Control of LTI plants over erasure channels

This paper studies linear time-invariant (LTI) control architectures for LTI plants when communication takes place over a scalar erasure channel. Assuming i.i.d. data dropouts, we first show that such a channel is equivalent, in a second order moment sense, to an additive white noise channel subject to an instantaneous signal-to-noise ratio constraint. This key result is then exploited in two ways: First, we use it to characterize the set of all LTI controllers that achieve mean square stability in control architectures closed over scalar erasure channels. Second, we use it to show that the optimal design of LTI controllers over scalar erasure channels can be carried out by using tools from standard quadratic optimal control theory. We finally apply our results to the dynamic output feedback control of LTI single-input single-output (SISO) plants subject to data dropouts. In this case, we are able to establish closed form necessary and sufficient conditions on the minimal successful transmission probability that allows one to design mean square stabilizing controllers.     

西门子S7-1200的设计与应用 第5讲 食品生产线喷嘴控制的S7-1200设计

PWM是一种周期固定、脉冲宽度可以调节的脉冲输出,是数字量输出。在S7-1200 PLC中,它提供两个输出通道用于高速脉冲输出,分别可以组态为PTO或PWM,本案例则充分利用了PWM功能来实现了食品生产线的喷嘴控制,取得了良好的效果。     

多重系统同时极点配置的动态补偿器的设计

本文研究了多重系统同时稳定或极点配置的控制器设计问题。同时稳定或极点配置是出于设计容错控制系统之所需。本文推导了由一个动态补偿器对多重系统进行同时极点配置的充分条件。对于单输入或单输出的情况,上述充分条件也是必要的。文章的最后给出了设计方法以及一个实例。     

Model-Free control performance improvement using virtual reference feedback tuning and reinforcement Q-learning

This paper proposes the combination of two model-free controller tuning techniques, namely linear virtual reference feedback tuning (VRFT) and nonlinear state-feedback Q-learning, referred to as a new mixed VRFT-Q learning approach. VRFT is first used to find stabilising feedback controller using input-output experimental data from the process in a model reference tracking setting. Reinforcement Q-learning is next applied in the same setting using input-state experimental data collected under perturbed VRFT to ensure good exploration. The Q-learning controller learned with a batch fitted Q iteration algorithm uses two neural networks, one for the Q-function estimator and one for the controller, respectively. The VRFT-Q learning approach is validated on position control of a two-degrees-of-motion open-loop stable multi input-multi output (MIMO) aerodynamic system (AS). Extensive simulations for the two independent control channels of the MIMO AS show that the Q-learning controllers clearly improve performance over the VRFT controllers.     

Input/output structure of the infinite horizon LQ bumpless transfer and its implications for transfer operator synthesis

The steady‐state input/output structure of the infinite horizon LQ bumpless transfer topologies for strictly proper controllers is analyzed. It is found that in these topologies (1) the steady‐state gain of the transfer function from the output of the online controller to that of the offline one is unity/asymptotically unity, and (2) the steady‐state gain of the transfer function from the input of the online controller to the output of the offline one is zero/asymptotically zero, for essentially all strictly proper controllers with the input dimension being no less than the output one. These facts (1) reveal the steady‐state gain structure of the closed‐loop transfer matrix in the standard LQ tracking problems, (2) demonstrate that the LQ bumpless transfer technique solves the ideal bumpless transfer problem for controllers with an integrator in each of their output channels, (3) reveal the structure of unavoidable signal discontinuities in the controller input/output upon transfer between controllers with non‐integrating channels, and (4) provide guidance for minimizing the above signal discontinuities and the resulting bumps in the plant output in bumpless transfer synthesis. Copyright © 2009 John Wiley & Sons, Ltd.     

Arbitrary decay rate for two connected strings with joint anti-damping by boundary output feedback

In this paper, we are concerned with the boundary stabilization of two connected strings with middle joint anti-damping for which all eigenvalues of the (control) free system are located on the right complex plane. We first design an explicit state feedback controller to achieve exponential stability for the closed-loop system. Consequently, we design the output feedback by using infinite-dimensional observer. The backstepping approach is adopted in investigation. It is shown that by using one boundary stabilizer only, the output feedback can make the closed-loop system exponentially stable with arbitrary decay rate.     

明渠网络中基于带权Lyapunov函数的边界反馈控制稳定性

以描述明渠非定常流的一维模型——Saint-Venant方程为基础, 对由两段渠道串联构成的梯级河道网络, 以加权熵函数构成其Lyaponov函数, 基于该Lyapunov函数证明了在一定的边界反馈控制作用下, 闭环系统在平衡点的一个邻域内是渐近稳定的.     

基于FPGA的测试控制板卡的设计与实现

设计了一种以FPGA作为中心控制器件,配以多路模拟信号采集与输出通道和多路数字信号输入输出通道,具有RS-232和RS-422串口通信功能的测试控制板卡。在Quartus II7.2编程平台下,编辑了数据采集、处理和控制以及通信的硬件描述语言程序。经应用测试,满足二维平台系统的技术要求,具有良好的稳定性和可升级性。     

Flatness-based boundary control of a class of quasilinear parabolic distributed parameter systems

Motion planning and control of a boundary controlled quasilinear parabolic partial differential equation in one spatial variable is considered. The approach relies on a flatness property of the system; namely, that the system solution can be differentially parameterized in terms of a flat output which, in the case considered, is a boundary value. Such a parameterization allows straightforward motion planning and computation of a control law. The approach is based on power series in the spatial variable, and the convergence of these series is ensured by choosing the flat output to be a nonanalytic, smooth function of appropriate Gevrey class.     

Modelling and control for a class of axially moving nonuniform system

In this paper, we deal with the active control problem for a class of axially moving system. The system is nonuniform due to the spatial-varying mass and spatiotemporally varying tension. The infinite dimensional model of the nonuniform system represented by the hybrid partial-ordinary differential equations is derived with consideration of the spatiotemporally varying distributed disturbance. To suppress the vibration of the nonuniform system, full state feedback boundary control is developed. For the case that the system states cannot be measured, output feedback boundary control is proposed by using the high-order observers for the estimation of the unmeasurable states. The disturbance observer is introduced to mitigate the effects of the boundary disturbance. With the proposed boundary control, the stability of the closed-loop nonuniform system is achieved through rigorous analysis and the uniform boundedness of the all closed-loop signals is guaranteed. Numerical simulations are performed to validate the performance of the control scheme proposed.