Design, analysis and experimental performances of a multi-mode friction inertial piezoelectric actuator

To enrich the output performances and application fields of friction inertial piezoelectric actuators, a multi-mode friction inertial piezoelectric actuator was proposed. It had three driving modes, i.e. the inertial stick-slip mode, the inertial impact mode and the compound driving mode. An integrated flexible mechanism (IFM) consisting of the lever-shaped flexible mechanism (LSFM) and the butterfly-shaped flexible mechanism (BSFM) was designed for achieving these three driving modes. Theoretical analysis of the IFM was performed by using the matrix-based compliance modeling method and the response surface methodology. An experimental system was established to test the output performances of the actuator under various driving modes. Experimental results indicated that the actuator in three driving modes presented different output performances, and the output displacement in the compound driving mode was equivalent to the sum of those in the two single inertial modes. In the compound driving mode, the actuator achieved larger step displacement, and it also achieved good speed, loading capacity as well as motion stability. For instance, the maximum speed was 10.04 mm/s at 250 Hz in the compound driving mode, while they were 5.06 mm/s at 250 Hz in the inertial impact mode and 10.81 mm/s at 450 Hz in the inertial stick-slip mode. Furthermore, output performances of the actuator could be easily tuned in the compound driving mode when two driving voltages were controlled separately, which provided an idea for achieving the linear smooth motion.