High accuracy path tracking for vehicles in presence of sliding: Application to farm vehicle automatic guidance for agricultural tasks

When designing an accurate automated guidance system for vehicles, a major problem is sliding and pseudo-sliding effects. This is especially the case in agricultural applications, where five-centimetre accuracy with respect to the desired trajectory is required, although the vehicles are moving on slippery ground. It has been established that RTK GPS was a very suitable sensor to achieve automated guidance with such high precision: several control laws have been designed for vehicles equipped with this sensor, and provide the expected guidance accuracy as long as the vehicles do not slide. In previous work, further control developments have been proposed to take sliding into account: guidance accuracy in slippery environments has been shown to be preserved, except transiently at the beginning/end of curves. In this paper, the design of this control law is first recalled and discussed. A Model Predictive Control method is then applied in order to preserve accuracy of guidance even during these curvature transitions. Finally, the overall control scheme is implemented, and improvements with respect to previous guidance laws are demonstrated through full-scale experiments.     

公路桥涵台背设计的理论方法探讨

介绍了近年来国内外研究人员对桥涵台背的设计研究方法，结合桥涵与台背结构组合的设计原则，从搭板的型式、坡度、长度、厚度、配筋等方面提出了搭板设计的方法。     

套管液压式φ106mm密封加固系统研究

针对套管液压式φ100mm密封加固系统在实际应用中的缺点,开展了大通径密封加固技术专题研究.研制的套管液压式φ106mm密封加固器承压达30 MPa以上,悬挂力达到500kN以上,可下入φ100mm小直径分层管柱.现场应用见到了明显的效果,为提高小直径分采分注管柱寿命创造了条件.     

在役油气管道安全评定软件

PSAforWindows是运行在Windows系统下的油气管道安全评定软件。该软件既可以用于在开挖中发现的管道局部缺陷的剩余强度的精确评定 ,又可以用于腐蚀检测之后对管道全线的安全评定与剩余寿命预测。软件中采用了非线性有限元分析、失效评定图和概率性的评定方法等最新成果。介绍该软件的结构、模块、软件特点、主要功能和操作界面     

马鞍山煤矿瓦斯地质理论在防突工作中的应用

总结了实际工作中防突管理的经验和问题 ,探讨了科学理论与具体实际的有机结合与统一 ,采取针对性强的有效措施 ,确保突出矿井的安全生产     

跨世纪的测井找油找气高技术

人类社会即将跨入21世纪,各行各业都在预测未来技术的发展,测井行业也不例外。预测成象测井技术将是跨世纪的测井找油找气高技术。     

精镗孔尺寸误差预测补偿技术的研究概况与趋势

提出了精镗孔尺寸误差预测补偿技术存在的主要问题，指出了今后所需研究的主要内容及关键技术。     

加强电炉钢短流程生产工艺研究与技术开发的建议

论述了加强电炉钢短流程生产工艺研究与技术开发的必要性和主要课题，并提出关于组织合金钢短流程生产工艺研究与技术开发“九五”国家科技攻关及提高高研究开发投资强度的建议。     

An application of expert systems techniques to the on-line control and fault diagnosis of a mixing process

An application of expert hierarchical control is described in this paper. The control is implemented in a two-level configuration, where the lower layer performs direct regulation control and the upper layer performs supervisory functions. In the regulation layer, a rule-based controller performs the regulation task, where the controller is constructed upon causal relations between subsystems. The control action is inferred from the measurement of both controlled and noncontrolled variables. In the supervisory layer, the main function is a fault diagnosis system which diagnoses faults on-line. The diagnosis is based upon reasoning from the structure of the system and the functions of its components, and efficient diagnosis is achieved by dividing the system into several subsystems. The overall technique has been successfully implemented on a pilot scale mixing process under on-line computer control.