A novel 3-UPU symmetrical parallel mechanisms is proposed, whose base and moving platform are always symmetrical about a middle plane. It has two rotational and one translational (2R1T) degrees of freedom (DOFs). The mobility and motion characteristics of this mechanism are studied by using the screw theory. And it has been approved that the moving platform can rotate continuously about a fixed axis or fixed point, which can be chosen freely on the middle plane. Therefore this mechanism has no parasitic motion, which will bring much convenience to the kinematics analysis and controlling. Meanwhile, it also has a translational DOF along the normal of the middle plane, and the moving platform can realize continuous translation along this direction. Based on the structure characteristics of this mechanism, the orientation of moving platform can be represented by two angle parameters, which is very convenient and visual. The forward and inverse solutions are derived and the analytical solutions are obtained which is very simple and make it easy for further study. The workspace is analyzed, which is large enough for ordinary requirement.
CHEN Ziming
,
ZHANG Yang
,
HUANG Kun
,
HUANG Zhen
. Symmetrical 2R1T Parallel Mechanism without Parasitic Motion[J]. Journal of Mechanical Engineering, 2016
, 52(3)
: 9
-17
.
DOI: 10.3901/JME.2016.03.009
[1] HUNT K H. Structural kinematics of in-parallel-actuated robot arms[J]. Journal of Mechanisms Transmissions and Automation in Design，1983，105(4)：705-712.
[2] WAHL J. Articulated tool head：US，US6431802[P]. 2000-11-05.
[3] BI Z M，JIN Y. Kinematic modeling of exechon parallel kinematic machine original research article[J]. Robotics and Computer-Intergrated Munufacturing，2011，27(1)：186-193.
[4] 王永，姚太克，周烽，等. 望远镜副镜的三自由度并联支撑构型研究与运动分析[J]. 光学精密工程，2013，21，(11)：2860-2869. WANG Yong，YAO Taike，ZHOU Feng，et al. Type synthesis of 3-DOF parallel support system for telescope secondary mirror[J]. Optics and Precision Engineering，2013，21(11)：2860-2869.
[5] 王永，姚太克，张丽敏，等. 望远镜副镜三自由度并联支撑的运动研究[J]. 中国科学技术大学学报，2013，43(10)：775-781. WANG Yong，YAO Taike，ZHANG Limin，et al. Motion analysis of a 3-DOF parallel support for the telescope’s secondary mirror[J]. Journal of University of Science and Technology of China，2013，43(10)：775-781.
[6] POULIOT N A，NAHON M A，GOSSELIN C M. Motion simulation capabilities of three-degrees-of-freedom flight simulators[J]. Journal of Aircraft，1998，35(1)：9-17.
[7] YU J J，HU Y D，BI S S. Kinematics feature analysis of a 3 DOF in-parallel compliant mechanism for micro manipulation[J]. Chinese Journal of Mechanical Engineering，2004，17(1)：127-131.
[8] LIU D，CHE R，LI Z. Research on the theory and the virtual prototype of 3-DOF parallel-link coordinating- measuring machine[J]. IEEE Trans. Instrum. Meas. ，2003，52(1)：119-125.
[9] CARRETERO J A，PODHORODESKI R P，NAHON M A. Kinematic analysis and optimization of a new three degree-of-freedom spatial parallel manipulator[J]. Journal of Mechanical Design，2000，122(1)：17-24.
[10] 刘辛军，吴超，汪劲松，等. [PP]S类并联机器人机构姿态描述方法[J]. 机械工程学报，2008，44(10)：19-23. LIU Xinjun, WU Chao, WANG Jinsong, et al. Attitude description method of [PP]S type parallel robotic mechanisms[J]. Chinese Journal of Mechanical Engineering，2008，44(10)：19-23.
[11] 汪劲松, 刘辛军，李枝东, 等. 一种无伴随运动的并联式三轴主轴头结构：中国，CN2009100798383[P]. 2009-08-05. WANG Jinsong，LIU Xinjun，LI Zhidong，et al. A kind of parallel three-axis spindle head structure without parasitic motion：China，CN2009100798383[P]. 2009-08-05.
[12] LI Qinchuan，HERVE J M. 1T2R parallel mechanisms without parasitic motion[J]. IEEE Transactions on Robotics and Automation，2010，26(3)：401-410.
[13] 李秦川，陈志，陈巧红，等. [PP]S类并联机构无伴随运动的结构条件[J]. 机械工程学报，2010，46(15)：31-35. LI Qinchuan，CHEN Zhi，CHEN Qiaohong，et al. Structural condition for [PP]S parallel mechanism without parasitic motion[J]. Journal of Mechanical Engineering，2010，46(15)：31-35.
[14] LI Qinchuan，CHEN Zhi，CHEN Qiaohong，et al. Parasitic motion comparison of 3-PRS parallel mechanism with different limb arrangements[J]. Robotics and Computer-Integrated Manufacturing，2011，27(2)：389-396.
[15] HERRERO S，PINTO C，CORRAL J，et al. Actuators orientation influence in the energy consumption of the 3-PRS manipulator[C]// ASME 2013 International Mechanical Engineering Congress and Exposition，November 15 – 21, 2013，San Diego，California. New York：ASME， 2013：V04BT04A071-V04BT04A080.
[16] TSAI L W. Kinematics of a three-dof platform with three extensible limbs[M]. Netherlands：Kluwer Academic Publishers，1996.
