Cross-coupled synchronization control strategy for rebar binding robots based on impedance control

Rebar node binding on construction sites is predominantly carried out manually, and existing mobile robots struggle to navigate complex rebar mesh due to desynchronization and kinematic instability caused by the unstructured grid-like holes and uneven nodes. To address this, we propose a dual-motor cross-coupled synchronous control strategy based on impedance control, applied to a wheel-legged rebar binding robot. This innovative strategy is accomplished by integrating synchronization error terms into the impedance model to establish a "virtual mechanical coupling" between bilateral motors, allowing for real-time torque redistribution when the robot encounters uneven environmental resistance. We conduct a dynamic analysis of the robot's lateral movement mechanism, deriving the theoretical output torque, followed by comprehensive validation. Quantitative results demonstrate that under conditions with obstacle interference, the proposed method reduces the peak displacement difference by 29.5% and the displacement variance by 75.9% compared to traditional decoupled impedance control. Notably, in high-friction threaded rebar mesh, the system successfully neutralizes internal force asymmetries, achieving nearly identical cumulative torque profiles for both legs. Furthermore, even at a velocity of 1600 mm/s, the longitudinal error is limited to 2.75 mm, effectively suppressing cumulative deviations stemming from off-center of gravity and mesh deformation. By harmonizing dynamic load distribution, this strategy ensures superior robustness and kinematic consistency for robotic platforms in complex construction environments.