永磁同步电机伺服系统自抗扰控制器设计

对永磁同步电机(PMSM)调速系统中的时变输入提出具有更高跟踪精确度的改进型自抗扰控制策略.传统的自抗扰控制主要针对阶跃信号进行快速和无静差追踪,对时变信号存在较大的跟踪误差,使自抗扰控制的应用受限.文中对稳态误差的存在原因进行了理论分析,进而设计带有微分前馈和并联线性扩张状态观测器(P-LESO)的改进型转速自抗扰控...     

Precise position control of shape memory alloy actuator using inverse hysteresis model and model reference adaptive control system

Position control of Shape Memory Alloy (SMA) actuators has been a challenging topic during the last years due to their nonlinearities in the governing physical equations as well as their hysteresis behaviors. Using the inverse of phenomenological hysteresis model in order to compensate the input–output hysteresis behavior of these actuators shows the effectiveness of this approach. In this paper, in order to control the tip deflection of a large deformation flexible beam actuated by an SMA actuator wire, a feedforward–feedback controller is proposed. The feedforward part of the proposed control system, maps the beam deflection into SMA temperature, is based on the inverse of the generalized Prandtl–Ishlinskii model. An adaptive model reference temperature control system is cascaded to the inverse hysteresis model in order to estimate the SMA electrical current for tracking the reference signal. In addition, a closed-loop proportional–integral controller with position feedback is added to the feedforward controller to increase the accuracy as well as eliminate the steady state error in position control process. Experimental results indicate that the proposed controller has great accuracy in tracking some square wave signals. It is also experimentally shown that the suggested controller has precise tracking performance in presence of environmental disturbances.     

An RMRAC Current Regulator for Permanent-Magnet Synchronous Motor Based on Statistical Model Interpretation

A new robust model reference adaptive control (RMRAC) scheme for the current regulation of a permanent-magnet synchronous motor (PMSM) is proposed in a synchronous frame, which is completely free from the control performance degradation caused by parameter uncertainties. The current regulator of the PMSM is the innermost loop of its electromechanical driving system and plays an important role in the control hierarchy. When the PMSM runs precisely at high speeds, the cross-coupling terms must be compensated for. In the proposed RMRAC, the input signal is composed of the control voltage obtained by the model reference adaptive control (MRAC) law and the output of the disturbance estimator. The gains of the feedforward and feedback controllers are estimated by the proposed modified gradient method, where the system disturbances are filtered out by the estimated current regulation error. A voltage corresponding to the estimated system disturbances is fed forward to the control input in order to filter out the disturbances. The proposed method compensates the cross-coupling terms in a synchronous current model regardless of parameter variations. It also shows a good real-time performance due to the simplicity of control structure. Through simulations and real experiments, the efficiency of the proposed method is verified.     

永磁同步电机优化控制

为了推进永磁同步电机在实际工程领域的应用,通过Matlab软件搭建了基于滑模变结构的永磁同步电机控制模型.为了使控制效果更加理想,提出了一种优化的指数滑模速度控制器,并针对这种连续的速度控制器在控制系统中进行了仿真.仿真结果表明,控制效果得到了很大改善.     

A novel AQM algorithm based on feedforward model predictive control

Developing feedforward model predictive controller as an active queue management (AQM) scheme is studied in this paper. MPC is an advanced control strategy for AQM. However, the conventional MPC is usually an implementable form of feedback MPC. In this paper, a feedforward and feedback optimal control law is presented. It is a clean, easily implementable, version of model predictive control that incorporates feedforward. Firstly, we use the nominal fluid model to design the feedforward control input so that the output tracks the given queue length with small error. Furthermore, in order to achieve robust performance and to reject the (unmeasured) disturbance, the feedback component is designed. In particular, a disturbance observer is incorporated into the prediction output in standard feedback MPC. This framework can significantly improve performance in the presence of measurement noise and certain types of model uncertainty. Finally, the simulation results show the effectiveness of FF‐AQM algorithm.     

Discrete sliding-mode control of a PWM inverter for sinusoidaloutput waveform synthesis with optimal sliding curve

This paper presents a discrete sliding-mode control scheme with feedforward compensation for the closed-loop regulation of the pulse-width modulated (PWM) inverter used in an uninterruptible power supply (UPS). The proposed feedforward controller can effectively improve the tracking performance of the PWM inverter. In designing the sliding-mode controller, we have taken load disturbance into consideration to enhance the robustness of the PWM inverter. Moreover, the upper bound of the load disturbance under which the sliding condition can be maintained has also been derived. The sliding curve of the sliding-mode controller is designed such that the behavior of the controlled PWM inverter is optimal subject to the selected cost function. Due to the coordinate transformation proposed in this paper, only the output voltage needs to be measured as feedback for the purpose of closed-loop regulation. Simulation and experimental results are given to show the effectiveness of the proposed control scheme     

直流调速系统减少超调及加强抗扰的研究

建立双闭环直流调速系统仿真模型,设计了一2输入1输出的转速模糊控制器,明显改善了系统动态性能.为了提高系统对电网电压谐波抗扰性能,进一步设计了PD混合模糊控制器,发现PD混合模糊控制器对高频正弦扰动的抗扰性能明显优于传统PID控制器.     

Design and Implementation of a Robust Current-Control Scheme for a PMSM Vector Drive With a Simple Adaptive Disturbance Observer

This paper introduces a robust current-control scheme for a permanent-magnet synchronous motor (PMSM) with a simple adaptive disturbance observer. The robust controller is realized by including an adaptive element in the reference-voltage-generation stage using the feedforward control. Due to the time-varying nature and the high-bandwidth property of the uncertainties in a practical PMSM drive system, the adaptive element is simply chosen as the estimated uncertainty function, which adaptively varies with different operating conditions. Subsequently, the frequency modes of the uncertainty function are embedded in the control effort, and a robust current-control performance is yielded. Furthermore, the inclusion of the estimated uncertainty function provides an efficient solution for torque-ripple minimization in PMSM drives. This is because the frequency modes of the disturbances to be eliminated, i.e., the flux harmonics, are included in the stable closed-loop system. To provide a high-bandwidth estimate of the uncertainty function, a simple adaptation law is derived using the nominal current dynamics and the steepest descent method. To guarantee the system's convergence and to properly tune the proposed observer, a stability analysis based on a discrete-time Lyapunov function has been used. Comparative evaluation experiments are presented to demonstrate the effectiveness of the proposed control scheme under different operating conditions.     

基于神经网络的IMC-PID超声波电机控制

由于常规PID控制器无法有效地控制超声波电机非线性的运行特性,提出了一种基于神经网络的可变增益型内模PID控制(IMC-PID),构建IMC-PID简化PID控制器的参数整定,只需调节其中一个参数,为弥补超声波电机的非线性问题,引入神经网络到控制器中来调节参数。实验基于超声波电机伺服系统,利用该控制系统对行波超声波电机进行控制,得到了控制输入和输出的响应关系,并得出了较小的稳态误差,实验证明对超声波电机特性变化及负载扰动适应能力强。     

Gain adjusting an optimal regulator

In the letter, starting with a varying output weighting matrix, an attempt has been made to construct an optimal controller comprising a feedback controller with variable gain depending on the variation of state and feedforward controller with gain proportional to derivatives, as well as deviations of polynomial-type measurable disturbance.     

A sensitivity optimization approach to design of a disturbanceobserver in digital motion control systems

This paper is concerned with a digital design methodology for the disturbance observer. The controller (disturbance observer) is designed such that the system sensitivity function is made to match a chosen target sensitivity function by numerical optimization. One advantage of the proposed design method is that the tradeoff between command following, disturbance suppression, and measurement noise rejection is made transparent in the process of the control system design. This allows the system designer to bypass the effort of obtaining a highly accurate system model. Another aim of this research, relative to previous works, is to study how the design specifications can be best structured in the digital filter (a main component of the disturbance observer) for easy implementation. The robust feedback controller, designed in the velocity loop, is used in conjunction with a feedback controller located in the position loop and a feedforward controller acting on the desired output to construct a control structure for high-speed/high-accuracy motion control. Simulation and experiments applied to a high-speed XY table designed for micro positioning demonstrate the effectiveness of the proposed controller     

时变扰动下的永磁同步电机滑模控制

时变扰动环境下,永磁同步电机(PMSM)采用鲁棒性较好的滑模控制.根据滑模控制中传统指数趋近律,提出一种改进型的趋近律,并基于改进型趋近律设计了一种PMSM调速系统的滑模速度控制器,提高电机的运行性能.通过仿真结果对比分析,设计的基于改进型趋近律的滑模速度控制器不仅可以提高系统的动态性能,而且削弱了系统的抖振现象,使电...     

Robust motion controller design for high-accuracy positioningsystems

This paper presents a controller structure for robust high speed and accuracy motion control systems. The overall control system consists of four elements: a friction compensator; a disturbance observer for the velocity loop; a position loop feedback controller; and a feedforward controller acting on the desired output. A parameter estimation technique coupled with friction compensation is used as the first step in the design process. The friction compensator is based on the experimental friction model and it compensates for unmodeled nonlinear friction. Stability of the closed-loop is provided by the feedback controller. The robust feedback controller based on the disturbance observer compensates for external disturbances and plant uncertainties. Precise tracking is achieved by the zero phase error tracking controller. Experimental results are presented to demonstrate performance improvement obtained by each element in the proposed robust control structure     

Robust tracking servo system considering force disturbance for the optical disk recording system

This paper proposes a new robust tracking servo system for the optical disk recording system with feedforward controller based on the prediction of the tracking error. In optical recording systems, the feedback servo system must suppress the influence of force disturbance and parameter variation. To overcome this problem, this paper designs the robust feedback control system by using coprime factorization and disturbance observer. The detecting signal of the optical disk recording system is only a tracking error. Hence, the feedforward controller of the proposed tracking control system is constructed based on both the "zero-phase-error tracking" control theory and the prediction of the tracking error. The experimental results point out that the proposed tracking servo system has a quick and precise tracking response and keeps the residual tracking error below its tolerance.     

Settling control and performance of a dual-actuator system for hard disk drives

This paper presents a settling control of a dual-actuator system for hard disk drives. The dual-actuator system consists of a voice coil motor (VCM) as a first stage actuator and a push-pull-type piezo-electric transducer (PZT) as a second-stage actuator. The settling controller is designed in three steps. In the first step, the VCM controller is designed so that the VCM feedback loop has basic performance and appropriate stability. In the second step, the PZT controller and a decoupling filter are designed in order to achieve superior performance of the dual-actuator system. The decoupling filter, which is placed between the PZT controller output and the VCM controller input, is a PZT output estimator so that the PZT actuator output is canceled at the VCM controller input. In the third step, the reference trajectory is designed for fast and smooth settling. In this study, the closed-loop sensitivity function is used as a performance index, and the gain and phase margins of the open-loop characteristic are used as stability measures. Experimental results show that the dual actuator system with the proposed settling controller achieves better performance than a single actuator system with the same VCM and a conventional settling controller.     

A current mode feed-forward gain control system for a 0.8 V CMOS hearing aid

A current mode feed-forward gain control（CMFGC）technique is presented,which is applied in the front-end system of a hearing aid chip.Compared with conventional automatic gain control（AGC）,CMFGC significantly improves the total harmonic distortion（THD）by digital gain control.To attain the digital gain control codes according to the extremely weak output signal from the microphone,a rectifier and a state controller implemented in current mode are proposed.A prototype chip has been designed based on a 0.13μm standard CMOS process.The measurement results show that the supply voltage can be as low as 0.6 V.And with the 0.8 V supply voltage,the THD is improved and below 0.06%（-64 dB）at the output level of 500 mV_p-p,yet the power consumption is limited to 40μW.In addition,the input referred noise is only 4μV_rmsand the maximum gain is maintained at 33 dB.     

Buck型变换器的线性化小信号补偿前馈控制

为减小由输入电源扰动引起的输出电压工频纹波,改善DC/DC变换器动态性能,根据平均变量建模思想,为电压型PWM控制的Buck型变换器建立连续导电工作模式（CCM）下统一的平均变量等效电路。分析等效电路并根据前馈控制的不变性原理提出Buck型变换器针对输入电压扰动的线性化小信号补偿前馈控制原理及实现方法,采用该方法的Buck型变换器可快速补偿输入电压扰动,加快变换器在输入电压扰动时的动态调节过程,显著减小输出电压中包括工频在内的低频纹波,改善变换器的动态性能。仿真研究结果验证了文中线性化小信号补偿前馈控制原理、方法及其分析的正确性。     

Perfect tracking control based on multirate feedforward controlwith generalized sampling periods

In this paper, a novel perfect tracking control method based on multirate feedforward control is proposed. The advantages of the proposed method are that: (1) the proposed multirate feedforward controller eliminates the notorious unstable zero problem in designing the discrete-time inverse system; (2) the states of the plant match the desired trajectories at every sampling point of reference input; and (3) the proposed controller is completely independent of the feedback characteristics. Thus, highly robust performance is assured by the robust feedback controller. Moreover, by generalizing the relationship between the sampling period of plant output and the control period of plant input, the proposed method can be applied to various systems with hardware restrictions of these periods, which leads to higher performance. Next, it is shown that the structure of the proposed perfect tracking controller is very simple and clear. Illustrative examples of position control using a DC servomotor are presented, and simulations and experiments demonstrate the advantages of this approach     

Random vibration test control of inverter-fed electrodynamic shaker

The random vibration control of an inverter-fed electrodynamic shaker is presented in this paper. First, the dynamic model of the shaker is found and a current-controlled pulsewidth modulation inverter is designed and implemented. The feedback controller is augmented with a command feedforward controller and a disturbance feedforward controller to let the armature exciting current have low harmonic content and possess excellent waveform tracking performance. Then, an acceleration controller and its random vibration command are arranged. In the proposed acceleration control scheme, a command feedforward controller and a robust disturbance feedforward controller are also employed to let the shaker have close random acceleration command waveform tracking control performance, and the performance be insensitive to the system parameter variations. It follows that the acceleration control with desired frequency response in a vibration test could be achieved through properly setting the command signal. The effectiveness of the proposed control scheme is verified by simulation and measured results     

A hybrid disturbance observer for delivery drone’s oscillation suppression

This paper proposes a new hybrid disturbance observer (DOB) to help suppress disturbance to the control systems. The proposed hybrid DOB consists of three main parts: (1) an actual system, (2) a simulated system, and (3) a learning filter that connects the actual and simulated systems. The simulated system aims to replicate the actual system response, where it leverages a neural network model to predict the input disturbance and generate the predicted system response. Such system response is used to generate a learning signal through a learning filter; this learning signal is then added to the feedforward loop of the estimation framework to enhance the disturbance estimate and its suppression performance for the actual system. The proposed hybrid DOB is designed to advance the standard DOB structure with a learning-based feedforward compensation. While the proposed method does not modify the baseline controller, it is well suited to systems whose baseline controllers are difficult or impossible to be changed. Considering the delivery drones are subject to oscillations when dropping payloads, experimental tests with multiple payload dropping scenarios have been conducted using both the hybrid and standard DOB, where the compared results validate the effectiveness and advantages of the proposed hybrid DOB.