Homing Strategy for a Redundantly Actuated Parallel Kinematic Machine

In the homing process of a regular parallel kinematic machine (PKM), all servoaxes are independently driven to return to their homing positions. However, in a redundantly actuated PKM, the redundant limb will interfere with other servoaxes. This paper concerns the homing of a redundant four degree of freedom PKM, and an assistant homing strategy is proposed for the machine to pass the singular configuration in the homing process. After the assistant homing is finished, the other four nonredundant axes are driven to return to their home positions independently. Based on the kinematic model and the length of the redundant limb, the condition that the redundant limb performs assistant homing is determined. The homing strategy is incorporated into the numerical control system of the studied PKM. The test shows that the homing strategy is effective, and it can also be useful for other kinds of redundantly actuated PKMs.

[1]  S. Nokleby,et al.  Force capabilities of redundantly-actuated parallel manipulators , 2005 .

[2]  Walter Schumacher,et al.  A parallel x-y manipulator with actuation redundancy for high-speed and active-stiffness applications , 1998, Proceedings. 1998 IEEE International Conference on Robotics and Automation (Cat. No.98CH36146).

[3]  Jun Wu,et al.  Analysis and Application of a 2-DOF Planar Parallel Mechanism , 2007 .

[4]  Sungbok Kim.  Operational quality analysis of parallel manipulators with actuation redundancy , 1997, Proceedings of International Conference on Robotics and Automation.

[5]  Zexiang Li,et al.  Dynamics and control of redundantly actuated parallel manipulators , 2003 .

[6]  Frank Chongwoo Park,et al.  Design and analysis of a redundantly actuated parallel mechanism for rapid machining , 2001, IEEE Trans. Robotics Autom..

[7]  Guanfeng Liu,et al.  Advantages and dynamics of parallel manipulators with redundant actuation , 2001, Proceedings 2001 IEEE/RSJ International Conference on Intelligent Robots and Systems. Expanding the Societal Role of Robotics in the the Next Millennium (Cat. No.01CH37180).

[8]  Clément Gosselin,et al.  Conceptual Design and Dimensional Synthesis of a Novel 2-DOF Translational Parallel Robot for Pick-and-Place Operations , 2004 .

[9]  Xiaoqiang Tang,et al.  Singularity analysis of redundant parallel manipulators , 2004, 2004 IEEE International Conference on Systems, Man and Cybernetics (IEEE Cat. No.04CH37583).