Long-range piezoelectric actuator with large load capacity using inchworm and stick-slip driving principles

Conventional long-range piezoelectric actuators (LRPAs) can produce large travel motions based on stepping driving actions. However, their load capacity is limited due to the difficulty in lifting the clamping force that acts against the external load when considering light wear on the clamping interface and fine displacement resolution. This study proposes a hybrid driving method that combines the inchworm and stick-slip driving principles, such that it can significantly improve the load capacity of LRPAs. By introducing a ball-screw-based clamping mechanism driven by the stick-slip rotary driving principle, a ball-screw-based inchworm piezoelectric actuator is designed, which achieves a driving force of 546 N, whereas the clamping force required to balance the external load is significantly reduced, leading to light wear on the clamping interface. Meanwhile, bidirectional motion with a resolution of less than 80 nm is achieved by relying only on a simple driving voltage sequence. The proposed hybrid driving method is instructional for the design of actuators used for the shape control of space structures, such as antennas and trusses, wherein a large driving stroke with fine resolution and a high load capacity with high reliability are important considerations.