A new type of multi-degree-of-freedom miniaturization actuator using symmetric piezoelectric pusher element for a pocket sun-tracking system

This study presents a 2 × 2 pocket sun-tracking system that combines a multi-degree-of-freedom motion (multi-DOF) piezoelectric actuator with a hemisphere concentrator lens. The multi-DOF piezoelectric actuator consists of two parallel symmetric piezoelectric pusher elements (SPPEs) and ball-bearing bases. The proposed multi-DOF piezoelectric actuator uses three SPPE vibration modes to rotate a hemisphere concentrator lens along three perpendicular axes. The experiment in this study demonstrates how the 2 × 2 pocket sun-tracking system is driven by different modes and rotates around the X-, Y-, and Z-axes. When applying 3 Vpp to a multi-DOF piezoelectric actuator, the rotating accuracies of the 2 × 2 pocket sun-tracking system along the X-, Y-, and Z-axes were 0.022°, 0.022°, and 0.007°, respectively, and the driving frequencies along the X-, Y-, and Z-axes were 223.4 kHz, 223.2 kHz, and 225 kHz, respectively. The results confirm that the 2 × 2 pocket sun-tracking system was accomplished successfully using the multi-DOF piezoelectric actuator.