Several piezoceramic motion control devices are used in bio-medical applications: XY microscope stages, rod-drive pushers, and sub-miniature slides.

Piezoelectric motors are already used successfully in ultrasonic emitters, artificial fertilization, micromonitoring, surgery devices, MRI-compatible robots, microdose dispensing, cell penetration and cell imaging in cytopathology, pick-and-place systems, drug delivery devices, 3D scanning, and laser beam steering in ophthalmology and dermatology.

For example, in Optical Coherence Tomography, piezoelectric motors are used to impart rapid periodic motion to the unit's reference mirror and imaging optics. To enable creation of 3D images from optical interference patterns, optical fibers must be moved both axially and laterally during scans. Here, piezomotors move more precisely for improved image resolution over conventional electromagnetic motors.

For point-of-care and medical test equipment in which extremely fine positioning and measuring is required, piezomotors create precision motion from inches to nanometers. Piezoelectric actuators are also finding use in transdermal drug delivery, as in needle-free insulin injectors. Endoscope-gastroscope monitoring benefits; similary, new biomedical and noninvasive microsurgery tools such as tweezers, scissors, drills, are adapted to a micro-robot base powered by piezomotors.

Another application: 3D Cone Beam Imaging is used in orthodontics and treating sleep-apnea patients. The imaging makes exact mouth models (for fitting oral appliances) using piezoelectric actuators.

Similarly, confocal microscopy in ophthalmology for implant quality control uses piezoelectric motors: Very precise motion of the optics is required to adjust the focal plane and for surface scanning. Piezoelectric positioning systems are integrated directly into the optics.

Piezo insects may run, work in colonies

New robots the size of ants could soon be marching into new applications with solid-state legs and mandibles. Developed by Perdue University researchers, West Lafayette, Ind., the design includes legs made of bundled piezoelectric beams. Computer simulations suggest that the bugs could be mass-produced using manufacturing technologies common to the semiconductor industry, and made to scavenge vibrational energy from the environment to recharge their power supply. A tripod gait — used by most insects — would enable the bugs to remain stable while traversing uneven terrain.

According to Jason Clark, assistant professor of electrical, computer, and mechanical engineering at Purdue, the new design differs from previous microscale robots — which use complex moving parts that mesh, touch, wear, and jam. “Because the new microids are solid state without discrete parts such as gears, they will likely be long-lasting and robust. If a microid were stepped on, it would probably just get up and walk away.”

Beams of piezoelectric material ordinarily do not expand enough to be useful for robotics, but simulations indicate the new design overcomes this limitation: If the three beams are joined together only at both ends, applying a voltage to one or more of the beams produces a surprisingly large lateral movement.