怎样选择电机惯量才能得到最大加速度

应用“惯量匹配原理”,使电机驱动力矩不变的情况下,得到负载最大加速度,是在设计系统时,无法使电机和负载惯量更小的情况下,依靠选择最佳传动比,使系统总的等效惯量最小。这是公认的道理。然而,对己有系统更换电机时,应尽可能选用惯量小的电机(电机其它参数不变),而不应维持原系统惯量匹惯时的电机惯量。     

天基平台快速反射镜扰动信号抑制方法

天基平台快速反射镜在工作过程中受到空间电离辐射和天体摄动力的影响,会在音圈电机和负载输出端引起电流以及位置扰动,降低系统稳态精度和跟踪精度.为了减小扰动对系统的影响,在音圈电机输出电流路径和负载输出位置路径分别设计了扰动观测环节用于实现对特定扰动的抑制.首先,分析了天基环境下各扰动信号对系统输出精度的影响;然后,在系统...     

SPWM全桥逆变器参数在线辨识研究

在对SPWM全桥逆变器结构模型进行分析的基础上,给出了SPWM中频全桥逆变器参数的在线辨识方法。该方法基于状态空间方程和递推最小二乘法,并通过检测电感电流、输出电压及开关量来在线辨识逆变器的滤波电感、滤波电容及其等效串联电阻和负载等参数,以便为故障诊断及自适应控制提供参考。     

一种基于新型自抗扰控制的舵机系统

根据导弹舵机系统的特点,设计一种自抗扰控制器进行位置环控制,运用遗传算法优化参数,对负载力矩外部扰动和模型参数摄动进行补偿,通过与误差分段式PD控制比较,证明采用自抗扰控制的舵机达到指标要求,自抗扰控制动态响应相移、幅值衰减指标都优于分段式PD,大动态负载扰动输出脉动频率小,在电枢电阻、转动惯量变化时,具有很好的快速性...     

变频器选型综述

本文从负载的转动惯量引起的加减速转矩、负载的阻力转矩出发,提供了换算到电动机轴的有效转矩和最大转矩的计算方法,以此作为选择电动机和变频器的基本依据,并指出变频器选型中应做的再次确认的要点。同时文中还提出了制动电阻选择方法和避免方法。     

互易性一端口网络等效阻抗的灵敏度分析

本文研究了互易性一端口网络等效阻抗对元件参数的灵敏度分析.利用互易二端口的T形等效电路,建立了等效阻抗对电阻、电感和电容的灵敏度公式.只需计算在单位电流源相量激励下的元件电流或电压,再计算这些相量的平方或乘积,便可得到严格的灵敏度.由此也为相量的平方,以及电压相量与电流相量之积找到了理论价值.     

悬臂梁式压电振动能量收集系统输出功率的优化研究

针对环境振动能量较小、振动源频带较宽导致压电能量收集系统输出功率较低的问题,探究了悬臂梁式结构能量收集系统采用并联或串联电感优化统输出功率的方法和特性,分析了不同并、串联电感值对输出功率的影响.鉴于压电悬臂梁的工作频率较低,匹配电感值较大,采用无损模拟电感进行了实验验证.理论分析与实验结果均表明,在不同的激振频率下对应不同的匹配电感值,在偏离谐振频率附近也可获得与谐振状态几乎相同的最大输出功率,从而拓宽了工作频率,提高了压电振动能量收集系统的能量收集水平.当激振频率分别是谐振频率的0.8和1.2倍时,并联或串联电感获得的最大输出功率分别是无电感纯电阻负载的26.4倍和18.2倍.     

Maxim推出用于NVIDIA GPU的单相Quick-PWM控制器

Maxim推出用于为NVIDIA GPU供电的单相降压控制器MAX17409。器件的有源电压定位功能可根据负载电流动态降低输出电压,从而有效降低功耗以及对输出电容的要求。在MAX17409的输出端通过电流检测电阻或电感的直流电阻检测负载电流,最大程度地降低了噪声敏感度。     

单相三绕组永磁同步电动机的起动性能分析

推导出永磁同步电动机的定子侧绕组的电压约束方程式,建立三绕组永磁同步电动机在d-q-0坐标系下的动态数学模型,对电机的起动瞬态特性进行分析;运用对称分量法分析三相永磁同步电动机的电路系统,计算起动和运行时需要的电容值;根据牵入同步判据,计算不同负载下所能牵入同步的最大转动惯量。通过实例对三绕组永磁同步电动机牵动负载的起动过程进行仿真分析,结果表明在单相电源供电系统下,可以选择合适的电容值使其起动和运行。     

基于特高频法识别的配电网电缆局部放电检测方法

配电网电缆局部放电检测过程中,未曾换算配电网电缆等效电阻、等效电感、等效电容三个参数值,导致配电网电缆局部放电位置检测不准确,为此提出基于特高频法识别的配电网电缆局部放电检测方法.建立配电网电缆电路模型,采用特高频传感器,采集电缆局部放电信号,换算配电网电缆等效电阻、等效电感、等效电容三个参数值,分析电缆中放电信号的传...     

带语音功能的数字转速表

系统采用凌阳十六位单片机SPCE061A实现转速测量，转速信号由LTHl650红外反射光电传感器和放大电路、滤波电路、整形电路提供。通过M／T算法实现对电机转速的实时测量，具有转速最大值、最小值、平均值的数字语音播报和显示及加速度显示；另外还有转速超限报警功能，通过键盘手工输入转速上限值，当所测量的转速超过这个值，发出语音报警。     

光电系统跟踪精度工程可实现性判断方法

阐述了一种简化的、可以通过数学解析求解的判断方法,用于判断光电系统跟踪精度的工程可实现性。本文的判断方法是一种必要性判断,利用跟踪系统闭环带宽的可实现性来评估系统跟踪精度的可实现性,充分性还依赖于其他条件,如电机的选取等。本文以切向匀速直线运动(变角加速度运动)目标为例分析目标的运动特性；以直流有刷力矩电机速度环位置环双闭环系统为例、以经典控制理论为基础,简化模型以分析求解跟踪所需带宽；最后对未简化的模型进行仿真,以验证简化模型的计算精度。     

Robust Smooth-Trajectory Control of Nonlinear Servo Systems Based on Neural Networks

The electromagnetic torque introduces ripples into the electromechanical motion system due to nonlinearities, such as uncertain changes of magnet field, load, and friction, which generate speed oscillations and deteriorate the tracking performance of servo system. Furthermore, the minimum time response and smooth trajectory tracking are cruces in servo control. In this paper, an available method is proposed to solve them by using neural networks (NNs) and a nonlinear smooth trajectory filter (STF) for the robust smoothing feedforward control of a class of general nonlinear systems. First, the online weight-tuning scheme based on Lyapunov function can guarantee the boundedness of tracking error by good performance of NNs modeling nonlinear functions. Second, a feedforward controller based on the output of nonlinear STF is designed to guarantee minimum time response and smooth trajectory tracking. Finally, as a example, the motion system can be equivalent to the two-order system under the linear closed-loop current control in view of the (d,q) mathematic model for PM synchronous motor, so that this robust smoothing control method using neutral networks can be applied into position servo control. Moreover, the validity and effectiveness of this control method are verified through simulations and experiments     

Stator-flux-oriented control of induction motor considering ironloss

Research to consider the influences of iron loss has been made in the vector control of an induction motor. However, little work has been done in the area of a stator-flux-oriented control system of an induction motor. This paper investigates the effects of iron loss in the direct stator-flux-oriented control system of an induction motor, and proposes a control algorithm considering iron loss. The iron loss is modeled by equivalent iron loss resistance in parallel to the magnetizing inductance. Torque control capability is much improved and the speed estimation error for a speed-sensorless drive is reduced by the proposed control algorithm. The effectiveness of the proposed method is verified by simulation and experimental results     

光电跟踪自抗扰控制技术研究

为了实现对快速运动目标高精度跟踪,对光电跟踪系统中的自抗扰控制技术进行了研究。根据速度闭环传递函数,利用三阶非线性扩张观测器估计系统状态变量,实现对不确定性因素的补偿,通过改变位置环被控对象传递函数提高系统的跟踪精度。对系统进行仿真与实验研究,分析自抗扰控制对光电跟踪系统动态和稳态性能的影响,与PI控制相对比,结果表明:对于高速运动目标,利用自抗扰控制技术可以将系统的跟踪精度提高7倍左右;对于低速运动目标,由于摩擦和系统噪声的影响,系统的跟踪精度仅提高了4倍左右。若在控制回路中引入相位超前环节,可以将系统的超调量降低40%,进一步改善了系统的动态性能,该技术的实现对于高精度跟踪控制的研究具有重要的应用价值。     

莫尔条纹光电信号的非线性跟踪微分测速方法

为了实现在低速情况下系统速度的检测,提出了一种基于莫尔条纹光电信号和非线性跟踪微分器的测量角速度和角加速度的方法。首先,分析了莫尔条纹光电信号特性;然后结合非线性跟踪微分器理论,对编码器输出的光电信号进行滤波和相位补偿;最后,将两级非线性跟踪微分器级联,同时得到速度和加速度。实验结果表明:该方法增加了低速时采样频率,提高了速度测量的平稳性、精度和实时性。将该方法应用于某采用21 位编码器作为角度传感器的系统中,成功实现了速度及加速度地检测。当速度降低到0.001 7（）/s 时,设置采样时间为5 ms,则采样频率为通常方法的20 倍,更好的解决了低速系统对测速平稳性、精度和实时性的要求。     

基于机械臂路径规划的内场轨迹实现技术研究

为了解决传统光电跟踪设备的跟踪性能测试系统参数调试繁琐、设备安装困难、靶标适用性差等问题,研究了基于机械臂路径规划的内场轨迹实现技术。通过规划六自由度机械臂的末端运动轨迹,设计了更加灵活、高效的跟踪性能测试系统。首先,对传统测试靶标系统进行分析,明确实现跟踪性能测试的数学模型;然后提出基于六自由度机械臂的新型技术方案,并分析了两种方案的差异性;接着通过靶标轨迹的坐标变换,根据传统动态靶标轨迹得到适用于六自由度机械臂的末端位姿参数,从而实现轨迹规划;最后,通过数值仿真验证了本文方法与传统方法的跟踪性能测试效果的一致性。仿真结果表明,两者具有相同的跟踪性能测试效果。相较于传统方法,采用机械臂的测试系统在参数调节、工具安装和靶标适用性上更具优势,完全能够满足光电跟踪设备内场跟踪性能测试的要求。     

GA-based multiobjective PID control for a linear brushless DC motor

This paper presents a robust output tracking control design method for a linear brushless DC motor with modeling uncertainties. Two frequency-domain specifications directly related to the mixed sensitivity function and control energy consumption are imposed to ensure stability and performance robustness. With regard to time-domain specifications, the rise time, maximum overshoot and steady-state error of the step response are considered. A generalized two-parameters proportional, integral, and derivative (PID) control framework is developed via a genetic searching approach ensuring the specifications imposed. The proposed design method is intuitive and practical that offers an effective way to implement simple but robust solutions covering a wide range of plant perturbation and, in addition, provides excellent tracking performance without resorting to excessive control. Extensive experimental and numerical results for a linear brushless motor confirm the proposed control design approach.     

Robust Linear Control of (Chaotic) Permanent-Magnet Synchronous Motors With Uncertainties

We solve the problem of set-point (respectively, tracking) control of a permanent-magnet synchronous motor via linear time-invariant (respectively, time varying) control. Our control approach is based on the physical properties of the machine: inherent stability and robustness to external disturbances. Our analysis is carried out under mild conditions, using cascaded systems theory. For all cases: constant operating point, trajectory tracking, and with known and unknown load, we show uniform global asymptotic stability of the closed-loop system with a linear controller that uses only velocity measurements. Furthermore, we explore natural extensions of our results to improve robustness with respect to external ldquodisturbancesrdquo and parametric uncertainties.     

Robust Control of PM Spherical Stepper Motor Based on Neural Networks

There are many uncertainties and disturbances in the real dynamic system of a spherical stepper motor that make traditional control methods with lower precision, such as uncertain changes of magnetic field, load, and friction that generate speed ripple and deteriorate the 3-D tracking performance of the spherical motor system. In this paper, an available method is proposed to solve them by using neural networks (NNs) and a robust control scheme for improving the performance. First, a simplified torque calculation model based on finite-element method results can guarantee quick prediction of electromagnetic torque with lower error. Thus, the system model considering the friction, load, and disturbances is developed. Second, a robust NN (RNN) control scheme is presented to eliminate uncertainties to improve the tracking robust stability and overcome the undesired influence of uncertainties based on the nonlinear system dynamic model under continuous-trajectory tracking mode. Finally, as an example, the step-response and continuous-tracking processes of the motor using an RNN controller are simulated, and experiments, including the tracking using RNN proportional–differential control, are carried out to confirm the usefulness of the proposed control scheme. The simulation and experimental results of the proposed control scheme on the spherical stepper motor system demonstrate the effectiveness on satisfactory tracking performance.