Accurate Straight-line Deployable Mechanism and Its Dynamics Analysis

Abstract

Abstract: Combining Hart straight-line mechanism with scissors mechanism， a new type straight-line deployable unit was proposed which consisted of revolute joint only.Then an accurate straight-line deployable mechanism was designed.According to the mechanism and machine theory， modular principles of the deployable mechanism were explained and the mechanism was composed with three kinds of modules including bottom module，middle module and top module.These modules were all composed by the straight-line deployable units.The kinematics model of a single straight-line deployable unit was established.Combining the modular principles of the mechanism， the recurrent relations of any module kinematics were derived which might be used to solve the whole kinematics model of the accurate straight-line deployable mechanisms consisted of multi-layer modules.The whole dynamics model of the mechanism was presented by Lagrange method based on the whole kinematics model.Taking mechanism consisted of three-layer modules as an example， the dynamics numerical calculation and virtual simulation were carried out， and the correctness and effectiveness of the kinematics and dynamics equations were verified.On the basis of geometric and physical parameters of real mechanism， required driving torque may be obtained when the motion of end-effector was given.The results show that there is no impacts during the whole working cycles by setting sine acceleration movement for end-effectors.

Key words: straight-line mechanism, deployable mechanism, dynamics modeling, driving torque

摘要： 将Hart直线机构和剪叉机构相结合，提出一种仅含转动副的直线可展单元，并设计得到一种精确直线可展机构。根据机构结构学分析理论，阐述可展机构的模块化组成原理，将机构的组成分解为底部模块、中部模块和顶部模块，3种模块均由直线可展单元构成；对单个直线可展单元进行运动学建模，结合机构的模块化组成原理，推导得到任意模块间的运动学递推关系，求解得到多层模块条件下机构的整体运动学模型，运用Lagrange方程构建机构的整体动力学模型；以3层可展机构为例，对其进行动力学数值计算和虚拟仿真，验证所建运动学和动力学模型的正确性和有效性。通过给定末端执行器的输出运动规律，求解得到机构所需的驱动力矩，结果表明：末端执行器为正弦加速度曲线时，机构在整个工作周期内无冲击，运动稳定性好。

关键词: 直线机构, 可展机构, 动力学建模, 驱动力矩

CLC Number:

TH112.1

CHANG Boyan1，2;LI Wenqi1;JIN Guoguang1，2;SONG Yanyan1. Accurate Straight-line Deployable Mechanism and Its Dynamics Analysis[J]. China Mechanical Engineering.

畅博彦1，2;李文启1;金国光1，2;宋艳艳1. 精确直线可展机构及其动力学分析[J]. 中国机械工程.

References

[1]孙光旭，袁端才.液压剪叉式升降台的动力学仿真[J].系统仿真学报，2010，22（11）：2650-2653.
SUN Guangxu，YUAN Duancai.Dynamics Simulation of Scissors Elevating Platform Powered Hydraulic Cylinder[J].Journal of System Simulation，2010，22 （11）：2650-2653.
[2]胡明，章斌，陈文华，等.“一字型”折叠翼展开试验与仿真验证分析[J].中国机械工程，2015，26（13）： 1801-1805.
HU Ming，ZHANG Bin，CHEN Wenhua，et al.Expand Performance and Simulation Verification of Line-styled Folding-wing[J].China Mechanical Engineering，2015，26（13）：1801-1805.
[3]韩莹莹，袁茹，郑钰祺.环状可展机构运动学分析方法及应用研究[J].中国机械工程，2013，24（9）：1142-1145.
HAN Yingying，YUAN Ru，ZHENG Yuqi.Research on Kinematics Analysis Method and Its Application of Circular Developable Mechanisms[J].China Mechanical Engineering，2013，24（9）：1142-1145.
[4]THOMAS W D R.RADARSAT-2 Extendible Support Structure[J].Canadian Journal of Remote Sensing，2004，30（3）：282-286.
[5]NORTON R L.Design of Machinery[M].New York： McGraw-Hill，2001.
[6]DIJKSMAN E A，SMALS A T J M.λ-formed 4-bar Linkages Set in a Translation-position to Design Mechanisms Approximating a Straight Line[J].Mechanism and Machine Theory，1996，31（8）：1033-1042.
[7]钱卫香，韩建友.实现近似直线轨迹的λ形机构综合方法[J].农业机械学报，2008，39（6）：154-158.
QIAN Weixiang，HAN Jianyou.Synthesis Method of λ-formed Linkages Approximating a Straight Line[J].Transactions of the Chinese Society of Agricultural Machinery，2008，39（6）：154-158.
[8]LU S N，ZLATANOV D，DING X L，et al.A New Family of Deployable Mechanisms Based on the Hoekens Linkage[J].Mechanism and Machine Theory，2014，73（2）：130-153.
[9]YANG J L，FENG G，ZHU K J，et al.Type Synthesis of Spatial Straight Line Mechanisms with Only Revolute Joints[J].Journal of Donghua University（English Edition），2012，29（2）：134-138.
[10]张武翔，杨毅，罗均，等.多环闭链可展机构尺寸调整方法[J].机械工程学报，2015，51（19）：11-20.
ZHANG Wuxiang，YANG Yi，LUO Jun，et al.Size Adjustment of Multi-closed-loop Deployable Mechanisms[J].Journal of Mechanical Engineering，2015， 51（19）：11-20.
[11]WEI Guowu，CHEN Yao，DAI Jiansheng.Synthesis， Mobility， and Multifurcation of Deployable Polyhedral Mechanisms with Radially Reciprocating Motion [J].Journal of Mechanical Design，2014，136（9）：1-12.
[12]DING X L，YANG Y，DAI J S.Design and Kinematic Analysis of a Novel Prism Deployable Mechanism[J].Mechanism and Machine Theory，2013，63（5）：35-49.
[13]杨毅，丁希仑.剪式单元可展机构静力学分析与拓扑优化设计[J].中国机械工程，2010，21（2）：184-189.
YANG Yi，DING Xilun.Analysis and Topology Optimization of Deployable Mechanism Based on Pantograph[J].China Mechanical Engineering，2010，21（2）： 184-189.
[14]李端玲，张忠海，于振.球面剪叉可展机构的运动特性分析[J].机械工程学报，2013，49（13）：1-7.
LI Duanling，ZHANG Zhonghai，YU Zhen.Kinematic Characteristic Analysis of Spherical Scissors Deployable Mechanisms[J].Journal of Mechanical Engineering，2013，49（13）：1-7.
[15]袁茹，王剑，王三民，等.剪刀机构环形阵列可展结构的运动学与动力学研究[J].中国机械工程，2014， 25（17）：2309-2313.
YUAN Ru，WANG Jian，WANG Sanmin，et al.Kinematics and Dynamics Analysis of Ring Array Deployable Structures Based on SLE[J].China Mechanical Engineering，2014，25（17）：2309-2313.
[16]孙远涛，王三民，刘霞.剪式机构线性阵列可展结构的动力学特性研究[J].中国机械工程，2012，23（24）： 2917-2925.
SUN Yuantao，WANG Sanmin，LIU Xia.Dynamics Research of Linear Array Deployable Structures Based on Structure of Scissor-like Element[J].China Mechanical Engineering，2012，23（24）：2917-2925.