卷绕张力控制系统的建模及张力观测器的设计

在物料传送系统中,如何对物料张力和线速度进行独立的控制,一直是关注的焦点问题;以典型的卷绕张力系统为研究对象,建立了其动态数学模型;详细地分析了基于传感器张力反馈的常规控制方案,并在此基础上提出了一种基于张力观测器的新型控制方案;它根据辊的动态转矩平衡方程式,利用系统原有的电机控制和速度检测信号,将观测的张力值作为反馈,构成张力闭环,从而实现无传感器反馈控制;最后,对两种方案进行了仿真比较,结果表明,提出的方案完全可以达到常规方案的动态性能,而且具有更高的稳态精度,这充分说明了该算法是可行的.     

多线切割机的无模型自适应交叉耦合控制

为提高硅材料切割加工的精度,在分析多线切割机钢丝线张力波动的基础上,将无模型自适应控制和交叉耦合控制相结合,提出了一种多轴同步的间接张力控制策略。无模型自适应控制提高了系统动态响应的快速性,增强了系统的鲁棒性,减小了跟踪误差,实现了准确跟踪;交叉耦合控制用于消除各轴之间的增益参数和动态参数不匹配的影响,减小了同步误差,实现了多轴同步。实验结果表明所提出的控制方案十分有效,可提高多轴同步的运动精度,减小钢丝线张力波动。     

模糊自适应整定PID在张力控制系统中的应用

本文针对印刷过程中的张力控制要求,提出了一种模糊自适应整定PID控制,通过仿真结果可以看出,与传统的PID控制相比,它能够有效解决系统的非线性时变及动态干扰等问题,是一种比较先进的印刷张力智能控制方法.     

连续退火机组张紧辊带钢张力的建模及解耦控制

在带钢连续退火机组中,张紧辊区域的带钢张力直接影响着机组的运行速度以及带钢质量,因此,张紧辊区域的带钢张力是连续退火机组中的关键被控变量.本文首先建立了张紧辊区域带钢张力的动态机理模型和状态空间模型,并针对张紧辊带钢张力系统的多变量、强耦合等特性,采用极点配置和动态解耦算法,提出了带钢张力的多变量解耦控制器.仿真实验结果表明,所提出的解耦控制器实现了多个带钢张力控制回路之间的动态解耦,并可获得良好的控制效果.     

可逆冷带轧机速度张力系统的动态滑模解耦控制

为削弱可逆冷带轧机速度张力系统中各变量间的非线性耦合影响,本文提出了一种基于幂指数趋近律的微分几何动态滑模解耦控制方法.首先,应用微分几何理论,通过非线性状态反馈和坐标变换,实现了可逆冷带轧机速度张力非线性耦合系统的输入/输出动态解耦和线性化.其次,针对解耦后得到的各独立线性子系统,综合考虑可逆冷带轧机速度张力系统的负载扰动、参数摄动和未建模动态等不确定部分的影响,基于幂指数趋近律设计了动态滑模控制器.理论分析表明,所提出的控制方法能够保证闭环系统渐近稳定,并能有效削弱系统抖振.最后,对某1422mm可逆冷带轧机速度张力非线性耦合系统进行仿真,并同其他解耦控制方法相比较,结果验证了所提出方法的有效性.     

基于一种新型控制算法的两电机同步控制系统研究

提出一种新的二阶自抗扰控制器的两电机同步系统控制方案,两个二阶ADRC分别控制速度回路和张力回路,实现系统速度和张力的动态解耦。扩张状态观测器将系统模型内扰、外扰和速度张力之间的耦合影响统一视为系统总扰动进行实时观测和补偿。在西门子S7-300PLC实验平台上完成了跟踪特性和解耦特性测试实验,与传统PID控制相比,方波速度响应时间提高了5.3s;稳态误差提高了4.31%;当速度突变时张力几乎没有影响。结果表明二阶ADRC控制器能够实现两电机同步系统中速度和张力的解耦控制。     

基于滑模控制的刮板输送机链条张力控制

针对煤矿井下刮板输送机链条张力控制的非线性、随机性和时变性特点,提出了一种基于滑模控制的刮板输送机链条张力控制方法来改善张力控制系统的动态性能。该方法采用指数趋近律,使系统在一定特性下沿规定状态轨迹运动。仿真结果表明,采用该方法的控制系统动态特性好,鲁棒性及抗干扰能力强。     

箭杆织机经张力控制方法的研究

介绍采用模糊PID控制系统实现箭杆织机经张力控制的研究及其设计方案。提出了简化的模糊PID控制方法，较好地解决了织机送经系统经张力的控制问题。试验结果和实际应用均表明该方案的可行性和有效性。     

SIMOTION D435在铜箔生产线电控系统中的应用

主传动为交流伺服的铜箔生产线电控系统，由西门子SIMOTION D435，TP270触摸屏和SINAMICS S120交流伺服控制器、张力传感器、张力放大器等构成。本文重点分析了以SIMOTION D435作为中心控制器设计的速度辊的速度控制，张力辊的张力闭环自动控制、动态补偿的实施、断箔报警连锁控制及电气一体化连锁控制等。     

可逆冷带轧机速度张力系统的分散重叠控制

针对可逆冷带轧机速度张力系统的耦合和协调控制问题,提出了速度张力分散重叠控制方法.该方法首先利用包含原理和重叠结构分解,扩展原系统的状态空间,得到多个解耦的重叠子系统,并应用线性二次型(LQ)最优控制和顺序设计方法,设计各子系统的控制律.其次,将所设计的控制律收缩至原系统的状态空间,得到原系统的控制器.最后对某1422mm可逆冷带轧机的速度张力控制系统进行了仿真研究.结果表明,本文所提出的速度张力分散重叠控制方法能有效弱化速度与张力间的耦合,实现主轧机与左、右卷取机间的协调控制,同时改善了张力控制系统的动态性能,保证了轧机升降速时的张力控制精度.     

An iterative learning control theory for a class of nonlinear dynamic systems

An iterative learning control scheme is presented for a class of nonlinear dynamic systems which includes holonomic systems as its subset. The control scheme is composed of two types of control methodology: a linear feedback mechanism and a feedforward learning strategy. At each iteration, the linear feedback provides stability of the system and keeps its state errors within uniform bounds. The iterative learning rule, on the other hand, tracks the entire span of a reference input over a sequence of iterations. The proposed learning control scheme takes into account the dominant system dynamics in its update algorithm in the form of scaled feedback errors. In contrast to many other learning control techniques, the proposed learning algorithm neither uses derivative terms of feedback errors nor assumes external input perturbations as a prerequisite. The convergence proof of the proposed learning scheme is given under minor conditions on the system parameters.     

Decoupling and tracking control for elastic joint robots with coupled joint structure

The paper deals with the modeling, identification, and control of a flexible joint robot developed for medical applications at the German Aerospace Center (DLR). In order to design anthropomorphic kinematics, the robot uses a coupled joint structure realized by a differential gearbox, which however leads to strong mechanical couplings inside the coupled joints and must be taken into account. Therefore, a regulation MIMO state feedback controller based on modal analysis is developed for each coupled joint pair, which consists of full state feedback (motor position, link side torque, as well as their derivatives). Furthermore, in order to improve position accuracy and simultaneously keep good dynamic behavior of the MIMO state feedback controller, a cascaded tracking control scheme is proposed, based on the MIMO state feedback controller with additional feedforward terms (desired motor velocity, desired motor acceleration, derivative of the desired torque), which are computed in a computed torque controller and take the whole rigid body dynamics into account. Stability analysis is shown for the complete controlled robot. Finally, experimental results with the DLR medical robot are presented to validate the practical efficiency of the approaches.     

多回路网络化控制系统级联反馈调度

针对动态环境下的多回路网络化控制系统，本文基于反馈控制与网络调度协同设计的思想，提出一种级联反馈调度策略．以优化系统整体控制性能为目标，根据可用带宽资源的动态变化，对控制回路采样周期进行在线调节，将截止期错过率控制在期望的较低水平，并对可用带宽进行优化分配．仿真实验结果表明，相对于传统设计方法，该方法能够明显改善整体控制性能．     

Motion Synchronization Control of Distributed Multisubsystems With Invariant Local Natural Dynamics

This paper addresses a new control strategy for synchronizing two or more distributed and interconnected dynamic systems having communication time delays. The proposed strategy that uses the Smith predictor principle and delay information not only achieves synchronization but also preserves the natural local dynamics of each subsystem without being affected by the feedback nature of control. The proposed synchronization scheme is generalized to cases that deal with an arbitrary number of heterogeneous interconnected systems through dynamic scaling of input under a ring-type network configuration. In addition, possibility of applying the proposed scheme to nonlinear systems is discussed. Simulation and experimental tests are conducted to validate theoretical results.     

Nonlinear adaptive speed control of a permanent magnet synchronous motor: A perturbation estimation approach

This paper presents a nonlinear adaptive control (NAC) scheme for the speed regulation of a permanent magnet synchronous motor (PMSM) based on perturbation estimation and feedback linearizing control. All PMSM system’s unknown nonlinearities, parameter uncertainties, and external disturbances including unknown time-varying load torque disturbance, are defined as lumped perturbation terms, which are estimated by designing perturbation observers. The estimates are used to adaptively compensate the real perturbations and achieve adaptive feedback linearizing control of the original nonlinear system. The proposed control scheme does not require accurate system model and full state feedback. Stability of the close-loop system with proposed NAC is investigated via Lyapunov theory, and the effectiveness of proposed NAC scheme is verified through both simulation and experimental studies. Both simulation and experimental results show that the proposed NAC scheme can provide less regulation error in speed tracking, better dynamic performance and robustness against parameter uncertainties and load torque disturbance, compared with conventional vector control and load torque estimated based control.     

六自由度机械臂约束预测控制系统的设计

本文提出了一种基于约束预测控制的机械臂实时运动控制方法.该控制方法分为两层,分别设计了约束预测控制器和跟踪控制器.其中,约束预测控制器在考虑系统物理约束的条件下,在线为跟踪控制器生成参考轨迹;跟踪控制器采用最优反馈控制律,使机械臂沿参考轨迹运动.为了简化控制器的设计和在线求解,本文采用输入输出线性化的方式简化机械臂动力学模型.同时,为了克服扰动,在约束预测控制器中引入前馈策略,提出了带前馈一反馈控制结构的预测控制设计.因此,本文设计的控制器可以使机械臂在满足物理约束的条件下快速稳定地跟踪到目标位置.通过在PUMA560机理模型上进行仿真实验,验证了预测控制算法的可行性和有效性.     

Two-wheeled mobile robot motion control in dynamic environments

In this paper, a feedback control scheme of a two-wheeled mobile robot is explored in dynamic environments. In the existence of local minima, the design of controller is based on Lyapunov function candidate and considers virtual forces information including detouring force. Simulation results are presented to show the effectiveness of the proposed control scheme.     

Online optimal control of nonlinear discrete-time systems using approximate dynamic programming

In this paper,the optimal control of a class of general affine nonlinear discrete-time(DT) systems is undertaken by solving the Hamilton Jacobi-Bellman(HJB) equation online and forward in time.The proposed approach,referred normally as adaptive or approximate dynamic programming(ADP),uses online approximators(OLAs) to solve the infinite horizon optimal regulation and tracking control problems for affine nonlinear DT systems in the presence of unknown internal dynamics.Both the regulation and tracking contro...     

Dual Integral Sliding Mode Control Loop for Mechanical Error Correction in Trajectory-Tracking of a Planar 3-<Emphasis Type="Underline">P</Emphasis>RP Parallel Manipulator

This paper presents a dual-loop control scheme based on an integral sliding mode control scheme for the task-space pose error correction in trajectory-tracking of a planar 3-PRP parallel manipulator due to mechanical inaccuracies. The proposed dual-loop control scheme uses redundant sensor feedback, i.e., individual active joint displacements, velocities (at the joint-space level) and, end-effector positions and orientation (at the task-space level) are obtained as feedback signals using appropriate sensors. Using the redundant feedback information, the actual pose errors of the end-effector are computed in the outer-loop (kinematic) control and rectified in joint-space inner-loop (dynamic) control to achieve the given desired task-space trajectory. To demonstrate the efficacy and show complete performance of the controllers, real-time experiments are executed on an in-house fabricated planar 3-PRP parallel manipulator. The experimentation results show that the manipulator tracing performance is considerably improved with the proposed dual-loop control scheme. In addition, the controller parameter sensitivity and robustness analyses are also accomplished.