A stick–slip piezoelectric actuator utilizing a special parallelogram flexible mechanism

A stick-slip actuator based on a parallelogram flexible mechanism is proposed to achieve high-performance output. This actuator utilizes the coupled motion generated when the parallelogram is driven by the piezo-stack to propel the slider. To minimize the shear force on the piezo-stack during operation, straight circular flexible hinge structure is added to the output end of the piezo-stack. In addition, a straight beam flexible hinges structure is incorporated into the parallelogram flexible mechanism to achieve a high output speed under conditions of low driving frequency. Static analysis, finite element simulation, optimized design, and experimental studies of the flexible mechanism were conducted. The finite element analysis indicates that the flexible mechanism, based on a parallelogram flexible mechanism, can generate motion in both the X and Y directions, reduce the shear force on the piezo-stack, and increase the output speed of the actuator, among other functions. A prototype of the stick-slip piezoelectric actuator was fabricated, and a measurement system was developed and experimentally validated against the results of the theoretical analysis and finite element simulation. The experimental results demonstrate that the actuator achieves a maximum output speed of 17.64 mm/s, a resolution of 62 nm, a maximum load capacity of 310 g, and excellent repetitive positioning accuracy, with the structural dimensions of the stator measuring only 43 × 44 × 10 mm3.