基于ESO的PMSM系统自抗扰FCS-MPC策略

为了提高三相永磁同步电机(PMSM)系统的控制性能,以反双曲正弦函数为基础,通过改进的扩张状态观测器(ESO)获取转速和反电动势项高精度估值,以自抗扰控制作为转速控制调节器,提出了基于ESO的自抗扰有限控制集模型预测控制(FCS-MPC)策略,以减小电磁转矩脉动,降低算法的复杂性和计算量.与基于PI的 FCS-MPC策略相比,新的控制策略能够保证 PMSM系统稳定运行,具有良好的转速跟踪性、抗干扰性和鲁棒性.     

车载光电侦察平台视轴稳定技术研究

为了进一步提高光电平台伺服控制系统的抗扰动能力,提出一种基于自抗扰控制器的改进型速度稳定回路。首先,分析了平台视轴稳定回路的数学模型并引入电流环对其进行了化简,通过伺服控制系统中扰动作用原理,引入扰动总和的思想。然后,设计含有降阶扩张状态观测器的自抗扰控制器,对扰动总和实时观测并进行线性化前馈补偿。最后,以某型车载光电平台为控制对象,进行了PI控制器与自抗扰控制器的对比实验。实验结果表明,采用自抗扰控制器伺服控制系统相比PI控制法的阶跃响应速度更快,超调幅值仅为PI控制法的26.98%。使用摇摆台引入的频率为2.5Hz的正弦扰动,系统稳态误差幅值仅为PI控制法的9.76%。在系统模型参数改变±15%范围内,自抗扰控制器仍具有良好的抗扰能力,表现出很强的鲁棒性,满足光电平台的性能要求,对提升平台抗扰能力有着较高的实用性。     

On the rejection of internal and external disturbances in a wind energy conversion system with direct-driven PMSG

This paper deals with the critical issue in a wind energy conversion system (WECS) based on a direct-driven permanent magnet synchronous generator (PMSG): the rejection of lumped disturbance, including the system uncertainties in the internal dynamics and unknown external forces. To simultaneously track the motor speed in real time and capture the maximum power, a maximum power point tracking strategy is proposed based on active disturbance rejection control (ADRC) theory. In real application, system inertia, drive torque and some other parameters change in a wide range with the variations of disturbances and wind speeds, which substantially degrade the performance of WECS. The ADRC design must incorporate the available model information into an extended state observer (ESO) to compensate the lumped disturbance efficiently. Based on this principle, a model-compensation ADRC is proposed in this paper. Simulation study is conducted to evaluate the performance of the proposed control strategy. It is shown that the effect of lumped disturbance is compensated in a more effective way compared with the traditional ADRC approach.     

永磁同步电机位置伺服系统改进变结构自抗扰控制

为进一步提高传统变结构自抗扰控制器的控制精度,增强永磁伺服驱动系统的抗干扰能力,提出一种改进变结构自抗扰控制策略。该方法在基于变结构原理设计的扩张状态观测器中引入位置、速度的观测误差以实现状态变量的无差估计,采用基于指数趋近律设计的非线性状态误差反馈控制律实现线性控制与非线性控制的平滑过渡,并在此基础上引入位置跟踪误差,提高伺服系统的跟踪性能。通过实验分析比较了改进变结构自抗扰控制与传统变结构自抗扰控制两种控制策略,结果显示改进控制策略较传统控制策略的位置跟踪误差减少了约30%。当负载突变时,传统控制策略的跟踪误差约为负载突变前最大跟踪误差的3.4倍,而改进变结构自抗扰控制策略仍能准确跟踪给定信号。     

Control of unstable processes with time delays via ADRC

Active disturbance rejection control (ADRC) treats the external disturbance and internal uncertainties as a general disturbance, and uses an extended state observer (ESO) to estimate it in real-time and feeds it back in the control loop, thus can achieve good disturbance rejection performance. However, ADRC is not quite suitable for unstable delayed processes due to its inherent structure. In this paper, a two-degree-of-freedom (2DOF) control structure is proposed for unstable time- delayed systems. Set-point tracking and disturbance rejection are separated in this structure and ADRC is solely responsible for disturbance rejection. A method to tune the ADRC parameters using all the information of the system is proposed, and robustness and performance of the proposed method are analyzed. Simulation examples show that 2DOF-ADRC can achieve good tracking and disturbance rejection performance.     

自抗扰技术在卫星姿态模拟系统中的应用

建立了高精度卫星姿态模拟系统用于光通信地面仿真试验,针对卫星轨迹特点,设计了一种改进的自抗扰控制算法。介绍了自抗扰控制技术的特点和控制原理,提出改进的伺服算法,为自抗扰算法引入了选择性积分项。针对系统±10″动态误差要求,设计了多阈值非线性函数,并添加状态判断模块实时更改非线性函数参数。同时,给出了算法主要参数的整定原则。然后,基于控制器开放伺服功能,给出了自抗扰控制的实现方法和计算流程。实验结果表明:系统具有良好的连续加减速能力,跟踪斜坡信号的动态误差为±6″;经对比,在跟踪卫星姿态轨迹时,自抗扰控制的抗干扰能力优于PID控制,跟随误差达到±7″,满足高精度姿态仿真要求。     

Design and implementation of a robust FNN-based adaptive sliding-mode controller for pneumatic actuator systems

An adaptive Fourier neural network sliding mode controller with H _∞ tracking performance (AFNN-SMC+ H _∞) is applied for a Pneumatic actuator system (PAS) to overcome time-varying nonlinear dynamics and external disturbances. Benefiting from the use of orthogonal Fourier basis function, the proposed AFNN has fast estimated convergence speed; also, because AFNN has unique solution, it can avoid falling into the local minimum. The architecture of AFNN can also easily be determined by its clear physical meaning of the neurons. To attenuate the vibration of proportional directional control valve and the adaptive approximation error, the H _∞ tracking design technique is incorporated into the proposed AFNN-SMC. Finally, practical experiments are successfully implemented in position regulation, trajectory tracking, and velocity control of the PAS, which illustrates the effectiveness of the proposed controller.     

Vehicle lateral stability management using gain-scheduled robust control

This paper deals with the design of a yaw rate controller based on gain-scheduled H_∞ optimal control, which is intended to maintain the lateral stability of a vehicle. Uncertain factors such as vehicle mass and cornering stiffness in the vehicle yaw rate dynamics naturally call for the robustness of the feedback controller and thus H_∞, optimization technique is applied to synthesize a controller with guaranteed robust stability and performance against the model uncertainty. In the implementation stage, the feed-forward yaw moment by driver’s steer input is estimated by the disturbance observer in order to determine the accurate compensatory moment. Finally, HILS results indicate that the proposed yaw rate controller can satisfactorily improve the lateral stability of an automobile.     

A novel practical control approach for rate independent hysteretic systems

A disturbance rejection based control approach, active disturbance rejection control (ADRC), is proposed for hysteretic systems with unknown characteristics. It is an appealing alternative to hysteresis compensation because it does not require a detailed model of hysteresis, by treating the nonlinear hysteresis as a common disturbance and actively rejecting it. The stability characteristic of the ADRC is analyzed. It is shown that, in the face of the inherent dynamic uncertainties, the estimation and closed-loop tracking errors of ADRC are bounded, with their bounds monotonously decreasing with the observer and controller bandwidths, respectively. Simulation results on a typical hysteretic system further demonstrate the effectiveness of the proposed approach.     

惯性参考单元的变增益PI位置控制技术

基于惯性参考单元的视轴稳定方式是克服运动载体光电跟瞄系统外部扰动,实现微弧度甚至亚微弧度级跟瞄的主要技术手段。惯性参考单元的初始校准需要构建以电涡流线位移传感器作为角位置反馈元件的闭环控制回路,角位置控制精度是影响光电跟瞄系统指向精度的主要因素。为了解决惯性参考单元系统位置控制面临的基座扰动、传感器噪声等问题,提出基于频段估计的变增益PI控制方法。设计改进扰动观测器,降低中低频传感噪声对控制精度的影响,设计频段估计器实现外部扰动频段的细分,据此动态调节控制器增益。仿真和实验结果表明,基于VGPI-IDOB控制算法能够有效提高系统的位置控制精度,无输入条件下,系统的静态输出均方根较PI控制降低了67.3%;15 Hz, 1 mrad正弦输入,20 Hz, 0.097 mrad扰动作用下,VGPI-IDOB的位置控制精度相较PI控制提升了72%。     

Active disturbance rejection control based human gait tracking for lower extremity rehabilitation exoskeleton

This paper presents an active disturbance rejection control (ADRC) based strategy, which is applied to track the human gait trajectory for a lower limb rehabilitation exoskeleton. The desired human gait trajectory is derived from the Clinical Gait Analysis (CGA). In ADRC, the total external disturbance can be estimated by the extended state observer (ESO) and canceled by the designed control law. The observer bandwidth and the controller bandwidth are determined by the practical principles. We simulated the proposed methodology in MATLAB. The numerical simulation shows the tracking error comparison and the estimated errors of the extended state observer. Two experimental tests were carried out to prove the performance of the algorithm presented in this paper. The experiment results show that the proposed ADRC behaves a better performance than the regular proportional integral derivative (PID) controller. With the proposed ADRC, the rehabilitation system is capable of tracking the target gait more accurately.     

基于跟踪微分器的永磁同步电主轴电流控制算法

永磁同步电主轴电流PI调节器存在阶跃响应超调与跟踪速度之间的矛盾,造成电流跟踪过程出现超调,增加了PI参数的整定难度。其原因主要是,控制的“快速性”与“超调”之间的矛盾是PI调节器的固有属性,为此,根据自抗扰控制理论,提出采用跟踪微分器为d轴和q轴电流指令安排过渡过程的方法,使PI调节器对输入电流阶跃信号的跟踪更加平滑。仿真和实验结果表明：相比于采用积分分离设计的PI调节器,该方法使电流更快速、平滑地跟踪指令值,且跟踪过程无超调,增强了电主轴电流控制的鲁棒性。     

音圈致动快速反射镜的降阶自抗扰控制

为改善航空光电载荷用音圈致动快速反射镜的控制性能,提出一种降阶自抗扰控制方法。首先,对快速反射镜(Fast Steering Mirror,FSM)模型进行了分析并获取了模型参数。根据自抗扰控制理论,设计了FSM的三阶通用自抗扰控制器。将电涡流传感器的测量结果视为已知,提出降阶扩张状态观测器及其对应的自抗扰控制器设计方法。根据控制器带宽设计思想,推导了对于FSM这类二阶欠阻尼对象的控制律,并给出了加入扰动补偿量的控制律的具体实现形式。实验结果表明,降阶自抗扰控制能明显改善FSM的位置阶跃响应动态性能,能实现无超调与振荡的阶跃响应,稳态时间由11.7 ms提升至9.2 ms,同时能够降低FSM对位置斜坡输入跟踪的稳态误差,并改善其速度响应动态过程,像移补偿稳速时间由10.2 ms提升至7.8 ms,提升约24%。降阶自抗扰控制具有实现简单、运算量小的特点,能够明显提升FSM的动态性能。     

基于控制增益实时辨识的BLDCM自抗扰控制

自抗扰控制具有算法简单、性能优良等优点,控制增益b对控制效果的影响较大,高效稳定地在线辨识出该参数对提高控制效果具有重要意义。设计了一种基于模型参考自适应参数辨识的新型自抗扰控制器,核心参数自适应变化使该控制器拥有更好的性能,仿真结果表明参数b辨识准确并且该控制器相对于传统自抗扰控制具有更好的控制效果。     

H ∞ control design for a seeker scan loop system

TwoH _∞ Controllers are presented for a seeker scan loop system which has model uncertainty and is subject to external disturbance. The controllers are designed using a newH _∞ control framework formulated by combining the mixed sensitivity and model matching approaches for one-and two-degree-of-freedom control structures. The proposed control methods are able to reflect not only frequency domain specifications but also time domain ones such as transient response characteristics and multivariable interaction between output channels, contrary to the mixed sensitivity problem. It is shown that the two-degree-of-freedomH _∞ controller offers better performance and robustness than one-degree-of-freedomH _∞ controller, but both controllers are very effective for the seeker scan loop system.     

基于优化ADRC的单臂机器人轨迹跟踪研究

针对机器人在不确定环境下受到内外界挠动的影响,末端执行器不能跟踪已规划的轨迹运行,以Kinova MICO2机器人为例,研究轨迹自抗挠跟踪模型。建立了机器人关节空间运动模型,根据挠动特点构造了二阶ADRC框架模型,解决了末端执行器偏离规划轨迹的问题。分析了机器人ADRC参数对轨迹跟踪的意义,为了确保系统跟踪的动态稳定性,建立GA-RBF网络优化了原始ADRC。最后分析轨迹跟踪前后的离散点绝对误差,验证机器人轨迹跟踪的可靠性。实验结果表明,GA-RBF优化的ADRC使得机器人实际轨迹能较好收敛于理想的规划轨迹,为工业应用中对轨迹要求较高的任务提供算法参考。     

Design of preview controllers for active roll stabilization

This paper presents design methods of H_∞ and sliding mode preview controllers for active roll stabilization. A lateral acceleration of the preceding vehicle is transmitted through vehicle-to-vehicle (V2V) communication. A preview controller can be designed for active roll stabilization considering the lateral acceleration to be a previewed disturbance. In order to design a preview controller, H_∞ and sliding mode control methodologies are adopted. The designed preview controllers are compared to LQ optimal one through simulation conducted on vehicle simulation package, CarSim.

     

A novel active disturbance rejection-based control strategy for a gun control system

To compensate for the nonlinearity and to achieve finely-tuned tracking accuracy of a gun control system driven by an AC machine, an improved active disturbance rejection control (IADRC) strategy with neural network embedding (NN-IADRC) is developed in this paper. The proposed IADRC, which has amnestic memory effects, can be regarded as an extension of the conventional ADRC (CADRC), making it a special case of the IADRC. To further attenuate the dependence on system models and enhance the disturbance rejection capacities of the IADRC strategy, an on-line NN-based optimum updating approach is also developed in this paper. Finally, a series of experiments are conducted on the semi-physical simulation platform to estimate the performance of the control system and the effects of the memory factor on the system. The experimental results confirm that the proposed NN-IADRC is highly robust. The results also confirm that it performs more excellently than the CADRC and that its fine tuning has attained tracking accuracy.     

Autonomous homing control of a powered parafoil with insufficient altitude

In order to realize safe and accurate homing of a powered parafoil under the condition of insufficient initial altitude, a multiphase homing path is designed according to the flight characteristics of the vehicle. With consideration that the traditional control methods cannot ensure the quality of path following because of the nonlinear, large inertial and longtime delay existed in the system and strong disturbances in a complex environment, a homing controller, composed of the vertical and horizontal trajectory tracking controllers, is designed based on active disturbance rejection control (ADRC). Then autonomous homing simulation experiment of the powered parafoil with insufficient altitude is carried on in a windy environment. The simulation results show that the planned multiphase homing trajectory can fulfill the requirements of fixed-point homing and flare landing; the designed homing controller can overcome the influences of uncertain items of the internal and external disturbances, track the desired homing path more rapidly and steadily, and possesses better control performances than traditional PID controllers.     

Robust H ∞ sliding mode control with pole placement for a fluid power electrohydraulic actuator (EHA) system

In this paper, we exploit the sliding mode control problem for a fluid power electrohydraulic actuator (EHA) system. To characterize the nonlinearity of the friction, the EHA system is modeled as a linear system with a system uncertainty. Practically, it is assumed that the system is also subject to the load disturbance and the external noise. An integral sliding mode controller is proposed to design. The advanced techniques such as the H _∞ control and the regional pole placement are employed to derive the optimal feedback gain which can be calculated by solving a necessary and sufficient condition in the form of linear matrix inequality. A sliding mode control law is developed such that the sliding mode reaching law is satisfied. Simulation and comparison results show the effectiveness of the proposed design method.