The word piezo comes from the Greek word piezein – to squeeze or press. A piezoelectric effect is the ability of some materials, often piezo ceramics, to generate an electrical charge in response to mechanical force (squeezing or pressing).

The piezoelectric effect is reversible, so materials exhibit “the inverse piezoelectric effect” – in which they change shape or size when excited by an electric charge. Although the inverse piezoelectric effect has been professionally studied for some years, practical applications of piezo technology in everyday devices like digital cameras, industrial valves, and toys have only been relatively recent.

As the demand for better energy efficiency, higher performance, more miniaturization, and greener technology grows, companies are shifting their focus to piezo motor technology as an alternative to conventional electromagnetic motors. This efficient and economical technology offers the answers to many modern-day problems at an affordable price.

PIEZO MOTION TECHNOLOGY

There are several types of piezo motors on the market; however, Piezo Motion’s design and technology produce unique standing wave-type piezo motors that provide certain key advantages in use and manufacturability. Piezo Motion motors come in various sizes and configurations, and the company’s full line of rotary and linear piezo motors addresses many modern-day requirements for motion control systems.

Whether rotary or linear, Piezo Motion’s motors work on the same principle of ultrasonic standing waves, which cause electrically induced excitation within a piezoelectric resonator/ceramic. Piezo Motion’s Blue series targeting is precise, lightweight, compact, and reliable whilst designed for volume manufacture making them ideal for OEM applications.

Piezo Motion’s motors operate under a patented principle of excitation that uses two right-angled or orthogonal vibration modes (with relative phase difference). The two modes of vibration cause the piezoceramic to oscillate so that, when harnessed, it enables the creation of precise continuous rotary and linear motion. Furthermore, this technique (which is part of Piezo Motion's IP portfolio) greatly simplifies drive circuit design and requires very low voltages, reducing the drive electronics cost. 

Piezo Motion's innovative technology combined with rigorous design philosophy, utilizing a combination of piezoceramics and modern materials and manufacturing, enables the company to produce precision motion products at a competitive cost.

PIEZO TECHNOLOGY IN ACTION

Piezo Motion’s ultrasonic piezo motors are used globally in industries such as biomedicine, optics, semiconductors, and nanotechnology, as well as industrial electronic and automotive systems. 

Click on the animations shown below to see the principle of piezo motor operation in unidirectional and bidirectional modes.

TECHNOLOGY FOR DEVELOPMENT

Piezo Motion employs different patented techniques based on our underlying standing wave principles to achieve both rotary and linear motion.

Piezo Motion’s most recent line of rotary and linear motors use a rectangular-shaped piezoceramic resonator (the stator). The resonator has a tooth-shaped protrusion at a midpoint along one length. The resonator is spring-loaded resulting in the tooth being held-pressed against the rotor (in the case of a rotary motor) or linear bearing/slider (in the case of a linear motor). Excitation of the resonator causes movement of the tooth, which in turn creates motion of the rotor/slider resulting in either rotary or linear motion (see animations below).

Piezo Motion also has a different line of rotary piezo motors based on a ring-shaped piezo resonator and stainless steel pushers, as shown in the figure. These pushers attach to the piezo resonator through a vibrational shell. An ultrasonic radial standing wave is electrically excited in the resonator, which causes the ring to expand and contract in radial directions and stimulates the pushers’ movement along the radius. 

Because of their elasticity, the pushers vibrate with the same frequency (although with shifted phase) in a direction orthogonal to the radius of the ring. The two different orthogonal movements result in elliptical actions from the pushers. Because the pushers are spring-loaded (held-pressed) against the rotor, their movement, combined with friction at the pusher contact area, causes the rotor to rotate. 

Piezo Motion’s expertise in the field of standing wave-type piezo motors culminates in several models, and each has been designed with a specific layout and distinctive materials to provide superior operating performance. 

This patented, practical design is applicable to many high-performance OEM applications such as surgical robots, nano-positioning stages, medical devices, laboratory equipment, precision automation, drones, and 3D printing.

PWM CONTROL OF THE PIEZO MOTION MOTOR

The Piezo Motion motor is straightforward to control using an external signal source on the driver board (the driver board is typically matched to a specific piezo motor model). A digitally controlled AC voltage source applies a train of electrical pulses directly to the piezoceramic. 

Motor speed is controlled by changing the sequence or duration of the pulses (i.e., PWM). To switch between a continuous rotation of the piezo motor to a precise stepping mode, one modulates the excitation voltage source.

Learn more about the specific technical details and the key benefits of each Piezo Motion product by clicking on the categories below (additional information is also provided in each product datasheets).