Ka频段卫星通信上行链路自适应功率控制

为提高Ka频段（30GHz／20GHz）卫星通信系统上行链路功率控制的可靠性,提出一种上行链路自适应功率控制算法。该方法基于自回归滑动平均模型,能由测量到的下行链路降雨衰减值预测出上行链路的降雨衰减值,从而提高功率控制精度。仿真结果表明,该方法对降雨衰减具有较好的补偿效果。     

基于克里金空间插值的位置指纹数据库建立算法*

为解决室内定位系统中建立位置指纹数据库工作量庞大的问题,提出了一种融合信号衰减因素的普通克里金空间插值建库算法。该方法首先采用高斯滤波对有限预选参考点的信号强度采样数据进行预处理,并基于球状模型由参考点预处理数据拟合出空间变异函数,然后采用普通克里金插值法对其它位置的信号强度进行估值并生成相应的位置指纹,最后由有限实测数据生成大容量高分辨位置指纹数据库,并通过KNN_Filter算法和对数权重算法完成了定位仿真,验证了该建库方法的有效性。仿真实验结果表明,该算法在保证定位精度的前提下相比传统建库方法可降低40%左右的工作量,提高了室内位置指纹定位方法的工作效率。     

Output feedback control of linear fractional transformation systems subject to actuator saturation

In this paper, the control problem for a class of linear parameter varying (LPV) plant subject to actuator saturation is investigated. For the saturated LPV plant depending on the scheduling parameters in linear fractional transformation (LFT) fashion, a gain-scheduled output feedback controller in the LFT form is designed to guarantee the stability of the closed-loop LPV system and provide optimised disturbance/error attenuation performance. By using the congruent transformation, the synthesis condition is formulated as a convex optimisation problem in terms of a finite number of LMIs for which efficient optimisation techniques are available. The nonlinear inverted pendulum problem is employed to demonstrate the effectiveness of the proposed approach. Moreover, the comparison between our LPV saturated approach with an existing linear saturated method reveals the advantage of the LPV controller when handling nonlinear plants.     

Consensus and disturbance attenuation in multi‐agent chains with nonlinear control and time delays

In this paper, we investigate consensus and disturbance attenuation in a chain of mobile agents, which include non‐autonomous agents, semi‐autonomous agents and autonomous agents. In particular, the nonlinear dynamics of non‐autonomous agents is given and cannot be designed, while the dynamics of semi‐autonomous and autonomous agents can be partially and fully designed, respectively. To improve the robustness of multi‐agent chains against disturbances, we propose a nonlinear control framework for semi‐autonomous and autonomous agents such that they mimic the behavior of non‐autonomous agents for compatibility while also exploiting long‐range connections with distant agents. This framework ensures the existence of a unique consensus equilibrium, which is independent of the network size, connectivity topologies, control gains and information delays. Robustness of multi‐agent chains against disturbances is investigated by evaluating the frequency response at the nonlinear level. For infinitely long multi‐agent chains with recurrent patterns, we also derive a condition that ensures the disturbance attenuation but only requires the analysis of the linearized model. A case study is conducted for a connected vehicle system where numerical simulations are used to validate the analytical results. Copyright © 2016 John Wiley & Sons, Ltd.     

模糊控制在电弧冶炼炉中应用

本文主要针对电弧冶炼在生产实际过程中是一个非线性且存在严重随机干扰的系统,运用常规控制难以取得令人满意的控制效果原情况下,将模糊控制理论运用到当中去,从而使系统得到较好的控制效果和较强的鲁棒性。     

Performance Analysis of Periodic Control for l1 and l∞ Disturbance Rejection

This paper presents a performance analysis of discrete time periodically time varying controllers for the rejection of l_p specific and uniform disturbances. Earlier results on l₂ performance are extended to l₁ and l_∞ performance to present a unified treatment of l_p performance for all p ε [1, ∞]. For a given linear time varying periodic controller, a linear time invariant controller is constructed and necessary and sufficient conditions are presented under which the linear time invariant controller gives strictly better l_p disturbance rejection performance than the time varying periodic controller.     

一类非线性系统的H∞鲁棒控制

考虑了在实际中具有工程应用背景的一类非线性不确定系统的H∞鲁棒控制问题.基 于Hamilton-Jacobi不等式,给出了这类非线性系统渐近稳定且L2增益有限的充分条件.在这个 条件下,得到了确保闭环系统满足H∞鲁棒扰动衰减性能准则的状态反馈控制器.     

Uniting Local and Global Controllers with Robustness to Vanishing Noise

We consider control systems for which we know two stabilizing controllers. One is globally asymptotically stabilizing, the other one is only locally asymptotically stabilizing but for some reason we insist on using it in a neighborhood of the origin. We look for a uniting control law being equal to the local feedback on a neighborhood of the origin, equal to the global one outside of a larger neighborhood and being a globally stabilizing controller. We study several solutions based on continuous, discontinuous, hybrid, time-varying controllers. One criterion of the selection of a controller is the robustness of the stability to vanishing noise. This leads us in particular to consider a kind of generalization of Krasovskii trajectories for hybrid systems. Date received: November 29, 1999. Date revised: August 7, 2000.     

Output regulation of two-time-scale hyperbolic PDE systems

This paper addresses the output regulation of flow systems described by a class of two-time-scale nonlinear PDE systems. Within the framework of singular perturbation, the reduced-order slow model comprised of first-order PDEs coupled with ODEs is obtained. Based on the numerical approximation technique and the solvability of an inertial manifold, the finite-dimensional nonlinear model with nonlinear input is developed in this paper. Extending from the geometric control method, the non-distributed nonlinear controller can be synthesized. A combination of the state-space internal model control scheme, the reduced observer-based controller can asymptotically attenuate the effect of external disturbances. Finally, the developed methodologies are successfully applied to the development of a PFR system asscociated with the cooling coil apparatus.