Accurate parameter identification is essential when designing controllers for inertially stabilized platforms （lSPs）. But traditional identification methods suffer from observation measurement noise and operating re...Accurate parameter identification is essential when designing controllers for inertially stabilized platforms （lSPs）. But traditional identification methods suffer from observation measurement noise and operating restrictions of ISPs. To address this issue, a novel identification method based on current command design and multilevel coordinate search （MCS） algorithm without any higher order measurement differentiations was proposed. The designed current commands were adopted to obtain parameter decoupled models with the platform operating under allowable conditions. MCS algorithm was employed to estimate the parameters based on parameter decoupled models. A comparison experiment between the proposed method and non-linear least square method was carried out and most of the relative errors of identified parameters obtained by the proposed method were below 10%. Simulation and experiment based on identified parameters were conducted. A velocity control structure was also developed with disturbance observer （DOB） for application in disturbance compensation control system of an ISR Experimental results show that the control scheme based on the identified parameters with DOB has the best disturbance rejection performance. It reduces the peak to peak value （PPV） of velocity error integral to 0.8 mrad which is much smaller than the value （10 mrad） obtained by the single velocity controller without DOB. Compared with the control scheme based on sweep model with DOB compensation, the proposed control scheme improves the PPV of velocity error integral by 1.625 times.展开更多
The presence of "comet-like" radial transport of acetylcholine receptors by actin microfilaments without the participation of myosin motors in the depression of acetylcholine-induced inward chloric current (...The presence of "comet-like" radial transport of acetylcholine receptors by actin microfilaments without the participation of myosin motors in the depression of acetylcholine-induced inward chloric current (ACh-current) in command neurons of defensive behavior of the land snail, Helix lucorum, in a cellular analog of habituation was investigated. For that purpose the effects of CK548, CK-636 (inhibitors of actin-related protein complex Arp2/3, whose activation triggers rapid actin polymerization and the formation of the "comet-like" tail on the actinic filament) and wiskostatin (an N-WASP protein inhibitor, activating Arp2/3) on the depression of ACh-current were studied. The attenuation of ACh-current depression was observed upon the addition of CK548. At the same time, CK-636 and wiskostatin irreversibly strengthened the depression of this current and suppressed its spontaneous recovery. The results of CK-548 action and its mathematical modeling allow suggesting the presence of "comet-like" transport of acetylcholine receptors, initiated by Arp2/3 protein complex in receptor endo and exocytosis in command neurons of Helix lucorum in a cellular analog of habituation. Irreversible inhibition of vital metabolic processes of the neuron by wiskostatin and CK-636, which lead to the decrease in the level of ATP, could have caused irreversible effects of these blockers on current depression.展开更多
针对行走机构双电动机驱动的严格同步要求,采用CAN(Controller Area Network)总线时钟同步协议实现同步组单轴速度指令的同步执行.为解决齿间隙造成的两轴实际速度不协调及刚性连接的两行走电动机间的耦合关系导致的负载不均衡问题,提...针对行走机构双电动机驱动的严格同步要求,采用CAN(Controller Area Network)总线时钟同步协议实现同步组单轴速度指令的同步执行.为解决齿间隙造成的两轴实际速度不协调及刚性连接的两行走电动机间的耦合关系导致的负载不均衡问题,提出电动机电流跟随算法.实验结果表明,该算法保证了两轴同步运动的精度,实现了焊接小车快速平稳运行.展开更多
配电系统中无功负载的投切会使公共耦合点(point of common coupling,PCC)电压发生波动。为了提高配电网的电压质量,该文详细分析了基于模块化多电平换流器的静止同步补偿器(static synchronous compensator-modular multilevel convert...配电系统中无功负载的投切会使公共耦合点(point of common coupling,PCC)电压发生波动。为了提高配电网的电压质量,该文详细分析了基于模块化多电平换流器的静止同步补偿器(static synchronous compensator-modular multilevel converters,MMC-STATCOM)的PCC电压调节原理,采用带有无功电流指令值反馈环路的PCC电压下垂控制方法,根据输出无功电流指令乘以可控的变换器等效阻抗以实时修正PCC电压参考值。与传统的基于输出无功电流反馈值的下垂控制方法相比,该文提出的下垂调节方法不受电流内环控制性能的影响,PCC电压可以根据装置补偿容量与负载特性在可以接受的一定范围内波动。同时,MMC-STATCOM采用3个环路的均压控制策略以维持每个子模块的电容电压平衡。基于Matlab/Simulink平台的仿真结果,以及基于60 V/2 k VA实验样机的实验结果,验证了该文PCC电压下垂控制方法的正确性与有效性。展开更多
为了提高电流跟踪的快速收敛性和准确性,提出采用非奇异终端滑模对三电平有源电力滤波器(active power filter,APF)的指令电流进行跟踪控制.对指令电流的d、q轴分量分别设计非奇异终端滑模面与控制律,使得补偿电流能在有限时间内收敛到...为了提高电流跟踪的快速收敛性和准确性,提出采用非奇异终端滑模对三电平有源电力滤波器(active power filter,APF)的指令电流进行跟踪控制.对指令电流的d、q轴分量分别设计非奇异终端滑模面与控制律,使得补偿电流能在有限时间内收敛到指令电流,并从理论上证明了其稳定性.仿真实验验证了该控制方法能有效地抑制电网中的谐波电流,与传统的三角波比较控制和常规滑模变结构控制方法相比,所提出的控制策略具有更好的谐波抑制性能.展开更多
基金Project(50805144) supported by the National Natural Science Foundation of China
文摘Accurate parameter identification is essential when designing controllers for inertially stabilized platforms （lSPs）. But traditional identification methods suffer from observation measurement noise and operating restrictions of ISPs. To address this issue, a novel identification method based on current command design and multilevel coordinate search （MCS） algorithm without any higher order measurement differentiations was proposed. The designed current commands were adopted to obtain parameter decoupled models with the platform operating under allowable conditions. MCS algorithm was employed to estimate the parameters based on parameter decoupled models. A comparison experiment between the proposed method and non-linear least square method was carried out and most of the relative errors of identified parameters obtained by the proposed method were below 10%. Simulation and experiment based on identified parameters were conducted. A velocity control structure was also developed with disturbance observer （DOB） for application in disturbance compensation control system of an ISR Experimental results show that the control scheme based on the identified parameters with DOB has the best disturbance rejection performance. It reduces the peak to peak value （PPV） of velocity error integral to 0.8 mrad which is much smaller than the value （10 mrad） obtained by the single velocity controller without DOB. Compared with the control scheme based on sweep model with DOB compensation, the proposed control scheme improves the PPV of velocity error integral by 1.625 times.
文摘The presence of "comet-like" radial transport of acetylcholine receptors by actin microfilaments without the participation of myosin motors in the depression of acetylcholine-induced inward chloric current (ACh-current) in command neurons of defensive behavior of the land snail, Helix lucorum, in a cellular analog of habituation was investigated. For that purpose the effects of CK548, CK-636 (inhibitors of actin-related protein complex Arp2/3, whose activation triggers rapid actin polymerization and the formation of the "comet-like" tail on the actinic filament) and wiskostatin (an N-WASP protein inhibitor, activating Arp2/3) on the depression of ACh-current were studied. The attenuation of ACh-current depression was observed upon the addition of CK548. At the same time, CK-636 and wiskostatin irreversibly strengthened the depression of this current and suppressed its spontaneous recovery. The results of CK-548 action and its mathematical modeling allow suggesting the presence of "comet-like" transport of acetylcholine receptors, initiated by Arp2/3 protein complex in receptor endo and exocytosis in command neurons of Helix lucorum in a cellular analog of habituation. Irreversible inhibition of vital metabolic processes of the neuron by wiskostatin and CK-636, which lead to the decrease in the level of ATP, could have caused irreversible effects of these blockers on current depression.
文摘针对行走机构双电动机驱动的严格同步要求,采用CAN(Controller Area Network)总线时钟同步协议实现同步组单轴速度指令的同步执行.为解决齿间隙造成的两轴实际速度不协调及刚性连接的两行走电动机间的耦合关系导致的负载不均衡问题,提出电动机电流跟随算法.实验结果表明,该算法保证了两轴同步运动的精度,实现了焊接小车快速平稳运行.
文摘配电系统中无功负载的投切会使公共耦合点(point of common coupling,PCC)电压发生波动。为了提高配电网的电压质量,该文详细分析了基于模块化多电平换流器的静止同步补偿器(static synchronous compensator-modular multilevel converters,MMC-STATCOM)的PCC电压调节原理,采用带有无功电流指令值反馈环路的PCC电压下垂控制方法,根据输出无功电流指令乘以可控的变换器等效阻抗以实时修正PCC电压参考值。与传统的基于输出无功电流反馈值的下垂控制方法相比,该文提出的下垂调节方法不受电流内环控制性能的影响,PCC电压可以根据装置补偿容量与负载特性在可以接受的一定范围内波动。同时,MMC-STATCOM采用3个环路的均压控制策略以维持每个子模块的电容电压平衡。基于Matlab/Simulink平台的仿真结果,以及基于60 V/2 k VA实验样机的实验结果,验证了该文PCC电压下垂控制方法的正确性与有效性。
文摘为了提高电流跟踪的快速收敛性和准确性,提出采用非奇异终端滑模对三电平有源电力滤波器(active power filter,APF)的指令电流进行跟踪控制.对指令电流的d、q轴分量分别设计非奇异终端滑模面与控制律,使得补偿电流能在有限时间内收敛到指令电流,并从理论上证明了其稳定性.仿真实验验证了该控制方法能有效地抑制电网中的谐波电流,与传统的三角波比较控制和常规滑模变结构控制方法相比,所提出的控制策略具有更好的谐波抑制性能.
