An Underwater Robot Inspection Anomaly Localization Feedback System Based on Sonar Technology

This article introduces an underwater robot inspection anomaly localization feedback system comprising a real-time water surface tracking,detection,and positioning system located on the water surface,while the underwater robot inspection anomaly feedback system is housed within the underwater robot.The system facilitates the issuance of corresponding mechanical responses based on the water surface’s real-time tracking,detection,and positioning,enabling recognition and feedback of anomaly information.Through sonar technology,the underwater robot inspection anomaly feedback system monitors the underwater robot in real-time,triggering responsive actions upon encountering anomalies.The real-time tracking,detection,and positioning system from the water surface identifies abnormal conditions of underwater robots based on changes in sonar images,subsequently notifying personnel for necessary intervention.

Flow Control for a Two-Stage Proportional Valve with Hydraulic Position Feedback

The current research mainly focuses on the flow control for the two-stage proportional valve with hydraulic position feedback which is named as Valvistor valve.Essentially,the Valvistor valve is a proportional throttle valve and the flow fluctuates with the change of load pressure.The flow fluctuation severely restricts the application of the Valvistor valve.In this paper,a novel flow control method the Valvistor valve is provided to suppress the flow fluctuation and develop a high performance proportional flow valve.The mathematical model of this valve is established and linearized.Fuzzy proportional-integral-derivative(PID)controller is adopted in the closed-loop flow control system.The feedback is obtained by the flow inference with back-propagation neural network(BPNN)based on the spool displacement in the pilot stage and the pressure differential across the main orifice.The results show that inference with BPNN can obtain the flow data fast and accurately.With the flow control method,the flow can keep at the set point when the pressure differential across the main orifice changes.The flow control method is effective and the Valvistor valve changes from proportional throttle valve to proportional flow valve.For the developed proportional flow valve,the settling time of the flow is very short when the load pressure changes abruptly.The performances of hysteresis,linearity and bandwidth are in a high range.The linear mathematical model can be verified and the assumptions in the system modeling is reasonable.

Velocity Feedback in Load Simulator with a Motor Synchronizing in Position

The velocity feedback in a load simulator with a motor synchronizing in position is achieved by installing a tachometer generator between tile shaft and shell of the loading motor, and thes not only decreases the disturbance torque of tile load simlilator greatly but also improves its dynamic performance.

Global Robust and Adaptive Output Feedback Dynamic Positioning of Surface Ships

A constructive method was presented to design a global robust and adaptive output feedback controller for dynamic positioning of surface ships under environmental disturbances induced by waves, wind, and ocean currents. The ship's parameters were not required to be known. An adaptive observer was first designed to estimate the ship's velocities and parameters. The ship position measurements were also passed through the adaptive observer to reduce high frequency measurement noise from entering the control system. Using these estimate signals, the control was then designed based on Lyapunov's direct method to force the ship's position and orientation to globally asymptotically converge to desired values. Simulation results illustrate the effectiveness of the proposed control system. In conclusion, the paper presented a new method to design an effective control system for dynamic positioning of surface ships.

Controlling Chaos in a Semiconductor Laser via Weak Optical Positive Feedback and Modulating Amplitude

控制混乱的弱光积极反馈(OPF ) 的数字分析在半导体激光被学习。控制经由 modulating 生产的混乱的物理模型半导体激光的水流在 OPF 的条件下面被介绍。我们发现非线性的获得系数和激光的线宽改进因素被 OPF 影响的物理机制以便系统的动态行为能高效地被控制。控制进射出力量的一个单人赛周期的状态，一个双周期的状态，一个 tri 周期的状态， aquadr 周期的状态，一个 penta 周期的状态，和激光的 Chaosis 被 OPF 在模拟增加。最后，反馈光的振幅被介绍并且数字地模仿了控制混乱激光进多周期的状态的有 modulating 的另一个混乱控制方法。

Development of photon beam position feedback system based on two PBPMs at HLS

In this paper,in order to stabilize the position and angle of the light source point,a new photon beam position feedback system based on the Photon Beam Position Monitors was developed on Hefei Light Source,and used to correct the position drift and angle variation of the light source at the same time.On introducing the feedback principle,the transfer function matrix is calibrated,indicating that the new system is workable and effective.

Two Positive Periodic Solutions of Delay Functional Difference System with Feedback Control

由在一个锥上使用一条固定的点定理与反馈控制调查下列延期差别系统的二个积极周期的解决方案的存在

Experimental study of delayed positive feedback control for a flexible beam

Recently, some researches indicate that positive feedback can benefit the control if appropriate time delay is intentionally introduced into control system. However, most work is theoretical one but few are experimental. This paper presents theoretical and experimental studies of delayed positive feedback control technique using a flexible beam as research object. The positive feedback weighting coefficient is designed by using the optimal control method. The available time delay is determined by analyzing the maximal real part of characteristic roots of the system. A DSP-based experiment system is introduced. Simulation and experimental results indicate that the delayed positive feedback control may effectively reduce the beam vibration if time delay is appropriately selected.

Explosive synchronization in a mobile network in the presence of a positive feedback mechanism

Synchronization is a process that describes the coherent dynamics of a large ensemble of interacting units.The study of explosive synchronization transition attracts considerable attention.Here,I report the explosive transition within the framework of a mobile network,while each oscillator is controlled by global-order parameters of the system.Using numerical simulation,I find that the explosive synchronization(ES)transition behavior can be controlled by simply adjusting the fraction of controlled oscillators.The influences of some parameters on explosive synchronization are studied.Moreover,due to the presence of the positive feedback mechanism,I prevent the occurrence of the synchronization of continuous-phase transition and make phase transition of the system a first-order phase transition accompanied by a hysteresis loop.

Analysis of positive feedback in the control of movement

Over the past three decades, neurophysiologists studying the neural circuitry responsible for control of skeletal muscles have developed several different general theories of sensorimotor control. These have usually invoked one or more of the sources of proprioceptive signals (e.g. muscle spindle and Golgi tendon organ afferents) in positive or negative feed-back loops to the homonymous alpha motoneurones. In this paper we consider to analyze the role of posi-tive feedback in combination of negative feedback due to important role of them in stabilizing the neu-romuscular system.

Robot Position Control Using Force Information for Cooperative Work in Remote Robot Systems with Force Feedback

This paper proposes robot position control using force information for cooperative work between two remote robot systems with force feedback in each of which a user operates a remote robot by using a haptic interface device while observing work of the robot with a video camera. We also investigate the effect of the proposed control by experiment. As cooperative work, we deal with work in which two robots carry an object together. The robot position control using force information finely adjusts the position of the robot arm to reduce the force applied to the object. Thus, the purpose of the control is to avoid large force so that the object is not broken. In our experiment, we make a comparison among the following three cases in order to clarify how to carry out the control effectively. In the first case, the two robots are operated manually by a user with his/her both hands. In the second case, one robot is operated manually by a user, and the other robot is moved automatically under the proposed control. In the last case, the object is carried directly by a human instead of the robot which is operated by the user in the second case. As a result, experimental results demonstrate that the control can help each system operated manually by the user to carry the object smoothly.

Hopf Bifurcation of a Positive Feedback Delay Differential Equation

Under some minor technical hypotheses, for each T larger than a certain rS > 0, Krisztin, Walther and Wu showed the existence of a periodic orbit for the positive feedback delay differential equation x(t) = -rμx(t) + rf(x(t-1)), where r and μ are positive constants and f : R → R satisfies f(0) = 0 and f' > 0. Combining this with a unique result of Krisztin and Walther, we know that this periodic orbit is the one branched out from 0 through Hopf bifurcation. Using the normal form theory for delay differential equations, we show the same result under the condition that f ∈ C3(R,R) is such that f''(0) = 0 and f'''(0) < 0, which is weaker than those of Krisztin and Walther.

Feedback Control of Plasma Current and Horizontal Position in HT-7

There is a strong magnetic coupling between poloidal field coils of superconducting tokamak HT-7, especially between ohinic heating and vertical field coils. These coils are connected to individual power supply. The control system for the plasma current and horizontal position control has been designed and showed satisfactory results with the feedback control of multivari- able feedforward-decoupling and var-parameter PID controller to simultaneously modulate power supplies. The design and analysls of the control system is presented.

Position Optimization for Mobile Relay Communications with Constrained Energy over a Whole Horizontal Plane

This paper concerns the position optimization problem of a mobile relay over a whole horizontal plane.This problem is important because the position of a mobile relay directly affects the end-to-end performance,e.g.,reliability,connectivity,and data rate.In this paper,we propose a new position optimization scheme of a mobile relay over a whole horizontal plane based on the one-bit feedback information from the destination node,which improves the performance over the prior scheme whose position of the mobile relay is optimized over a fixed orbit.In the proposed scheme,the mobile relay is equipped with merely one single onboard antenna.Moreover,no prior information about the positions of both the source node and the destination node is required.Thus,the proposed scheme can work at low network resources scenario,which is particularly suitable for mobile relay communication with constrained energy,e.g.,the communications in a disaster area where the infrastructure is heavily damaged,volcano monitoring,and wireless powered communication networking.According to the characteristics of the proposed scheme,we further design two heuristic implementations to calculate the optimal position of a mobile relay over a whole horizontal plane.The first implementation has better steady performance whereas the second implementation has better convergence speed.We implement the proposed scheme and conduct an extensive performance comparison between the proposed scheme and prior schemes to verify the advantages of the proposed scheme.

一维光学位置传感器融合的非接触多自由度位姿测量系统

为实现机器人末端位姿多自由度实时测量反馈,融合一维光学位置传感器(Position Sensitive Detector,PSD)建立了平面3自由度非接触测量系统,对其测量原理,信号处理电路,环境光干扰去除和非线性标定算法等进行研究。根据PSD传感器测量特性和平面3自由度测量要求设计了4-PSD测量系统,并建立测量系统数学模型。研究了PSD传感器的信号处理电路,通过运放和除法器实现了单个PSD的信号处理,结合单片机与A/DC采样电路,实现了上位机的高频率信号采集。对4-PSD测量系统进行预实验,为消除环境光干扰,通过激光调制和数字滤波等方法进行验证。最后,通过激光位移传感器标定4-PSD测量系统,介绍了4-PSD的标定步骤(原点、转角、长度和二阶非线性标定),测定了系统标定后的误差分布。该测量系统具有较高的测量频率(50 Hz)。标定实验结果表明:标定后的4-PSD测量系统在70 mm×70 mm内,测量精度平均为0.49 mm,比标定前降低了90%的误差,能满足大部分高速、高精度机器人末端的非接触式实时测量反馈需求。

基于相似度加速的自适应聚类联邦学习

为了解决联邦学习过程中数据异质性导致模型性能下降的问题,考虑对联邦模型个性化,提出了一种新的基于相似度加速的自适应聚类联邦学习(ACFL)算法,基于客户端本地更新的几何特性和客户端联邦时的正向反馈实现自适应加速聚类,将客户端划分到不同任务簇,同簇中数据分布相似的客户端协同实现聚类联邦学习(CFL),从而提升模型性能。该算法不需要先验确定类簇数量和迭代划分客户端,在避免现有基于聚类的联邦算法计算成本过高、收敛速度慢等问题的同时保证了模型性能。在常用数据集上使用深度卷积神经网络验证了ACFL的有效性。结果表明,所提算法性能与聚类联邦学习算法相当,优于传统的迭代联邦聚类算法(IFCA),且具有更快的收敛速度。

股票市场正反馈交易的空间溢出效应——基于新冠疫情冲击的计量检验

利用空间自相关正反馈交易模型,对新冠疫情爆发前后国际股票市场的正反馈交易进行了检验.结果表明,新冠疫情爆发后国际股票市场正反馈交易显著增强并呈现空间相关特征.相关国家反危机的调控措施,虽然一度抑制了股票市场下行,但同时强化了投资者非理性的外推性预期,加剧了股票市场正反馈交易的空间溢出效应.因此,在新冠疫情不断持续的情况下,监管当局应充分考虑反危机调控措施对投资者心理账户和市场预期的影响,防范疫情冲击下股票市场正反馈交易空间溢出的风险联动效应.

基于自适应分数阶正位置反馈的垂尾振动主动控制

针对自适应正位置反馈(Adaptive Positive Position Feedback,APPF)控制器在控制效果与分数阶正位置反馈(Fractional Order Positive Position Feedback,FOPPF)控制器在针对摄动区间小的不足,提出一种分数阶APPF(Fractional Order Adaptive Positive Position Feedback,FOAPPF)控制器,使得控制器在控制效果提升的同时兼具强鲁棒性。基于不同参数对FOPPF控制器的影响,推导参数的最佳范围,将系统多个摄动模型的正弦扫频响应进行综合加权处理,并考虑系统远离共振频段的控制性能,构建附带约束条件的控制设计的目标函数。以粘有宏纤维复合材料(Macro Fiber Composites,MFC)的垂尾模型及其摄动模型为被控对象,设计相应的FOAPPF控制器。研究结果表明:相比FOPPF控制器,FOAPPF控制器闭环极点对参数摄动不敏感;相比APPF控制器,FOAPPF控制器的相频曲线在摄动频带内变化平缓,其控制效果受固有频率在线估计误差的影响更小;多种试验工况表明,FOAPPF控制器在不同摄动模型下均具有较好的控制效果,垂尾抖振响应均方根值至少降低了55%,且具有较好的鲁棒性,因此该控制器对垂尾结构的振动主动控制具有良好应用潜力。

振动控制中的局部应变补偿和改进PPF算法

为了克服压电结构振动同位配置中局部应变和正位移反馈(PPF)算法补偿阻尼比的两面性问题,运用低通滤波器来滤除高频局部应变模态,用速度负反馈混合PPF算法来进一步提高系统的阻尼比,通过劳斯判据分析了改进后算法的稳定性条件.以飞机壁板结构为研究对象,根据激光测振仪识别出其中的两阶模态振型,并粘贴压电片进行振动控制.仿真和实验结果表明,无论是在正弦激励还是随机信号激励下,混合了低通滤波、PPF和速度负反馈(DVFB)的新方法都能较大幅度降低结构的90 Hz和162 Hz模态振幅,并有效抑制单一PPF实验过程中出现的谐波分量,两阶模态同时控制效果都达到10 dB以上.