Control of a novel hybrid conveying mechanism for electro-coating of automobile bodies

For a novel conveying mechanism which is highly nonlinear, highly time-varying and highly coupled, a synchronized sliding mode control with nonlinear disturbance observer is proposed to improve the synchronization performance and the disturbance-rejection performance. First, the kinematic analysis of the conveying mechanism is completed and the dynamic model with lumped disturbances of the conveying mechanism is established by the Lagrange formulation. Second, the coupling error is defined with the tracking error and the synchronization error, and the synchronized sliding mode control is designed. Third, a nonlinear disturbance observer is introduced into the controller in order to estimate and compensate for the various uncertainties. The stability of the proposed controller is proved in theory when the lumped disturbances are not zero. Finally, Matlab simulation results show that compared with the sliding mode control with nonlinear disturbance observer and the synchronized sliding mode control without nonlinear disturbance observer, the proposed controller not only has good synchronization performance, but also has strong robustness and the ability to overcome uncertainties.