A non-resonant bionic piezoelectric robot with fast, load-carriable, and precise movement inspired by crab’s lateral walking gait

Abstract To accomplish fast, load-carriable, and precise movement, a non-resonant bionic piezoelectric robot (BPR) was proposed inspired by crab’s lateral walking gait. A compact two‐stage displacement amplification mechanism was adopted to obtain satisfactory output displacement: the first-stage mechanism employs a spatial parallelogram mechanism, while the second-stage one utilizes a crab‐inspired flexible hinge mechanism. To verify its feasibility, first, a dynamic model was established, and the dimensions of the robot were optimized to improve the driving-force‐to‐weight ratio. Subsequently, a BPR prototype with the size of 78 × 90 × 85 mm 3 and the weight of 102.12 g was fabricated to evaluate its moving, carrying, and positioning performance. In the continuous operation, the BPR yielded the maximal speed of 180.6 mm s −1 , relatively high compared to the non-resonant PRs and comparable to several resonant ones. Its maximal payload reached 1500 g (14.68 times of its self-weight) and its maximal towing force was 0.8 N (corresponding to the towing-force-to-weight ratio of 19.8 N kg −1 ). Furthermore, it achieved the turning/rotating movement, crossed a cylindrical tube, climbed a slope of 3.27°, and passed a runway. In the stepping operation, the BPR produced the minimal step displacement of 273 nm. This paper demonstrates the BPR’s fast, load-carriable, and precise movement, and provides an efficient approach to design compact piezoelectric robots.