The olivo-cerebellar circuit as a universal motor control system

The olivo-cerebellar system is one of the central networks organizing movement coordination in vertebrates. This system consists of three main anatomical structures: the inferior olive (IO), the cerebellar nuclei, and the cerebellar cortex. Over the last four decades studies in many laboratories have contributed significantly to our understanding of the electrophysiology of IO and cerebellar neurons. However, addressing the dynamic properties of olivo-cerebellar network requires information beyond the limits attainable using single cell recordings. Research at the neuronal network level is presently being implemented in order to determine the spatiotemporal activity profiles of ensemble neuronal activity using optical imaging of voltage-sensitive dye signals. We summarize here results of such type of study using the in vitro IO slices. The dynamic characteristic of the system is addressed using the imaging results as well as mathematical modeling of the network, as a heuristic tool. A computer-based control system based on such biological findings is outlined.     

The optimum control of thruster system for dynamically positioned vessels

An offshore vessel with a dynamic positioning system (DP system) needs fast response to produce thrust to counteract the environmental forces acting on it for the purpose of maintaining its position and heading as close as possible to the working position. Therefore, quick and effective modulation of the thrust is the problem to determine the thrust and the rotation angle of the thruster devices of the ship. This paper presents an effective optimum control for a thruster system, using the sequential quadratic method to achieve economical and effective modulation of the thrust and the direction of the thruster. An optimum control study of a 2280 tons DP coring vessel with five rotary azimuth thruster marine positioning is studied in detail, which can quickly and exactly estimate the thrusts and angles of direction of all the thrusters. The results can provide a valuable thruster system for a dynamically positioned vessel.     

基于单片机的海洋环境监测系统的控制电路设计

设计并实现了一种基于C8051F340单片机的节能型自治式多功能海洋环境监测系统的控制电路.该电路利用模块化设计方法,通过合理选用器件和设计器件的工作模式,使控制电路具有低功耗、高可靠的特点.实验表明,该控制电路实现了潜标式主浮体对浮标式搭载平台的实时控制,同时实现了浮标搭载平台单向下潜、定点测量、自由上浮、自动避碰等状态的控制,方法简单新颖,实现了对海洋要素的长期连续观测.     

长江口南北港分汊口河势控制工程及实施效果研究

南北港分汊口采用新浏河沙护滩及南沙头通道限流潜堤工程控制河势,既是长江口最复杂的分汊口河段整治工程组成部分,又为长江口综合治理和长江口深水航道逐步延伸至南京起到关键性作用,其治理思路、方案及工程经验均值得借鉴.论述了新浏河沙护滩及南沙头通道限流潜堤工程治理思路及方案研究过程,并根据最新资料分析了工程的整治效果,总结了工程特点及经验,可供相关类似工程借鉴参考.     

贝类养殖风险控制体系建设的基本构想

随着贝类养殖技术的提高,贝类养殖种类与养殖方式日趋多元化,养殖规模逐步扩大,养殖产量不断增加,现已成为中国水产养殖的重要组成部分。基于对中国贝类养殖发展现状的分析,将贝类养殖风险归纳为自然、生态、经济社会与技术风险等四类,并对四大风险的来源进行了深入分析,提出了建立贝类养殖"一体两翼"风险控制体系的基本构想。最后,从政府扶持、团队建设、科技攻关、融资等方面提出了保障措施与建议。     

Acoustic telemetry system for underwater control

Underwater acoustic communication in the multipath environment encountered in shallow water is restricted mostly by signal fading. It degrades the signal detection and time synchronization required for reliable acoustic communication. An approach to time synchronization and to the frequency diversity method is presented. A communication algorithm for obtaining a reliable acoustic underwater link, and offering an easy-to-implement decoding scheme is introduced, and system realization is described     

Supervisory control system for the JASON ROV

A prototype supervisory control system for a remotely operated vehicle (ROV) is described and several key elements demonstrated in simulation and in-water tests. This system is specifically designed to fill the needs of JASON, a new ROV under development that will perform scientific tasks on the seafloor to depths of 6000 m. JASON will operate from the ARGO towed imaging platform, which is currently operational. Supervisory control is a paradigm for combined human and computer control. Several key elements of the supervisory control system are presented. These include the closed-loop positioning system based on a high-resolution acoustic navigation system, a monitoring capability for assessing performance and detecting undesirable changes, and an interface that allows the human operator and the computer system to specify the desired vehicle trajectory jointly.     

A microstructure flux profiler control system design

A microstructure flux profiler (MFP) which uses variation of its buoyancy to maintain the speed required for data logging is detailed. The variation of buoyancy to control speed is uncommon among profilers, and the autonomous operation of this device allows a much greater degree of flexibility in the data collection. The complete development of the control system, from modeling through simulation and control system design to commissioning, is examined, and the performance is reviewed     

Feedback control system for blow-out preventer positioning

During the drilling of ultra-deep-water subsea petroleum wells, a blow-out preventer (BOP), a piece of safety equipment, must be assembled on the wellhead. The BOP is suspended using the drilling riser during the wellhead approach operation, and the riser's top end is connected to the floating platform rig. This article presents a feedback control system for the automatic approach of the BOP to the wellhead. Compared to state-of-the-art controls, ours does not require ancillary thrusters installed alongside the riser nor inclination sensors atop of the drilling riser. Additionally, our proposed control embeds a closed-loop dynamic positioning system, thus retaining the characteristics of the original control system and adding an extra closed-loop. This eases implementation of the BOP approach control to an existing platform. To calculate the optimal gains for the BOP controller, we assume a linear system for the riser, including only the pendulum-shape. The simulation is carried out using nonlinear models for both riser and floating platform. We assume an International Towing Tank Conference standard semi-submersible platform, coupled with a 3000-m free-hanging vertical riser for the time-domain simulation. The results show the BOP tracking to be a step-shaped input signal under current and wave loads. A discussion of the performance of feedback control under different environmental loads is also included.     

潜水器控制系统层次故障诊断模型设计

在潜水器控制系统的基础上,按照结构、功能和组件的关系,为潜水器控制系统进行故障诊断建模。依据基于模型的层次故障诊断技术,建立了适用于潜水器控制系统故障诊断的具体诊断和推理策略,开发了故障诊断软件系统,描述了故障诊断具体过程,并利用数字仿真验证系统设计的有效性。     

Marine ecosystem-based management as a hierarchical control system

Although many jurisdictions have embraced ecosystem-based management for the marine environment, it is unclear what this entails in terms of both theory and practical action. I examine the management of complex systems in industrial control as a source of practical guidance on how to approach the ideals of marine ecosystem management. Industrial control systems focus on objectives and outcomes, are hierarchical and localise and distribute control tasks. The principles of hierarchical control systems and focussing on ecosystem services helps overcome the conceptual difficulties with ecosystem management while retaining the idea of a holistic approach to managing human impacts.     

Nonlinear control of an active heave compensation system

Heave motion of a vessel or a rig has an adverse impact on the response of a drill-string or a riser. To compensate for heave motion, passive and active devices are usually used. Active heave compensators, in which a control system is an essential part, allow conducting operations under more extreme weather conditions than passive ones. This paper presents a constructive method to design a nonlinear controller for an active heave compensation system using an electro-hydraulic system driven by a double rod actuator. The control system reduces the effect of the heave motion of the vessel on the response of the riser by regulating the distance from the upper end of the riser to the seabed. The control development is based on Lyapunov's direct method and disturbance observers. The paper also includes a method to select the control and disturbance observer gains such that actuator saturations are avoided. Stability of the closed loop system is carefully examined. Simulation results illustrate the effectiveness of the proposed control system.     

光学浮标控制系统硬件设计

以光学浮标为控制对象, 以工作稳定、低功耗为目的, 设计海上工作控制硬件。采用嵌入式PC/104 CPU主板和以单片机为核心多功能板组合, 由PC/104 CPU主板完成采集数据、保存数据、通讯等工作, 多功能板实现计数、I/O控制、A/D转换、定时等功能。单片机结合日历时钟和电源总开关组成二级“看门狗”, 实现了海洋光学浮标控制系统无人值守、全天候、全过程独立工作。     

基于单片机的海洋要素垂直剖面测量系统的控制电路设计

设计了一种基于AT89C2051单片机的海洋要素垂直剖面测量系统(简称“海马”)的控制电路。实验表明,该控制电路实现了“海马”的核心部件——棘爪机构单向抓紧、阻尼锁定和自由上浮3个状态的控制,方法简单新颖,同时实现了“海马”下潜运动的能量全部来自波浪,上浮依靠自身浮力的目标。     

The influence of thruster dynamics on underwater vehicle behaviorand their incorporation into control system design

A nonlinear parametric model of a torque-controlled thruster is developed and experimentally confirmed. The model shows that the thruster behaves like a sluggish nonlinear filter, where the speed of response depends on the commanded thrust level. A quasi-linear analysis which utilizes describing functions shows that the dynamics of the thruster produce a strong bandwidth constraint and a limit cycle, which are both commonly seen in practice. Three forms of compensation are tested, utilizing a hybrid simulation combining an instrumented thruster with a real-time mathematical vehicle model. The first compensator, a linear lead network, is easy to implement and greatly improves performance over the uncompensated system, but does not perform uniformly over the entire operating range. The second compensator, which attempts to cancel the nonlinear effect of the thruster, is effective over the entire operating range but depends on an accurate thruster model. The final compensator, an adaptive sliding controller, is effective over the entire operating range and can compensate for uncertainties or the degradation of the thruster     

An intelligent control system for remotely operated vehicles

The application of a neural network controller to remotely operated vehicles (ROVs) is described. Three learning algorithms for online implementation of a neural net controller are discussed with a critic equation. These control schemes do not require any information about the system dynamics except an estimate of the inertia terms. Selection of the number of layers in the neural network, the number of neurons in the hidden layer, initial weights for the network and the critic coefficient were done based on the results of preliminary tests. The performances of the three learning algorithms were compared by computer simulation. The effectiveness of the neural net controller in handling time-varying parameters and random noise is shown by a case study of the ROV system     

Phase control through load control of oscillating-body wave energy converters with hydraulic PTO system

Oscillating bodies constitute an important class of wave energy converters, especially for offshore deployment. Phase control by latching has been proposed in the 1970s to enhance the wave energy absorption by oscillating bodies (especially the so-called point absorbers). Although this has been shown to be potentially capable of substantially increasing the amount of absorbed energy, the practical implementation in real irregular waves of optimum phase control has met with theoretical and practical difficulties that have not been satisfactorily overcome. The present paper addresses the case of oscillating-body converters equipped with a high-pressure hydraulic power take-off mechanism (PTO) that provides a natural way of achieving latching: the body remains stationary for as long as the hydrodynamic forces on its wetted surface are unable to overcome the resisting force (gas pressure difference times cross-sectional area of the ram) introduced by the hydraulic PTO system. A method of achieving sub-optimal phase-control is developed, based on the theoretical time-domain modelling of a single-degree of freedom oscillating body in regular and irregular waves, by adequately delaying the release of the body in order to approximately bring into phase the body velocity and the diffraction (or excitation) force on the body, and in this way get closer to the well-known optimal condition derived from frequency-domain analysis for an oscillating body in regular waves.     

大型模型试验水沙循环调制设备及控制系统

介绍了水沙循环调制设备及控制系统结构及原理,该系统可用于大型模型试验的流量测量与控制、含沙量测量与控制、水沙循环调制、水位测量与控制、水库水位测量报警和流速、水位、含沙量、泥沙颗粒级配等数据多点同步采集与处理,还设计安装了监测监控系统。全套系统已应用于多项国家重点科技攻关项目和省部级重点科技项目。