This paper deals with the error modelling and analysis of a 3-PPR planar parallel manipulator with joint clearances. The kinematics and the Cartesian workspace of the manipulator are analyzed. An error model is established with considerations of both configuration errors and joint clearances. Using this model, the upper bounds and distributions of the pose errors for this manipulator are established. The results are compared with experimental measurements and show the effectiveness of the error prediction model.
Wu, G., Bai, S., Kepler, J. A., & Caro, S. (2012). Error modelling and experimental validation of a planar 3-PPR parallel manipulator with joint clearances. Journal of Mechanisms and Robotics, 4(4), 041008-1-041008-12. https://doi.org/10.1115/1.4007487