测试转台陀螺伺服系统全数字控制实现

讨论了测试转台中陀螺伺服状态的构成原理，提出了一种基于全数字控制的陀螺伺服系统实现方案。该方案不仅方便系统参数在线调整，而且可以完成多种不同类型，不同参数的陀螺仪伺服实验，目前已经成功地用于某型空气轴承伺服转台，取得了满意的结果。     

伺服转台恒温装置结构及控制系统

本文在完成某高精度伺服转台恒温系统的研制任务基础上，全面阐述了伺服转台台面恒温系统的实现措施及理论依据。主要包括结构设计、恒温箱与台面间的非接触密封、恒温箱的设计及模型参数估计、温度检测及控制系统设计     

机器人无标定视觉伺服控制研究进展

视觉伺服控制是机器人系统重要的控制手段. 相比传统的在标定条件下使用的视觉伺服系统,无标定视觉伺服系统具有更高的灵活性与适应性,是机器人伺服控制系统未来重要的发展方向和研究热点. 本文从目标函数选择、控制器设计、运动轨迹规划三方面综述了无标定视觉伺服控制系统近年来的主要研究进展. 首先根据目标函数的形式,分析了基于位置的视觉伺服、基于图像的视觉伺服以及混合视觉伺服各自的特点与应用;在控制器设计方面,根据是否在设计过程中考虑机器人的非线性动力学特性,分别介绍了考虑机器人运动学与考虑机器人动力学的无标定视觉伺服控制器的设计,重点突出了雅克比矩阵的构造与估计方法;针对无标定视觉伺服系统运动轨迹可能存在的问题,从空间轨迹优化与障碍规避的角度,阐述了已有的可行解决方案. 最后,基于当前的研究进展展望了无标定视觉伺服的未来研究方向.      

静电伺服微加速度计的量程设计

详细推导了静电伺服加速度计在定极板上施加直流偏压、交流驱动电压，动极板上有反馈直流电压和交流检测电压的情况下，检测质量(动极板)受到的静电力。通过对静电力的分析，得出静电伺服彻。速度计的量程除了受系统能提供的最大静电力限制外，还需满足电刚度小于与机械刚度的条件，该电刚度是极板上所有的直流电压、交流电压产生的电刚度之和。离心实验证明，利用该原则设计的“叉指”结构静电伺服微加速度计的量程达到了设计值。该设计原则可以为此类加速度计的设计提供参考。     

海洋重力传感器伺服回路分析与设计

海洋重力仪是改善舰船惯导系统精度的重要设备，其重力传感器的伺服回路决定着仪器的精度和动态性能。作在介绍零长弹簧海洋重力传感器结构原理的基础上，研究其伺服回路的结构组成和设计方法，分析了其主要环节参数对系统性能的影响，考察了其时域性能，对海洋重力仪的研制具有重要指导作用。     

全数字IMU方案研究

分析了现有IMU内部模拟电路的不足，提出全数字IMU方案和结构框图，其内容包括高精度模数转换电路、高速数学运算平台、陀螺数字伺服电路、高精度数字温控电路和以数字滤波数据融合为核心的计算方法。论证了陀螺回路数字控制方案、陀螺模糊温度控制方案，确定出陀螺回路A／D采样频率应大于3000Hz，高精度A／D转换器采样频率应大于500Hz，且位数不应低于18bit。最后，展示了已经研制成功的3项试验结果：24bit A／D与陀螺和加速度计联机实测结果、CPU和24bit A／D间接口通讯逻辑接口和基于模糊控制的陀螺温控系统。     

伺服转台高精度控制系统带宽设计的探讨

以实际的伺服控制系统设计为例,从跟踪误差、干扰控制、噪声衰减和系统不稳定性的限制等几个方面研究了伺服控制系统的带宽问题,给出了选择带宽的方法结果,在实际应用中较好地折衷了系统稳定和系统性能的关系。     

陀螺仪漂移测试小角度伺服法实验方案的改进

为了提高陀螺仪的使用精度,研究了陀螺仪漂移测试的伺服法实验技术.依托973项目,在国内首次完成了高精度单自由度静压液浮陀螺仪的伺服法实验.找到了影响小角度伺服法实验测试精度的主要误差源,即小角度伺服法实验的方法误差,通过对该误差的分析,提出了改进的小角度伺服实验方案.建立了小角度伺服法实验方法误差的仿真模型,用改进方案和原始方案分别进行了仿真和实验,结果表明改进方案同原始方案相比,陀螺仪漂移误差模型中的三项系数辨识精度均有提高.     

三轴台陀螺伺服状态的实现

本文阐述了陀螺伺服状态中陀螺作为敏感元件给系统带来的新问题,即带进了陀螺的时间常数及其他问题,以及对于动力调谐陀螺这些问题的处理.为保护陀螺,在大偏差时加入测速机进行阻尼,当小偏差时死区电路自动切断测速机回路以确保伺服精度.文中还介绍了其他提高伺服精度的措施,如增大带宽及抑制干扰等,并对伺服数据进行了分析,说明陀螺伺服状态设计是正确的,实践上是可行的.     

运动控制的数字随动系统

介绍了采用数字随动系统解决模拟伺服回路的设计技术，即选用智能化运动控制处理器用于无刷或有刷直流电动机控制。这种技术具有实时采集，操作简单，可靠性高，精度高等优点，在导航系统、雷达系统、火炮系统、汽车等领域具有广阔的发展前景。     

浮动基座空间机械臂系统的动力学建模与惯性轨迹跟踪的滑模控制

本文利用多刚体系统动力学方法对载体位置、姿态均不受控制的浮动基空间机械臂系统的运动学、动力学作了分析,并结合系统的动量与动量矩守恒关系建立了系统的动力学方程及运动的广义Jacobi关系。以此为基础,对空间机械臂末端抓手追踪惯性空间期望轨迹的控制问题作了研究。考虑到空间机械臂系统的结构复杂性及某些参数（如液体控制燃料的数量）的变动性,根据具有较强鲁棒性的变结构滑模控制理论,设计了轨迹跟踪控制的变结构滑模控制方案。此控制方案的优点在于：在操作过程中不需要对空间机械臂载体的位置、姿态进行主动控制,因此将大大减少位置、姿态控制装置的燃料消耗。通过对平面三杆自由浮动空间机械臂系统的仿真计算,证实了文中提出的变结构滑模控制方案的有效性。     

射流元件控制通道流动的三维数值模拟

针对一种射流元件控制通道的复杂结构 ,采用分块对接技术和网格“融合”技术生成计算网格 ,并运用五步显式格式的 Runge-Kutta法和多重网格法对含全 N-S方程、RNG k-ε湍流模型和两层分区壁面模型的流动模型进行数值求解。通过对控制通道内部流动的数值模拟和流场特性分析 ,提出了改进方案     

Local joint information based active fault tolerant control for reconfigurable manipulator

This paper is concerned with the active fault tolerant control problem for reconfigurable manipulator actuator based on local joint information. It is considered that the entire reconfigurable manipulator system consists of a couple of independent joint modules as subsystems, which are controlled using unified radial basis function neural network adaptive algorithm using local joint information when actuators are fault free. For the subsystem in actuator fault situation, fault detection is achieved through comparing the user defined threshold to the residual between actual velocity value and nonlinear velocity observation value. The unknown input state observer is exploited for fault identification. Based on the information aforementioned, a compensation term is added to the proposed control algorithm for switching to realize active fault tolerant control when subsystem in fault. The advantages of the presented scheme are that unlike the complex control structure in centralized control, this scheme possesses simple control structure, as well as could isolate and tolerant the fault in subsystem. Furthermore, it can be easily applied to different configurations without any parameters modification. It means that the local fault could not affect the joint in normal situation. In order to demonstrate the effectiveness of the proposed method, two different 2-DOF reconfigurable manipulators are employed for simulation.     

Stabilization of Unstable Limit Cycles in Systems with Limited Controllability: Expanding the Basin of Convergence of OGY-Type Controllers

The underlying geometric structure of the standard OGY control scheme is analyzed. Some of the main mechanisms that under certain conditions lead to failure of the control algorithm are revealed. The limited controllability available in a system is investigated and it is shown that it may lead to serious problems that will significantly enlarge the state space region of failure of the standard OGY controller. A minimal distance algorithm is analyzed and shown to be, for some problems, more advantageous than the standard OGY technique. Nevertheless, for a broad category of problems, the minimal distance scheme is also shown to fail. As a solution for these problems, two new techniques are proposed: the penalized minimal distance and the multi-step OGY-type scheme. The standard OGY and minimal distance algorithms are particular cases of the new techniques proposed. Finally, we give a necessary condition that estimates the region of controllability under the multi-step OGY-type control. We demonstrate a significantly improved basin of convergence for the new multi-step OGY-type algorithm.     

存在关节力矩输出死区及外部干扰的漂浮基空间机械臂积分滑模神经网络自适应控制

探讨了载体位置和姿态都不受控时,漂浮基空间机械臂在带有关节力矩输出死区及外部干扰情况下轨迹跟踪的控制算法设计问题。死区与外部干扰影响系统的跟踪精度与稳定性。为此引入积分型切换函数,减少外部干扰引起的稳态误差,并利用径向基函数神经网络逼近动力学方程的未知部分,设计了一种积分滑模神经网络控制方案。控制算法的优点是,在死区斜率与边界参数不确定及最优逼近误差上确界未知的条件下,可以利用最优逼近误差、死区及干扰的补偿项来消除影响。李亚普诺夫稳定性分析证明了闭环系统的稳定性,且轨迹跟踪误差将收敛到0的某个小邻域内。仿真算例证实了该控制算法的有效性,实现了空间机械臂的轨迹跟踪控制。     

Intelligent quadratic optimal synchronization of?uncertain chaotic systems via LMI approach

This paper proposes an intelligent quadratic optimal control scheme via linear matrix inequality (LMI) approach for the synchronization of uncertain chaotic systems with both external disturbances and parametric perturbations. First, a four-layered neural fuzzy network (NFN) identifier is constructed to estimate system nonlinear dynamics. Based on the NFN identifier, an intelligent quadratic optimal controller is developed with robust hybrid control scheme, in which H _?? optimal control and variable structure control (VSC) are embedded to attenuate the effects of external disturbances and parametric perturbations. The adaptive tuning laws of network parameters are derived in the sense of the Lyapunov synthesis approach to ensure network convergence, and the sufficient criterion for existence of the controller is formulated in the linear matrix inequality (LMI) form to guarantee the quadratic optimal synchronization performance. Finally, a numerical simulation example is illustrated by the chaotic Chua??s circuit system to demonstrate the effectiveness of our scheme.     

Step-like contrast structure for class of nonlinear singularly perturbed optimal control problem

The step-like contrast structure for a class of nonlinear singularly perturbed optimal control problems is considered. The existence of the step-like contrast structure for the singularly perturbed optimal control problem is proved by equivalence, which is based on the necessary conditions. The authors not only give the conditions under which there exists a step-like contrast structure, but also determine where the internal transition time is. Meanwhile, the uniformly valid asymptotic expansion of the step-like contrast structure solution is constructed by the direct scheme method. Finally, an example is presented to show the result.     

Composite synchronization of four exciters driven by induction motors in a vibration system

In this paper, a newly composite synchronization scheme is proposed to ensure the straight line vibration form of a linear vibration system driven by four exciters. Composite synchronization is a combination of self-synchronization and controlled synchronization. Firstly, controlled synchronization of two pairs of homodromous coupling exciters with zero phase differences is implemented by using the master–slave control structure and the adaptive sliding mode control algorithm. On basis of controlled synchronization, self-synchronization of two coupling exciters rotating in the opposite directions is studied. Based on the perturbation method, the synchronization and stability conditions of composite synchronization are obtained. The theoretical results indicate that composite synchronization of four exciters with zero phase differences can be implemented with different supply frequencies and the straight line vibration form of the linear vibration system also can be obtained. Some simulations are conducted to verify the feasibility of the proposed composite synchronization scheme. The effects of some structural parameters on composite synchronization of four exciters are discussed. Finally, some experiments are operated to validate the effectiveness of the proposed composite synchronization scheme.

     

Adaptive synchronization of fractional-order chaotic systems via a single driving variable

This letter investigates the synchronization of a class of three-dimensional fractional-order chaotic systems. Based on sliding mode variable structure control theory and adaptive control technique, a single-state adaptive-feedback controller containing a novel fractional integral sliding surface is developed to synchronize a class of fractional-order chaotic systems. The present controller, which only contains a single driving variable, is simple both in design and implementation. Simulation results for three fractional-order chaotic systems are provided to illustrate the effectiveness of the proposed scheme.     

Neural network based robust hybrid control for robotic system: an H �� approach

A novel robust hybrid tracking control for robotic system is proposed. This hybrid control scheme combines computed torque control (CTC) with neural network, variable structure control (VSC) and nonlinear H _?? control methods. It is assumed that the nominal system of robotic system is completely known, which is controlled by using CTC method. Neural network is designed to approximate parameter uncertainties, VSC is used to eliminate the effect of approximation error, and H _?? control is employed to achieve a desired robust tracking performance. Based on Lyapunov stability theorem, it can be guaranteed that all signals in closed loop are bounded and a specified H _?? tracking performance is achieved by employing the proposed robust hybrid control. The validity of the control scheme is shown by computer simulation of a two-link robotic manipulator.