A three-legged stick-slip piezoelectric actuator inspired by haystack unloading device and it’s driving method

• Waveform Innovation: Triangular waveforms with three legs ensure no backward motion. • High Interchangeability: Unique wedges and 3D printing ensure cost-effective assembly. • Cost Reduction: Flexible hinges and bases are 3D-printed, lowering manufacturing costs. Currently, the driving waveforms of existing stick-slip piezoelectric actuators are mostly sawtooth or modified sawtooth waveforms. The steep descending edge of the sawtooth waveform causes vibrations and backward motion, significantly limiting their applications. We argue that the sawtooth waveform is not the optimal driving waveform. Inspired by a haystack unloading device, this study proposes a three-legged driving method based on triangular waveforms and a low-cost, 3D-printed three-legged stick-slip piezoelectric actuator. The proposed method achieves no backward motion under both low and high frequencies. Utilizing the weak stiffness of PLA-based flexible mechanisms, the design eliminates the micro-displacement plateform. Preload between the driving foot and the slider is achieved by designing interference-fit gaps. This simple and low-cost structure is suitable for low-frequency laboratory environments. The actuator achieves a maximum driving speed of approximately 580 μm/s, a maximum horizontal load of 50 g, and a maximum vertical load of 2 kg, and achieve higher low-noise performance. The three-legged driving method is novel, offering advantages such as low vibration, low noise, and no backward motion, holding significant research value.