机动平台光电跟踪系统的自抗扰控制研究

针对机动平台光电跟踪系统跟踪目标需具备较强动态抗扰能力的问题,提出了一种将包含了非线性跟踪微分器、扩张状态观测器、非线性状态误差反馈三个环节的结构完整的自抗扰控制器用于光电跟踪伺服系统的速度环的思路。针对某单轴稳定转台设计了二阶自抗扰控制器,并进行了仿真研究。结果表明,该控制器对外扰变化及系统模型不确定性具有良好的鲁棒性和适应性,且能有效抑制系统中存在的非线性因素的影响。     

Fractional-order optimal fuzzy control for network delay

Fuzzy logic control has been used frequently in tuning network control system (NCS) due to its on-line dynamic static non-linear match and several remarkable fractional-order controllers have achieved satisfactory control performance when applied to NCS in present years, therefore, in this paper, a novel fractional fuzzy logic controller which combined the fractional algorithm and fuzzy logic control together has been proposed to deal with fixed and random network induced delays in closed-loop feedback systems. The comparisons of set-point tracking performances of fractional fuzzy logic PID controller (FFuzzyPID), conventional fuzzy logic PID controller(FuzzyPID), fractional optimal PID controller (FOPID), and optimal PID controller(OPID) on a representative plant with fixed and random network delays have been shown with simulations. The simulation results indicate that fractional fuzzy logic controller has higher capability to handle network delays compared with other controllers in most cases.     

Assignment of submillimeter laser lines in CH3I

We propose explanations for three laser lines observed in CH₃I by Dyubko, Svich and Fesenko. Two lines are respectively assigned to (J = 16, K = 6) → (J = 15, K = 6) and (J = 45, K = 6) → (J = 44, K = 6) in the ν₆ = 1 state. Th e third one might be explained as (ν₃ = 2, J = 54, K) → (ν₃ = 2, J = 53, K).     

PD-Based Optimal ADRC with Improved Linear Extended State Observer

Taking dead-zone nonlinearlity and external disturbances into account, an active disturbance rejection optimal controller based on a proportional-derivative (PD) control law is proposed by connecting the proportional-integral-derivative (PID) control, the active disturbance rejection control (ADRC) and particle swarm optimization (PSO), with the purpose of providing an efficient and practical technology, and improving the dynamic and steady-state control performances. Firstly, in order to eliminate the negative effects of the dead-zone, a class of 2-order typical single-input single-out system model is established after compensating the dead-zone. Following that, PD control law is introduced to replace the state error feedback control law in ADRC to simplify the control design. By analyzing the characteristics of the traditional linear extended state observer, an improved linear extended state observer is designed, with the purpose of improving the estimation performance of disturbances. Moreover, employing PSO with a designed objective function to optimize parameters of controller to improve control performance. Finally, ten comparative experiments are carried out to verify the effectiveness and superiority of the proposed controller.     

A Simplified Fractional Order PID Controller’s Optimal Tuning: A Case Study on a PMSM Speed Servo

A simplified fractional order PID (FOPID) controller is proposed by the suitable definition of the parameter relation with the optimized changeable coefficient. The number of the pending controller parameters is reduced, but all the proportional, integral, and derivative components are kept. The estimation model of the optimal relation coefficient between the controller parameters is established, according to which the optimal FOPID controller parameters can be calculated analytically. A case study is provided, focusing on the practical application of the simplified FOPID controller to a permanent magnet synchronous motor (PMSM) speed servo. The dynamic performance of the simplified FOPID control system is tested by motor speed control simulation and experiments. Comparisons are performed between the control systems using the proposed method and those using some other existing methods. According to the simulation and experimental results, the simplified FOPID control system achieves the optimal dynamic performance. Therefore, the validity of the proposed controller structure and tuning method is demonstrated.     

Experimental studies by complementary terahertz techniques and semi-classical calculations of N2- broadening coefficients of CH335Cl

Room-temperature N₂-broadening coefficients of methyl chloride rotational lines are measured over a large interval of quantum numbers (6≤J≤50, 0≤K≤18) by a submillimeter frequency-multiplication chain (J≤31) and a terahertz photomixing continuous-wave spectrometer (J≥31). In order to check the accuracy of both techniques, the measurements of identical lines are compared for J=31. The pressure broadening coefficients are deduced from line fits using mainly a Voigt profile model. The excellent signal-to-noise ratio of the frequency-multiplication scheme highlights some speed dependence effect on the line shape. Theoretical values of these coefficients are calculated by a semi-classical approach with exact trajectories. An intermolecular potential including atom–atom interactions is used for the first time. It is shown that, contrary to the previous theoretical predictions, the contributions of short-range forces are important for all values of the rotational quantum numbers. Additional testing of modifications required in the semi-classical formalism for a correct application of the cumulant expansion is also performed. It is stated that the use of the cumulant average on the rotational states of the perturbing molecule leads, for high J and small K values, to slightly higher line-broadening coefficients, as expected for the relatively strong interacting CH₃Cl–N₂ system. The excellent agreement between the theoretical and the experimental results ensures the reliability of these data.     

多移动机器人轨迹跟踪控制系统设计与实现

针对轮式移动机器人的轨迹跟踪控制问题,在分析了机器人运动学模型的基础上,构建多机器人的领航-追随模型。采用跟踪微分器在输入输出两端安排过渡过程,设计了一种基于多变量解耦的非线性PID轨迹跟踪控制器。搭建以Arduino Mega 1280控制板为核心的移动机器人实验平台,采用速度PID控制器以满足机器人驱动电机的实时调速要求,基于ROS提出一种结构化和模块化的多机器人控制系统。在此基础上进行实验,并将实验结果与传统PID方法控制的实验结果进行对比。实验结果验证了本文所提算法的有效性,控制器易于实现且具有一定的鲁棒性。     

自适应模糊PID前馈补偿在机载挂飞摆扫转台控制中的应用

针对机载挂飞转台的摆扫速度控制问题,提出了一种利用模糊自适应PID技术进行前馈补偿的复合控制策略。首先根据实际应用提出摆扫转台的期望摆扫速度曲线,并对直流力矩电机驱动的摆扫转台进行了建模;然后根据扰动前馈补偿的控制原理,提出了模糊自适应PID前馈补偿方法,为摆扫转台的速度环设计了模糊PID控制器,并在此基础上设计了与之相适应的的自适应前馈补偿函数;最后进行了仿真结果验证。通过Matlab仿真结果表明,相对于模糊PID控制,所设计的模糊自适应PID前馈补偿控制器能有效的跟踪期望的转台摆扫速度,大幅地提高了在有稳定干扰和摆扫速度越变情况下的跟踪精度。     

基于模糊PID控制的永磁同步电机控制器研究

为了提高复杂环境条件下永磁同步电机（PMSM）控制器的动态控制性能与抗干扰能力,分析了永磁同步电机的速度-电流（或力矩）双闭环控制调速结构,提出了一种基于模糊PID控制原理的速度环控制策略。速度环运行时,模糊PID控制器首先将永磁同步电机转速的误差及误差变化率进行模糊化处理,然后依据模糊规则进行模糊推理,并自动在线整定出速度环PID的三个系数（比例系数、积分系数、微分系数）,不仅减少了速度环的调节时间,也能增强抵御来自电流环（或力矩环）的干扰。仿真结果表明,当永磁同步电机的转速发生变化或负载发生扰动时,相比于传统的PID控制器,模糊PID控制器能提高系统的动态性能与鲁棒性。该方法用于永磁同步电机的控制是可行、有效的。     

Temperature dependence of pressure broadening of NH3 perturbed by H2 and N2

The temperature dependence of pressure broadening of 134 rovibrational transitions of several branches in the ν₄ and 2ν₂ bands of ammonia perturbed by H₂ and N₂ has been measured using a high-resolution Fourier transform spectrometer. The temperature range covered during the experiments was between 235 and 296 K. The pressure-broadening linewidths were obtained using the method of multipressure fitting to the measured shapes of the lines. These broadenings were also calculated using a semiclassical model leading to a reasonable agreement with the observations and reproduces well the strong systematic experimental J and K quantum number dependencies. The retrieved values of the linewidths, along with those previously determined from the spectra at room temperature, were used to derive the temperature dependence of both H₂ and N₂ broadening of NH₃ lines. The broadening coefficients were shown to fit closely the well-known exponential law. For both experimental and theoretical results, the temperature exponent n has been obtained. Careful inspection of the experimental values shows that, contrary to the linewidths, the coefficient n is nearly K independent within each J multiplet. Also for a given J it does not seem to exhibit any noticeable variation with the type of rotational transition. On the other hand, the calculated n values exhibit a strong J and K systematic dependencies. n increases with K for a given J, decreases with J for a given K and are independent of the type of rotational transition.     

基于状态观测器的分数阶时滞混沌系统同步研究

研究分数阶时滞混沌系统同步问题,基于状态观测器方法和分数阶系统稳定性理论,设计分数阶时滞混沌系统同步控制器,使得分数阶时滞混沌系统达到同步,同时给出了数学证明过程.该同步控制器采用驱动系统和响应系统的输出变量进行设计,无需驱动系统和响应系统的状态变量,简化了控制器的设计,提高了控制器的实用性.利用Lyapunov稳定性理论和分数阶线性矩阵不等式,研究并给出了同步控制器参数的选择条件.以分数阶时滞Chen混沌系统为例,设计基于状态观测器的同步控制器,实现了分数阶时滞Chen混沌系统同步,并将其应用于保密通信系统中.仿真结果证明了该同步方法的有效性.     

H2-broadening coefficients in the ν2 and ν4 bands of PH3

H₂-broadening coefficients are measured for 41 transitions of PH₃ in the QR branch of the ν₂ band and the PP, RP, and PQ branches of the ν₄ band, using a tunable diode-laser spectrometer. The recorded lines with J values ranging from 2 to 16 and K from 0 to 11 are located between 995 and . The collisional widths are determined by fitting each spectral line with a Voigt profile, a Rautian profile, and a speed-dependent Rautian profile. The latter model provides larger broadening coefficients than the Voigt model. These coefficients γ₀(J,K) are found to decrease slightly on the whole as J increases and they decrease significantly for K values approaching or equal to J(J?4). The H₂-broadenings are also calculated on the basis of a semiclassical model of interacting linear molecules, using an atom-atom Lennard-Jones potential in addition to the weak electrostatic contributions. The theoretical results are in satisfactory agreement with the experimental data and reproduce the J and K dependencies of the broadenings, but the decrease observed for the QR(J,K) transitions with K=J is notably overestimated.     

Diode-laser measurements and calculations of H2-broadening coefficients in the ν3 band of CH3D

Using a tunable diode-laser spectrometer, we have measured at room temperature the H₂-broadening coefficients of for 36 lines belonging to QP and QR branches in the ν₃ parallel band. The recorded lines with J values ranging from 1 to 15 and K from 0 to 9 (K?J) are located between 1196 and 1412 cm⁻¹. The H₂-broadening coefficients were determined by fitting each spectral line with Voigt, Rautian, and Galatry profiles. They were also calculated on the basis of a semiclassical model of interacting linear molecules performed by considering in addition to the weak electrostatic contributions the atom-atom Lennard-Jones potential. The theoretical results are in reasonable agreement with the experimental data, except for high J transitions where they are overestimated and for K approaching or equal to J with J?3 where they are underestimated. The latter discrepancy may be caused by the assumption to consider only ΔK=0 collision-induced transitions, associated with |ΔJ| transitions up to 4.     

Dynamics of the one-dimensional random transverse Ising model with next-nearest-neighbor interactions

The dynamics of the one-dimensional random transverse Ising model with both nearest-neighbor (NN) and next-nearest-neighbor (NNN) interactions is studied in the high-temperature limit by the method of recurrence relations. Both the time-dependent transverse correlation function and the corresponding spectral density are calculated for two typical disordered states. We find that for the case of bimodal disorder the dynamics of the system undergoes a crossover from a collective-mode behavior to a central-peak one and for the case of Gaussian disorder the dynamics is complex. For both cases, it is found that the central-peak behavior becomes more obvious and the collective-mode behavior becomes weaker as K_i increase, especially when K_i>J_i/2 (J_i and K_i are the exchange couplings of the NN and NNN interactions, respectively). However, the effects are small when the NNN interactions are weak (K_i<J_i/2).     

Experimental determination of pressure-broadening parameters of millimeter-wave transitions of HNO3 perturbed by N2 and O2, and of their temperature dependences

We report on linewidth measurements on the J=24_K,11−23_K^′,10 and J=38_K,33−37_K^′,32 millimeter wave transitions in the ground vibrational state of nitric acid, located near 470.23 and 544.36 GHz, respectively. Experiments were performed with N₂ and O₂ as perturber molecules, in the 240-350 K temperature range by using a video-type spectrometer. The foreign-gas broadening parameters and their temperature dependence coefficients were determined using the Voigt profile, no narrowing effect being observed. In order to check the reliability of reported values, we carried out measurements on the J=14_K,12−13_K^′,11 transition located near 206.6 GHz, previously observed in two other laboratories. For this last line all the reported values are consistent themselves within one claimed standard deviation.     

“Forbidden” millimeter-wave transitions in arsine

A millimeter-wave spectrometer having a sensitivity of 4 × 10^?10 cm^?1 in the 2-mm region has been used for observation of the “forbidden” transitions J → J, K = ±4 → ±1 and J → J, K = ±5 → ±2 in AsH₃. A comprehensive computer analysis was made of the frequencies measured in this work together with available microwave frequencies of other transitions. This analysis provides accurate values of the rotational constants, nuclear quadrupole couplings, and effective structural parameters of the molecule. The spectral constants B₀ and C₀ (in MHz) are 112 470.597 and 104 884.665, respectively.     

N2-broadening coefficients of methyl chloride at room temperature

Methyl chloride is of interest for atmospheric applications, since this molecule is directly involved in the catalytic destruction of ozone in the lower stratosphere. In a previous work [Bray et al. JQSRT 2011;112:2446], lines positions and intensities of self-perturbed ¹²CH₃³⁵Cl and ¹²CH₃³⁷Cl have been studied into details for the 3.4 μm spectral region. The present work is focused on measurement and calculation of N₂-broadening coefficients of the ¹²CH₃³⁵Cl and ¹²CH₃³⁷Cl isotopologues. High-resolution Fourier Transform spectra of CH₃Cl–N₂ mixtures at room-temperature have been recorded between 2800 and 3200 cm^?1 at LADIR (using a classical source) and between 47 and 59 cm^?1 at SOLEIL (using the synchrotron source on the AILES beamline). 612 mid-infrared transitions of the ν₁ band and 86 far-infrared transitions of the pure rotational band have been analyzed using a multispectrum fitting procedure. Average accuracy on the deduced N₂-broadening coefficients has been estimated to 5% and 10% in the mid- and far-infrared spectral regions, respectively. The J- and K-rotational dependences of these coefficients have been observed in the mid-infrared region and then a simulation has been performed using an empirical model for 0≤J≤50, K≤9. The ¹²CH₃³⁵Cl–N₂ line widths for 0≤J≤50 and K≤10 of the ν₁ band and for 55≤J≤67 and K≤15 of the pure rotational band have been computed using a semi-classical approach involving exact trajectories and a real symmetric-top geometry of the active molecule. Finally, a global comparison with the experimental and theoretical data existing in the literature has been performed. Similar J- and K-rotational dependences have been appeared while no clear evidence for any vibrational or isotopic dependences have been pointed out.     

Pure rotational spectra of allene-1, 1-d2 and allene-d1 observed by microwave Fourier transform spectroscopy

Pure rotational transitions of allene-1, 1-d₂ and allene-d₁ in their vibronic ground state have been observed with a pulsed microwave Fourier transform spectrometer for the 8- to 18-GHz frequency range. Thirteen new transitions of allene-1, 1-d₂ with J up to 32 have been assigned. The measured transition frequencies have been combined with earlier measurements of Hirota and Matsumura [J. Chem. Phys. 59, 3038–3042 (1973)] in a least-squares fit of the rotational constants B and C and the centrifugal distortion constants Δ_J, Δ_JK, δ_J, and δ_K. Fifteen transition of allene-d₁ with J up to 34 have been assigned. The rotational constants A, B, and C, and the quartic centrifugal distortion constants Δ_J, Δ_JK, Δ_K, δ_J, and δ_K have been determined from the measured frequencies in a least-squares fit.     

车载光电稳定跟踪平台自抗扰伺服系统设计

为了提高光电稳定跟踪平台伺服性能,针对车载光电稳定平台的扰动特点,依据自抗扰控制算法的分离特性,提出一种含有积分补偿项的自抗扰控制伺服系统,系统对指令信号安排过渡过程,即采用最速控制方案。实际摇摆测试结果表明:设计的自抗扰控制伺服系统既保证了车载光电稳定平台稳定误差为0.129 mil（1）,又提高了平台的自动跟踪性能,是一种可应用在稳定跟踪平台系统中的理想控制器。     

Millimeter wave spectrum of glycine

We present new investigations of the millimeter wave spectra of the two lowest-energy conformers of glycine (NH₂CH₂COOH). Measurements of these spectra have been carried out between 75 and 260 GHz using the millimeter-wave spectrometer in Kharkov. The new data set involves rotational transitions with J up to 44 and K_a up to 15 for conformer I and transitions with J up to 43 and K_a up to 14 for conformer II. This represents a more than twofold expansion both in the frequency range and J quantum-number range in comparison with previous investigations. The improved sets of spectroscopic parameters obtained for both conformers provide accurate transition frequencies for the key lines necessary for radio astronomy searches for interstellar glycine.