共查询到20条相似文献,搜索用时 109 毫秒
1.
运动副间隙对汽车摆振系统非线性动力学行为影响分析 总被引:4,自引:0,他引:4
在前期研究中发现运动副间隙对机构的动力学响应影响显著,因此做出转向系统中的间隙也会对转向摆振系统的响应产生重要影响的推断。为此,将转向梯形机构简化为一个连杆机构,并就机构中运动副间隙对转向系统摆振的影响进行了分析。借助拉格朗日方程建立考虑转向机构运动副间隙的6自由度转向系统摆振动力学模型,基于该摆振模型,应用四阶龙格-库塔法对间隙参数发生变化时摆振系统的响应进行仿真分析。通过仿真分析结果发现:转向机构运动副间隙是诱发转向轮摆振系统混沌运动的重要因素,在摆振系统建模过程中应予以充分考虑;随着运动副间隙增大,转向摆振系统会由周期运动状态经过拟周期运动状态逐渐进入混沌状态,造成摆振运动加剧。相关结论可为转向系统摆振的有效控制奠定理论基础。 相似文献
2.
对于Consteel振动输送机,四轴惯性激振器产生水平激振力,槽体在拉杆作用下可看做一个倒立摆。当激振力为水平激振力且拉杆较长时,槽体在垂直方向的运动很小,可以看做只有水平运动。当不考虑物料与槽体的滑动,把物料看做附加质量时,得到槽体和基座的两自由度模型。当把基座看做固定不动时,得到槽体和物料的两自由度模型。同时考虑基座、槽体和物料得到一个三自由度模型,以便综合分析输送机的水平运动。 相似文献
3.
基于轮胎侧偏频率响应的汽车摆振分析 总被引:2,自引:0,他引:2
基于小幅纯转向运动时的轮胎侧偏频率响应函数,分析了轮胎的侧偏频率响应及其与汽车前轮摆振的关系。根据车轮摆动时路面对汽车转向系统的能量传输的大小和方向,提出了减小汽车摆振倾向的途径。 相似文献
4.
5.
6.
7.
8.
9.
由于轮胎侧向力对垂向载荷的变化较为敏感,从而使得汽车簧载质量的运动对摆振的影响不容忽视。在汽车垂向运动和侧向运动之间的动力学耦合机制分析的基础上,建立多维耦合的独立悬架汽车摆振系统动力学模型。由系统微分方程组的雅克比矩阵,考察摆振系统特征值随车速的变化情况,并应用中心流形理论得到了系统的二维中心流形。此外,通过中心流形的稳定性参数,讨论系统极限环的稳定性。最后,采用数值算例对稳定性分析结果进行了验证,并考察系统参数对摆振幅值的影响,结果表明,汽车的轻量化和簧载质量质心到其侧倾轴距离的减小均有利于抑制汽车摆振,从而提高汽车行驶稳定性和安全性。 相似文献
10.
为研究回转起重机回转作业中吊重的摆振特性,寻求抑制吊重摆振的控制方法,将回转起重机工作装置等效有开链机械手的形式,采用机器人动力学方法建立吊重摆振的动力学模型,提出了基于最优调节器理论的控制方案用以抑制回转作业中的吊重摆振。该方案通过1个切换开关将2个最优调节器结合起来分别控制吊重在回转运动中的切向摆振和到达目标位置后的摆振,研究结果表明,该控制方法可以实现吊重在回转运动中摆振最小,在到达目标位置后迅速静止的控制目的,具有良好的摆振抑制效果。 相似文献
11.
Information about the dynamic loading of a steel structure is important for its static design as well as for an assessment of its fatigue life. In the case of tower cranes, these loads are mainly caused by vibrations and load sway, which occurs as a result of the slewing motion of the jib around the vertical axis and from the radial movement of the load's suspension point. In this paper, only the slewing motion that produces the spatial motion of the pendulum is considered, because this kind of motion has received much less attention than the translation of the suspension point. In order to achieve this, a non-linear mathematical model of the load sway during the slewing motion was formulated, and the non-linear nature of the swinging motion for large angles and the non-linearity of the power transmission were considered. The structure's elasticity and damping, the friction in the main bearing, and the air resistance were also taken into account. The dynamic forces acting on the steel structure of the crane during payload transport were obtained. In order to confirm the mathematical model, an actual model of a crane was built and used as the basis for measurements. A comparison of the results shows good agreement between the predicted and the measured values. 相似文献
12.
回转起重机吊重摆振的动力学模型与控制 总被引:6,自引:0,他引:6
为研究回转起重机回转作业中吊重的摆振特性,寻求抑制吊重摆振的控制方法,将回转起重机工作装置等效为开链机械手的形式,采用机器人动力学方法建立吊重摆振的动力学模型,提出了基于最优调节器理论的控制方案用以抑制回转作业中的吊重摆振.该方案通过1个切换开关将2个最优调节器结合起来分别控制吊重在回转运动中的切向摆振和到达目标位置后的摆振.研究结果表明,该控制方案可以实现吊重在回转运动中摆振最小,在到达目标位置后迅速静止的控制目的,具有良好的摆振抑制效果. 相似文献
13.
Yon-Kyu Park Dae-Im Kang Jong-Ho Kim Min-Seok Kim 《Journal of Mechanical Science and Technology》2009,23(11):2956-2963
Deadweight force machines cause oscillating components strongly related to the pendulum motion of the deadweight in the measured
force signals. An estimating method of the pendulum motion using a build-up system has been proposed in previous papers. In
this paper, the estimation algorithm was confirmed by comparison with the directly measured trajectory through the analysis
of a 500 kN deadweight force standard machine in Korea Research Institute of Standards and Science. After the dynamic analysis
of the force machine, it was modified to decrease the pendulum motion effects by accurately controlling its loading speed.
As a result of the modification, the oscillating level due to the dynamic behavior of the force machine has been reduced considerably. 相似文献
14.
为了研究塔式起重机载荷摆动特性 ,寻找抑制载荷摆动的控制方法 ,本文基于非惯性参考系中质点相对运动动力学基本方程 ,建立塔式起重机同时进行变幅、回转、起升运动的情况下载荷摆动动力学模型 ,定量地分析载荷摆动的平衡状态 ,推导出线性化模型 ,对载荷摆动特性进行了计算机仿真。研究表明 :由于惯性力或离心力的作用 ,载荷摆动中心线发生倾斜 ,当载荷在倾斜的重力场内做空间摆运动 ,其摆动模型就是线性化模型 ,摆动中心线倾斜量就是平衡状态值 相似文献
15.
科里奥利力是在旋转坐标系中由于物体相对于旋转坐标系运动所产生的一种惯性力,简称科氏力。水力旋流器的内部流场是高速旋转的离心分离流场。本研究采用计算流体力学方法模拟水力旋流器内高浓度分散相的分布,对颗粒受到的科氏力进行分析。RSM模型用于描述流场的湍动特性,LPT模型对颗粒相的运动进行追踪,模拟结果与试验数据的吻合性较好。结果表明,在水力旋流器内,由于锥体段的湍流强度较高,科氏力的方向具有较强的随机性。在切向方向,随粒径增大,曳力和压力梯度力递减而科氏力递增,当粒径增大到52μm时,科氏力的量级与曳力相当,此时科氏力的作用是不可忽略的。 相似文献
16.
17.
In this paper, the skew control of the load (container) in the quay crane used in the dockside of a container terminal is
investigated. The mathematical model of the 3-dimensional (3D) motions of the load is first derived. The container hooked
to a spreader is suspended by four ropes in air. When the container is accelerated by the trolley or is disturbed by winds,
it will make a rotational motion (trim, list, and skew) as well as a sway motion in the vertical plane. In such a case, the
position of the container becomes difficult to control accurately due to the rotational motion even with the sway motion under
control. This paper proposes an input shaping technique for the skew control based on the 3D dynamics of the container. The
adopted skew control system uses four electric motors to vary the length of the four ropes individually. Simulation results
show the effectiveness of the proposed system in controlling the skew motion. 相似文献
18.
Quang Hieu Ngo Keum-Shik Hong Il Hyo Jung 《Journal of Mechanical Science and Technology》2009,23(11):3071-3078
The objective of this paper is to move a load hanging under a very long rope from one place to another and to suppress the
transverse vibrations of the load at the end of movement by adaptive control. The disturbance affecting the gantry motion
is estimated and is incorporated into the control law design. The control command is given as a function of the position and
velocity of the trolley, the hoisting speed, the sway angle of the rope at the gantry side, and the estimated disturbance
force. The Lyapunov function taking the form of the total mechanical energy of the system is adopted to ensure the uniform
stability of the closed-loop system. Through experiments, the effectiveness of the proposed control law is demonstrated. 相似文献
19.
A thrust stand calibration technique for use in testing repetitively pulsed electric thrusters for in-space propulsion has been developed and tested using a modified hanging pendulum thrust stand. In the implementation of this technique, current pulses are applied to a solenoid to produce a pulsed magnetic field that acts against a permanent magnet mounted to the thrust stand pendulum arm. The force on the magnet is applied in this non-contact manner, with the entire pulsed force transferred to the pendulum arm through a piezoelectric force transducer to provide a time-accurate force measurement. Modeling of the pendulum arm dynamics reveals that after an initial transient in thrust stand motion the quasi-steady average deflection of the thrust stand arm away from the unforced or "zero" position can be related to the average applied force through a simple linear Hooke's law relationship. Modeling demonstrates that this technique is universally applicable except when the pulsing period is increased to the point where it approaches the period of natural thrust stand motion. Calibration data were obtained using a modified hanging pendulum thrust stand previously used for steady-state thrust measurements. Data were obtained for varying impulse bit at constant pulse frequency and for varying pulse frequency. The two data sets exhibit excellent quantitative agreement with each other. The overall error on the linear regression fit used to determine the calibration coefficient was roughly 1%. 相似文献