A robust speed controller for induction motor drives

A speed controller considering the effects of parameter variations and external disturbance for indirect field-oriented induction motor drives is proposed in this paper. First a microprocessor-based indirect field-oriented induction motor drive is implemented and its dynamic model at nominal case is estimated. Based on the estimated model, an integral plus proportional (IP) controller is quantitatively designed to match the prescribed speed tracking specifications. Then a dead-time compensator and a simple robust controller are designed and augmented to reduce the effects of parameter variations and external disturbances. The desired speed tracking control performance of the drive can be preserved under wide operating range, and good speed load regulating performance can also be obtained. Theoretic basis and implementation of the proposed controller are detailedly described. Some simulated and experimental results are provided to demonstrate the effectiveness of the proposed controller     

飞机自动着陆的一种非线性鲁棒控制器设计

将一种直接基于非线性模型的带神经网络补偿信号的逆系统方法用于具有强非线性和受不确定扰动干扰的飞机自动着陆控制,并对神经网络补偿的方式进行了改进。采用神经网络补偿动态逆反馈线性化后伪系统的逆误差,使得非线性系统在参数受到摄动或外部扰动的情况下仍能保持良好的控制效果。可以证明该方法在理论上是收敛的,对于任意的状态初值和给定的期望输出信号,能控制到指定的精度。神经网络的权值是局部收敛的,同时大量仿真表明,经过较少的神经网络离线训练,即能够获得很好的控制效果。最后通过飞机着陆下滑段的仿真验证表明,该方法具有强的鲁棒性和良好的跟踪精度。     

柔性机械臂有限时问控制器设计与仿真实现

为了验证系统在有限时间控制律的作用下具有收敛速度快,稳态精度高的优点,采用有限拍控制方法设计有限时间控制器。并以一个单连杆机器人手臂为研究对象,先建立柔性机械臂的数学模型,再基于近似线性化方法得到机械臂的线性数学模型,并在Matlab仿真软件Simulink环境中做了柔性机械臂在有限时间控制器作用下的响应速率与稳态误差实验。分析试验数据,得到系统在有限时问控制律作用下具有较好的收敛速度与稳态误差。     

A robust adaptive controller for PM motor drives in roboticapplications

The paper deals with theoretical development and practical implementation of an adaptive speed and position regulator suitable for robotic applications. The proposed adaptive control scheme is characterized by a reduced amount of computation and is based on the model reference adaptive control approach to compensate the variations of the system parameters, such as inertia and torque constant. A disturbance torque observer is employed to balance the required load torque and reduce the complexity of the adaptive algorithm. Simulation tests of a robotic drive, including an interior type permanent magnet synchronous (IPMS) motor, are reported in order to compare the proposed control scheme with standard speed and position regulators. Experimental results, obtained from a prototype based on a commercial PC board, are also reported in order to practically evaluate the feasibility and the features of the proposed adaptive control scheme     

A robust controller for insulin pumps based on H-infinity theory

The feedback control of insulin pumps for diabetic patients is discussed. Because the parameters in the mathematical model of the blood glucose dynamics present a considerable amount of uncertainty, the H-∞ framework is well suited for the design of controllers that take into account a nice compromise between robust closed-loop regulation of a constant set point and performance expressed in terms of peak values of the plasma glucose concentration     

The distributed robust traffic controller for ATM networks

We propose an approach to design a distributed rate‐based traffic controller to flow‐regulate the best‐effort service (e.g. ABR) traffic and guaranteed service traffic through an ATM switch. The controller is distributed among the source nodes and has a very simple structure. Its local controller at each source node is open‐loop stable and only requires the knowledge of the buffer occupancy at the bottleneck switch. We show that this controller is fair and is not sensitive to the change of VCs over time. It does not have oscillation and can achieve a high utilization. Copyright © 2001 John Wiley & Sons, Ltd.     

Duality-based robust polynomial matrix controller

Summary Complex dynamic processes partly contain unknown parameters (in the controller) and known parameters (in the process). The latter are frequently deteriorated by uncertainties. The inverse problem results from the challenge to find the unknown system parameters such that the over-all input output behaviour turns out close to some given performance. As the index of performance the stability margin is selected. In this paper, a computer-assisted gradient approach is presented which improves the stability margin of a multivariable control system in the presence of spherical uncertainties. Following the appropriate gradient and observing a heuristic stopping condition from the viewpoint of design engineering, the method provides a unified approach both for controller design and robustification.      

Adaptive robust controller design for multi-link flexible robots

Energy-based robust control strategy was proposed in [12] to improve the control performance of the traditional joint PD control by introducing additional control efforts through the evaluation of vibration related variables. Although the energy-based robust controller always guarantees closed-loop stability, it is not easy to find suitable gains of the terms for a satisfactory control performance. In this paper, adaptive energy-based robust control is presented for both closed-loop stability and automatic tuning of the gains of the additional control terms for desired performance. Simulation results are provided to show the effectiveness of the presented approach.     

A newly robust controller design for the position control ofpermanent-magnet synchronous motor

A robust controller which is designed by employing variable-structure control and linear-quadratic method is presented for a permanent-magnet synchronous motor (PMSM) position control system. It is to achieve accurate control performance in the presence of plant parameter variation and load disturbance. In addition, it possesses the design flexibility of the conventional state feedback control. It is applied to the position control of a PMSM. Simulation and experimental results show that the proposed approach gives a better position response and is robust to parameter variations and load disturbance     

Neural net-based robust controller design for brushless DC motordrives

A nonlinear neuro-controller is developed for controlling the speed of brushless dc motors operating in a high performance drives environment. The control inputs and the identification parameters of the system are adjusted simultaneously in real time using a system composed of three hidden-layer dynamic neural networks while the system is in operation. The control architecture adapts and generalizes its learning to a wide range of operating conditions and provides the necessary abstraction when measurements are contaminated with noise. The problem of persistently spanning excitation faced with the use of an online neuro-controller is addressed. In particular, the ability of the neuro-controller to “remember” previously trained reference tracks when confronted with an input excitation that is markedly different from what it was trained with is investigated. The intent is to capture the nonlinear dynamics of a brushless dc motor over any arbitrary time interval in its range of operation. The sensitivity of real time neuro-controllers to random changes in the load torque also is investigated and very promising results are observed     

无人直升机非线性鲁棒控制器设计及仿真

按照Tornambe型非线性鲁棒控制器设计方法,基于某型无人直升机侧向运动数学模型,设计了该型无人直升机侧向飞行姿态保持分散非线性控制系统,该控制系统包含的积分环节补偿了系统内部各种未知因素及外部扰动,通道间解耦效果良好。仿真结果与PID控制相比较,具有很强的抗扰动能力。     

Variable-structured robust controller by fuzzy logic forservomotors

A variable-structure robust controller whose structure is continuously changed by fuzzy logic so that the system responds quickly if the error or its rate is large and vice versa is proposed. Such a controller is insensitive to both the plant noise and the observation noise. It is applied to speed control for an induction servomotor. Experiments show that the controller is superior to both a sliding-mode controller and a proportional integral-derivative (PID) controller. The paper includes the stability analysis of the overall system and the design procedure by using Lyapunov's method     

折叠翼飞行器气动建模及变形稳定控制律设计

折叠翼飞行器是一个由机身和内外翼组成的多刚体系统,当机翼折叠时,展长、机翼面积、全机气动焦点和飞机重心都会随之改变.采用准定常假设,通过DATCOM计算了7组中间构型的气动参数,并通过Matlab曲线拟合工具对不确定的气动参数进行拟合.对折叠翼系统的仿射线性LPV模型进行了多胞形分解,并采用二次Lyapunov函数方法设计了鲁棒变增益状态反馈控制器.仿真结果表明在鲁棒变增益控制器的作用下,变体飞行器在机翼折叠过程中波动较小,且折叠结束后能够快速回到稳定状态.     

High-power-factor single-stage converter with robust controller foruniversal off-line applications

This paper presents a robust-controlled single-stage converter (SSC) operating either in discontinuous conduction mode (DCM) or in continuous conduction mode (CCM) to achieve high power factor for universal line voltage range from 90 to 264 V_rms. At light load, the proposed system is operated in the DCM, while at heavy load the system is operated in the CCM, thus, the DC-link voltage can be properly controlled within a certain voltage range and the efficiency can be improved as well. The overall system is with a robust controller and is operated in a fixed frequency. In the design, the load variation and line voltage variation are treated as plant uncertainty and control disturbance, respectively. The H^∞ robust control method is adopted to design a proper robust controller to achieve robust stability and robust performance. The measured results from a prototype have confirmed the effectiveness and feasibility of the proposed system     

A nonlinear disturbance observer for robotic manipulators

A new nonlinear disturbance observer (NDO) for robotic manipulators is derived in this paper. The global exponential stability of the proposed disturbance observer (DO) is guaranteed by selecting design parameters, which depend on the maximum velocity and physical parameters of robotic manipulators. This new observer overcomes the disadvantages of existing DOs, which are designed or analyzed by linear system techniques. It can be applied in robotic manipulators for various purposes such as friction compensation, independent joint control, sensorless torque control and fault diagnosis. The performance of the proposed observer is demonstrated by the friction estimation and compensation for a two-link robotic manipulator. Both simulation and experimental results show the NDO works well     

Observer-based robust controller design and realization of a gantry stage

A precise positioning operation is typically required for gantry systems in applications such as drop-on-demand (DOD) printing processes, precision metrology, and circuit assembly. This work presents experimental results from studies of a disturbance observer (DOB) based variable structure controller (VSC) for a gantry stage. For DOB-based controllers, a nominal model is needed; however, obtaining the nominal model is difficult for systems with friction. A pseudo-random binary signal (PRBS) is utilized to identify the linear nominal model of the gantry stage with friction. To compensate for friction effects, a filtered-VSC is studied to increase robustness and compensate for modeling uncertainties and external disturbances. Experimental results demonstrate the effectiveness of the proposed robust control structure.     

A method for robust stabilization

LetP(y,M) be a family of polynomials, depending on a controller parameter vector y in ⁿ⁺¹, defined as follows: a family of interval matrices, and y in ⁿ⁺¹, set Given an initial stabilizing controller y⁰, this paper provides a simple method to robustify y⁰, i.e., to obtain a controller parameter vector y¹ which is more robust than y⁰. Furthermore we define the stability factort for a given robustly stable controller y, which serves as a measure of the robustness of y.     

A simple active damping control for compliant base manipulators

When a robotic manipulator is mounted to a crane, boom or mobile platform, it loses its accuracy and speed due to the compliance of the base. This paper presents a simple robust control strategy that will reduce mechanical vibrations and enable better tip positioning. The control algorithm uses the sensory feedback of the base oscillation to modulate the manipulator actuator input to induce the inertial damping forces. The authors' previous work (1999) demonstrated the feasibility of the proposed concept using linear analysis. This work extends the concept to a more general case of a nonlinear multiple link manipulator using acceleration feedback and one sample delayed torque. A simulation and an experimental study show very promising results for a test bed consisting of a two-link manipulator and a compliant base