The assembly process is one of the most important spots in the process of product production. A reasonable assembly sequence can not only reduce the assembly workload but also reduce the manufacturing cost of products. Therefore, this paper proposes a product assembly sequence planning method based on the semantic process. First of all, a research framework of product assembly sequence planning based on semantic process knowledge was constructed by analyzing the requirement of product assembly sequence planning for assembly process semantic knowledge. Secondly, an assembly semantic process knowledge information model was proposed. Based on this, assembly sequence planning ontology and SWRL (Semantic Web Rule Language) assembly semantic rules were constructed in Protege software. Thirdly, an iterative modification method for inferring the sequence of an atypical sub-assembly group was designed. Finally, taking the assembly sequence planning process of the drive axle of construction machinery as an example, the construction method of the assembly semantic process knowledge information model and the assembly sequence planning decision technology in this thesis were applied to verify the reliability of the information model.

烛式油气悬架兼有主销的作用,所以通常具有2°～5°的安装内倾角,内倾角会造成油气缸承受横向力的作用,从而增大缸筒和活塞之间的摩擦力.摩擦力增大会影响油气缸的减振性和车辆乘坐舒适性,严重时会造成油气缸"摩擦锁死"现象,使油气缸失去减振能力.以某矿用自卸车的烛式油气悬架为研究对象,通过理论分析了缸筒和活塞之间摩擦力的影响因素,得出了延长活塞导向长度可以减小缸筒和活塞之间摩擦力的结论.通过装载试验和矿区路面行驶试验对比了导向长度分别为0.10,0.15,0.20 m时,油气缸的减振能力和车辆乘坐舒适性.结果 表明:其他参数不变,当活塞导向长度由0.10m增加至0.20 m时,油气缸的振动传递率由0.65变为0.47,油气缸的减振能力提高了27.7％;整车的总加权加速度均方根值从1.06 m/s2下降到0.72 m/s2,车辆乘坐舒适性明显提高.

A mine dump truck is exposed to heavy load and harsh working environment. When the truck passes over the road bumps, it will cause the body to tilt and the tires to "jump off the ground" (JOTG), which will affect the stability and safety of the truck, and will cause impact damage to the body and suspension system. To avoid this situation, a kind of Novel Single-side Coupling Hydro-pneumatic Suspension (NSCHs) is presented. NSCHs consists of two cylinders in parallel, which are connected to the accumulator by rubber pipes and mounted on the same side of the dump truck. Theoretical analysis and experimental research were respectively carried out under the road and loading experimental condition. The experimental results show that compared to the conventional single cylinder hydro-pneumatic suspension, under the loading experiment condition, the maximum overshoot pressure of the NSCHs was reduced by 0.4 MPa and the impact oscillation time was shortened by 4.13 s, which plays the effective role in reducing vibration and absorbing energy. Further, it is found that the two cylinders are coupled during the working process, and the NSCHs system can achieve uniform loading and displacement compensation, thus the novel dump truck can avoid the occurrence of the JOTG phenomenon.

为提高薄壁框体结构件铣削加工精度及加工效率,提出一种薄壁框体结构件铣削加工工艺参数优化方法.针对标准粒子群算法存在易陷入局部最优解,且不能自适应调整权重系数等问题,将混沌算法与多目标粒子群算法结合,建立了以铣削力和单位时间材料去除率为优化目标,以铣削4因素为优化变量,以机床主轴转速、进给量、铣削深度和表面粗糙度为约束条件的多目标约束优化模型.利用有限元仿真准确计算每个优化解的加工误差,将结果及时反馈到优化算法中,进而找到最优加工工艺参数组合.以典型薄壁结构侧壁铣削为例,分别采用试验参数、标准粒子群优化参数和本文所提算法优化结果进行仿真模拟,对仿真结果进行分析比较,证明了该方法的有效性.

为提高机械原理课程的教学质量,本文分析了在教学过程中存在的教与学的问题,针对机械原理课程理论和实践教学内容非常多且抽象的特点,本文提出将源于思维导图的知识点脉络图融入机械原理教学模式中,运用思维导图来梳理课程中的知识和概念,构建知识点脉络图,借助"互联网+"技术来实现基于思维导图的机械原理课件的底层软件架构,形成思维可视化的机械原理课程教学模式,探索机械原理知识深入认知的底层思维与教学方法.