Contact-mechanics-based compliant control in force-moment ratio space for dual pin-hole assembly of a robotic manipulator

Purpose Because normal and tangential forces in pin-hole assembly are coupled nonlinearly in a pose-dependent manner, jamming-diagram-based methods may violate contact limits and fail. To address this issue, this paper proposes a pose-dependent elastic contact model and a convex-polygon mechanical constraint in force-moment ratio space to guide the selection of compliant assembly strategies. Design/methodology/approach The configurations of cylindrical and flat pin-hole assemblies, together with contact mechanics models that account for dimensional tolerances, are established. The contact limits are then formulated and linearly mapped into jamming-diagram ratio space. Distance metrics between the jamming-diagram boundary and the convex polygon are used to select among four force/position-compliant strategies. Different scenarios are experimentally validated on a pneumatic-assisted manipulator platform. Findings Different clearances have different effects on the position of the contact point, and interference size is positively correlated with deformation. Comparative experiments on four compliant control strategies verified the effectiveness of the proposed method, which achieved smaller force-moment ratios in directions with limited margins. Experimental results for mixed pin-hole assemblies under clearance-fit and interference-fit conditions confirm the general applicability of the proposed method while maintaining small force-moment ratios. Originality/value This work links microscale contact mechanics with macroscale control decisions by integrating a pose-dependent edge-contact model with a convex constraint in jamming-diagram space, thereby enabling strategy selection that yields smaller force-moment ratios.