Fast-response high-quality rectifier with sliding mode control

A PWM rectifier including an uncontrolled rectifier and a Cuk converter stage driven by a sliding mode controller is described. Like other high-quality rectifiers, this solution allows low-distorted and in-phase line current. Moreover, due to the sliding mode control, fast and stable response is achieved, in spite of the large output filter. Control complexity is the same as that of standard current-mode controls. Converter analysis, design criteria, and experimental results are reported     

Optical sequence generation based on collision avoidance usingchaotic mode transitions

An adaptive optical sequence generation scheme has been described in a nonlinear optical ring which exhibits chaotic dynamics. The adaptation is based on avoidance of collisions between the ring output and signals from another source. It is shown that collision-avoiding sequences can be autonomously selected via chaotic mode transitions induced by the feedback of collision signals. Experimental results demonstrate that the method can be successful for various collision signal patterns with different periods and pulsewidths. The mechanism of inducing chaos with collision signals is examined both experimentally and with numerical simulations and the results verify the effectiveness of the proposed adaptation method. A possible application of the proposed signal generation scheme in intelligent optical communication networks is mentioned     

Fuzzy sliding mode control for a class of piezoelectric system with a sliding mode state estimator

A new fuzzy sliding mode hysteresis compensating control strategy for a kind of typical piezoelectric system (PES) is proposed in this paper. Firstly, a typical nonlinear dynamic model of the PES is introduced. In order to compensate the hysteresis of the PES, an ideal linear hysteretic model is introduced by analyzing the characteristic of dynamic hysteretic model. Then, the ideal hysteretic model is transformed into an expected linear model by multiplying a slope conversion factor which can be obtained by experiment. Further, the sliding mode control principle is constructed to calculate the hysteretic compensating control law, which can guarantee the practical hysteretic characteristic to reach the expected linear output feature. Consider the unmeasured hysteresis output of the PES, we further design a sliding mode estimator to estimate the hysteretic part’s output. Finally, we derive the adaptive law of the fuzzy sliding mode controller, and demonstrate its stability through Lyapunov stability theory. The simulation results show the validity of the sliding mode compensator for this kind of nonlinear dynamic model of PES.     

Performance analysis of the distributed queuing collision avoidance (DQCA) protocol with link adaptation

DQCA is a near-optimum Medium Access Control (MAC) protocol designed for Wireless Local Access Networks (WLANs). The protocol operates as a random access scheme under low traffic load and switches smoothly and automatically to a reservation scheme as the traffic grows. The inherent feedback mechanism of DQCA facilitates the implementation of a link adaptation algorithm that properly selects the best transmission rate taking into account the state of the wireless channel. This paper presents an analytical model for the evaluation of the performance in terms of throughput and mean message delay in the presence of a time-variant channel response.     

Small-signal analysis of DC-DC converters with sliding mode control

This paper deals with small-signal analysis of DC-D converters with sliding mode control. A suitable small signal model is developed which allows selection of control coefficients, analysis of parameter variation effects, characterization of the closed loop behavior in terms of audiosusceptibility, output and input impedances, and reference to output transfer function. Unlike previous analyses, the model includes effects of the filters used to evaluate state variable errors. Simulated and experimental results demonstrate model potentialities     

Adaptive minimum energy cognitive lighting control: Integer order vs fractional order strategies in sliding mode based extremum seeking

To achieve comfortable illumination while minimizing the energy consumption in hybrid lighting, a minimum energy point tracking algorithm is developed to achieve the minimized energy usage despite of environmental variations in this paper. A hardware-in-the-loop prototype of an adaptive minimum energy cognitive lighting control is proposed, designed and built. A sliding mode based extremum seeking controller (SM–ESC) including integer order (IO) and fractional-order (FO) strategies is firstly employed to minimize energy usage in the lights, while a PID controller is applied to maintain a light level. The performance of the designed controller is compared with both fractional order and integer order controllers which are designed based the proposed lighting system. The hardware-in-the-loop experimental results are presented to demonstrate the practicality and effectiveness of the proposed cognitive lighting control scheme.     

Neuro sliding mode control of robotic manipulators

In this paper, a synergistic combination of neural networks with sliding mode control (SMC) methodology is proposed. As a result, the chattering is eliminated and error performance of SMC is improved. In the approach, two parallel Neural Networks (NNs) are utilized to realize a neuro-SMC. The equivalent control and the corrective control terms of SMC are the outputs of the NNs. The weight adaptations of NNs are based on the SMC equations in such a way that the use of the gradient descent method minimizes the control activity and the amount of chattering while optimizing the error performance. The approach is almost model-free, requiring a minimal amount of a priori knowledge and robust in the face of parameter changes. Experimental studies carried out on a direct drive arm are presented, indicating that the proposed approach is a good candidate for trajectory control applications.     

Congestion control in cognitive radio networks with event-triggered sliding mode

The increasing demand for assorted services from extensive wireline and wireless users place a significant burden on the band-limited radio spectrum. To settle the demand, smart reuse and management of the spectrum are necessary. In this contribution, Cognitive Radio being an emerging technology provides a platform to share the same spectrum between Primary Users (licensed) and Secondary Users (unlicensed) for significant improvement in the spectrum efficiency. The coexistence of users for data communications in a band-limited channel calls for a robust congestion controller to maximize throughput. This work presents the design of a robust nonlinear congestion controller based on event-triggered sliding mode for Cognitive Radio Networks. The goal is to maintain desired Quality of Service of the network with optimum bandwidth and resource utilization. The controller has been designed on the notions of sliding mode, better known for its inherent robustness and disturbance rejection capabilities. An event-triggering scheme has been incorporated with the sliding mode for optimum utilization of the available resources. The signal is sampled and control is updated only when a predefined condition gets violated while ensuring acceptable closed-loop behavior of the system. The efficiency of the proposed controllers has been validated using simulations.     

滑模变结构在AUV航向控制中的应用

针对自主式水下机器人的控制特点,建立了机器人的动力学数学模型。利用运动解耦的方法完成了水下机器人完备控制量的构建。在滑模变结构控制理论的基础上,设计了水下机器人的分布式滑模控制系统,并在Simulink下完成滑模控制器的建模。预先设定了仿真过程中机器人的运动轨迹跟踪,结果表明,滑模控制能有效地控制AUV的航向,对外部扰动具有较强的鲁棒性。     

基于自治水下机器人纵向运动的滑模定深控制

针对自治水下机器人(AUV)的控制特点,建立了AUV纵向运动的动力模型,采用高阶滑模非线性控制的方法,并运用计算机仿真的手段进行了验证,仿真结果显示了该系统具有良好的控制性能,有效地消除了滑模控制的抖振,对外部扰动具有较强的鲁棒性。     

Adaptive sliding mode fuzzy control for unknown robots with arbitrarily-switched constraints

This article addresses the control problem of robots with unknown dynamics and arbitrarily-switched unknown constraints. Such kind of robots will be shown to be unknown hybrid systems with arbitrary switching and an Adaptive Sliding Mode Fuzzy Control (ASMFC) strategy is proposed that handles the unknown dynamics of the robot along with the unknown constraints arbitrary switching. The ASMFC is a synergy of finding a Common Lyapunov Function (CLF) between the resulted switched subsystems of the considered robots, employing the Fuzzy Logic Systems (FLS), and the use of the Sliding Mode Control (SMC). The CLF accommodates the constraints arbitrary switching, the SMC adds robustness against possible parameters drift, and the FLS approximates the unknown robot dynamics. All unknown parameters are adapted online and all closed loop signals are guaranteed to be bounded. The proposed strategy is validated by conducting an experiment on a KUKA Lightweight Robot (LWR) doing a typical force-guided peg-in-hole assembly task that falls in the category of robot systems under consideration. Excellent tracking performance is obtained when using the ASMFC strategy. Comparison is conducted with the performance of a PD controller that is widely used in commanding industrial robots and the superiority of the proposed strategy is shown.     

滑模变结构控制对象研究

从滑模变结构的控制领域着手,分析了不同控制对象的状态方程,通过数字仿真对比了滑模变结构和PID对不同阶数、不同时间常数对象在快速性、参数整定及搞干扰上不同的特性表现.在此基础上,总结了滑模变结构控制不同对象的优劣.由此,提出了滑模变结构控制的最佳适用性.     

基于自适应模糊滑模的PMSM无速度传感控制研究

为研究永磁同步电机（PMSM）在无速度传感器工况下的速度跟踪估计,以PMSM的工作原理为基础,建立了内埋式PMSM的数学模型。利用自适应模糊微分积分滑模鲁棒性强的优点,提出了在自适应模糊微分积分滑模控制条件下采用旋转高频电压注入法对电机转速估计的无速度传感器控制方案,并分析了电机在高低速运行时特点。仿真结果表明,采用高频注入法的自适应模糊微分积分滑模控制系统在高、低速工况下运行时稳定可靠,并具有较好的鲁棒性,能够实现速度跟踪估计。     

Phase-synchroniser based on gm-C all-pass filter chain with sliding mode control

Phase-synchronisers have many applications in VLSI circuit designs. They are used in CMOS RF circuits including phase (de)modulators, phase recovery circuits, multiphase synthesis, etc. In this article, a phase-synchroniser based on g_m-C all-pass filter chain with sliding mode control is presented. The filter chain provides good controllable delay characteristics over the full range of phase and frequency regulation, without deterioration of input signal amplitude and waveform, while the sliding mode control enables us to achieve fast and predetermined finite locking time. IHP 0.25 µm SiGe BiCMOS technology has been used in design and verification processes. The circuit operates in the frequency range from 33 MHz up to 150 MHz. Simulation results indicate that it is possible to achieve very fast synchronisation time period, which is approximately four time intervals of the input signal during normal operation, and 20 time intervals during power-on.     

滑模控制策略在具有不确定性的混沌系统同步中的应用

根据滑模控制原理求取混沌同步控制形式，利用扩张状态观测器对系统信息进行渐进估计，得到物理可实现的同步控制策略，以此实现具有不确定性混沌系统的同步。以Duffing和VanderPol系统为例进行仿真，效果良好。