Axis-Specific Haptic-Interaction Assistance Based on Concern For Others in Dyadic Collaborative Plate Control

Quantifying coordination in physical human-human interaction (pHHI) is challenging because classical mechanical metrics cannot distinguish individual operational skill from the coordination itself. We previously introduced Concern For Others (CFO)—a metric that isolates the behavioral changes attributable to considering one's partner—and demonstrated through regression analysis that the pitch-axis summation component and the roll-axis deviation component of Position CFO are the primary predictors of performance improvement in a dyadic plate-control task.

This work-in-progress paper proposes two CFO-based haptic assistance methods: PSUM (which augments pitch-axis summation) and RDEV (which augments roll-axis deviation). We evaluated these methods, their combination (PSUM+RDEV), a standard PD controller, and a no-assist baseline in a two-person plate-control task involving eight participants (four dyads).

Results show that RDEV alone significantly degraded velocity-tracking performance, likely due to an asymmetric force distribution between operators. Conversely, PSUM and PSUM+RDEV caused no significant degradation. These findings suggest that augmenting the summation component can be safely applied, whereas amplifying the deviation component impairs velocity coordination in dyadic motor tasks.