基于摄影测量的飞机阻力伞运动参数测量技术

针对某型阻力伞性能鉴定试飞科目要求，需要精确测量阻力伞在稳定工作时的垂直、水平摆角，从而为该产品的技术鉴定提供依据。本文根据加装在飞机机背中段的高速摄像机，获取阻力伞的运动影像，通过图像分析处理识别特征点的亚象素坐标，采用摄影测量的解算算法，推导出数学解算模型，实现了阻力伞运动参数的最优解算。结合真实飞行试验对测量结果进行了分析，数据结论准确。     

Prediction and identification of rotary axes error of non-orthogonal five-axis machine tool

This paper proposes an efficient and automated scheme to predict and identify the position and motion errors of rotary axes on a non-orthogonal five-axis machining centre using the double ball bar (DBB) system. Based on the Denavit-Hartenberg theory, a motion deviations model for the tilting rotary axis B and rotary C of a non-orthogonal five-axis NC machine tool is established, which considers tilting rotary axis B and rotary C static deviations and dynamic deviations that total 24. After analysing the mathematical expression of the motion deviations model, the QC20 double ball bar (DBB) from the Renishaw Company is used to measure and identify the motion errors of rotary axes B and C, and a measurement scheme is designed. With the measured results, the 24 geometric deviations of rotary axes B and C can be identified intuitively and efficiently. This method provides a reference for the error identification of the non-orthogonal five-axis NC machine tool.     

Design and construction of a two-dimensional hydrodynamic tunnel to study the free motions of solids in a uniform flow

Autonomous Underwater Vehicles (AUVs) are increasingly important tools for marine applications. A reasonably reliable prediction of their six degrees of freedom (6DOF) motions is essential. The manoeuvrability of these unmanned submarines relies on the capability to predict the hydrodynamic forces on a freely moving submerged body. Numerical simulators integrating the full physics of the problem have been developed but their validation remains the key issue. Three-dimensional calculations still take too much computing power to complete the very large number of simulations which is required for a full validation procedure. Furthermore, a very large pool with expensive measuring devices is also necessary to obtain experimental results. It was therefore decided to construct a 2D hydrodynamic tunnel in which an object can move with three degrees of freedom solely subjected to gravity and hydrodynamic forces. In the present paper, we describe the experimental device ensuring a simple and rapid implementation of trials: a 2D channel with a constant uniform flow. A general validation is considered with an ellipse. The experimental trajectories are compared with the corresponding analytical results and discussed at the end of the paper.     

淮安区殡仪馆规划设计中人文意境建构

殡仪馆建筑是一种特殊类型的公共建筑，是人类文明的重要标志，具有丰富的精神文化内涵。文章以江苏省淮安区新殡仪馆建筑环境设计创作实践为例，阐述在现代殡仪馆建筑设计中，应以地域文化为前提，进行合理的流线、空间布局、建筑造型等设计，创造出具有人文意境的精神场所；并总结人文意境建构的几个原则，为建筑师创作时提供借鉴。     

A step-by-step performance assessment and improvement method for ERP implementation: Action case studies in Chinese companies

The implementation of enterprise resource planning (ERP) is a complex process, and the failure rate remains very high. The literature has reported over 80 critical success factors for ERP implementation, but companies typically do not know to exploit them. In this article, a step-by-step assessment and improvement method for ERP implementation is proposed and applied in three companies. First, a five-stage ERP implementation model is proposed. Second, about 80 critical success factors (CSFs) from the literature are elaborated into key performance indices (KPIs), which are associated with each stage of ERP implementation by ten local ERP experts. Third, the weights of the KPIs are calculated using the Dumpster–Shafer method and the evaluation of ten experts. During the implementation process, performance is measured at each stage and remedial actions are identified if the performance is below expectation. An implementation flowchart is developed based on a five-stage model and the philosophy of continuous improvement. Three action cases in Chinese manufacturing companies are conducted to illustrate the effects of the assessment model, which is also currently being used by a consulting company specialising in ERP implementation. With further evaluation by local experts, the model has the potential to serve as a guideline for ERP implementation in other countries.     

A web-based software tool for participatory optimization of conservation practices in watersheds

WRESTORE (Watershed Restoration Using Spatio-Temporal Optimization of Resources) is a web-based, participatory planning tool that can be used to engage with watershed stakeholder communities, and involve them in using science-based, human-guided, interactive simulation–optimization methods for designing potential conservation practices on their landscape. The underlying optimization algorithms, process simulation models, and interfaces allow users to not only spatially optimize the locations and types of new conservation practices based on quantifiable goals estimated by the dynamic simulation models, but also to include their personal subjective and/or unquantifiable criteria in the location and design of these practices. In this paper, we describe the software, interfaces, and architecture of WRESTORE, provide scenarios for implementing the WRESTORE tool in a watershed community's planning process, and discuss considerations for future developments.     

设施园艺在观光农业园规划设计的应用

设施园艺可以让农业生产者通过一定的技术手段,提高农业生产效益,改变农作物的生长周期。文章在农业观光园的设计中可以利用这种技术方法来突出园区的农业特色,吸引非农业人口前来旅游观光和消费。     

压电精密驱动柔性微夹钳设计

为了实现对微纳尺度下物件的精密夹持,建立了柔性微夹钳系统。并对该系统柔性夹钳设计、运动学、动力学和控制方法等进行研究。首先,利用柔性铰链设计方法设计了柔性微夹钳,利用伪刚体法建立了机械的伪刚体模型。接着,以伪刚体模型法建立了系统的运动学模型,即机械放大比和输入刚度等数学模型。然后,利用拉格朗日方法建立了系统的动力学方程,得出系统的自然振动频率。最后,通过ANSYS有限元方法对系统建立的模型进行了仿真分析和验证,此外,利用PID控制算法对微夹钳系统进行实验控制。实验结果表明:跟踪控制结果误差为2.4%;放大比为9.12倍。基本满足微纳尺度下的微夹持工作,其工作精度可达微米级别甚至纳米级别,符合设计要求。     

Design,analysis, and neural control of a bionic parallel mechanism

Frontiers of Mechanical Engineering - Although the torso plays an important role in the movement coordination and versatile locomotion of mammals, the structural design and neuromechanical control...     

Generation expansion planning in electricity markets: A novel framework based on dynamic stochastic MPEC

This paper presents a novel framework for generation expansion planning (GEP) of restructured power systems under uncertainty in a multi-period horizon, which includes generation investment from a price maker perspective. The investment problem is modeled as a bi-level optimization problem. The first level problem includes decisions related to investment in order to maximize total profit in the planning horizon. The second level problem consists of maximizing social welfare where the power market is cleared. Rival uncertainties on offering and investment are modeled using sets of scenarios. The bi-level optimization problem is then converted to a dynamic stochastic MPEC and represented as a mixed integer linear program (MILP) after linearization. The proposed framework is examined on a typical six-bus power network, MAZANDARAN regional electric company (MREC) transmission network as an area of IRAN interconnected power system and IEEE RTS 24-bus network. Simulation results confirm that the proposed framework can be a useful tool for analyzing the behavior of investments in electricity markets.