三平动并联机构动力学建模与工作空间分析

目的 以可以实现空间三维平动的3-UPU并联机构为研究对象, 对其进行运动学建模、 动力学建模以及工作空间和动力学仿真。方法 通过几何法建立机构的运动学模型, 同时使用拉格朗日方法建立3-UPU并联机构的动力学模型, 最后采用优化后的极限边界搜索法, 建立并分析并联机器人的工作空间, 求解工作空间的面积。在工作空间和速度与加速度的约束下, 采用五次样条曲线进行轨迹规划, 利用Matlab进行逆运动学与逆动力学建模与仿真。结果 通过对动力学建模仿真与工作空间的分析可知,该机构有较大和对称的工作空间, 同时拥有相对简单的动力学方程和较好的动力学性能。结论 3-UPU并联机构在工业自动化柔性包装、 搬运与加工装配中, 有广泛的应用前景。     

基于牛顿-欧拉递推法的3-RRRT并联机器人动力学建模及仿真

研究一种3-RRRT新型高速并联机器人的运动学及动力学建模及分析方法.采用D-H法建立了各构件体坐标系,以此为基础,建立了3-RRRT并联机器人运动学模型,并给出了其位置解析解;基于牛顿欧拉递推动力学方法进行了系统动力学模型构建,并利用MATLAB进行运动学和动力学数值仿真,得出了系统实现既定轨迹跟踪所需的驱动力矩,并对结果进行了分析.该建模方法的优点是计算量小,并可求得杆件的受力情况,便于实时控制,可为3-RRRT并联机器人的研究提供分析数据,进而为改进其控制策略提供参考和依据.     

六自由度空间柔性机械臂的动力学分析与仿真

突破了仅对两自由度平面柔性机械臂进行研究的传统,而对多自由度空间柔性机械臂进行动力分析.用假设模态法表示臂杆柔性,并将变形量融入D-H坐标系,通过对机械臂末端的轨迹规划得到刚性运动学的逆解.运用Kane方法对多自由度的空间柔性机械臂进行动力学建模,推导出完整的系统动力学方程,采用较高精度的四阶龙格一库塔法对动力方程进行积分求解.给定一个六自由度柔性机械臂模型,并对其进行数值仿真,验证了臂杆柔性时机械臂的动力响应产生的重要影响.     

六自由度空间柔性机械臂的动力学分析与仿真

突破了仅对两自由度平面柔性机械臂进行研究的传统,而对多自由度空间柔性机械臂进行动力分析。用假设模态法表示臂杆柔性,并将变形量融入D-H坐标系,通过对机械臂末端的轨迹规划得到刚性运动学的逆解。运用Kane方法对多自由度的空间柔性机械臂进行动力学建模,推导出完整的系统动力学方程,采用较高精度的四阶龙格-库塔法对动力方程进行积分求解。给定一个六自由度柔性机械臂模型,并对其进行数值仿真,验证了臂杆柔性对机械臂的动力响应产生的重要影响。     

基于P-Rob六自由度机械臂运动学建模与仿真

目的为实现后续机械臂控制算法研究,检验机械臂运动学模型构建的正确性,基于PersonalRobotics,对六自由度机械臂进行运动学模型构建和轨迹仿真。方法通过标准D-H法建立运动学模型,实现机械臂的正、逆运动学方程求解,根据机械臂的结构特性,对传统逆向运动学求解的解析法进行改进。结果使用仿真软件Matlab验证了运动学模型建立的准确性,改进的逆向运动学求解算法降低了传统求解算法的复杂度。使用仿真软件Matlab验证了运动学模型建立的准确性,并通过Matlab对改进的逆行运动学求解方法进行了验证,结果表明,改进的逆向运动学求解速度是传统逆向运动学求解速度的一半。结论根据六自由度机械臂的运动学研究,对实际机械臂的运动控制具有一定的参考价值。在实际的P-Rob机械臂上进行了仿真数据的测试,再次验证了运动学模型建立的准确性,仿真数据可应用于实际的机械臂控制中。实验现象表明针对此机械结构的机械臂,使用改进解析法求解逆解的方法计算简单、误差小、可行性强。     

混凝土湿喷机臂架系统的动力学建模与分析

 针对混凝土湿喷机臂架系统的液压油缸驱动力难以显式计算的问题,采用解析几何法和拉格朗日方程建立混凝土湿喷机臂架系统的动力学模型．将驱动油缸等效为活塞杆沿着套筒运动的二连杆机构,这样臂架成为不完全开链的十连杆机构．采用解析几何法,推导臂架杆件转角与液压油缸行程的函数关系,即臂架系统的运动学方程．在运动学基础上根据拉格朗日动力学方程,建立广义力（液压油缸驱动力）对广义坐标（油缸行程）的数学模型．仿真分析时选择了湿喷机的一个典型工作过程,利用符号运算工具MAPLE求解广义力的解析式,并导入MATLAB进行数值求解．同时,利用PRO/E的机构动力学仿真工具对臂架进行分析．对比可见MATLAB与PRO/E仿真结果相吻合,验证了混凝土湿喷机臂架系统动力学模型的正确性．最后,结合动力学模型分析驱动油缸铰点位置变化对油缸工作过程中最大驱动力的影响,结果表明原湿喷机臂架系统结构有待进一步优化．因此,该动力学模型为油缸选型和油缸受力优化提供了理论依据．     

非线性干摩擦阻尼结构叶片系统动力学研究现状

综述了非线性干摩擦阻尼结构叶片系统的动力学研究现状.引述国内外大量文献,对非线性干摩擦阻尼结构叶片系统动力学研究中的5个主要问题进行了讨论,它们是干摩擦阻尼结构叶片非线性动力学方程的求解方法、界面摩擦模型简化、接触运动学模型、叶片主结构模型的简化、摩擦约束叶片系统的非线性动力学行为.阐述了常用的各种模型及求解方法的优缺点,最后并提出了该领域值得进一步研究的几个关键问题.     

三自由度并联分拣机器人的动力学建模与仿真

目的 针对自动化生产线上分拣机器人的动力可控性问题,提出一种2UU-UPU三自由度并联分拣机器人,以提高分拣的精度可控性。方法 分析该机器人的机构自由度,以及各参数之间的关系,基于闭环矢量法建立并联机构的运动学逆解模型;利用拉格朗日动力学方程推导该机器人的动力学表达式,并进行数值计算,采用Matlab Simulink和Adams进行动力学联合仿真,对理论值和仿真值进行误差分析。结果 揭示了该机器人动平台的运动规律,得到了驱动力矩曲线,理论值与仿真值的误差较小,3个驱动力矩的最大误差分别为0.379%、0.283%、0.146%。结论 通过验证可知,该机构具有较好的动力学特性,这为后续电机的选型和精准控制奠定了基础。     

基于多体动力学的轮式悬架移动刚-柔并联机械手动力学性能研究

考虑到移动串联机械手不能很好地满足高速、大负载工况下准确作业的要求,提出了轮式悬架柔性移动并联机械手这一新的构型,并对其进行了动力学性能研究.基于多柔性体动力学,在笛卡尔坐标下构建了系统动力学模型,建模方法具有通用性与完备性.在此基础上,分别针对串联、并联、刚性、柔性四类移动机械手的动力学模型进行了数值仿真,并对仿真结果进行了比较、分析,验证了建模方法的正确性并佐证了新构型移动机械手的动力学性能特点,提出了提高柔性并联机械手的工作速度、刚度和工作精度的技术方法,为后续控制算法的构建提供了理论基础.     

兵力需求系统动力学模型研究

针对兵力需求的动态不确定问题，定性分析兵力需求的影响因素及其相互关系，运用Vensim软件构建兵力需求系统动力学模型，定量研究兵力需求相关变量间因果关系及需求变化的动态规律，并进行数值仿真．结果表明，系统动力学用于兵力需求的研究，有效地解决了系统某些参数关系难以量化、数据不足等问题．     

Dynamic analysis of 6-SPS parallel mechanism

This paper presents the kinematics and inverse dynamic analysis of a 6-SPS parallel mechanism based on the principle of Kane. The parameters of orientation and Euler angles of the moving platform are adopted as generalized coordinate. The gravity and inertial forces of all links and moving platform are considered in the mathematical model of inverse dynamics. Both kinematics and inverse dynamics equations are derived. Driving forces–time relation is derived form inverse dynamics model. The approach is verified by simulation results, which are consistent with the planned trajectory and kinematics parameters.     

新型组合式Sepic逆变器双闭环控制研究

针对适用于太阳能并网发电系统的光伏并网逆变器,提出了一种电压电流双闭环控制策略,并据此建立了新型组合式Sepic逆变器的双闭环控制系统。利用Matlab/Simulink模仿工具建立了该控制系统的仿真模型,对该系统进行了稳态仿真和动态仿真,以验证此系统的可行性和有效性。仿真实验结果表明,这种新型组合式Sepic逆变器双闭环控制具有良好的动态和稳态性能。     

Integrating run-based preventive maintenance into the capacitated lot sizing problem with reliability constraint

A joint model for integrating run-based preventive maintenance (PM) into the capacitated lot sizing problem (CLSP) is proposed, in which the production system is subject to deterioration with usage and PM operations are implemented to restore the system. In this model, both production and PM operations are restricted by the system's maximum capacity, and the system reliability has to be maintained above a threshold value throughout the planning horizon. By linearisation of the reliability constraints, the problem is formulated as a mixed-integer linear programming. An explanatory example is given to illustrate the advantage of the joint model comparing with the interval-based PM policy in terms of system's overall cost. A three-stage heuristic is proposed to solve this integrated model, which includes a Lagrangian-based heuristic for the CLSP. The numerical experiments are conducted to evaluate the performance of the developed heuristics and the computational results show that the heuristics can provide good feasible solutions for the corresponding models. The discussion of the results is finally given in detail.     

A numerical model for a dew-point counter-flow indirect evaporative cooler using a modified boundary condition and considering effects of entrance regions

A numerical model for dew-point counter-flow indirect evaporative coolers was presented. Unlike the conventional models, a more realistic boundary condition on separating wall was obtained by simultaneous solving of momentum, energy, and mass transfer equations of flows coupled. In addition, the model's accuracy was increased through considering 3D hydrodynamical and thermal developing flows. The model predicted the supply air temperature and the results were compared to experimental data as well as previous numerical models. It was shown that the maximum deviation of the supply air temperature was under ±3.53 %. It was found that these modifications on the numerical model reduced the computation error about 41.1 %. Moreover, it was found that the difference between maximum errors of 3D and 2D models was about 4.5 %; however, the 3D model consumes 14 times more CPU time. Finally, the sensitivity of the system's operation was studied using the developed model.     

基于光纤光栅的波分复用系统设计

设计了两种基于光纤布拉格光栅的波分复用(WDM)系统,一种为基于光纤光栅的四路波分复用系统,另一种为结合光分插复用器(OADM)的四路波分复用系统。给出了基于Opti System的波分复用光传输系统仿真模型,对复用及解复用后的光信号进行仿真得出了光谱图,对传输性能及Q因子、误码率、眼图等参数进行分析。在第二种结构中光纤光栅作为色散补偿器、光反射器和滤波器使用,可以实现任一波长的上载和下路。两种波分复用系统眼图张开良好,误码率均低于10e-9。证明了波分复用系统的正确性和设计方案的可行性。     

大芯径大数值孔径光纤测试系统测量不确定度评定

简述了大芯径大数值孔径光纤测试系统的测量原理,建立了测试系统的数学模型并对该系统的测量不确定度进行了评定。     

Facility layout optimization using simulation and genetic algorithms

Traditionally, the objective of a facility layout problem has been to minimize the material handling cost of the manufacturing system. While it is important to reduce the amount of material handling, the traditional methods do not address the actual time at which the material is transported. In today's short cycle time production environments, the timing of material movement may have a bigger impact on the productivity of the system than its cost. In this paper, a facility layout optimization technique is presented that takes into consideration the dynamic characteristics and operational constraints of the system as a whole, and is able to solve the facility layout design problem based on a system's performance measures, such as the cycle time and productivity. Each layout solution is presented in the form of a string that is suitable for analysis by a genetic algorithm technique. These solutions are then translated into simulation models by a specially designed automated simulation model generator. Genetic algorithms are used to optimize the layout for manufacturing effectiveness while simulation serves as a system performance evaluation tool. Combined with a statistical comparison technique to reduce the simulation burden, the test results demonstrate that the proposed approach overcomes the limitations of traditional layout optimization methods and is capable of finding optimal or near optimal solutions.