Modeling and Experiments of Bipedal Actuated Linear Piezoelectric Platform With Smooth Motion and Strong Load Capacity

Piezoelectric platforms commonly use step accumulation to achieve large strokes. However, frequent starts and stops cause velocity fluctuations, particularly under large load conditions. To achieve smooth motion in large strokes and with strong load capacity, a biped cooperative actuation method (BCAM) using continuous alternate stepping is proposed. The two driving feet contact or separate the mobile platform at a constant velocity, and at least one driving foot contacts and moves the mobile platform at any moment. The motion principle and exciting schemes of BCAM are illustrated. Subsequently, the theoretical model of BCAM is derived, and numerical simulations are conducted to predict the output performances and load characteristics. To verify the feasibility of BCAM, a bipedal actuated linear piezoelectric platform prototype is designed, and its output performances are tested. Experimental results indicate that the prototype can achieve smooth motion with a wide velocity range from 2.8 nm/s to 1180.82 µm/s. Most importantly, the designed piezoelectric platform worked at BCAM has good smoothness even under a carrying load of 11.8 kg and an output force of 11 N. This work is conducive to broadening the motion characteristics and application prospects of piezoelectric platforms.