Straightness error modeling and compensation for gantry type open hydrostatic guideways in grinding machine

This study presents an approach to model and compensate the vertical straightness error of gantry type open hydrostatic guideways. The straightness error is measured at different measurement points on the beam using a laser interferometer. To investigate different trends in the straightness error, a static analysis model is established, based on the error averaging effect considering the guiderail profile error. The linear deviation of the slider is computed and the vertical straightness error is calculated using a least-square method. The simulation results indicate that the measurement points have a big impact on the straightness error. The minimum value appeared when measurement point located at the middle of the X beam. And more closer to Y guide rails, higher value will be. The positions of the measurement points are chosen according to the change trend of the vertical straightness error. Finally, vertical straightness error is compensated and the compensation results are compared between different coordinate values. Experimental results show that the straightness error model and error compensation strategy help to effectively improve the accuracy of gantry type open hydrostatic guideways in grinding machines.