Constraint-dependent friction parameter drift and compliance-based stabilization in over-constrained rolling linear guide systems

Rolling-element linear guide systems with multiple runner blocks and two parallel rails can become mechanically over-constrained, leading to parasitic loading and friction-parameter drift. This study distinguishes the friction contribution of additional rolling-contact interfaces from the excess friction associated with dual-rail engagement and evaluates a compliance-based stabilization strategy. LuGre-based friction identification was performed using sequential one-, two-, three-, and four-runner-block configurations. Friction increased in an approximately additive manner when runner blocks were installed on the same rail, whereas non-proportional growth emerged after the opposite rail was engaged. Relative to the additive prediction established from the measured same-rail runner-block increment, the four-block configuration exhibited excess maximum static and Coulomb friction forces of 0.864 and 1.097 N, respectively. A SUS304 flexure blade was then introduced to provide targeted lateral compliance while retaining high stiffness in the motion and vertical directions. The average velocity-wise standard deviation showed a descriptive reduction of 40.6% in the short-term repeatability assessment and a point estimate corresponding to a 31.1% reduction in the reassembly-based reproducibility assessment conducted under nominally consistent laboratory conditions. Mean friction levels changed only modestly, indicating that the principal benefit of the flexure blade was improved friction-response stability. These results support a consistent trend toward reduced sensitivity of the stage-level friction response to geometric and assembly variations, with potential benefits for friction-model reliability in precision motion systems.