This paper presents dimensional synthesis of a 3 degrees of freedom (DOF) spatial 3-revolute-prismatic-spherical (RPS) parallel manipulator. Tsai and Kim ((2003) ASME J. Mech. Des., 125, pp. 92–97) have shown that the dimensional synthesis can be carried out for at the most six prescribed positions and orientations of the moving platform. The method of synthesis is modified (least-square technique) to make it possible to synthesize the 3-RPS manipulator for any number of positions and orientations of the moving platform. The effectiveness of the modified method of synthesis is demonstrated by considering an example for ten-position synthesis. The modified method of synthesis is an approximation method.

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