聚氨酯橡胶摩擦轮有限元及疲劳寿命分析

针对汽车滑板输送机聚氨酯橡胶摩擦轮的开裂问题,对摩擦轮与滑板之间的相互作用进行预压紧力和接触摩擦驱动有限元分析,获得摩擦轮的应力和变形分布等结果. 在获得摩擦轮周向应力分布的基础上,根据疲劳裂纹扩展公式对聚氨酯橡胶部分进行疲劳寿命分析,验证是否满足设计要求. 分析过程和结果能为聚氨酯橡胶摩擦轮的详细设计提供参考.     

聚氨酯橡胶摩擦轮有限元及疲劳寿命分析

针对汽车滑板输送机聚氨酯橡胶摩擦轮的开裂问题,对摩擦轮与滑板之间的相互作用进行预压紧力和接触摩擦驱动有限元分析,获得摩擦轮的应力和变形分布等结果.在获得摩擦轮周向应力分布的基础上,根据疲劳裂纹扩展公式对聚氨酯橡胶部分进行疲劳寿命分析,验证是否满足设计要求.分析过程和结果能为聚氨酯橡胶摩擦轮的详细设计提供参考.     

基于Adams的摆杆输送机动力学仿真分析

采用Adams脚本语言建模,自动完成摆杆输送机整体系统的轨道、链条、摆杆和工件之间的装配约束和载荷边界条件的设定等.对某卡车白车身涂装过程进行动力学仿真分析,求得系统整体运行时所需的驱动力大小、链节间的相互作用力和进行静力学分析所需的载荷条件等,分析结果可指导摆杆输送机的整体设计.     

电铲工作装置EDEM-Adams-Simulink联合动态仿真

针对电铲工作装置驱动力设计问题,使用EDEM计算挖掘阻力,计算结果与理论值一致。在Adams中建立电铲工作装置动力学模型,利用Simulink生成接近实际的提升和推压位移曲线,并将EDEM输出的挖掘阻力转化为挖掘阻力曲线,实现Adams-Simulink联合仿真。挖掘轨迹、驱动力仿真结果与理论计算结果一致。该方法可克服传统计算只取个别位姿的不足,为后续设计提供依据。     

位－力驱动的线驱连续型机器人的动力学建模及实验验证

提出了一种位－力混合驱动的线驱连续型机器人的动力学模型。首先,基于集中质量矩阵法进行机器人动力学建模,将机器人动能的连续积分等效离散为三点求和形式,可简化建模过程并提升仿真的计算效率。其次,分析了驱动力与驱动线几何约束的力学关系,将线驱动作用等效建模为电机的驱动参数与牵引线张力的线性方程组,不仅可以精确地满足牵引线对系统的约束条件,还可以在不使用拉力传感器的条件下得到线的驱动力,降低了机器人成本及控制难度,这种方法适用于任意数量牵引线的连续型机器人。最后,将线驱连续型机器人的仿真和实验结果进行对比,机器人末端点的轨迹最大误差为3.85%,验证了所提模型的有效性。     

大倾角长距离带式输送机阻力规律分析

给出了长距离带式输送机的力学结构模型,分段建立了不同倾角的带式输送机的阻力模型;针对黄陵建庄矿长度为1 200m的双滚筒驱动带式输送机的实际情况,对倾角为0、3、15°的承载段和回程段、机尾改向滚筒、机头驱动滚筒的动态阻力进行了计算和故障仿真,得到了带式输送机的阻力对位移影响的规律,为长距离带式输送机故障预测提供了依据。     

受电弓摩擦副载流磨损特性研究

为了解决电气化铁路受电弓网中摩擦副的磨损严重问题,采用自行开发的滑动电接触实验机,基于浸铜碳滑板和纯铜接触线为实验材料,在不同条件下进行了载流磨损实验,分析了受电弓滑板的磨损率与接触压力,接触电流和滑动速度之间的关系。基于方差分析表,采用F检验方法比较接触压力、接触电流、滑动速度3个因素对磨损率的影响程度,通过数据拟合的方法,建立磨损率的数学模型,并通过实验验证了所建立模型的有效性。     

翻转机构驱动力的优化及Adams仿真验证

在某航天器装配平台中,需要设计一个翻转机构实现部件与总体结构的对接工作,其中,外舱板翻转机构的驱动系统设计是重要内容之一.从外舱板翻转系统中外舱板翻转机构驱动力的设计出发,通过对特定负载的分析和理论分析,得到驱动力的大小以及驱动系统安装的最优位置.采用Adams的优化分析功能,以驱动系统安装位置为设计变量,以外舱板翻转机构在翻转过程中所需的最大驱动力中的最小值为目标函数,进行驱动系统的最优化仿真分析.应用Adams对优化设计结果进行仿真分析验证,得到最优结果.     

摩擦提升机的虚拟样机研究

钢丝绳传动特性是摩擦式提升机设计一个重要的考虑因素.为了研究摩擦提升机提升过程中钢丝绳的动力学特性,为安全运行提供保证,通过虚拟样机技术及其支撑软件ANSYS和RecurDyn,利用相对节点法建立了钢丝绳的多体动力学仿真模型,构建了简化后的摩擦式提升机虚拟样机仿真模型.通过对摩擦提升机虚拟样机的仿真分析,获得了仿真模型的运动学、动力学特性数据,得到了与理论分析相吻合的结果.为设计经济、可靠的多绳摩擦提升机系统提供了有力的工具和实现方法,还可以推广应用到其他挠性传动的分析.     

刮板输送机-采煤机协同调速方案设计与仿真

针对刮板输送机控制系统存在的实时性差、稳定性不高的问题,设计刮板输送机、采煤机协同调速控制方案.在分析刮板输送机、采煤机基本结构、协同工作过程的基础上,分别设计基于PID控制、模糊PID控制的协同调速方案,并搭建仿真模型,完成正常运行模式、扰动模式的系统仿真.仿真结果表明,基于模糊PID的协同调速控制方案能够提升系统的...     

四轮驱动滑动吸盘爬壁机器人的动力学研究

研究了四轮驱动滑动吸盘式爬壁机器人在滑动导向运动方式下的动力学问题．首先分析了机器人在壁面上安全移动的运动状态和约束条件, 然后对驱动轮支撑力分布、驱动轮与壁面间的横向摩擦力以及密封圈摩擦力进行分析,进而基于牛顿---欧拉法建立了机器人的动力学方程, 并用驱动力矩安全系数来表征驱动力矩的安全程度．通过动力学仿真,分析了吸附压力、驱动轮分布、密封圈刚度等对驱动力矩的影响, 为四轮驱动滑动吸盘式爬壁机器 人结构优化和安全运动控制提供理论依据．     

Modeling and simulation of longitudinal dynamics coupled with clutch engagement dynamics for ground vehicles

During the engagement of the dry clutch in automotive transmissions, clutch judder may occur. Vehicle suspension and engine mounts couple the torsional and longitudinal models, leading to oscillations of the vehicle body that are perceived by the driver as poor driving quality. This paper presents an effective formulation for the modeling and simulation of longitudinal dynamics and powertrain torsional dynamics of the vehicle based on non-smooth dynamics of multibody systems. In doing so friction forces between wheels and the road surface are modeled along with friction torque in the clutch using Coulomb’s friction law. First, bilateral constraint equations of the system are derived in Cartesian coordinates and the dynamical equations of the system are developed using the Lagrange multiplier technique. Complementary formulations are proposed to determine the state transitions from stick to slip between wheels and road surface and from the clutch. An event-driven scheme is used to represent state transition problem, which is solved as a linear complementarity problem (LCP), with Baumgarte’s stabilization method applied to reduce constraint drift. Finally, the numerical results demonstrate that the modeling technique is effective in simulating the vehicle dynamics. Using this method stick-slip transitions between driving wheel and the road surface and from the clutch, as a form of clutch judder, are demonstrated to occur periodically for certain values of the parameters of input torque from engine, and static and dynamic friction characteristics of tire/ground contact patch and clutch discs.     

Simulation of Wheels in Nonlinear,Flexible Multibody Systems

This paper is concerned with the modeling of wheels within the framework of finite element-based dynamic analysis of nonlinear, flexible multibody systems. The overall approach to the modeling of wheels is broken into four distinct parts: a purely kinematic part describing the configuration of the wheel and contacting plane, a unilateral contact condition giving rise to a contact force, the friction forces associated with rolling and/or sliding, and a model of the deformations in the wheel tire. The formulation of these various aspects of the problem involves a combination of holonomic and non-holonomic constraints enforced via the Lagrange multiplier technique. This work is developed within the framework of energy-preserving and decaying time integration schemes that provide unconditional stability for nonlinear, flexible multibody systems involving wheels. Strategies for dealing with the transitions from rolling to sliding and vice-versa are discussed and are found to be more efficient than the use of a continuous friction law. Numerical examples are presented that demonstrate the efficiency and accuracy of the proposed approach.     

A Regularized Contact Model with Asymmetric Damping and Dwell-Time Dependent Friction

A general regularized contact model, including normal compliance, energydissipation, and tangential friction, is described in this paper. Thenormal damping coefficient is formulated as a function of the coefficientof restitution e and the impact velocity only; the results areenergy-consistent, with continuous force progression at the beginningand end of the impact, for both small and large values of e.The introduced seven parameter friction model based on an explicitformulation of the friction forces is suitable for real-timeapplications. The friction forces are split into its sliding andsticking contribution and a temporal lag effect, the dwell-time, isincluded using a novel dwell-time dependent stick state variable. Several examples are presented to demonstrate the features of thisgeneral contact model. The simulation results for a double pendulumhitting a plane are obtained, and a comparison with a benchmark problem shows the model behavior is in good agreement with published results.     

Design and analysis of a pneumatic high-impact force drive mechanism for in-pipe inspection robots

A pneumatic actuator is suitable and safe for in-pipe inspection robots in inflammable circumstances because of its ability to withstand explosions. However, ordinary pneumatic actuators limit driving speed because of their slow response. In this paper, we propose a novel pneumatic drive mechanism that can produce a high-impact force to move the in-pipe robot forward with sufficient speed by a catastrophic phenomenon using rapid release between a magnet and springs. We also introduce an anisotropic friction mechanism that uses a self-locking phenomenon to transmit the impact force to the pipe walls efficiently. A pin retraction mechanism that releases the self-locking condition is applied to retrieve the robot from the pipes. Optimizations of the proposed design were conducted based on a motion simulation model and verified in experiments. The experimental results obtained for maximum driving speeds in a straight pipe with different material types were approximately 90 and 50 mm/s for horizontal and vertical pipes, respectively. Stable strokes were also observed at different driving frequencies from 0.5 to 2.0 Hz.     

Twin Brush Floor Polishing Robot

A self-propulsive polishing robot is proposed as a method that automates a floor polisher and enables the omni-directional motion of a mobile robot without wheels. The proposed robot is composed of twin rotary brushes and does not require any mechanism such as driving wheels for the locomotion of the robot. When the robot polishes a floor with its brushes rotating, the friction forces occur between the brushes and the floor. The friction forces can be controlled by adjusting the posture of the brushes and it enables the robot to move in any desired direction.In this paper, we present a dynamics model of a brush, which corrects the errors of the currently existing model, and propose a new type of polishing robot, which has the twin brushes rotating in the opposite direction to each other. We also present the dynamics of the proposed robot and found the inverse dynamics solution for the omni-directional motion of the robot: we compute the values of the manipulating variables such as tilting directions and tilting amounts of the brushes for the translational, the rotational, and the combined general motion of the robot.     

电动汽车驱动防滑控制系统(ASR)的研究

本文介绍了一种新型电动汽车的驱动防滑控制系统(ASR)、对所建立的简化电动汽车驱动模型,采用模糊PD控制算法对左右两侧驱动轮单独控制,应用此算法可使各车轮的滑转率控制在最佳滑转率附近。此系统已在Matlab上进行仿真试验,仿真结果证明,在电动汽车高速直线行驶在不同附着系数的路面的情况下,按此算法设计的驱动防滑控制系统,能显著提高汽车的安全性和稳定性。