Double shaft–hole assembly for a manipulator based on the force/moment balance equivalent jamming method

Purpose – Due to the unique geometric conditions of the assembly objects, jamming during the manipulator assembly process can lead to excessive contact forces or even assembly failure. This study aims to propose an assembly method–an equivalent jamming approach that balances forces and moments—to overcome problems caused by objects whose geometric features substantially affect the assembly process. Design/methodology/approach – Quasi-static force/moment balance equations are derived for three stages of the assembly process under defined conditions. The vertical force is obtained from force/moment balance, while the coordinate in the direction without moment feedback is replaced using known geometric and force/moment information from the jamming diagram. The proposed method is validated through manipulator assembly experiments, including jamming diagram verification, at different assembly angles and assembly tests in both planar and spatial scenarios. Findings – Experimental results indicate that the jamming diagram, which accounts for various assembly angles, is effective. The jamming diagram using the equivalent method can effectively facilitate the assembly of manipulators in both planar and spatial environments. Originality/value – The innovative manipulator assembly method proposed in this study not only addresses the challenges posed by the target’s geometric characteristics on the assembly process but also leverages the consistency of the balance conditions in the jamming diagram to substitute for force feedback in certain directions.