共查询到17条相似文献,搜索用时 218 毫秒
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为了改善并联6-DOF运动平台的轨迹跟踪效果提出了一种新颖的控制算法。该控制方法结合了非奇异Terminal滑模控制(NTMSMC)和迭代学习控制(ILC),非奇异Terminal滑模控制器可以在有限的时间到达和消除控制器奇异,将其作为第一控制器来处理模型参数不确定性、未知的非线性和外部干扰;在到达滑模面之后,用PD型迭代学习控制器作为第二控制器来消除周期性轨迹跟踪误差。Simulink仿真结果表明,这种组合控制器与其它控制器(如PID控制、滑模控制、迭代学习控制)相比有更高的轨迹跟踪精度和较强的鲁棒性。 相似文献
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基于PDFF的直线电机驱动XY平台H∞交叉耦合控制 总被引:1,自引:0,他引:1
XY平台直线伺服系统中,负载扰动、机械惯性及双轴响应速度不匹配会影响轮廓加工精度,为此提出了一种将PDFF及H∞交叉耦合控制相结合的控制策略.单轴速度控制器采用兼顾快速性和鲁棒性的PDFF控制,间接减小轮廓误差.并在X、Y轴间引入交叉耦合控制,将基于PDFF的XY平台交叉耦合控制框架等效为一反馈系统,采用H∞次优方法设计交叉耦合控制器,直接减小轮廓误差.仿真结果表明该控制方案可增强系统的鲁棒性,提高系统的快速性和轮廓加工精度. 相似文献
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冯宗杰 《组合机床与自动化加工技术》2011,(5)
在高速精密非圆加工中,伺服刀架系统的幅值衰减产生较大的刀具轨迹跟踪误差,从而降低加工精度.针对活塞外圆数控加工数据控制,设计了一种迭代学习的前馈反馈控制方法,该控制算法中的前馈采用迭代学习控制,利用以往批次信息实现精确跟踪.反馈部分用于克服当前批次的扰动.推导该控制算法在频域下的收敛条件,经仿真实验验证,这种控制方法运用于活塞外圆加工中可以取得良好的控制效果. 相似文献
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铣削加工效率和加工精度的提高,必然要求铣床加工速度的提高。随着磁悬浮技术的发展,高速磁悬浮电主轴已成为铣床的关键部件。然而磁悬浮电主轴转子系统在高速运行时存在较强的陀螺耦合效应,其过强的耦合效应使得高速铣削的稳定性区域变窄,甚至使铣削系统失稳。为此,提出基于PD控制器的模态解耦-状态反馈的控制方法。通过该方法对转子系统的平动模态和转动模态之间的耦合以及2个方向上转动模态之间的耦合进行解耦,独立调节各个模态控制器的比例和阻尼系数来降低陀螺耦合效应对磁悬浮铣削系统稳定性区域的影响,从而增大铣削的稳定性区域。通过仿真研究基于PD控制器的模态解耦-状态反馈控制前后陀螺耦合效应对铣削稳定性区域的影响。结果表明:通过基于PD控制器的模态解耦-状态反馈控制技术,不仅能够降低陀螺效应对铣削稳定型的影响,也能够改善铣削的稳定性区域。 相似文献
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为实现某型设备快速可靠地起竖,采用双电动缸并列驱动的结构。起竖设备是一个具有复杂机电耦合效应的多体系统,每支缸的负载变化规律不确定。针对设备在两缸负载不一致时,存在同步误差的问题,提出了一种带有偏差耦合策略的主从式同步控制方案,设计了基于规则的模糊PD同步控制器,以两缸位置误差为控制器输入量,以对从动缸的位置补偿量为输出量。在MATLAB/Simulink环境下模拟极限偏载情况,对双缸设备的起动和运行进行仿真。结果表明:主从同步控制方案使设备在偏载条件下也能达到同步精度要求,而采用模糊PD控制器既能有效抑制起动段的同步误差,又能克服负载扰动对同步误差的影响。 相似文献
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对组合机床在孔的复合加工过程进行了研究,在分析了切削速度对孔的加工精度的影响,设计了一种模糊PID调速控制方法来解决钻铰组合机床只有一种切削速度的问题.建立了钻铰组合机床的数学模型,结合系统传递函数在Simulink环境下进行了控制仿真.结果表明:与传统PID控制相比,模糊PID控制器拥有更好的动静态性能,能够适应组合机床加工时的调速需求. 相似文献
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Servo presses provide flexible punch motions, which satisfy different production needs. To achieve this merit, the control system must maintain the punch motion accurately despite versatile desired trajectories or varied loadings. Against this backdrop, the current paper proposes an iterative learning control (ILC) scheme for a hybrid-driven servo press. A proportional derivative (PD) type ILC controller that contains a closed-loop feedback controller is adopted. The sensitivity Jacobian is introduced into the controlling algorithm as the proportional gain in order to smoothen and increase the error convergence rate. The proposed ILC controller is then developed and verified on a servo press prototype. Experimental validations of a cup-shaped drawing are also carried out. The results show that the proposed ILC scheme effectively made the punch position root-mean-square (RMS) errors converge to less than 0.2 mm within five iterations. The precision was also improved to less than 50 μm that was equivalent to 35–40% of the original level without the ILC. 相似文献
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提出了一种以主动纠偏原理为基础的模锻压机平衡控制系统,通过解析法和拉氏变换法,对模锻压机系统的活动横梁、驱动缸以及驱动系统完成数学建模,同时分析了偏心载荷作用于活动横梁不同位置时系统的同步纠偏精度。在简化控制变量的基础上,利用MATLAB软件进行仿真。分析结果表明,活动横梁在最大压制速度、最大偏心载荷、偏心载荷作用点最远处时的主动纠偏调整时间最长,调整时间为2.00 s,主动同步纠偏精度为0.714 mm·m-1;相比于现有基于被动纠偏原理的同步平衡控制系统,主动同步系统的纠偏调整时间更短,纠偏精度更高。 相似文献
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Modern injection molding machines can reproduce machine values, such as the position and speed of the plasticizing screw, with a high precision. To achieve a further improvement of the part quality, adaption and self-optimization strategies are required, which is realized by the implementation of a model-based self-optimization to an injection molding machine. Within this concept, a pvT-optimization allows an online control of the holding pressure that is tailored to the plastics material, considering the relationship between pressure, specific volume and temperature. A control strategy is required that controls the cavity pressure with respect to the reference generated by the pvT-optimization. However, cavity pressure control, in contrast to pressure control in the plasticizing unit, is hitherto not possible without a time-consuming system parametrization. Due to the repetitive character of the injection molding process, the iterative learning control (ILC) is a suitable approach. The ILC uses information gained within the previous cycle and a model to generate the optimal controller outputs for the following cycle. Based on this iterative learning, the reference tracking of the cavity pressure can be improved over several cycles. Additionally, repetitive disturbances can be compensated automatically. To improve the convergence speed of the ILC, a process model can be used explicitly. Based on this premise, an ILC for cavity pressure control is developed and researched in injection molding experiments. It is shown that the flexibility of the control strategy can be improved without compromising performance. 相似文献
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《International Journal of Machine Tools and Manufacture》2005,45(7-8):923-931
A non-linear method, iterative learning control (ILC), is proposed to control the electro-hydraulic feeding process of a new slotting machine. The method attempts to acquire high precision of feeding length and trapezoid feedrate, whereas the complexity of iterative learning control algorithm does not increase much more than that of industrial PID controller. After an analysis of the two-way proportional feeding system, a non-linear dynamical mathematic model with system delay, saturation and dead-zone is developed. The computer flowrate control and the ILC controller are investigated in detail. PID controller, ILC of displacement and ILC of feedrate are compared with the dynamical model under the same desired trajectory. It is experimentally found that the proposed control scheme is more effective to improve the tracking accuracy of hydraulic feeding system of the slotting machine than that of fuzzy PID controller. 相似文献
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锻造液压机在工作过程中需要有良好的刚性,因此一般采用两个液压缸进行同步驱动。为保证锻造液压机在工作过程中两个驱动液压缸具有精确的同步性,采用BP神经网络PID自适应控制方式对锻造液压机驱动液压缸进行同步控制。使用AMESim与MATLAB搭建锻造液压机仿真模型,针对两个驱动液压缸所受负载恒定、负载连续变化以及负载阶跃变化工况时,对两个驱动液压缸的同步性能进行分析。仿真结果表明:在锻造液压机两个驱动液压缸各种受力情况下,该系统均能较好地实现两个驱动液压缸的同步控制,并且位移误差最大仅0.6 mm,满足锻造液压机的工作需求。该系统具有较高的同步控制精度以及较好的鲁棒性。 相似文献