A low-complexity flight controller for Unmanned Aircraft Systems with constrained control allocation

In this paper, we propose a framework for joint allocation and constrained control design of flight controllers for Unmanned Aircraft Systems (UAS). The actuator configuration is used to map actuator constraint set into the space of the aircraft generalised forces. By constraining the demanded generalised forces, we ensure that the allocation problem is always feasible; and therefore, it can be solved without constraints. This leads to an allocation problem that does not require on-line numerical optimisation. Furthermore, since the controller handles the constraints, and there is no need to implement heuristics to inform the controller about actuator saturation. The latter is fundamental for avoiding Pilot Induced Oscillations (PIO) in remotely operated UAS due to the rate limit on the aircraft control surfaces.

A hierarchical model of goal directed navigation selects trajectories in a visual environment

We have developed a Hierarchical Look-Ahead Trajectory Model (HiLAM) that incorporates the firing pattern of medial entorhinal grid cells in a planning circuit that includes interactions with hippocampus and prefrontal cortex. We show the model’s flexibility in representing large real world environments using odometry information obtained from challenging video sequences. We acquire the visual data from a camera mounted on a small tele-operated vehicle. The camera has a panoramic field of view with its focal point approximately 5 cm above the ground level, similar to what would be expected from a rat’s point of view. Using established algorithms for calculating perceptual speed from the apparent rate of visual change over time, we generate raw dead reckoning information which loses spatial fidelity over time due to error accumulation. We rectify the loss of fidelity by exploiting the loop-closure detection ability of a biologically inspired, robot navigation model termed RatSLAM. The rectified motion information serves as a velocity input to the HiLAM to encode the environment in the form of grid cell and place cell maps. Finally, we show goal directed path planning results of HiLAM in two different environments, an indoor square maze used in rodent experiments and an outdoor arena more than two orders of magnitude larger than the indoor maze. Together these results bridge for the first time the gap between higher fidelity bio-inspired navigation models (HiLAM) and more abstracted but highly functional bio-inspired robotic mapping systems (RatSLAM), and move from simulated environments into real-world studies in rodent-sized arenas and beyond.

Making informed decisions on selecting promising Work Zone Safety Treatments

Lack of detailed and accurate safety records on incidents in Australian work zones prevents a thorough understanding of the relevant risks and hazards. Consequently it is difficult to select appropriate treatments for improving the safety of roadworkers and motorists alike. This paper presents a method for making informed decisions about safety treatments by 1) identifying safety issues and hazards in work zones, 2) understanding the attitudes and perceptions of both roadworkers and motorists, 3) reviewing the effectiveness of work zone safety treatments according to existing research, and 4) incorporating local expert opinion on the feasibility and usefulness of the safety treatments. Using data collected through semi-structured interviews with roadwork personnel and online surveys of Queensland drivers, critical safety issues were identified. The effectiveness of treatments for addressing the issues was understood through rigorous literature review and consultations with local road authorities. Promising work zone safety treatments include enforcement, portable rumble strips, perceptual measures to imply reduced lane width, automated or remotely-operated traffic lights, end of queue measures, and more visible and meaningful signage.

Towards making informed decisions on selecting promising work zone safety treatments

Lack of detailed and accurate safety records on incidents in Australian work zones prevents a thorough understanding of the relevant risks and hazards. Consequently it is difficult to select appropriate treatments for improving the safety of roadworkers and motorists alike. This paper outlines development of a conceptual framework for making informed decisions about safety treatments by: 1) identifying safety issues and hazards in work zones; 2) understanding the attitudes and perceptions of both roadworkers and motorists; 3) reviewing the effectiveness of work zone safety treatments according to existing research, and; 4) incorporating local expert opinion on the feasibility and usefulness of the safety treatments. Using data collected through semi-structured interviews with roadwork personnel and online surveys of Queensland drivers, critical safety issues were identified. The effectiveness of treatments for addressing the issues was understood through rigorous literature review and consultations with local road authorities. Promising work zone safety treatments include enforcement, portable rumble strips, perceptual measures to imply reduced lane width, automated or remotely-operated traffic lights, end of queue measures, and more visible and meaningful signage.

Biogeographic analysis of the Tortugas Ecological Reserve: Examining the refuge effect following reserve establishment

Almost 120 days at sea aboard three NOAA research vessels and one fishing vessel over the past three years have supported biogeographic characterization of Tortugas Ecological Reserve (TER). This work initiated measurement of post-implementation effects of TER as a refuge for exploited species. In Tortugas South, seafloor transect surveys were conducted using divers, towed operated vehicles (TOV), remotely operated vehicles (ROV), various sonar platforms, and the Deepworker manned submersible. ARGOS drifter releases, satellite imagery, ichthyoplankton surveys, sea surface temperature, and diver census were combined to elucidate potential dispersal of fish spawning in this environment. Surveys are being compiled into a GIS to allow resource managers to gauge benthic resource status and distribution. Drifter studies have determined that within the ~ 30 days of larval life stage for fishes spawning at Tortugas South, larvae could reach as far downstream as Tampa Bay on the west Florida coast and Cape Canaveral on the east coast. Together with actual fish surveys and water mass delineation, this work demonstrates that the refuge status of this area endows it with tremendous downstream spillover and larval export potential for Florida reef habitats and promotes the maintenance of their fish communities. In Tortugas North, 30 randomly selected, permanent stations were established. Five stations were assigned to each of the following six areas: within Dry Tortugas National Park, falling north of the prevailing currents (Park North); within Dry Tortugas National Park, falling south of the prevailing currents (Park South); within the Ecological Reserve falling north of the prevailing currents (Reserve North); within the Ecological Reserve falling south of the prevailing currents (Reserve South); within areas immediately adjacent to these two strata, falling north of the prevailing currents (Out North); and within areas immediately adjacent to these two strata, falling south of the prevailing currents (Out South). Intensive characterization of these sites was conducted using multiple sonar techniques, TOV, ROV, diver-based digital video collection, diver-based fish census, towed fish capture, sediment particle-size, benthic chlorophyll analyses, and stable isotope analyses of primary producers, fish, and, shellfish. In order to complement and extend information from studies focused on the coral reef, we have targeted the ecotone between the reef and adjacent, non-reef habitats as these areas are well-known in ecology for indicating changes in trophic relationships at the ecosystem scale. Such trophic changes are hypothesized to occur as top-down control of the system grows with protection of piscivorous fishes. Preliminary isotope data, in conjunction with our prior results from the west Florida shelf, suggest that the shallow water benthic habitats surrounding the coral reefs of TER will prove to be the source of a significant amount of the primary production ultimately fueling fish production throughout TER and downstream throughout the range of larval fish dispersal. Therefore, the status and influence of the previously neglected, non-reef habitat within the refuge (comprising ~70% of TER) appears to be intimately tied to the health of the coral reef community proper. These data, collected in a biogeographic context, employing an integrated Before-After Control Impact design at multiple spatial scales, leave us poised to document and quantify the postimplementation effects of TER. Combined with the work at Tortugas South, this project represents a multi-disciplinary effort of sometimes disparate disciplines (fishery oceanography, benthic ecology, food web analysis, remote sensing/geography/landscape ecology, and resource management) and approaches (physical, biological, ecological). We expect the continuation of this effort to yield critical information for the management of TER and the evaluation of protected areas as a refuge for exploited species. (PDF contains 32 pages.)

Behavior ecology of the Humboldt squid, Dosidicus gigas: insights from an animal-borne video and data logging system

Dosidicus gigas is a large pelagic cephalopod of the eastern Pacific that has recently undergone an unexpected, significant range expansion up the coast of North America. The impact that such a range expansion is expected to have on local fisheries and marine ecosystems has motivated a thorough study of this top predator, a squid whose lifestyle has been quite mysterious until recently. Unfortunately, Dosidicus spends daylight hours at depths prohibitive to making observations without significant artificial interference. Observations of this squid‟s natural behaviors have thus far been considerably limited by the bright illumination and loud noises of remotely-operated-vehicles, or else the presence of humans from boats or with SCUBA. However, recent technological innovations have allowed for observations to take place in the absence of humans, or significant human intrusion, through the use of animal-borne devices such as National Geographic‟s CRITTERCAM. Utilizing the advanced video recording and data logging technology of this device, this study seeks to characterize unknown components of Dosidicus gigas behavior at depth. Data from two successful CRITTERCAM deployments reveal an assortment of new observations concerning Dosidicus lifestyle. Tri-axial accelerometers enable a confident description of Dosidicus orientation during ascents, descents, and depth maintenance behavior - previously not possible with simple depth tags. Video documentation of intraspecific interactions between Dosidicus permits the identification of ten chromatic components, a previously undescribed basal chromatic behavior, and multiple distinct body postures. And finally, based on visualizations of spermatophore release by D. gigas and repetitive behavior patterns between squid pairs, this thesis proposes the existence of a new mating behavior in Dosidicus. This study intends to provide the first glimpse into the natural behavior of Dosidicus, establishing the groundwork for a comprehensive ethogram to be supported with data from future CRITTERCAM deployments. Cataloguing these behaviors will be useful in accounting for Dosidicus‟ current range expansion in the northeast Pacific, as well as to inform public interest in the impacts this expansion will have on local fisheries and marine ecosystems.

Measurements of total scattering spectra from bocaccio (Sebastes paucispinis)

Marine sportfishing in southern California is a huge industry with annual revenues totaling many billions of dollars. However, the stocks of lingcod and six rockfish species have been declared overfished by the Pacific Fisheries Management Council. As part of a multifaceted fisheries management plan, marine conservation areas, covering many million square nautical miles, have been mandated. To monitor the recovery of the rockfish stocks in these areas, scientists are faced with the following challenges: 1) multiple species of rockfish exist in these areas; 2) the species reside near or on the bottom at depths of 80 to 300 m; and 3) they are low in numerical density. To meet these challenges, multifrequency echosounders, multibeam sonar, and cameras mounted on remotely operated vehicles are frequently used (Reynolds et al., 2001). The accuracy and precision of these echosounder results are largely dependent upon the accuracy of the species classification and target strength estimation (MacLennan and Simmonds, 1992).

A guide to the deep-water sponges of the Aleutian Island Archipelago

The first dedicated collections of deep-water (>80 m) sponges from the central Aleutian Islands revealed a rich fauna including 28 novel species and geographical range extensions for 53 others. Based on these collections and the published literature, we now confirm the presence of 125 species (or subspecies)of deep-water sponges in the Aleutian Islands. Clearly the deep-water sponge fauna of the Aleutian Islands is extraordinarily rich and largely understudied. Submersible observations revealed that sponges, rather than deep-water corals, are the dominant feature shaping benthic habitats in the region and that they provide important refuge habitat for many species of fish and invertebrates including juvenile rockfish (Sebastes spp.) and king crabs (Lithodes sp). Examination of video footage collected along 127 km of the seafloor further indicate that there are likely hundreds of species still uncollected from the region, and many unknown to science. Furthermore, sponges are extremely fragile and easily damaged by contact with fishing gear. High rates of fishery bycatch clearly indicate a strong interaction between existing fisheries and sponge habitat. Bycatch in fisheries and fisheries-independent surveys can be a major source of information on the location of the sponge fauna, but current monitoring programs are greatly hampered by the inability of deck personnel to identify bycatch. This guide contains detailed species descriptions for 112 sponges collected in Alaska, principally in the central Aleutian Islands. It addresses bycatch identification challenges by providing fisheries observers and scientists with the information necessary to adequately identify sponge fauna. Using that identification data, areas of high abundance can be mapped and the locations of indicator species of vulnerable marine ecosystems can be determined. The guide is also designed for use by scientists making observations of the fauna in situ with submersibles, including remotely operated vehicles and autonomous underwater vehicles.

Mapping reef fish and the seascape: using acoustics and spatial modeling to guide coastal management

Reef fish distributions are patchy in time and space with some coral reef habitats supporting higher densities (i.e., aggregations) of fish than others. Identifying and quantifying fish aggregations (particularly during spawning events) are often top priorities for coastal managers. However, the rapid mapping of these aggregations using conventional survey methods (e.g., non-technical SCUBA diving and remotely operated cameras) are limited by depth, visibility and time. Acoustic sensors (i.e., splitbeam and multibeam echosounders) are not constrained by these same limitations, and were used to concurrently map and quantify the location, density and size of reef fish along with seafloor structure in two, separate locations in the U.S. Virgin Islands. Reef fish aggregations were documented along the shelf edge, an ecologically important ecotone in the region. Fish were grouped into three classes according to body size, and relationships with the benthic seascape were modeled in one area using Boosted Regression Trees. These models were validated in a second area to test their predictive performance in locations where fish have not been mapped. Models predicting the density of large fish (≥29 cm) performed well (i.e., AUC = 0.77). Water depth and standard deviation of depth were the most influential predictors at two spatial scales (100 and 300 m). Models of small (≤11 cm) and medium (12–28 cm) fish performed poorly (i.e., AUC = 0.49 to 0.68) due to the high prevalence (45–79%) of smaller fish in both locations, and the unequal prevalence of smaller fish in the training and validation areas. Integrating acoustic sensors with spatial modeling offers a new and reliable approach to rapidly identify fish aggregations and to predict the density large fish in un-surveyed locations. This integrative approach will help coastal managers to prioritize sites, and focus their limited resources on areas that may be of higher conservation value.

Deep coral and associated species taxonomy and ecology: (DeepCAST) II Expedition Report, Roatan, Honduras, May 21-28, 2011

NOAA has a mandate to explore and understand deep-sea coral ecology under Magnuson-Stevens Sustainable Fisheries Conservation Act Reauthorization of 2009. Deep-sea corals are increasingly considered a proxy for marine biodiversity in the deep-sea because corals create complex structure, and this structure forms important habitat for associated species of shrimp, crabs, sea stars, brittle stars, and fishes. Yet, our understanding of the nature of the relationships between deep-corals and their associated species is incomplete. One of the primary challenges of conducting any type of deep-sea coral (DSC) research is access to the deep-sea. The deep-sea is a remote environment that often requires long surface transits and sophisticated research vehicles like submersibles and remotely operated vehicles (ROVs). The research vehicles often require substantial crew, and the vehicles are typically launched from large research vessels costing many thousands of dollars a day. To overcome the problem of access to the deep-sea, the Deep Coral and Associated Species Taxonomy and Ecology (DeepCAST) Expeditions are pioneering the use of shore-based submersibles equipped to do scientific research. Shore-based subs alleviate the need for expensive ships because they launch and return under their own power. One disadvantage to the approach is that shore-based subs are restricted to nearby sites. The disadvantage is outweighed, however, by the benefit of repeated observations, and the opportunity to reduce the costs of exploration while expanding knowledge of deep-sea coral ecology.

An investigation of survey technologies and modeling techniques for improving deepwater surveys of nonindigenous species in the Northwestern Hawaiian Islands

Nonindigenous species (NIS) are a major threat to marine ecosystems, with possible dramatic effects on biodiversity, biological productivity, habitat structure and fisheries. The Papahānaumokuākea Marine National Monument (PMNM) has taken active steps to mitigate the threats of NIS in Northwestern Hawaiian Islands (NWHI). Of particular concern are the 13 NIS already detected in NWHI and two invasive species found among the main Hawaiian Islands, snowflake coral (Carijoa riseii) and a red alga (Hypnea musciformis). Much of the information regarding NIS in NWHI has been collected or informed by surveys using conventional SCUBA or fishing gear. These technologies have significant drawbacks. SCUBA is generally constrained to depths shallower than 40 m and several NIS of concern have been detected well below this limit (e.g., L. kasmira – 256 m) and fishing gear is highly selective. Consequently, not all habitats or species can be properly represented. Effective management of NIS requires knowledge of their spatial distribution and abundance over their entire range. Surveys which provide this requisite information can be expensive, especially in the marine environment and even more so in deepwater. Technologies which minimize costs, increase the probability of detection and are capable of satisfying multiple objectives simultaneously are desired. This report examines survey technologies, with a focus on towed camera systems (TCSs), and modeling techniques which can increase NIS detection and sampling efficiency in deepwater habitats of NWHI; thus filling a critical data gap in present datasets. A pilot study conducted in 2008 at French Frigate Shoals and Brooks Banks was used to investigate the application of TCSs for surveying NIS in habitats deeper than 40 m. Cost and data quality were assessed. Over 100 hours of video was collected, in which 124 sightings of NIS were made among benthic habitats from 20 to 250 m. Most sightings were of a single cosmopolitan species, Lutjanus kasmira, but Cephalopholis argus, and Lutjanus fulvus, were also detected. The data expand the spatial distributions of observed NIS into deepwater habitats, identify algal plain as an important habitat and complement existing data collected using SCUBA and fishing gear. The technology’s principal drawback was its inability to identify organisms of particular concern, such as Carijoa riseii and Hypnea musciformis due to inadequate camera resolution and inability to thoroughly inspect sites. To solve this issue we recommend incorporating high-resolution cameras into TCSs, or using alternative technologies, such as technical SCUBA diving or remotely operated vehicles, in place of TCSs. We compared several different survey technologies by cost and their ability to detect NIS and these results are summarized in Table 3.

ROV模糊控制导航方法

本文提出一种水下 ROV(Remotely Operated Vehicles)的模糊导航方法和基于该方法的控制器结构 .通常由于水下环境光照不足或是水质混浊 ,很难依赖摄像机准确地为 ROV导航 ,引导 ROV到达预定目标 ,尤其是工作空间存在障碍物时 ,ROV很可能发生碰撞 .文中提出的模糊控制方法 ,将 ROV在 3D空间运动的状态、局部环境信息以及导航规划数据表示为多重模糊条件 ,然后结合 ROV的导航特点 ,建立了一个三级模糊控制器 ,该控制器使用同一种控制模式完成 ROV有障碍和无障碍的导航任务 .仿真实验结果验证了所提出方法的有效性

虚拟监控遥操作水下机器人控制系统的研究

随着海洋科学考察和水下工程的日益增多，人类的研究趋势不断地向海洋深处发展。然而，水下环境与陆地和空间环境相比更加恶劣，对人类的威胁更大，因此水下机器人作为人的替代者，正在越来越多地在实际水下操作中应用。传统的水下机器人是采用主从遥操作控制，陆地上或母船上的操作员借助水下摄像机观察机器人的工作情况，通过主手或操纵杆操纵机器人，这种工作方式已不能满足当前水下作业的需要，所以研制具有高效率、高操作精度的水下机器人系统成为当今机器人领域的研究热点。本论文的研究内容是国家“863”高技术计划研究项目“虚拟监控遥操作水下机器人系统”的重要组成部分，以水下机器人检查海底石油钻井平台导管架焊缝的实际工作为背景，建立了一个完整的水下机器人实验系统，详细研究了虚拟遥操作控制、机器人监控控制及ROV(Remotely Operated Vehicles)模糊控制导航方法，并将这些控制方法应用到所建立的机器人系统中，完成实际操作实验。为了解决运动学逆解无解析解一类机械手的实时控制问题，本文提出一种适合于实时求解的算法--“跟踪搜索算法"，并使用该算法实现了5DOF水下机械手的运动学解算和实时控制。水下机器人载体ROV的导航问题一直被研究者们关注，在水下机器人控制中占重要地位。本文提出一种模糊控制导航方法，使用统一控制模式实现ROV在3D空间的导航，避免了ROV水下导航中多模控制切换点难以确定和切换过程造成ROV波动的问题。根据对ROV和机械手运劫特征的分析，以及水下环境的先验知识，建立了机器人和水下环境的虚拟模型。为了适应机器人在非结构化环境中工作的要求，提出“交互虚攒建模”方法，在环境发生变化时，重新建立虚拟环境模型，使虚拟环境反映真实环境的变化。在此基础上，建立了一个多功能虚拟仿真平台。监控控制是目前水下机器人最好的控制方法，本论文将虚拟现实技术应用在机器人监控系统中，提出虚拟监控系统的双层结构，发展了监控思想。研究并实现了四种虚拟监控控制方法：(1)基于虚拟显示的控制方法，(2)基于虚拟视觉的控制方法，(3)虚拟层任务规划，(4)虚拟投射控制。将上述各部分集成，设计并实现了虚拟监控遥操作控制系统，以该控制系统为核心，连接真实水下机器人和视觉系统，建立了虚拟监控遥操作水下机器人实验系统。本论文提出的系统结构、虚拟建模方法、模糊导航方法，虚拟监控控制方法均应用到机器人实验系统中。实际操作结果和仿真实验结果验证了所提出的虚拟监控系统结构的合理性，方法的正确性，体现了这些结构和方法的先进性。该实验系统和上述实验结果作为“863”项目“虚拟监控遥操作水下机器人系统”的重要组成部分，通过了专家组的验收，得到专家们的肯定。此外，为了适应开展网络遥操作研究的需要，本论文基于Internet网络技术，建立了机器人的网络通讯框架，使本论文中建立的机器人系统具有网络扩展性。论文的研究工作为研制可实用的高性能水下机器人系统奠定了基础，研究成果对水下机器人遥操作具有理论指导意义，为其实际应用提供了技术实现的途径。

基于超短基线的缆控水下机器人动力定位

动力定位 (DynamicPositioning(DP) )技术是水下机器人的关键技术之一。因此针对当前动力定位主要在缆控水下机器人 (ROV)中应用的情况 ,给出了ROV动力定位技术的实施方法。通过声学定位技术确定ROV的坐标 ,计算出与期望位姿的差 ,将其作为神经网络控制器的输入量来控制ROV ,从而进行动力定位。同时还重点研究了ROV动力定位中的主要研究内容即水声定位技术和定位控制技术的构建。

有缆水下机器人主动升沉补偿技术研究

随着水下机器人技术的不断进步，水下机器人的作业范围和作业深度不断增加，深海水下机器人在深海领域有着其他手段无法比拟的优势。在深海区域，海面的海况条件相对比较恶劣，支持母船受风、浪、涌、流影响而产生较大幅度的升沉运动对有缆水下机器人正常作业和收放操作有较大的影响，水下机器人中继器的升沉运动甚至可以造成系缆的损坏而使机器人本体丢失。如何提高水下机器人在相对恶劣海况条件下的安全性能、特别是水下机器人与中继器安全的释放与回收成为当前深海有缆水下机器人开发所需要面临的一个重要问题。有缆水下机器人主动升沉补偿技术的研究，对于提高水下机器人在相对恶劣海况条件下的安全作业和收放具有重要的意义，对提高水下机器人抵御恶劣海况的能力具有重要的作用。 本文结合中国科学院沈阳自动化研究所研制的作业型遥控潜水器（ROV）在4级海况条件下安全作业和收放的实际需求以及“十五”期间国家863计划专题项目“基于母船升沉预测的深海装备主动升沉补偿测控单元的研究开发”的要求，开展有缆水下机器人主动升沉补偿技术研究，降低相对恶劣海况条件下母船升沉运动对水下机器人中继器的干扰，保证水下机器人与中继器安全的释放与回收。重点研究母船升沉运动的测量方法；研究以液压绞车为动力机构的主动升沉补偿控制方法；研究母船与水下机器人中继器升沉运动预报方法；研究母船、铠缆、水下机器人及中继器系统的有限元建模与运动分析方法。本文的主要研究内容如下： （1）研究海况条件、船舶尺寸与母船升沉运动之间的关系，分析在4级海况条件下作业型ROV母船升沉运动幅值和频率的分布范围和规律。利用惯性测量传感器测量母船升沉运动加速度值，通过积分和数字高通滤波处理得到母船升沉速度或位移信号。研究升沉运动测量误差来源，设计升沉运动自适应滤波器。 （2）以有缆水下机器人液压收放绞车为动力机构，开展基于常规液压收放绞车的主动升沉补偿控制方法研究。针对液压收放绞车的功率无法满足主动升沉补偿闭环控制的要求，研究在欠功率条件下液压绞车主动升沉补偿前馈控制策略，利用控制预值消除不对称负载作用时出现的液压绞车运动偏移。控制算法简单可靠，便于工程实现。 （3）针对液压绞车大负载、大惯量且系统参数时变、非线性等特征，研究液压绞车主动升沉补偿预测控制策略，通过水下机器人主动升沉补偿预测控制仿真实验分析液压绞车主动升沉补偿预测控制的补偿效率。 （4）研究母船与水下机器人中继器升沉运动预报方法。利用AR模型以及母船升沉运动历史数据，实现对母船未来极短时间内的运动预报，为液压绞车预测控制算法的应用提供参考轨迹。研究基于ARMA模型以及母船和水下机器人中继器升沉运动历史数据的水下机器人中继器升沉运动预报方法。 （5）通过升沉运动测量实验分析升沉运动测量模块的可靠性和测量精度的影响因素。利用模拟液压绞车主动升沉补偿实验验证常规液压绞车主动升沉补偿前馈控制的效率。并利用作业型ROV收放系统的实际液压绞车进行主动升沉补偿实验。结合模拟液压绞车与作业型ROV液压绞车主动升沉补偿实验的实验结果，分析4级海况条件下液压绞车主动升沉补偿控制效率。 （6）利用有限元理论建立母船、铠缆、水下机器人及中继器的有限元集中质量模型，通过数值方法求解有限元方程，得到母船与水下机器人中继器之间的运动耦合关系，仿真分析在液压绞车主动升沉补偿控制状态下水下机器人中继器升沉运动规律及铠缆张力变化规律。