Design and fabrication of a high-power eyeball-like microactuator using a symmetric piezoelectric pusher element

A novel multidegree-of-freedom (MDOF) eyeball-like microactuator was developed using a symmetric piezoelectric plate and an NiCo alloy micropusher element. A LIGA-like technique was employed to manufacture an NiCo alloy micropusher with a Vickers hardness value of 550, which was then attached at the midpoint of the long side of a piezoelectric plate with dual electrodes to construct a symmetric piezoelectric pusher element (SPPE). The research integrated the concept of LEGO bricks, and three different vibration modes of the SPPE were designed to develop a high-power MDOF motion platform, which was able to rotate a spherical charge-coupled device (CCD) along three perpendicular axes. This MDOF eyeball-like microactuator consisted of a stator and a rotor: The stator was created from two mutually orthogonal sets of parallel SPPEs to form an MDOF motion platform, and the rotor was a spherical CCD. The experiment demonstrated high-power MDOF eyeball-like microactuator working frequencies along the X-,Y-, and Z-axes to be 223.4, 223.2, and 225 kHz and the rotation speeds to reach 50, 52, and 180 r/min, respectively, at a driving voltage of 30 V_pp. The volume ratio of rotor to stator was 20.32, and this design can therefore drive a rotor of a volume greater than ten times that of the stator. In addition, the driving voltage was proportional to the rotation speed; hence, when the rotor diameter was increased or the spherical rotor weight reduced, the rotation speed increased. In the future, this MODF eyeball-like microactuator may be used for a number of applications, such as sun-tracking systems for green-energy harvesters and eyeball-like devices for use in the biomedical field.