An Experimental Study on the Dynamics Calibration of a 3-DOF Parallel Tool Head

In this article, by taking a 3-DOF parallel tool head as an object of study, a dynamics calibration method is investigated to improve the calculation accuracy of driving forces and dynamic parameters. First, the dynamic model of the parallel tool head is established in joint space, and the dynamics prediction problem is described through a typical reciprocating feed motion experiment on a prototype. Next, a decoupled polynomial model is proposed to fit dynamic parameter in workspace, which is used to solve the parameters coupling problem of parallel mechanism, and related simulations are further given to validate the reasonability and determine the optimum order of the polynomial model. Finally, a complete dynamics calibration experiment is designed considering the characteristic of the decoupled fitting model, and all actual coefficients are obtained. Moreover, some verification experiments are performed at the nontest positions, and the results show that the calculation results at these nontest positions are consistent very well with the actual values by using the calibrated model, which proves the effectiveness of the proposed dynamics calibration method.