研究一类离散时间一阶线性系统的自适应调节器,采用不同的估计器分别结合修改的“必然等价”控制律,克服了当系统增益的估计值为零时可能丧失稳定性(或能控性)的困难,并指出Middleton and Kokotovic的有关论文[1]的一些实质性错误.对所...研究一类离散时间一阶线性系统的自适应调节器,采用不同的估计器分别结合修改的“必然等价”控制律,克服了当系统增益的估计值为零时可能丧失稳定性(或能控性)的困难,并指出Middleton and Kokotovic的有关论文[1]的一些实质性错误.对所设计的闭环系统的状态方程组获得显式解或相平面轨道的显式表达式,完全描述了这些自适应调节系统的非线性性质,并对某些情况下所估计的模型可能丧失稳定性的问题进行了分析,还探讨了这些结果对于具有未知控制方向和模型参数的离散时间高阶线性系统的间接自适应调节的意义.展开更多
Most of studies on Distributed Antenna System(DAS) focus on maximizing the sum capacity and perfect channel state information at transmitter(CSIT).However,CSI is inevitable imperfect in practical wireless networks.Bas...Most of studies on Distributed Antenna System(DAS) focus on maximizing the sum capacity and perfect channel state information at transmitter(CSIT).However,CSI is inevitable imperfect in practical wireless networks.Based on the sources of error,there are two models.One assumes error lies in a bounded region,the other assumes random error.Accordingly,we propose two joint antenna selection(AS) and robustbeamforming schemes aiming to minimize the total transmit power at antenna nodes subject to quality of service(QoS) guarantee for all the mobile users(MUs) in multicell DAS.This problem is mathematically intractable.For the bounded error model,we cast it into a semidefinite program(SDP) using semidefinite relaxation(SDR) and S-procedure.For the second,we first design outage constrained robust beamforming and then formulate it as an SDP based on the Bernstein-type inequality,which we generalize it to the multi-cell DAS.Simulation results verify the effectiveness of the proposed methods.展开更多
Robust control design is presented for a general class of uncertain non-affine nonlinear systems. The design employs feedback linearization, coupled with two high-gain observers: the first to estimate the feedback lin...Robust control design is presented for a general class of uncertain non-affine nonlinear systems. The design employs feedback linearization, coupled with two high-gain observers: the first to estimate the feedback linearization error based on the full state information and the second to estimate the unmeasured states of the system when only the system output is available for feedback. All the signals in the closed loop are guaranteed to be uniformly ultimately bounded(UUB) and the output of the system is proven to converge to a small neighborhood of the origin. The proposed approach not only handles the difficulty in controlling non-affine nonlinear systems but also simplifies the stability analysis of the closed loop due to its linear control structure. Simulation results show the effectiveness of the approach.展开更多
By using the so-called SP-stable polynomials, this paper reconsiders the problem of global stabilization of linear systems with input saturation. Firstly, a new nonlinear feedback law consisting of parallel connection...By using the so-called SP-stable polynomials, this paper reconsiders the problem of global stabilization of linear systems with input saturation. Firstly, a new nonlinear feedback law consisting of parallel connections of saturation functions by means of the so-called state-dependent saturation function is proposed for global stabilization of chains of integrators system. The state-dependent saturation function allows increasing the control energy when some of the states are badly scaled and can improve significantly the transient performances of the closed-loop system. Secondly, this type of global stabilization nonlinear feedback laws is extended to a class of linear systems that can be globally stabilized by bounded controls. Numerical examples show the effectiveness of the proposed approach.展开更多
文摘研究一类离散时间一阶线性系统的自适应调节器,采用不同的估计器分别结合修改的“必然等价”控制律,克服了当系统增益的估计值为零时可能丧失稳定性(或能控性)的困难,并指出Middleton and Kokotovic的有关论文[1]的一些实质性错误.对所设计的闭环系统的状态方程组获得显式解或相平面轨道的显式表达式,完全描述了这些自适应调节系统的非线性性质,并对某些情况下所估计的模型可能丧失稳定性的问题进行了分析,还探讨了这些结果对于具有未知控制方向和模型参数的离散时间高阶线性系统的间接自适应调节的意义.
基金ACKNOWLEDGEMENTS This work is supported by Natural Science Foundation of China （No. 61340035） and Guangzhou science and technology plan projects （2014-132000764）.
文摘Most of studies on Distributed Antenna System(DAS) focus on maximizing the sum capacity and perfect channel state information at transmitter(CSIT).However,CSI is inevitable imperfect in practical wireless networks.Based on the sources of error,there are two models.One assumes error lies in a bounded region,the other assumes random error.Accordingly,we propose two joint antenna selection(AS) and robustbeamforming schemes aiming to minimize the total transmit power at antenna nodes subject to quality of service(QoS) guarantee for all the mobile users(MUs) in multicell DAS.This problem is mathematically intractable.For the bounded error model,we cast it into a semidefinite program(SDP) using semidefinite relaxation(SDR) and S-procedure.For the second,we first design outage constrained robust beamforming and then formulate it as an SDP based on the Bernstein-type inequality,which we generalize it to the multi-cell DAS.Simulation results verify the effectiveness of the proposed methods.
基金Project(60974047)supported by the National Natural Science Foundation of ChinaProject(S2012010008967)supported by the Natural Science Foundation of Guangdong Province,China+4 种基金Project supported by the Science Fund for Distinguished Young Scholars,ChinaProject supported by 2011 Zhujiang New Star Fund,ChinaProject(121061)supported by FOK Ying Tung Education Foundation of ChinaProject supported by the Ministry of Education for New Century Excellent Talent,ChinaProject(20124420130001)supported by the Doctoral Fund of Ministry of Education of China
文摘Robust control design is presented for a general class of uncertain non-affine nonlinear systems. The design employs feedback linearization, coupled with two high-gain observers: the first to estimate the feedback linearization error based on the full state information and the second to estimate the unmeasured states of the system when only the system output is available for feedback. All the signals in the closed loop are guaranteed to be uniformly ultimately bounded(UUB) and the output of the system is proven to converge to a small neighborhood of the origin. The proposed approach not only handles the difficulty in controlling non-affine nonlinear systems but also simplifies the stability analysis of the closed loop due to its linear control structure. Simulation results show the effectiveness of the approach.
基金supported in part by the National Natural Science Foundation of China under Grant Nos. 60904007 and 61074111the China Postdoctoral Science Foundation under Grant No.20100480059+2 种基金the Heilongjiang Postdoctoral Foundation of China under Grant No.LRB10-194the Foundation for Innovative Research Group of the National Natural Science Foundation of China under Grant No.601021002the Development Program for Outstanding Young Teachers at the Harbin Institute of Technology under Grant No. HITQNJS.2009.054
文摘By using the so-called SP-stable polynomials, this paper reconsiders the problem of global stabilization of linear systems with input saturation. Firstly, a new nonlinear feedback law consisting of parallel connections of saturation functions by means of the so-called state-dependent saturation function is proposed for global stabilization of chains of integrators system. The state-dependent saturation function allows increasing the control energy when some of the states are badly scaled and can improve significantly the transient performances of the closed-loop system. Secondly, this type of global stabilization nonlinear feedback laws is extended to a class of linear systems that can be globally stabilized by bounded controls. Numerical examples show the effectiveness of the proposed approach.
