Development of an Untethered Self-Moving Piezoelectric Actuator With Load-Carriable, Fast, and Precise Movement Driven by Piezoelectric Stack Plates

This article presents an untethered self-moving *piezoelectric actuator (USPA) capable of producing the load-carriable, fast, and precise movement. Here, a pair of piezoelectric stack plates, a two-level amplifying mechanism, and an onboard circuit composed by several operational amplifiers with large capacity are integrated to form a compact transducer. The USPA has the wooden ox and gliding horse-inspired configuration and adopts the walking gait by adjusting two transducers’ phases. Initially, by constructing a dynamic model, the transducer is structurally optimized to enhance the driving-force-to-weight ratio. Subsequently, a prototype with the size of 72 × 66 × 80 mm³ and the weight of 147.76 g was fabricated to assess its performance. In continuous operation, the USPA yielded the maximal speed of 241.5 mm/s and climbed the slope of 8.6° at 800 Hz frequency. Meanwhile, it carried the maximal payload of 2265 g (equal to 66.7 and 15.3 times of the mechanical part’s weight and the entire USPA’s weight, respectively) and produced the minimal cost of transport of 12.2. In stepping operation, its minimal step displacement reached 48.5 nm. This article validates that the USPA offers good moving/carrying/positioning capability, and provides technical reference for designing the untethered actuators driven by piezoelectric stack.