An elaborate dynamic model of dual-motor precision transmission mechanism for performance optimization

Abstract The dual-motor precision transmission mechanism (DMPTM) is an alternative way to eliminate backlash completely while ensuring the stiffness of the servo system. However, most of the established models of DMPTM are not accurate enough, which are not conducive to the optimization of system performance and the design of high-precision controllers. In this paper, based on the detailed linear model of the single components of the DMPTM, the dead zone model considering the time-varying stiffness is proposed to describe the backlash of the two transmission chain and the friction of the mechanism is depicted by Stribeck model. Then, a high-precision dynamic model of the DMPTM is formed. Finally, the model validation experiments of the open-loop and closed-loop are carried out in the time domain and frequency domain. The experimental results show that the proposed model can accurately describe the nonlinear characteristics of the mechanism. The Pearson correlation coefficient between the proposed model and the actual system is ropen-loop >99.41% for open-loop and rclosed-loop >83.7% for closed-loop, which are both better than the existing model. In the frequency domain, whether it is open-loop or closed-loop, the frequency response of the proposed model also reproduces the actual system well, which verifies the accuracy of the model.