Comparison of error modeling between inverse kinematics and product of exponentials methods for a 5-DOF hybrid perfusion manipulator

Establishing a comprehensive error model that encapsulates all kinematic error parameters constitutes a critical foundation for achieving satisfactory kinematic calibration performance. In this study, a 5-DOF 5PRR+5PUS-PRPU hybrid perfusion mechanism with a variable structure is selected as the research object, and error modeling is conducted using inverse kinematics and the product of exponentials (POE) method, respectively. Comparative analysis of these two error modeling approaches is performed through kinematic calibration simulations of the hybrid mechanism. Firstly, error models of the 5-DOF hybrid perfusion mechanism are established via inverse kinematics and the POE formula method. To replicate real-world kinematic calibration scenarios, the actual kinematic parameters of the mechanism and the actual pose of the moving platform are defined. Owing to the presence of the 5PRR variable base, kinematic calibration simulations of the hybrid perfusion mechanism are executed separately when the base is positioned at different locations. The results demonstrate that, in comparison to the calibration results obtained via the traditional inverse kinematics modeling method, the mean position and orientation errors of the moving platform after kinematic calibration based on the POE error model are reduced by 89.04 % and 63.79 %, respectively. This verifies the correctness and effectiveness of the proposed POE-based error modeling method and kinematic calibration simulation approach, which can be extended to the error analysis of most parallel mechanisms.