高齿准双曲面齿轮的设计方法与试验研究

通过增加工作齿高和对根切条件的深入研究，提出了高齿准双曲面齿轮的优化设计方法。这种方法可以有效地增大端面重合度，并保证所设计的齿轮不根切、齿顶不变尖，可在现有机床上使用标准系列刀具加工。台架试验表明，这种高齿准双曲面齿轮的噪声和振动量比普通准双曲面齿轮明显降低。     

EGR率对柴油机排放特性影响的试验

研究了增压直喷柴油机在不同工况下不同EGR率对性能和排放的影响规律,确定了各个工况下EGR率的优化原则,并获取了柴油机最佳EGR率的M AP图,设计出一套EGR电子控制系统,可以对EGR系统中的进气节流阀和EGR阀进行控制,确保不同工况的最佳EGR率。发动机台架试验证实,设计的EGR电控系统按所获取的最佳EGR率运行,可以使NOx排放量降低19.9%,CO和HC排放量略有增加,动力性和经济性与原机相当,对EGR回路冷却可以抑制柴油机因使用EGR技术而导致的PM排放的增加。     

汽蒸荞麦干燥参数对单位耗热量影响的试验

通过单因素试验以及二次正交旋转组合试验，研究了温度、风速、厚度对单位耗热量的影响。建立了各因素与单位耗热量的回归数学模型。利用非线性优化理论与方法得到了汽蒸荞麦干燥的最优工艺参数为温度105℃、风速3．3m／s、厚度52mm。     

基于混合遗传算法的谐波齿轮传动优化设计

以谐波齿轮传动体积最小为优化设计目标,建立了混合离散变量优化设计数学模型。引入混沌移民算子,对基本遗传算法进行了改进,以维持群体的多样性,提高全局收敛能力。提出了一种设计变量的离散化处理方法,结合染色体编码的修正技术,在遗传算法中染色体按离散化后的设计变量进行离散搜索。开发了混合离散变量优化的改进遗传算法程序,给出了谐波齿轮传动的混合离散变量优化设计实例,所得优化设计参数符合设计规范,不需进一步处理就可直接用于制造。     

Determining crop-water production functions using yield–irrigation gradient algorithms

Crop-water production functions (CWPFs) are a useful tool for irrigation planning, but derivation of CWPFs by field experimentation is expensive, and traditional analytical techniques are not well suited to derivation of CWPFs. Physiologically based crop models provide a useful tool for simulation of agricultural experiments, but they have not been extensively applied to the task of CWPF determination. A new algorithm type based upon differential crop yield response to irrigation (“yield–irrigation gradients” [YIG]) is presented that uses these crop models to determine planning-level irrigation schedules and CWPFs. Three specific algorithms are developed within this type, varying in complexity, performance, and computational costs. Performance of the YIG methods is compared against a standard reference evapotranspiration method. In particular, the randomized iterative YIG (RIYIG) algorithm provides near-optimal results but at the highest computational costs of all the methods specified. All of the techniques presented have general applicability and are not limited to any one crop or location.     

一般6R机器人的高精度逆运动学优化算法

为提高一般6R机器人逆运动学算法的精度和效率,提出一种基于符号运算和矩阵分解的优化算法。对6个基础逆运动学方程作变换,采用符号运算预处理得到14个逆运动学方程,避免大量浮点数计算累积误差。利用其中6个方程与关节变量3无关的特点,将目标矩阵从24阶降低到16阶,包含的关节变量从3个增加到4个。把一元16次方程求根问题转换为矩阵特征分解问题,并选取较高数量级的相关数据元素计算关节变量,进一步提高了算法精度。以一般6R机器人为例,求解结果表明,提出的算法能够得到具有任意期望精度的最多16组实数逆运动学解。     

Optimizing competitive uses of water for irrigation and fisheries

Choosing the appropriate reservoir water management strategy can be difficult when the water has multiple uses. This study examines this problem for reservoir managers where water use involves irrigation and fisheries. A stochastic dynamic programming (SDP) model is developed to facilitate reservoir management, using a case study illustration for southern Vietnam. The model includes the response of rice and fish yields to key factors including reservoir water levels, the timing and quantity of water release, and climatic conditions. The model also accounts for variation in rainfall patterns, irrigation requirements, and the demand for low water levels during the fish harvest season. Three production scenarios are examined where the reservoir's water is used for: only producing rice (scenario 1), only producing fish (scenario 2), and producing rice and fish (scenario 3). Key findings are: (1) for scenario 1, adequate water should be released to meet rice growing water requirements and residual water should be stored as a source of water in case of low rainfall, (2) for scenario 2, sufficient water needs to be released prior to the fish harvest to maximize this harvest; and (3) for scenario 3, water should be released prior to fish harvest, but sufficient water should remain to satisfy the water requirements of rice. When the reservoir is managed for joint production of rice and fish, net benefits are 6% greater than when the reservoir is managed solely for rice production. The SDP model developed in this paper could be adapted and applied to other multiple-use resources such as forests, river basins, and land.     

内插管式消声器结构优化与试验研究

在大量试验的基础上，研究了二级扩张室式消声器中穿孔管结构的变化对消声器消声效果的影响，并优选出最佳结构的消声器，该消声器消声量大且功率损失小，能满足对内燃机日益严格的噪声要求。     

纯电动汽车传动系参数的区间优化方法

在分析纯电动汽车传动系减速比传统优化模型的基础上,提出了区间优化方法。优化的目的是在满足电动汽车基本动力性能的前提下,求优化变量的最大可行区间,而不是一个确定的最优值。区间优化方法便于产品的系列化,可以解决传动系齿轮配齿问题。以XL2000型纯电动汽车传动系参数的优化设计为例,对所建模型进行了验证。     

基于有限元的连杆优化设计

首先对连杆进行有限元分析,确定了连杆的应力集中点和最大变形量,然后对连杆的应力点及其相关尺寸参数进行灵敏度分析,找出对其影响最大的尺寸参数。利用优化设计和有限元计算相结合的技术,以连杆质量最小作为目标函数对连杆进行优化设计。