Modeling closed-loop mechanisms in robots for purposes of calibration

A method for modeling the significant parameters of closed-loop mechanisms in robots for purposes of calibration is presented. Nonlinear kinematic and mechanical characteristics of the closed-loop mechanisms are modeled in such a way that they can be integrated into an open-loop manipulator model and identified. This integration is accomplished through a separation of the spatial open-loop manipulator (defining the kinematic model) and its joint-actuating mechanisms or actuator models which can be nonlinear in case of closed-loop mechanisms. Identifiability of model parameters (including elasticity) is analyzed and calibration results are presented.