Please wait a minute...

Frontiers of Mechanical Engineering

Front Mech Eng    2011, Vol. 6 Issue (4) : 463-467     https://doi.org/10.1007/s11465-011-0225-z
RESEARCH ARTICLE |
A redundantly actuated PRPRP radial mechanism in the segment erector of a shield machine for synchronization control
Wanghui BU, Zhenyu LIU(), Jianrong TAN, Jin CHENG
State Key Laboratory of CAD & CG, Zhejiang University, Hangzhou 310027, China
Download: PDF(170 KB)   HTML
Export: BibTeX | EndNote | Reference Manager | ProCite | RefWorks
Abstract

The shield machine is a heavy construction machine for tunnel excavation, and the segment erector is an important subsystem of the shield machine. It is difficult to achieve precise control in the 6-DOF (degree of freedom) erector in the 2-DOF 5-bar radial mechanism. Hence, this paper proposes a redundantly actuated PRPRP radial mechanism for the segment erector. When the redundant actuator is unlocked, the radial mechanism is able to adjust its posture, which has two degrees of freedom. On the other hand, when the redundant actuator is locked or produces enough pre-tightening tensile force, the PRPRP mechanism can ensure the synchronization of the two driving hydraulic cylinders along the radial direction based on the mechanical structure, which has one degree of freedom. The redundant actuator also facilitates the equal application of two flexural torques at the hydraulic cylinders; thus, preventing the overload of a single cylinder.

Keywords redundant actuation      parallel mechanisms      five-bar mechanisms      segment erectors      shield machines     
Corresponding Authors: LIU Zhenyu,Email:liuzy@zju.edu.cn   
Issue Date: 05 December 2011
 Cite this article:   
Wanghui BU,Zhenyu LIU,Jianrong TAN, et al. A redundantly actuated PRPRP radial mechanism in the segment erector of a shield machine for synchronization control[J]. Front Mech Eng, 2011, 6(4): 463-467.
 URL:  
http://journal.hep.com.cn/fme/EN/10.1007/s11465-011-0225-z
http://journal.hep.com.cn/fme/EN/Y2011/V6/I4/463
Fig.1  A shield machine containing a cutterhead, the hydraulic cylinders of the thrust subsystem, a segment erector, etc.
Fig.2  A segment erector consisting of the circumferential, radial, and pose adjustment mechanisms
Fig.3  The PRRP mechanism in a 3-DOF erector. Sections marked as joints and denote the two driving hydraulic cylinders, joints and are two revolute joints, and load denotes the segment
Fig.4  The PRRRP mechanism in an existing 6-DOF erector. The sections marked as joints and denote the two driving hydraulic cylinders; joints , , and are three revolute joints; and load denotes the segment
Fig.5  The redundantly actuated PRPRP mechanism in the improved 6-DOF erector. The sections marked as joints and denote the two driving hydraulic cylinders, joints and are two revolute joints, load denotes the segment, and joint is the redundant actuator. The length of link is constant, whereas that of link is changeable
Fig.6  The variations of torques with . The blue real line denotes the flexural torques of joints and , and the red dashed line denotes the flexural torques of joint
Fig.7  The variations of forces with . The red real line denotes the driving force of joint ; the green dashed line denotes the driving force of joint ; the blue dotted line denotes the redundant driving force
Fig.8  The variations of torques with (). The blue real line denotes the flexural torques of joints and , and the red dashed line denotes the constant flexural torques 15379.5 N·m of joint
1 Takashi W, Toshiharub T, Tsuyoshic A, Katsuhiko M. Development of a new composite structure segment for large diameter shield tunnel. Tunnelling and Underground Space Technology, 2004, 19(4–5): 449–450
doi: 10.1016/j.tust.2004.02.059
2 Qian X, Gao F, Guo W.Design and analysis of 6-DOF segment erector mechanism for shield machine. Machine design and research , 2008, 24(1): 17–20
3 Nokleby S B, Fisher R, Podhorodeski R P, Firmani F. Force capabilities of redundantly-actuated parallel manipulators. Mechanism and Machine Theory, 2005, 40(5): 578–599
doi: 10.1016/j.mechmachtheory.2004.10.005
4 Wu J, Wang J, Wang L. Optimal kinematic design and application of a redundantly actuated 3-DOF planar parallel manipulator. Journal of Mechanical Design, 2008, 130(5): 054503
doi: 10.1115/1.2890118
5 Garg V, Nokleby S B, Carretero J A. Wrench capability analysis of redundantly actuated spatial parallel manipulators. Mechanism and Machine Theory, 2009, 44(5): 1070–1081
doi: 10.1016/j.mechmachtheory.2008.05.011
6 Bu W, Liu Z, Tan J, Gao S. Detachment avoidance of joint elements of a robotic manipulator with clearances based on trajectory planning. Mechanism and Machine Theory, 2010, 45(6): 925–940
doi: 10.1016/j.mechmachtheory.2010.01.006
Related articles from Frontiers Journals
[1] D. GOUBET, J. C. FAUROUX, G. GOGU. Gripping mechanisms in current wood harvesting machines[J]. Front Mech Eng, 2013, 8(1): 42-61.
Viewed
Full text


Abstract

Cited

  Shared   0
  Discussed