Parameter identification of inertially stabilized platforms using current command design

Accurate parameter identification is essential when designing controllers for inertially stabilized platforms (ISPs). 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 ISP. 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.     

烟浓度试验测定仪的研制

该仪器是根据聚合物燃烧时所产生的烟雾会使光强度衰减的原理而研制的。介绍了其工作原理、主要技术特征、结构设计及各部分的作用。测试结果表明：①该仪器性能稳定、灵敏度高、试样测试重复性好且数据准确；②它在防止烟雾附着装置和温度补偿等方面有明显的改进；③其设计合理、结构简单、便于操作，测试结果的可信度高，且价格较低。该仪器的研制成功，为有效地贯彻国家标准《纺织品烟浓度测定──减光系数法》、研究阻燃新产品和开展消防科研工作等方面提供了重要的测试手段。除纺织品外，它还可以用于测定建材、纸张、皮革、塑料等材料的烟浓度。     

熔融盐粗燃气调质实验研究

在固定床内进行了熔融盐粗燃气成份调质实验,对熔融盐粗燃气调质实验的运行稳定性、反应过程对熔融盐的物性变化的影响、粗合成气成份对调质实验的影响等问题进行了考察.结果分析表明,350～500℃所有实验工况下,熔融盐均能有效的吸收粗燃气中的CO2,得到的合成气中CO2体积分数在2％附近,熔融盐处理技术能有效增加合成气中H2体积分数,降低CO体积分数,连续运行11h后合成气成份仍相对稳定.实验完成后熔融盐中Na2CO3分布呈现中部高两头低的分布规律,Na2CO3和NaOH比例变化时熔融盐熔点变化较小.这些特性都表明熔融盐粗燃气成份调质适合作为气化、热解制备合成气的后续工艺,提升燃气品质.     

墙体防裂建筑钢网的选用与施工

本文在调查和试验的基础上，提出了建筑墙体用钢网的分类、适用范围、选用原则和挂网施工工艺．并对墙体挂网防裂的效果和作用进行了讨论，可供有关技术人员参考。     

BP神经网络PID控制器在机载光电平台中的应用

通过对机载光电平台结构和惯性隔离原理的分析.根据光电平台结构复杂的特点和神经网络自学习的特性,提出了基于神经嘲络的控制策略,使其通过对系统性能的学习,自适应地整定PID控制器的三个参数,以达到最优控制的目的.基于这一思想,设计了稳定平台速度环的PID控制器,并对系统进行了仿真研究.仿真结果表明,基于BP神经网络的PID控制器设计获得了良好的控制效果.     

正佳广场地铁区间隧道上部结构施工技术

在跨越地铁区间隧道的某大体积混凝土结构施工中,因地制宜地选取合理的施工方案,并采取有效的技术措施和方法,保证了施工质量及地铁的正常营运。     

Multi-rate tracking controller analysis and design for target tracking systems

As the sampling rates of the inner loop and the outer loop of the target tracking control system are different, a typical digital multi-rate control system was formed. If the traditional single-rate design method was applied, the low sampling rate loop will seriously impact the dynamical characteristic of the system. After analyzing and calculating the impact law of the low sampling rate loop to the bandwidth and the stability of the tracking system, a kind of multi-rate control system design method was introduced. Corresponding to the different sampling rates of the inner loop and the outer loop, the multi-rate control strategy was constituted by a high sampling rate sub-controller and a low sampling rate sub-controller. The two sub-controllers were designed separately and connected by means of the sampling rate converter. The low sampling rate controller determined the response rapidity of the system, while the high sampling rate controller applied additionally effective control outputs to the system during a sampling interval of the low sampling rate controller. With the introduced high and low sampling rates sub-controllers, the tracking control system can achieve the same performance as a single-rate controller with high sampling rate, yet it works under a much lower sampling rate. The simulation and experimental results show the effectiveness of the introduced multi-rate control design method. It reduces the settling time by 5 times and the over shoot by 4 times compared with the PID control.     

浅谈市政给排水工程常见施工质量问题和控制措施

市政给排水工程随着改革开放以来,经济文化的快速发展,越来越成为市政工程中的重要部分,市政排水工程属于市政工程的基础建设,不仅关系着人民生活的质量问题,还在于表现政府的形象和实力。因为施工质量问题和安全性在管理中尤为重要,本文便针对市政给排水工程中常见的施工质量问题和控制措施展开分析。     

高超声速飞行器实时最优伪谱反馈末制导算法研究

针对高超声速飞行器攻击目标末制导阶段快速、准确的任务要求,提出了一种飞行器实时最优伪谱反馈末制导算法.该算法首先离线生成一条满足各种约束的飞行器攻击最优轨迹,然后在某一时刻点应用伪谱算法优化轨迹;通过连续应用伪谱反馈制导算法,实时在线更新再入轨迹,直至命中目标.在考虑模型中存在误差及干扰的情况下,证明了该算法的收敛性;并通过对飞行器攻击固定目标及移动目标分别进行仿真,验证所提算法的有效性.仿真结果表明,伪谱反馈末制导算法能够对固定目标准确打击且能够修正目标机动带来的落点偏差.     

机载光电跟踪平台的控制系统设计

传统的PID参数整定方法难以达到光电跟踪系统这种延时小、性能指标高的控制系统要求,为此提出了基于遗传算法的PID控制器参数整定方法.通过系统性能分析,对光电跟踪平台的控制系统进行了设计.最后运用Matlab/Simulink工具箱进行了仿真,仿真结果证明了有关理论的正确性.