轮带系统横向振动控制的Lyapunov方法

研究轴向运动弦线和作动器组成的耦合系统的横向振动控制。利用Hamilton原理给出弦线和作动器的动力学方程,作动器的动力学方程中包含有张紧轮的质量。采用Lyapunov方法分析未控弦线的有界性,获得控制律,并证明受控弦线的指数稳定性。通过数值仿真,给出初始扰动下弦线的横向振动位移曲线,证实控制规律的有效性。     

轴向运动弦线横向振动状态反馈的 H∞控制

首先运用鲁棒控制理论中状态反馈的H∞控制,对轮带系统作动器的角位移和角速度进行调控,实现了对轴向运动皮带横向振动的位移和角速度的控制。然后运用MATLAB进行仿真,对该控制方法的有效性进行了验证。结果表明,该方法解决了轴向运动弦线横向振动系统的不确定系统鲁棒镇定控制器的设计难题,保证了控制器的有效性、可靠性和实用性。     

轴向运动弦线横向振动的控制:能量方法

基于行波能量的传输原理，研究轴向运动弦线耦合系统的纵向振动控制。通过使系统的能量耗散最大而获得的控制器最优控制参数，使系统的能量达到最小值，从而达到控制弦线横向振动的目的。采用有限差分法进行数值模拟的结果证实此方法的有效性。     

多楔带传动系统带横向振动计算方法及优化控制

多楔带传动系统带横向振动的计算和控制是研究的难点。文中分别将带简化为弦线模型和梁模型,计算了典型三带轮多楔带传动系统中带横向振动的幅值;将基于弦线模型的带横向振动求解结果与梁模型结果对比分析,探讨在带横向振动的计算中用弦线模型替代梁模型的可行性;并以稳定状态下带横向振动幅值最小和弦线模型与梁模型结果之间相对误差最小为目标,通过优化带的各设计参数,实现对带横向振动的控制。     

新型高效电磁作动器的研制及特性分析

研制了一种应用于发动机振动主动控制系统的新型高效电磁作动器。介绍了作动器的结构原理，对作动器的磁场进行了计算，利用Ansys软件对其弹簧刚度进行了分析。将作动器的力传递模型简化为单自由度振动系统，计算了作动器的作动力，通过Matlab仿真软件对其力传递特性进行了仿真分析。以正弦信号输入对作动器的作动特性进行了试验，结果表明，试验分析和仿真分析比较吻合，作动器作动力大，性能良好，可以很好地应用于发动机的振动主动控制。     

Delta并联机器人弹性振动控制

采用有限元理论建立Delta并联机器人弹性动力学模型,将弹性振动引起的位置和方向误差看作是对名义运动的摄动,得出动平台位形误差与结点位移的关系方程,作为评定机构运动精度的依据。在柔性构件上粘附阻尼层,消耗系统振动能量,抑制杆的横向振动,对杆的纵向振动采用压电作动器进行主动控制,兼顾响应与控制能量实现最优控制。实例显示,对机构综合采用以上两种振动抑制措施,可以将机构的振动水平控制在很低的水平。     

基于工程车辆减振系统的单向电磁作动器结构及控制律设计

阐述了单向电磁作动器的工作原理，结合交流电磁铁的简化模型与电磁机构的设计原理，设计出单向电磁作动器的结构。将振动主动控制应用到工程车辆座椅的减振系统中，建立减振系统的数学模型，将现代控制理论应用于控制器的控制律设计。以振动压路机为模型，应用Matlab软件对闭环系统进行了振动响应仿真，结果表明单向电磁作动器能够有效地减小工程车辆的振动响应。     

一种新型压电作动器及在结构振动主动控制中的应用

针对传统压电片作动器直接粘贴到被控结构表面时受到的各种限制,文中提出并设计制作一种新颖的弓型压电作动器.该作动器由一个弓型梁座和粘贴于其上的压电片构成,使用时将弓型梁座粘贴于被控结构上,压电片驱动弓型梁弯曲变形,进而对被控结构产生作动.随后将其应用在弹性梁振动主动控制中,以验证这种新型作动器的可行性和有效性.采用热弹性比拟方法建立带弓型压电作动器的悬臂梁振动主动控制系统的状态空间模型,采用LQR(linear-quadratic regulator)方法进行控制器设计.基于dSPACE硬件在线控制仿真系统,进行悬臂梁振动的主动控制实验,并对这种新型压电作动器与传统压电片作动器的振动控制效能进行实验对比.实验结果表明,这种弓型压电作动器具有良好的作动效能和安装方便灵活、可重复使用等优点.     

光驱动压电作动器用于薄壳振动控制策略的研究及可行性验证

为提高薄壳结构工作性能,突破现有的结构振动控制方法局限性,采用新材料PLZT,开启了利用光电压驱动压电作动器的新研究。现对利用光驱动压电作动器方法用于薄壳振动控制进行了研究,设计其控制策略,并通过试验研究验证了所设计的控制策略的有效性和光驱动压电作动器方法用于薄壳振动控制的可行性。     

轴向加速度运动弦线横向振动的数值计算方法

讨论轴向加速度运动弦线横向振动的数学模型、数值计算方法等问题。基于Coriolis加速度和Iagrangian应力公式，利用Newton第二定律导出轴向加速度运动弦线横向振动的动力学模型；通过线性变换将方程化为一阶无量纲的非线性微分方程组；并利用Crank-Nicoson的中点离散技巧，给出运动方程的单步二阶差分方法；算法把对运动方程和本构方程分别离散，使之可以用于不同本构的运动弦线的数值仿真。且方法对线性问题绝对稳定，对非线性问题也有较好的稳定性。作为应用实例，利用该方法对一类加速度运动弦线的横向振动进行数值仿真，利用弹性弦线的守衡公式检验数值结果的精度。并利用给出的数值方法分析速度、加速度、弹性模量等参数对弦线横向振动的影响。     

Adaptive vibration reduction of an axially moving string via a tensioner

Adaptive vibration control is investigated for axially moving strings with a tensioner. The tensioner is treated as an actuator. The Lyapunov analysis is employed to design a control law that asymptotically stabilizes the string. The proposed controller can estimate the parameters online. The Lyapunov stability guarantees the convergence of the transverse vibration of the controlled span of the string as well as the estimation error of the unknown parameters to zero. The proposed controller is numerically tested for the string under initial and external disturbances. Simulation results demonstrate the effectiveness of the controller.     

多楔带传动系统轮——带振动的实测与计算方法研究

以一典型的由驱动轮、从动轮、张紧器和多楔带组成的三轮—带系统为研究对象,并对多楔带传动系统中轮的旋转振动、带的横向振动、张紧臂的摆动角度进行实测。针对三轮—带传动系统轮—带耦合振动,建立相应的数学模型。模型中,将带简化为轴向运动弦线,计算时应用Garlerkin法将带的时间—空间连续方程离散成为时间函数与空间函数之积。计算从动轮旋转角度波动、从动轮—带的滑移率、带段中点的横向振动位移、带横向振动的固有频率,并和试验值进行对比分析。结果表明,计算值与实测值吻合较好,从而计算模型和测试方法的正确性得到验证。该测试方法和计算方法对诸如发动机前端附件驱动系统等复杂的多楔带附件驱动系统动态特性的设计具有参考价值。     

A study of moving string with partial state feedback

In this paper, we present the optimal gain for the boundary control of moving string system with which the transverse vibration decays with the largest negative exponent to zero exponentially. Also we use semi-difference scheme to convert the system to a lumped system and prove that the latter system is exponentially stable. For the case that moving string system does not have boundary control, we prove that every solution of the system is bounded and the total mechanical energy is changing periodically.     

Vibration reduction of the nonlinearly traveling string by a modified variable structure control with proportional and integral compensations

In recent years, the variable structure control (VSC) method is widely exploited for suppressing vibration. The reduction of vibration in an axially moving string can improve productive quality and enhance competitive ability. Our object of this paper is not only to supress vibration of the string, but also to achieve the command in a shorter time. The controllers, like VSC, fuzzy, neuro-network and so on, have not achieved all the requirements of transient and steady-state situations; nevertheless, combining the advantages of different controllers is inevitable today. In our research, it is both to propose more cost-saving controllers and to achieve not only suppressions of vibration string but decreasing time for transient and steady-state situations.     

Stabilization of an axially moving accelerated/decelerated system via an adaptive boundary control

In this study, an adaptive boundary control is developed for vibration suppression of an axially moving accelerated/decelerated belt system. The dynamic model of the belt system is represented by partial-ordinary differential equations with consideration of the high acceleration/deceleration and unknown distributed disturbance. By utilizing adaptive technique and Lyapunov-based back stepping method, an adaptive boundary control is proposed for vibration suppression of the belt system, a disturbance observer is introduced to attenuate the effects of unknown boundary disturbance, the adaptive law is developed to handle parametric uncertainties and the S-curve acceleration/deceleration method is adopted to plan the belt׳s speed. With the proposed control scheme, the well-posedness and stability of the closed-loop system are mathematically demonstrated. Simulations are displayed to illustrate the effectiveness of the proposed control.     

轴向运动简支-固支梁的横向振动和稳定性

研究一端简支一端固支轴向运动梁的横向振动和稳定性。提出在给定边界条件下确定一匀速运动梁固有频率和模态函数的方法。当轴向运动速度在其常平均值附近作简谐波动时，应用多尺度法给出轴向变速运动梁参数共振时的不稳定条件。用数值仿真说明相关参数对固有频率和不稳定边界的影响。     

轴向运动矩形板的谐波共振与稳定性分析

针对轴向运动矩形薄板的非线性振动问题,在给出薄板运动的动能和应变能的基础上,应用哈密顿变分原理,推得几何非线性下轴向运动薄板的非线性振动方程。通过位移函数和应力函数的设定,并应用伽辽金积分法,得到四边简支边界约束条件下受横向激励载荷作用轴向运动薄板的达芬型振动方程。利用多尺度法对系统的非线性谐波共振问题进行求解,得到稳态运动下关于共振幅值的幅频响应方程。依据李雅普诺夫运动稳定性理论对定常解的稳定性进行分析,得到解的稳定性判别式。通过数值算例,得到不同横向载荷和轴向速度下共振幅值的变化规律曲线图以及对应的相图,讨论分岔点变化以及倍周期运动规律,分析横向激励载荷和轴向运动速度对系统非线性动力学行为的影响。     

Boundary control of an axially moving string: actuator dynamics included

In this paper, an active vibration control of a translating tensioned string with the use of an electro-hydraulic servo mechanism at the right boundary is investigated. The equations of motion of the string are derived by using Hamilton’s principle for the systems with changing mass. The control objective is to suppress the transverse vibrations of the string via a rightboundary control. An energy-based right-boundary control law, generating a specific current input to the servo-valve, is derived. It is revealed that a time-varying boundary force, as a function of the slope of the string at the right end and a suitably chosen damping coefficient of the actuator, can successfully suppress the transverse vibrations. The exponential stability of the closed loop system is proved. The effectiveness of the proposed control law is demonstrated via simulations.     

Output feedback boundary control of an axially moving system with input saturation constraint

This paper is concerned with boundary control for an axially moving belt system with high acceleration/deceleration subject to the input saturation constraint. The dynamics of belt system is expressed by a nonhomogeneous hyperbolic partial differential equation coupled with an ordinary differential equation. First, state feedback boundary control is designed for the case that the boundary states of the belt system can be measured. Subsequently, output feedback boundary control is developed when some of the system states can not be accurately obtained. The well-posedness and the uniformly bounded stability of the closed-loop system are achieved through rigorous mathematical analysis. In addition, high-gain observers are utilized to estimate those unmeasurable states, the auxiliary system is introduced to eliminate the constraint effects of the input saturation, and the disturbance observer is adopted to cope with unknown boundary disturbance. Finally, the control performance of the belt system is illustrated by carrying out numerical simulations.