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The end-effector of the robot can reach the required workspace: 300mm in z-axis, ±100 mm in x and y-
axis and the orientations about x and y-axis are more than ±20°. The position accuracy is less than ±
0.05mm and repeatability is less than ±0.01mm after calibrating. Fig.6 shows the trajectory of the end
tip and the corresponding motion of the hydraulic cylinders. In this experiment the robot tracks the
trajectory with a 50kg payload and 500mm/min speed.

CONCLUSION
A parallel robot, driven by five hydraulic cylinders, has been developed to assemble and to repair the
Vacuum Vessel of ITER and can accurately and stably hold all necessary machining and welding end-
effectors in all positions.
A control system has been designed. A prototype has been built, some tests have been carried out and
its position accuracy and repeatability have been investigated and found to be in good agreement with
the theory.

REFERENCES
[1 ] http://www.parallemic.org/Patents.html.
[2] M. Honegger, A. Codourey and E.Burdet .Adaptive Control of the Hexaglide , A 6 dof Parallel
Manipulator. In proceedings of the IEEE International Conference on Robotics and Automation.
Albuquerque, New Mexico. April 1997.
[3] K.H. Hafele , H.Haffner and P. Spencer , Automatic Fettling Cell- An Example For Applying
Computer- Aided Robotics . Industrial Robot. Industrial Robot, Vol.19 No. 5.1992, pp.31-34
[4] L. Jones, Study to Optimise Intersected Welding Robot Design And Machining Characteristics.
Final report. January 2002
[5] H. Wu, H. Handroos. Parallel Mechanisms Based On Telescopic Structure and Applications. In
nd
Proceedings of the 32 International Symposium on Robotics, Seoul, April 2001.
[6] H. Wu, H. Handroos, ..., L. Jones. Design of Parallel Tntersector Weld/Cut Robot for Machining
Processes in ITER Vacuum Vessel. International Journal of Fusion Engineering and Design, Vol.
69(2003) pp327-331 .