Excitation Friction-Reducing Method Considering Low Power Consumption and High Operational Stability

Applying mechanical vibration at resonance-frequency is widely recognized for achieving friction reduction, yet it often involves high vibration amplitudes that can cause tip wear and require substantial energy. This study reveals that a friction minimum also occurs at sliding velocity-dependent washboard-frequency under both in-plane and out-of-plane excitation. Compared with resonance-frequency excitation, washboard-frequency excitation exhibits higher stability. Both washboard- and resonance-frequency excitations can achieve over 80% friction reduction, while the energy input required for washboard-frequency excitation is only approximately 1.7% of that for near-resonance-frequency excitation. Friction reduction at washboard-frequency stems from excitation-induced changes in normal force and tip stick-slip dynamics. Concurrently, the friction reduction efficiency is strongly related to the excitation phase. Only when the instantaneous excitation perfectly matches the stick-slip motion can the most obvious friction reduction effect be achieved. Furthermore, we have also demonstrated that the technique of reducing friction, through excitation of washboard-frequency, can be employed to the sliding surface of the strain-induced moiré superlattice. This work provides insights for designing friction-reduction strategies that prioritize low power consumption and high operational stability.