Accuracy of the TurfTrax Racing Data System for determination of equine speed and position

Reasons for performing study: The speed and position data collected by TurfTrax Racing Data Limited during UK Thoroughbred racing have potential to benefit equine science and welfare. The size (the 2006 data set alone consists of 30,932 individual horse starts across 2667 races) and nature (speed and 2D position for each horse at 4 updates per second) of the data make it a unique resource for questions in equine safety, welfare, performance, and animal locomotion. Objective: To determine the accuracy of the TurfTrax tracking system in estimating the speed and position of horses during racing. Methods: Measurements from the TurfTrax wireless tracking system were compared with those of a survey‐grade global positioning system (GPS) receiver. Results: The TurfTrax system was found to give position measurements to within ± 11 and ± 64 cm in the fore‐aft and lateral directions, respectively, averaging ± 38 cm (interquartile range) and speed to within 0.15 m/s. Potential relevance: The data collected by the TurfTrax system are of sufficient accuracy to inform new diagnoses, training regimens and basic locomotor scientific studies. The position data can provide the precise distance, going, inclination, rate of turn and pack positioning through which each horse has raced. The speed profile can be used to examine the level of exertion, effect of training regimens and influence of racecourse features on performance. A first clinical application would be to analyse retrospectively these factors on occurrence of injury to compare with past training regimens, levels of exertion, and/or racecourse conditions.     

Modeling the egg and larval transport pathways of the Antarctic toothfish (Dissostichus mawsoni) in the East Antarctic region: New insights into successful transport connections

The Antarctic toothfish (Dissostichus mawsoni) is an important fishery species widely distributed in the Southern Ocean, especially in areas covered by sea ice. Understanding fish distributions and life cycles, including the transport and survival of eggs and larvae, is essential for the assessment and sustainable management of the fishery. However, owing to difficulties with in situ winter observations, information on the early life stages of D. mawsoni is lacking. Here, we investigated the transport pathways of fish eggs and larvae through a particle tracking study, using satellite-derived ocean surface velocities in the East Antarctic region, which includes important D. mawsoni habitats and exploratory fisheries. Our results indicate that particles released from continental slopes are more likely to be successfully transported to suitable settlement grounds than those released from the BANZARE Bank (the southern region of the Kerguelen Plateau), which is situated further north and has been hypothesized to be a potential spawning ground for D. mawsoni. This study demonstrates successful source–settlement connections in relation to ocean recirculation and suggests important settlement regions for D. mawsoni larvae in the East Antarctic region.     

基于滑模变结构控制的温室喷药移动机器人路径跟踪

为解决作物种植密集,地面障碍与空间障碍并存等非结构化环境因素对温室喷药移动机器人路径跟踪运动控制精度的影响,在建立移动机器人运动学模型的基础上,设计一种基于指数趋近律的滑模变结构控制方法以保证系统对不确定参数及外界干扰的鲁棒性。与此同时,为有效解决滑模控制固有的抖振问题,提出一种加权增益趋近律算法,在该趋近律的积分项中引入负的加权值,可有效避免当系统状态不在滑模切换时的切换增益的增大,使得控制器输出量平滑,并利用Lyapunov函数证明了其稳定性,并采用该文所设计的基于加权积分增益趋近律的滑模控制器对喷药移动机器人进行路径跟踪控制。试验结果表明,该算法可以顺利消除横向偏差,使实际运动轨迹平稳跟随理想作业路线,避免在作业区域产生较严重的重喷和漏喷现象,其研究成果为温室作物实施精准喷药提供了依据。     

电动拖拉机PC-DSPM电机电子变极策略与分析

针对田间作业和转场运输等不同工况时的行驶速度需求,该研究提出使用双凸极变极永磁（pole-changing doubly-salient permanent magnet,PC-DSPM）电机作为电动拖拉机的驱动电机,通过变极获得驱动电机的多种机械特性。基于气隙磁场调制理论,将PC-DSPM电机气隙磁场中的主要工作谐波分为2组,采用电子变极改变电枢绕组连接方式,从而选择不同组别的气隙磁场谐波参与机电能量转换,形成PC-DSPM电机3种运行模式。根据不同模式下的转矩-转速曲线,选取电机在恒功率区的2个变极切换点,并据此将拖拉机的运行速度划分为0～7.7、7.7～10.5和10.5～32.7 km/h共3个区间。为实现平滑变极,构建自抗扰控制和跟踪微分器的PC-DSPM电机变极策略。与采用自抗扰控制的阶跃响应变极相比,虽然2个切换点处的变极时间分别延长至400和600 ms,但变极过程中dq轴电流过渡平稳,转矩波动分别下降8.5%和11.8%,转速恒定在920和1 250 r/min。研究结果可为实现电动拖拉机多工况高效运行及变极永磁电机平滑切换提供理论参考。     

基于自纠正NMS-ByteTrack的套袋葡萄估产方法

针对套袋后的葡萄体积增加和葡萄叶片表面积大容易出现重叠遮挡,及人工拍摄视频的速度不稳定可能导致套袋葡萄目标丢失的问题,该研究提出一种基于自纠正NMS(non-maximum suppression)-ByteTrack的套袋葡萄估产方法。该方法首先通过目标检测方法YOLOv5s检测视频中的套袋葡萄,将检测阶段的NMS操作后置到追踪阶段,保留因遮挡而被过滤的果实检测框;其次在ByteTrack的基础上加入相机运动补偿和改进的卡尔曼滤波算法,以自动纠正果实预测框的位置并进行追踪;最后提出一种划线计数策略对套袋葡萄自动计数。试验结果表明,该方法的多目标追踪准确率、多目标追踪精度和ID调和平均数分别为64.6%、82.4%和80.8%,相比ByteTrack分别提高了1.7个百分点、1.0个百分点和4.1个百分点,平均计数精度达到82.8%。因此,基于自纠正NMS-ByteTrack的估产方法能有效解决套袋葡萄的追踪计数问题,实现对套袋葡萄更精确地估产。     

Where do you think you’re going? Accounting for ontogenetic and climate‐induced movement in spatially stratified integrated population assessment models

Understanding spatial population structure and biocomplexity is critical for determining a species’ resilience to environmental and anthropogenic perturbations. However, integrated population models (IPMs) used to develop management advice for harvested populations have been slow to incorporate spatial dynamics. Therefore, limited research has been devoted to understanding the reliability of movement parameter estimation in spatial population models, especially for spatially dynamic marine fish populations. We implemented a spatial simulation–estimation framework that emulated a generic marine fish metapopulation to explore the impact of ontogenetic movement and climate‐induced distributional shifts between two populations. The robustness of spatially stratified IPMs was explored across a range of movement parametrizations, including ignoring connectivity or estimating movement with various levels of complexity. Ignoring connectivity was detrimental to accurate estimation of population‐specific biomass, while implementing spatial IPMs with intermediate levels of complexity (e.g. estimating movement in two‐year and two‐age blocks) performed best when no a priori information about underlying movement was available. One‐way distributional shifts mimicking climate‐induced poleward migrations presented the greatest estimation difficulties, but the incorporation of auxiliary information on connectivity (e.g. tag‐recapture data) reduced bias. The continued development of spatially stratified modelling approaches should allow harvested resources to be better utilized without increased risk. Additionally, expanded collection and incorporation of unique spatially explicit data will enhance the robustness of IPMs in the future.     

At sea movement of Macquarie Island giant petrels: Relationships with marine protected areas and Regional Fisheries Management Organisations

Satellite tracking devices were used to examine the at sea movements of southern and northern giant petrels from Macquarie Island during the Austral summers of 2005-06 and 2006-07. Time spent at sea for nine northern giant petrels (four breeding adults, five recently fledged juveniles) and 10 southern giant petrels (three breeding adults, one non-breeding adult, and six recently fledged juveniles) was examined in relation to marine protected areas and fishing activity in the area immediately adjacent to Macquarie Island in 2005-06, and in terms of the jurisdictions of Regional Fisheries Management Authorities (RFMOs) at a broader scale during both seasons. Breeding adult southern and northern giant petrels spent a large proportion of their time at sea in the Macquarie Island Marine Park (25% and 65%, respectively), primarily during chick rearing. Further from Macquarie Island, the most important foraging areas for adult giant petrels were the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) statistical sub-areas 58.4.1 and 88.1, where foraging activity was concentrated around the ice edge and the Polar Frontal Zone. Fledglings of both species spent time in the Marine Park immediately after fledging, before moving into international waters. We found significant temporal and spatial overlap in the areas used by recently fledged juvenile northern giant petrels and the areas utilised by the single trawler that operated in these waters during 2005-06. Adult giant petrels spent little time in RFMO waters other than those under the jurisdiction of CCAMLR, but fledgling southern and northern giant petrels spent considerable time (56% and 78% of total time at sea) on the high seas of the Pacific Ocean, in areas under the jurisdictions of the Commission for the Conservation of Southern Bluefin Tuna (CCSBT), the Western and Central Pacific Fisheries Commission (WCPFC), the Inter American Tropical Tuna Commission (IATTC) and the South Pacific Regional Fisheries Management Organisation (SPRFMO). Band returns indicate that the International Commission for the Conservation of Atlantic Tunas (ICCAT) and the South East Atlantic Fisheries Organisation (SEAFO) areas are likely to be extensively utilised by Macquarie Island giant petrels in the first three years after fledging. Overall, Macquarie Island’s giant petrel populations are well protected by marine reserves during the breeding season. However, after fledging birds move into RFMO areas that currently have low standards of observer coverage and by catch mitigation, and where fisheries related mortality is likely to pose a significant risk.     

基于自主导航和全方位转向的农用机器人设计

为了提高农业作业的自动化程度,在对传感器技术、信息技术、自动导航技术等进行研究的基础上,设计了一种自动导航农用轮式移动机器人.针对目前农业机器人存在的操纵、路径跟踪等技术问题,机器人采用四轮全方位转向,操纵灵活;利用CAN总线使导航、控制等模块的通讯效率得以改善;选用模糊控制模仿人在路径跟踪控制时的控制策略,提高了移动机器人的智能化程度.仿真和试验表明机器人有较好的转向性能且在速度为1 m/s时跟踪路径的偏差为0.1 m左右.     

基于摆线运动的黄瓜采摘机器人终端滑模轨迹跟踪控制

黄瓜采摘机器人是机器人技术在农业中的具体应用,而快速稳定地到达目标采摘点的轨迹规划则是黄瓜采摘机器人研究的主要内容之一。根据摆线运动曲线光滑,并能在有限区间的端点产生零速度和零加速度的特点,将其应用于黄瓜采摘机器人关节空间的轨迹规划,该方法计算简单,实时性好。同时,为了实现对期望轨迹的精确跟踪,构造了一种快速非奇异的终端滑模控制器,采用指数和幂次结合的趋近率方法,引入非线性滑模面,突破了普通滑模控制器在线性滑模条件下渐进收敛的特点,并且不会出现传统终端滑模控制的奇异性和抖振问题。李亚普诺夫稳定性分析和仿真试验证明：它能够准确的跟踪期望轨迹,并能使位置跟踪误差在有限时间内收敛到零,响应时间短,跟踪效果好。