A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been developed.The mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding stages.The simulation findings are compared to the analytical calculation results in the steady state,and both methods show good agreement.In the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model 2.Meanwhile,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting stage.The established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system operation.It is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

Unsteady aerodynamics modeling for flight dynamics application

In view of engineering application, it is practicable to decompose the aerodynamics into three components： the static aerodynamics, the aerodynamic increment due to steady rotations, and the aerodynamic increment due to unsteady separated and vortical flow. The first and the second components can be presented in conventional forms, while the third is described using a one-order differential equation and a radial-basis-function （RBF） network. For an aircraft configuration, the mathematical models of 6- component aerodynamic coefficients are set up from the wind tunnel test data of pitch, yaw, roll, and coupled yawroll large-amplitude oscillations. The flight dynamics of an aircraft is studied by the bifurcation analysis technique in the case of quasi-steady aerodynamics and unsteady aerodynam- ics, respectively. The results show that： （1） unsteady aerodynamics has no effect upon the existence of trim points, but affects their stability; （2） unsteady aerodynamics has great effects upon the existence, stability, and amplitudes of periodic solutions; and （3） unsteady aerodynamics changes the stable regions of trim points obviously. Furthermore, the dynamic responses of the aircraft to elevator deflections are inspected. It is shown that the unsteady aerodynamics is beneficial to dynamic stability for the present aircraft. Finally, the effects of unsteady aerodynamics on the post-stall maneuverability

Control-oriented modeling of a high-aspect-ratio flying wing with coupled flight dynamics

The flight-structural dynamics of a high-aspect-ratio wing challenge the flight control design.This paper develops a reduced model of coupled dynamics with stability consideration.The structural dynamics are formulated with dihedrals,and the central loads drive the deformation.The control-oriented model with essential coupled dynamics is formulated.Modal sensitivity anal-ysis and input–output pairing are performed to identify the control structure.Besides,an example of flight control design is provided to discuss the necessity of considering structural dynamics in controller design.Analytical coupled flight dynamics provide a system-theoretic approach for sta-bility and facilitate model-based control techniques.Simulation results reveal the characteristics of flight-structural coupled dynamics and demonstrate that the influence of flexible modes should be considered in control design,especially in lateral dynamics.

Flight dynamics characteristics of canard rotor/wing aircraft in helicopter flight mode

The aerodynamic layout of the Canard Rotor/Wing(CRW) aircraft in helicopter flight mode differs significantly from that of conventional helicopters. In order to study the flight dynamics characteristics of CRW aircraft in helicopter mode, first, the aerodynamic model of the main rotor system is established based on the blade element theory and wind tunnel test results. The aerodynamic forces and moments of the canard wing, horizontal tail, vertical tail and fuselage are obtained via theoretical analysis and empirical formula. The flight dynamics model of the CRW aircraft in helicopter mode is developed and validated by flight test data. Next, a method of model trimming using an optimization algorithm is proposed. The flight dynamics characteristics of the CRW are investigated by the method of linearized small perturbations via Simulink. The trim results are consistent with the conventional helicopter characteristics, and the results show that with increasing forward flight speed, the canard wing and horizontal tail can provide considerable lift,which reflects the unique characteristics of the CRW aircraft. Finally, mode analysis is implemented for the linearized CRW in helicopter mode. The results demonstrate that the stability of majority modes increases with increasing flight speed. However, one mode that diverges monotonously,and the reason is that the CRW helicopter mode has a large vertical tail compared to the conventional helicopter. The results of the dynamic analysis provide optimization guidance and reference for the overall design of the CRW aircraft in helicopter mode, and the model developed can be used for control system design.

Underconstrained Cable-Driven Parallel Suspension System of Virtual Flight Test Model in Wind Tunnel

An underconstrained cable-driven parallel robot(CDPR)suspension system was designed for a virtual flight testing(VFT)model.This mechanism includes two identical upper and lower kinematic chains,each of which comprises a cylindrical pair,rotating pair,and cable parallelogram.The model is pulled via two cables at the top and bottom and fixed by a yaw turntable,which can realize free coupling and decoupling with three rotational degrees of freedom of the model.First,the underconstrained CDPR suspension system of the VFT model was designed according to the mechanics theory,the degrees of freedom were verified,and the support platform was optimized to realize the coincidence between the model’s center of mass and the rotation center of the mechanism during the motion to ensure the stability of the support system.Finally,kinematic and dynamical modeling of the underconstrained CDPR suspension system was conducted;the system stiffness and stability criteria were deduced.Thus,the modeling of an underconstrained,reconfigurable,passively driven CDPR was understood comprehensively.Furthermore,dynamic simulations and experiments were used to verify that the proposed system meets the support requirements of the wind tunnel-based VFT model.This study serves as the foundation for subsequent wind tunnel test research on identifying the aerodynamic parameters of aircraft models,and also provides new avenues for the development of novel support methods for thewind tunnel testmodel.

基于MATLAB编程的“机械原理”课程教学改革探索

“机械原理”课程是机械设计制造及其自动化专业的主干专业基础课,如何结合实际控制目标对“机械原理”课程教学进行创新改革值得深入思考。针对目前“机械原理”课程中涉及的机构,很难利用尺规作图法来快速得到任意机构中某一构件的运动学和动力学分析结果。为此,将基于MATLAB的计算机辅助编程融入“机械原理”课程教学中,让学生通过该部分的学习从理论上彻底了解并理解各机构的运动特点及其主要的设计思路。结果表明,参与教改班学生的知识体系在一定程度上得到了提升,成功实现了将基于MATLAB的计算机辅助编程融入“机械原理”课程教学改革中。为培养兼具机械结构设计、计算机编程技术及刚体动力学的复合型人才提供了强有力的支撑。

基于Matlab的时序全局主成分分析方法及应用

时序全局主成分分析法是经典的主成分分析法和时间序列分析法的结合,可以用来了解系统的总体水平随时间的变化轨迹。文章编写了一个Matlab函数来实现时序全局主成分分析法的全部运算过程,并对安徽省国民经济的发展态势进行了动态分析。

基于Matlab Web Server技术的飞行数据远程综合分析系统的实现

Matlab Web Server技术为基于Internet/Intranet的数据远程分析和二次开发提供了快捷而又强大的实现方法,利用此技术实现了飞行数据远程综合分析系统,并结合实例详细介绍了系统开发过程中的关键技术难点。

VB/Matlab在机构动力学分析中的应用

介绍了在VB6.0中利用ActiveX技术使用和操作Matlab的方法。以四杆机构的动力分析系统为例,在Matlab中建立了系统的仿真模型,在VB中设计了系统界面、编制了相应代码,系统能方便、准确地得到机构的动力数据。通过VB与Matlab的混合编程,有效的提高了程序的设计效率。

基于MATLAB的叉车动态稳定性分析与仿真

通过分析叉车动态稳定性应满足的条件,基于MATLAB软件建立数学模型,并进行制动、转弯稳定性分析与仿真,为叉车动态稳定性分析提供了一种方便快捷、准确有效的计算方法.

基于MATLAB的某型履带吊管机吊物系统动态特性分析

吊管机在外部工况激励的作用下会产生危险的大幅摆动,不仅会降低施工的吊装精度,严重时还会引起吊物和结构的碰撞。因此对吊管机进行吊物系统动态特性分析对吊管机的作业安全具有重要的意义。依据吊管机的工作环境,总结和对比国内外的相关研究。建立吊物系统的数学模型,推导吊管机吊物系统的非线性动力学方程,并利用MATLAB进行吊管机吊物系统的数值分析。结果可以看出吊索长度、外部激励频率、吊物的升降速度分别对吊物系统的动态响应、吊物摆振、吊物的面内外摆角产生影响。

基于Matlab的飞行器系统动态特性分析

以Ecolifter为参考模型,推导适用于Matlab的飞行器系统运动数学模型.利用Matlab科学计算平台,求解飞行器运动方程,分析飞行器系统的动态稳定性,求解传递函数和过渡过程响应,研究飞行器设计参数对动态特性的影响.与传统的动态特性分析方法相比,利用Matlab分析飞行器系统动态特性更为简便,一体化设计程度提高.

Dynamic Modeling, Testing, and Stability Analysis of an Ornithoptic Blimp

In order to study omithopter flight and to improve a dynamic model of flapping propulsion, a series 0f tests are conducted on a flapping-wing blimp. The blimp is designed and constructed from mylar plastic and balsa wood as a test platform for aerodynamics and flight dynamics. The blimp, 2.3 meters long and 420 gram mass, is propelled by its flapping wings. Due to buoyancy the wings have no lift requirement so that the distinction between lift and propulsion can be analyzed in a flight platform at low flight speeds. The blimp is tested using a Vicon motion tracking system and various initial conditions are tested including accelerating flight from standstill, decelerating from an initial speed higher than its steady state, and from its steady-state speed but disturbed in pitch angle. Test results are used to estimate parameters in a coupled quasi-steady aerodynamics/Newtonian flight dynamics model. This model is then analyzed using Floquet theory to determine local dynamic modes and stability. It is concluded that the dynamic model adequately describes the vehicle＇s nonlinear behavior near the steady-state velocity and that the vehicle＇s linearized modes are akin to those of a fixed-wing aircraft.

基于MATLAB的波浪补偿平台动力学分析

为提高具有波浪补偿能力的船舶起重机的作业能力和工作稳定性,基于波浪补偿平台工作原理设计一种电动自动补偿控制系统,对船舶升沉运动展开动力学建模与动力学分析。用PID算法对建立的波浪补偿平台展开运动轨迹跟踪。利用MATLAB进行轨迹跟踪仿真发现,PID控制系统具有良好的灵敏性和稳定性。

MATLAB的平面连杆机构运动分析与动态仿真

以杆组法为基础,采用MATLAB进行平面连杆机构的运动分析和动态仿真,编程简单,运行效率高,计算结果可以存储为数据表格、图形乃至电影动画文件等多种形式.

Matlab.NET混合编程在潮汐调和分析与预报中的应用

利用.NET中C#强大的界面开发能力和经典的Matlab潮汐调和分析程序包T_TIDE,采用Matlab.NET混合编程技术,创建潮汐调和常数计算THCCalculate.dll和潮汐预报Tide Forecast.dll,在主程序中调用对应的函数,实现了操作简单且具有良好用户界面的潮汐调和分析与潮位预报系统,具有潮位数据读取、调和分析和预报、数据绘制等功能。结果表明:使用混合编程技术能充分发挥C#与Matlab各自的特点,较好地提高程序开发和运行效率,具有较广泛的应用范围。

Matlab与Excel在心音分析中的应用

针对心音信号时频分析结果中时、频、能量特征数据多样性的问题,我们研究了Matlab与Excel动态链接方法。为得到心音信号时、频、能量特征值统计量,提出了利用Matlab与Excel动态链接实现对心音的时、频、能量特征数据统计分析。仿真结果表明:Matlab与Excel动态链接不仅具有Matlab强大的信号处理能力,而且又可以充分发挥Excel电子表格独特的数据分析功能。

MATLAB在二阶动态电路中的应用

MATLAB语句简练,功能强大,简单实用,用途广泛,可大大提高计算效率,缩短编程时间,是一种简便实用的计算工具,在分析二阶动态电路时更具有突出的作用.文中通过几个典型的电路实例,重点探讨了其在二阶动态电路分析计算方面的应用,为解决二阶动态电路问题提供了很好的帮助.

基于Matlab的并联机器人机构动力分析与动态仿真

在当前的机器人机构动力分析方法以及相关仿真工作中,仅能对机器人的单一运动方向进行仿真,若变换方向则需重新建立模型,导致其仿真精度低、效率差。因此,文中提出基于Matlab的并联机器人机构动力分析与动态仿真。首先建立并联机器人的数学模型,以确定机器人运动机构的运动初始位置及其坐标;其次根据拉格朗日方程获得机器人的动力平台相关参数,并对其进行动力平台分析,根据获取的参数分析结果进行机器人的运动描述。最后将上述内容作为仿真基础,导入Matlab软件中,实现动态仿真。为了验证设计方法的可行性,使用该方法对某型号的并联机器人进行仿真实验。实验结果证明,设计方法可以实现对正运动和逆运动双向的动态仿真,不需要重新进行动力分析,同时仿真精度较高,具有适用性。

Matlab仿真在双闭环直流调速实验教学中的应用

电力拖动运动控制系统是自动化专业的核心课程之一。高性能的直流调速系统多采用双闭环串级控制的结构:外环为转速反馈,实现转速调节;内环为电流反馈,加快瞬态过程。由于原理的复杂性,历来是教学的难点。Matlab是一种强大的仿真工具,已广泛应用于高校教学活动。以双闭环直流调速为例,将Matlab仿真技术引入运动控制实验教学。利用Sim Power System模块搭建系统模型;通过仿真,对比分析系统在突加给定和突增负载时的动态响应特性;验证了双闭环结构相对于开环、单闭环系统的优势。与传统实物实验相结合,更有利于学生加深对相应知识点的理解和掌握。