运动,在这两种速度下进行实验,并与基于库仑摩擦前馈补偿模型比较。实验结果表明:精密定位平台在速度为0.005 m/s的低速运动时,优化模型的跟随误差减小了67.67%;在速度为0.05 m/s的高速运动时,优化模型的跟随误差减小了51.63%,验证了优化Stribeck摩擦模型补偿算法的有效性。本文提出的优化Stribeck摩擦模型可用于提高由直线电机驱动的精密定位系统的定位精度。 相似文献
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This paper proposes a friction compensator and a design method for control systems to improve the response characteristics of linear motor feed drive systems. The proposed friction compensator cancels the real nonlinear friction of feed drive systems by using the nonlinear friction model proposed in this study and introduces virtual linear friction to facilitate the control system design. The proposed design method enables the determination of servo gains and friction compensator parameters that lead to desirable tracking performance and disturbance rejection without many trial-and-error tuning processes. In addition, the proposed method facilitates the design of the velocity feedforward compensator by using the inverse transfer function of the velocity control loop to correct the position tracking errors for various position commands. The effectiveness of the proposed method with the friction compensator and the velocity feedforward compensator was verified in simulations and experiments using a one-axis feed drive system consisting of a rod-type linear motor and linear roller guides. The results confirmed that the proposed method enables desirable overshoot-free responses and corrects motion trajectory errors due to nonlinear friction characteristics, and the proposed velocity feedforward compensator can correct tracking errors in both constant velocity motion and circular motion. 相似文献
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The dynamic characteristics of stick-slip motion in reciprocating friction drive systems are investigated under dry contact using a 0.45% carbon steel pair. Based on this dynamic analysis, the stick-slip motion can be eliminated under certain experimental conditions depending upon driver speed, normal load and spring constant. The effects of normal load, driver speed, and spring constant on the positioning accuracy of the reciprocating friction drive system are examined under harmonic oscillation without stick-slip motion. Results show that at very low spring constants, the slip increases with increasing driver speed such that higher normal load has better positioning accuracy or smaller slip than does lower normal load. However, at high spring constants and high normal loads, there exhibits severe wear or peak at two limit positions on the sliding region. As a result, smaller normal loads have a better positioning accuracy than larger normal loads due to severe wear at high normal loads. 相似文献
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干摩擦阻尼叶片周期振动响应的解析计算 总被引:5,自引:2,他引:3
研究一个描述干摩擦阻尼器叶片振动的质量-弹簧-阻尼器振动系统。阻尼器摩擦力由黏滞模型描述,由接触面滑动或黏滞状态决定。将滞后摩擦力分为四个阶段,从而得到各个阶段上的线性振动系统,给出求干摩擦阻尼叶片周期响应的解析公式。计算表明,阻尼端压力取适当值时,阻尼器会处于最优的摩擦接触状态,获得较好减振效果。同时引入阻尼器处对叶片还起到调频作用,也可以起到使激振频率避开共振频率的作用,减小振动幅值。 相似文献
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Ren Yongsheng College of Mechanical Electronic Engineering Shandong University of Science Technology Qingdao China Zhang Hongbing College of Science Taiyuan University of Technology Taiyuan China Liu Lihou School of Basic Science Shanghai University of Engineering Science Shanghai China 《机械工程学报(英文版)》2005,18(2):169-173
The rigid-interface friction model is usually used in the nonlinear vibration of the rectangular plate with dry friction support edges. The present study provides an extension by using a hysteretic spring friction model and taking account of the stick-slip motion of the plate. Results for a range of problem parameters have been obtained. The results show that the nonlinear frequency response behavior of the system can be quite different from the rigid-interface friction model. The effects of the stiffness at friction interfaces and the stick-slip motion on the nonlinear vibration of the plate are significant and hence cannot be neglected. 相似文献
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Results of investigation into the relationship between friction in the O-ring type seal and gauge pressure at the commencement of linear motion of a shaft are presented and discussed. A number of different O-ring materials were studied and the lowest friction under dry conditions was found to be produced by a PTFE-encapsulated silicone seal. The effect of a number of lubricating fluids on friction in the seal was also studied and the results obtained are included. 相似文献
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We have constructed a sliding block cryotribometer designed to measure friction at cryogenic temperatures and UHV conditions. An optical cryostat and high speed video was used to monitor the motion of the block. The temperature range of the measurements was 4–460 K. Both the static and dynamic friction coefficients were determined for a steel ball on stainless steel, sapphire, and PTFE (Teflon) plates, and for a sapphire ball on a sapphire plate. For all material combinations, no systematic variation of friction with temperature was observed in the temperature range 4–200 K. 相似文献