扰动分离自抗扰控制在光电稳定平台上的应用

针对当前光电稳定平台伺服系统中扰动抑制能力不足的问题,提出一种扰动分离自抗扰控制（DSADRC）算法。扰动分离自抗扰控制充分利用工程实际中可获取到的部分已知的光电稳定平台模型信息及经典控制中的控制器信息,并将其加入到自抗扰控制的设计中。该算法通过减少光电稳定平台系统中的总扰动量,增加系统的扰动观测精度及扰动抑制能力。同时,通过算法设计实现了经典控制器的复用,减少了设计工作量。仿真实验结果表明:在控制器相同、扰动条件相同的情况下,扰动分离自抗扰控制阶跃响应调节时间减少58.8%,上升时间减少26.5%,且无超调量;在1V2Hz等效扰动下,系统稳态精度提高51.5%,系统性能提升效果明显。在实物验证实验中,对于不同频率的等效扰动,相比PID控制,扰动分离自抗扰控制稳态精度提升50%以上,有效地提高了光电稳定平台的稳态精度。     

Reducing the manufacturing costs associated with hard disk drives-a new disturbance rejection control scheme

A new disturbance rejection control scheme is developed for cost-effective hard disk drive manufacturing. The proposed disturbance rejection controller is capable of attenuating both repeatable disturbances and nonrepeatable disturbances, which are two of the major detractors to hard disk drive quality and performance. The control scheme overcomes the drawback of typical internal-model-based repetitive control schemes which cancel repeatable disturbances, but amplify disturbances at other frequencies. This is achieved by a systematic combination of the internal-model-based repetitive controller with a loop shaping filter. It is shown that the internal-model-based repetitive controller is a special case of the proposed controller. Robustness of the controller is also studied. Simulations using disturbances reconstructed from actual drive level position error signal (PES) measurements have been carried out to show the effectiveness of this control scheme.     

Control design of a novel compliant actuator for rehabilitation robots

Rehabilitation robots have direct physical interaction with human body. Ideally, actuators for rehabilitation robots should be compliant, force controllable, and back drivable due to safety and control considerations. Series Elastic Actuators (SEA) offers many advantages for these applications and various designs have been developed. However, current SEA designs face a common performance limitation due to the compromise on the spring stiffness selection. This paper presents a novel compact compliant force control actuator design for portable rehabilitation robots to overcome the performance limitations of current SEAs. Our design consists of a servomotor, a ball screw, a torsional spring between the motor and the ball screw, and a set of translational springs between the ball screw nut and the external load. The soft translational springs are used to handle the low force operation, while the torsional spring with high effective stiffness is used to deal with the large force operation. It is a challenging task to design the controller for such a novel design as the control system needs to handle both the force ranges. In this paper, we develop the force control strategy for this actuator. First, two dynamical models of the actuator are established based on different force ranges. Second, we propose an optimal control with friction compensation and disturbance rejection which is enhanced by a feedforward control for the low force range. The proposed optimal control with feedforward term is also extended to the high force range. Third, a switching control strategy is proposed to handle a transition between low force and high force control. The mathematical proof is given to ensure the stability of the closed-loop system under the proposed switching control. Finally, the proposed method is validated with experimental results on a prototype of the actuator system and is also verified with an ankle robot in walking experiments.     

A DSP-based active disturbance rejection control design for a 1-kW H-bridge DC-DC power converter

This paper presents the design and implementation of an advanced digital controller for a 1-kW H-bridge dc-dc power converter. A new control algorithm based on the active disturbance rejection concept is developed to cope with the highly nonlinear dynamics of the converter and the disturbances. An experimental digital control system is used to implement the new control strategy. It consists of a digital control board based on the TMS320C6711 digital signal processor chip, an analogy I/O board, and a complex programmable logic device pulsewidth-modulation generation board. Using a newly developed bandwidth-parametrization technique, an autotuning method based on noise quantification is also developed and tested. Experimental results show the advantages and flexibilities of the new control method for the H-bridge dc-dc power converter.     

Disturbance rejection control method for permanent magnet synchronous motor speed-regulation system

The speed-regulation problem for permanent magnet synchronous motor (PMSM) system is studied in this paper. To guarantee the disturbance rejection ability of the closed loop system, most of the existing advanced control methods develop disturbance rejection control laws only for speed loop. To further improve the disturbance rejection ability, a control scheme which employs disturbance rejection control laws for not only speed loop but also the q-axis current loop, is developed here. Considering the dynamics of q-axis current, the coupling between rotor speed and d-axis current as well as the back electromotive force are regarded as lumped disturbances for the q-axis current loop, which are estimated by introducing an extended state observer (ESO). Thus a composite control law consisting of proportional feedback and disturbance feedforward compensation is developed to control the q-axis current. Simulation and experiment comparisons are presented to verify the effectiveness of the proposed method.     

A New Approach to Active Noise and Vibration Control—Part II: The Unknown Frequency Case

This paper presents a new approach to rejection of complex-valued sinusoidal disturbances acting at the output of a discrete-time stable linear plant with unknown and possibly time-varying dynamics. It is assumed that both the instantaneous frequency of the sinusoidal disturbance and its amplitude may be slowly varying with time and that the output signal is contaminated with wideband measurement noise. It is not assumed that a reference signal, correlated with the disturbance, is available. The proposed disturbance rejection algorithm is an extension of the algorithm derived for the constant-known-frequency case, described in Part I of this paper.      

Optimal feedback control of direct-current motors

A methodology for real-time speed control of a thyristor-driven DC motor in the presence of measurement noise and load torque disturbance is developed. An optimal state feedback controller using the Kalman-filter state estimation technique is derived. This is followed by an adaptive control algorithm to compensate for the effects of noise and disturbance. These two algorithms working together are capable of providing a very high-speed regulation and dynamic response over a wide range of operating conditions. Simulated responses using an i80386-based PC with a mathematics coprocessor are presented to highlight the effectiveness of the control strategy     

基于多自由度性能指标的模型预测控制算法

 传统的模型预测控制算法是一自由度控制器,不具有使系统的目标跟踪特性和干扰抑制特性同时到达最佳的能力.本文提出一种基于多自由度性能指标的模型预测控制算法,对设定值跟踪、抗可测扰动、抗不可测扰动与模型失配等情况,允许设置不同的响应参数,提高了控制器品质.仿真结果表明了算法的有效性.     

Dynamic hysteresis band control of the buck converter with fast transient response

A dynamic hysteresis control of the buck converter for achieving high slew-rate response to disturbances is proposed. The hysteresis band is derived from the output capacitor current that predicts the output voltage magnitude after a hypothesized switching action. Four switching criteria are formulated to dictate the state of the main switch. The output voltage can revert to the steady state in two switching actions after a large-signal disturbance. The technique is verified with the experimental results of a 50 W buck converter.     

基于自抗扰控制半潜平台动力定位控制器设计

本文采用自抗扰控制技术,设计了半潜式平台动力定位控制器.跟踪微分器实现给了平台定位置的快速稳定跟踪;非线性扩张观测器能进行平台运动位置、速度和系统扰动的估计,通过非线性反馈控制对系统总扰动进行补偿,实现了平台定位的精确控制.经仿真实验验证：该控制器具有响应快、精度高、稳定性好,抗干扰能力强、鲁棒性强等优点.     

Large travel ultra precision x-y-/spl theta/ motion control of a magnetic-suspension stage

This paper presents an indirect adaptive-control approach and its implementation for realizing large travel ultra precision x-y-theta motion control of a magnetic-suspension stage, which is actuated by ten electromagnets and is capable of six-degrees-of-freedom motion. Feedback linearization of the nonlinear force relationship of the electromagnet in terms of the coil current and the air gap is implemented. Due to modeling errors, perfect feedback linearization is not possible, and parameter variations of the feedback-linearized system are demonstrated through closed-loop system identification. Each axis of the feedback-linearized system is then modeled as a double integrator having gain value depending on the position of the stage and subjected to a disturbance. For the purpose of large travel x-y-theta motion control, an indirect adaptive-control algorithm is designed and implemented for each axis of the feedback-linearized system. The developed control algorithm consists of three procedures: a) real-time parameter estimation; b) model cancellation; and c) nominal linear control. Experimental results demonstrate that the indirect adaptive controllers have superior tracking ability when compared to constant gain robust linear H/sup /spl infin// controllers.     

基于萤火虫优化算法的不平衡网压下VSR自抗扰控制

传统控制方式下,三相VSR在电网电压不平衡时的网侧电流谐波较大,且其动态性能容易受到负载扰动的影响.针对这一问题,文中提出了一种基于萤火虫优化算法的自抗扰控制策略.在系统的电流内环加入一种与对象模型无关的自抗扰控制器对其进行闭环控制,及时对系统内外扰动进行主动补偿和抑制.同时,利用萤火虫优化算法对自抗扰控制器的关键参数...     

Just-in-time adaptive disturbance estimation for run-to-run control of semiconductor processes

Run-to-run control is the term used for the application of discrete parts manufacturing control as practiced in the semiconductor industry. This paper presents a new algorithm for use in run-to-run control that has been designed to address some of the challenging issues unique to batch-type manufacturing. Just-in-time adaptive disturbance estimation (JADE) uses recursive weighted least squares parameter estimation to identify the contributions to variation that are dependent upon manufacturing context. The strengths and weaknesses of the JADE algorithm are demonstrated in a series of test cases developed to separate the various disturbances and processing issues a control system would be expected to encounter.     

A new switching surface sliding-mode speed control for inductionmotor drive systems

In this paper, a sliding-mode speed controller based on a new switching surface is proposed for induction motor systems. With this variable structure control switching surface, the exponential stability is guaranteed for the speed servo control and insensitivity to uncertainties and disturbances are obtained as well. Moreover, an adaptive variable structure speed control is studied to relax the need for the bound of disturbance in variable structure control. The insensitivity or robustness of the proposed method for general speed servo systems is maintained, and the dynamic performances are improved as well. Finally, the validity of proposed scheme is demonstrated by computer simulations and experimentations     

Control for PWM ac chopper feeding nonlinear loads

This paper presents a novel robust control technique for PWM ac choppers with the ability to generate high quality sinusoidal waveforms with adjustable amplitudes over a wide range control. For this purpose a deadbeat-based digital controller has been developed to perform tight closed-loop control of the ac chopper. This controller is based on a generalized predictive control (GPC) approach. A dedicated control algorithm has been developed and implemented. The proposed controller presents the advantages of allowing a very fast transient response and compensating effectively for load disturbance and the effects of nonlinear loads. Computer simulations are performed to investigate the proposed controller performance. The simulation results show that the designed controller has a good dynamic behaviour, a good rejection of impact load disturbance, and is ;very robust. To evaluate the proposed approach an experimental prototype has been constructed. Experimental results under various loading conditions have demonstrated that the system performs well.     

基于非线性干扰观测器的主动队列管理

针对主动队列管理系统存在UDP流干扰的拥塞问题,本文基于非线性干扰观测器提出了一种主动队列管理算法。采用非线性干扰观测器对UDP流干扰进行估计,从而减小了主动队列管理系统的干扰。然后利用设计的非线性干扰观测器,使用反步滑模方法设计了一种主动队列管理算法。由于观测误差的界未知,设计了一种自适应律来避免必须事先知道观测误差的界。仿真结果表明,该算法对UDP流干扰具有较强的鲁棒性,能使队列长度较好地稳定在期望的队列长度附近。     

基于滑模控制的DC-DC降压变换器实验平台

为了实现DC-DC降压变换器的高精度控制,设计了一种基于滑模控制的输出电压调节器。首先根据DC-DC降压变换器的工作原理建立了系统的动态模型;接着利用转换后的受扰动态模型设计了滑模控制器,同时基于李雅普诺夫函数证明了闭环系统的稳定性;最后使用Matlab/Simulink软件和DC-DC降压变换器硬件电路搭建了实验测试平台。测试结果表明与传统的PID控制方法相比,DC-DC降压变换器系统在所设计的滑模控制器的作用下可以获得更快的动态性能与更强的扰动抑制能力。该实验平台不仅有利于大学生理解和掌握滑模控制理论,还可以提高大学生的工程应用能力。     

Trajectory tracking control for a wheel mobile robot on rough and uneven ground

This paper investigates a dual closed-loop trajectory tracking control strategy for a non-holonomic wheeled mobile robot (WMR) with unknown external disturbances caused by rough and uneven ground. Firstly, a novel dynamic model without coupling is established by introducing a direct current motor model with uncertain parameters. Then a linear extended state observer (LESO) is presented to estimate unknown external disturbance of the WMR. And a dynamic controller based on sliding mode control method is provided in an inner loop to ensure exponential convergence of velocity error while compensating for observational error of the LESO. Considering that the robot’s center of mass and geometric center do not overlap, a kinematic controller is designed in an outer loop to make positional error asymptotically stabilized. Finally, experiments are given to verify performance of tracking and disturbance rejection of the WMR.     

基于改进扩张状态观测的机载目标指示稳定控制

为了满足先进航空目标指示装备对视轴速度平稳性误差的设计需求,提出了一种基于扰动估计与补偿理论的控制算法。设计了一种改进扩张状态观测器以减小高阶观测器的相位延迟,提高视轴控制精度。对改进的控制算法进行了阶跃响应和速度稳定两部分实验,并与传统PID算法进行了比较。通过分析阶跃实验结果可得,该控制算法在不同的闭环控制带宽下,均能达到更短的稳定时间和更低的超调量,在35 Hz的闭环带宽下,相比PID算法的稳定时间减少了49.1%、超调量降低了88.4%,系统动态性能提升明显;速度稳定实验结果表明,该控制算法对幅值为1°、频率为2.5 Hz以内的不同扰动的抑制能力显著提高,视轴的速度误差均控制在0.1 (°)/s以内,扰动残值均小于0.1 (°)/s。该控制算法满足先进目标指示装备的设计需求,对提高系统动态性能和视轴速度平稳性具有较高的实用价值。