Development of a teleoperation system for agricultural vehicles

A teleoperation system for a hydro-static transmission (HST) drive crawler-type robotic vehicle is described in this paper. The system was developed to satisfy the needs of various farm operations and teleoperation in unknown agricultural fields. The controller has a layered architecture and supports two degrees of cooperation between the operator and robot, direct and supervisory control. The vehicle can travel autonomously by using an RTK-GPS and a fiber-optic gyroscope during supervisory control, and the operator interface also provides a field navigator based on Google Map technology. The vehicle's position and heading direction was capable of 1 Hz update using precise satellite image maps. The results of field tests using direct control showed that it is difficult for the operator to control the movement of the vehicle along the target lines. On the other hand, the vehicle could travel in a straight line with a maximum lateral error of 0.3 m by using supervisory control.     

Development of a low-cost attitude sensor for agricultural vehicles

The objective of this research was to develop a low-cost attitude sensor for agricultural vehicles. The attitude sensor was composed of three vibratory gyroscopes and two inclinometers. A sensor fusion algorithm was developed to estimate tilt angles (roll and pitch) by least-squares method. In the algorithm, the drift error of the gyroscopes was estimated using the inclinometers. In addition to tilt angles, the attitude sensor also estimated the absolute heading angle and position with inclination error correction by integrating a GPS. Tests were conducted on a flat field, a sloping ground and a bumpy road. Results showed that the attitude sensor was able to estimate the roll angle with the maximum root mean square error of 0.43°, the pitch angle with 0.61° and the heading angle with 0.64°. Moreover, the attitude sensor dramatically improved the positioning accuracy from 25.9 cm to 3.0 cm in the sloping ground test and from 8.4 cm to 3.7 cm in the bumpy road test. The proposed technology used in the attitude sensor will help to develop advanced agricultural applications.     

A two-stage optimal motion planner for autonomous agricultural vehicles

This paper presents a two-stage motion planning algorithm which can compute low-cost motions for autonomous agricultural vehicles, for a given cost function defined over the entire path (e.g., shortest path, maximum clearance, etc.). In the first stage, the algorithm utilizes randomized motion planning to explore the space of possible motions and computes a feasible sub-optimal trajectory. In the second stage, the optimization of the stage-1 motion is formulated within the optimal control framework and function-space gradient descent is used to minimize the cost of the entire motion. The numerical results suggest that the two-stage motion planner can compute optimal or quasi-optimal motions in free space very quickly. In the presence of obstacles however, the execution time increases significantly. Furthermore, kino-dynamic, or dynamic motion models seem to be necessary in order to produce smooth motion trajectories.     

Optimal vision-based guidance row locating for autonomous agricultural machines

Precision Agriculture - With the rapid advances in precision agriculture technology, machine vision is emerging as a means to obtain accurate spatial information for a control system at relatively...     

农科大学生心理挫折的矫正与防治

综合分析了农科大学生心理挫折的表现及成因 ,并据此提出防治与矫正农科大学生心理挫折的方法与对策 ,对广大同学树立正确的挫折认知 ,适应激烈的社会竞争 ,建立正确的人生态度具有重要意义     

超声波辅助渗透脱水预处理的农产品干制研究进展

超声波能够有效提高农产品渗透脱水效率。综述了渗透脱水的主要影响因素及其传质动力学研究,并阐述超声波辅助渗透脱水的原理、影响超声波辅助渗透脱水的因素和近年来关于超声波辅助农产品渗透脱水的研究现状,以期为超声波辅助农产品渗透脱水研究提供参考。     

基于最小二乘支持向量机的车用铂电阻温度传感器非线性校正

依据铂电阻温度传感器样本,提出了一种采用最小二乘支持向量机辨识传感器逆模特征的校正铂电阻温度传感器非线性误差的原理和方法.该方法不需逆模型函数形式的先验知识,能够保证找到的极值解就是局最优解,具有较好的泛化能力.实例应用表明,其检测精度可达到0.1 ℃,铂电阻温度传感器非线性校正效果好.     

农业机械化专家系统的研究现状与问题

文章在介绍专家系统的基本概念和结构的基础上,较全面地论述了专家系统在农业机械化方面的国内外研究与应用现状,并指出了农业机械化专家系统研究和应用方面存在的问题,为农业机械化专家系统的进一步研究与应用提供参考。     

宿州市农业技术推广体系的调查与思考

当前,我国农业技术推广体系和推广方法,都是在计划经济体制下形成的,如何在社会主义市场经济体制下开展工作,是摆在各级农业部门面前的新课题。本文从分析农业技术推广所存在问题的原因着手,提出了农业推广改革的设想。     

Machine-to-machine communication for agricultural systems: An XML-based auxiliary language to enhance semantic interoperability

This paper puts forth an Internet-based architecture for machine-to-machine communication and computation that enhances bio-productivity in agriculture. The approach utilizes an auxiliary language to enable data interoperability in a synthetic computing environment and to make connections between data and mathematical models. The approach also includes some aspects of cloud and context aware computing. At the prototype level, a practical application from the Florida citrus industry demonstrates the concept. In general, future agricultural systems will be Internet-based thus reducing cost and increasing capability. Standards organizations are certain to play an important role in this development, which might continue for the next decade or longer.     

Evaluation of agronomic and economic benefits of using RTK-GPS-based auto-steer guidance systems for peanut digging operations

Increasing the peanut (Arachis hypogea L.) digger efficiency by accurate placement over the target rows could minimize damaged pods and yield losses. Producers have traditionally relied solely on tractor operator skills to harvest peanuts. However, as peanut production has shifted to new growing regions in the Southeast US, producers face difficulties digging peanuts under conventional and new management schemes. The present study aimed to: (i) determine the effect of row deviations (RD) of the digger from the target row on peanut yield and quality, and (ii) determine the economic value of using RTK auto-steer guidance systems to avoid tractor deviations during peanut harvest. The study consisted of a randomized complete block design of tillage [conventional (CT) and strip tillage (ST)], row patterns [single (SR) and twin (TWR)] and row deviation (RD_0 mm, RD_90 mm, and RD_180 mm). The RD_90 mm and RD_180 mm treatments exemplify manual driving deviations compared to using an RTK auto-steer guidance system (RD_0 mm). Higher yields and higher net returns resulted from using the RTK auto-steer guidance system. Data showed that for every 20 mm row deviation, an average of 186 kg ha^?1 yield loss can be expected. Overall, yield was higher for the conventional tillage and twin row pattern treatments compared to the other treatments. Yield losses for the SR-CT treatment were higher as the row deviation increased compared with the TWR-CT treatment. In contrast, higher yield losses for TWR-ST compared to SR-ST were observed when deviations of 180 mm occurred instead of digging using the RTK auto-steer guidance system. While a farmer using an RTK auto-steer guidance system with an accuracy within 25 mm (RD_0 mm treatment) could potentially expect additional net returns of between 94 and 404 $ ha^?1 compared to those from row deviations of 90 mm, higher net returns of between 323 and 695 $ ha^?1 could be perceived if the guidance system is used instead of having row deviations of 180 mm. Therefore, the use of RTK auto-steer guidance system will allow growers to capitalize on the increases in yield potential by implementing changes in tillage and row patterns as those evaluated in this study.     

我国低碳农业发展技术路径及支撑体系研究

从我国低碳农业发展中存在的主要问题来看,推广应用"节省"型农业技术、循环再利用技术、资源化技术以及农作制度创新技术等,能够有效降低农业生产系统中的碳排放量,是现阶段我国发展低碳农业的关键所在。文章主要从降低碳排放的视角出发,在深入探讨低碳农业科学内涵和我国低碳农业发展中存在主要问题的基础上,提出我国发展低碳农业的技术路径,并构建包含科技硬支撑及政策制度软支撑在内的低碳农业发展的支撑体系。     

农业院校现代文献信息服务体制探讨

文章以南京农业大学近几年文献信息工作的实践为基础 ,介绍了一种将网络中心、文献信息中心及电化教育中心一体化管理的新型服务模式 ,评价了这种一体化模式对现代文献信息服务的影响。     

Strategies for scaling out impacts from agricultural systems change: the case of forages and livestock production in Laos

Scaling out and up are terms increasingly being used to describe a desired expansion of beneficial impacts from agricultural research and rural development. This paper explores strategies for scaling out production and livelihood impacts from proven technologies. We draw on a case study of forages and livestock production in Laos, a Southeast Asian country undergoing rapid economic and agricultural change. A facilitated learning environment stimulated farmers to adapt forages, livestock housing, and animal health practices to their own situations (scaling out). Regular follow-up visits and on-the-job mentoring for extension staff provided institutional support (scaling up). Within 5 years, the number of villages and households using forages and fattening livestock had increased six fold, with a 50% reduction in the time required for farmers to get significant benefits. The paper concludes that scaling out positive impacts from systems change requires field tested and proven technologies, evidence of significant livelihood impacts, fostering of local innovation, competent field staff, effective peer learning, and ongoing institutional support.     

Effect of basic soil tillage systems on weediness of agricultural crops in various rotations

The effect of four basic soil tillage systems in various crop rotations on the quantity and mass of weeds as well as their group and species composition in agricultural crops has been studied in a multifactor permanent field experiment.     

A case study from the post-new deal state agricultural experiment station system: a life of mixed signals in southern Illinois

A wide literature in the sociology of agriculture has depicted the development of agricultural experiment stations at land grant colleges as part of a development project to improve agricultural productivity in particular commodities. Some experiment stations developed regional agricultural centers or stations to improve productivity and address local concerns, recognizing the importance of context in rural development. Through analysis of one such station, the Dixon Springs Agricultural Center in Southern Illinois, this paper describes how regional agricultural stations played a key role in the often conflicting agricultural programs of and following the New Deal. Changes in university structure from the 1970s to present and the current national recession have led to financial crises that have put these stations in a precarious position. Still, we argue that these institutions ought to be recognized as regional resources for a new era of agricultural development, and we suggest approaching that new era by building on the existing literature of community–university partnerships.     

农业高校信息类专业应对农业信息化发展的策略研究

分析了农业信息化发展的现状,根据农业信息化进程中出现的农业集约化程度不高、信息资源建设不足、农业信息人才缺乏、农业信息化发展不平衡等问题,提出了农业高校信息类专业在学科研究方向、信息资源建设、研究生和本科人才培养等方面的策略。     

略论我国农业开放存取期刊发展策略

通过分析国内外农业OA期刊发展现状,指出我国农业科技期刊存在出版与传播手段不适合开放存取环境的需要,网络化服务程度不高、难以适应OA期刊发展的要求,农业科技期刊影响力不高、边缘化迹象明显等问题。提出由学会牵头制订策略和技术方案、争取国家政策和财政支持,构建农业OA期刊国家平台和地方网站,采用OA期刊模式、创新经营运作方式,加大OA期刊宣传力度等发展策略。