The piezoelectric effect


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.


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.


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 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.



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.


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).

Applications in industrial


Piezo Motion products are used in a broad range of industrial equipment applications, including food and pharmaceutical processing, gas and oil pipelines, power reactors, chemical reactors, steam/water pipelines, and vacuum systems.

Technology benefits & features


At Piezo Motion, we are leading the way in Piezoelectric Motor Technology. See some of the key benefits of choosing Piezoelectric motors over traditional Electromagnetic motors (e.g. Stepper Motors):

  • High Performance

    Technology that provides >1000 X’s Better Resolution, >100 X’s Faster Reaction Time and >10X’s Greater Specific Power Stall Torque/Force compared to conventional DC motors.

  • Energy & Cost Saving

    Piezo Motion’s piezo motors operate at low voltage (e.g. 12 VDC, customizable down to 5 VDC) and have increased energy efficiency. They are designed for direct-drive applications where the need for a gearhead is eliminated altogether.

  • Unique properties

    Piezo Motion’s piezo motors are scalable in design (rotary and linear), can be operated silently and consume zero energy in hold position.

  • Non-magnetic

    Piezo Motion’s piezo motors are available in non-magnetic configurations making them ideal for specialized applications where traditional DC motors cannot be used (e.g. medical MRI)

  • Affordable Technology

    Modern engineered thermoplastic design enables Piezo Motion’s piezo motors to be priced extremely competitively compared to other brands and technologies. Simplified driver electronics lowers ownership cost further.

  • Environmental

    Piezo Motion’s piezo motors are immune from electromagnetic interference (EMI /RFI) and do not contain any rare earth elements (REE’s).

Electronic driver overview

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Piezo Motion's electronic driver PCB has been designed to provide an economical user-control interface compatible with all Piezo Motion piezo motors. Each driver PCB is supplied pre-programmed for the specific motor model and is software configurable to provide optimization of drive signals and integrated controls. The primary purpose of the driver PCB is the formation of electrical pulses with specific frequency and amplitude for excitation of the piezo motor.


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Closed- or open-loop 

The driver PCB can be programmed to work in either open-loop or closed-loop modes. In open-loop mode, the driver PCB controls the motor as a standalone device without any positional feedback information. When either the environmental temperature or the load of the motor changes the driver PCB implements stabilization of the pre-programmed current (which is different for each model of piezo motor). This provides maximum speed of movement according to the published motor specifications.

Manual control of motor motion can be performed by pressing either of the two Manual Control Buttons located on the driver PCB. External control of the motor is implemented by applying a logical TTL “0” to either of the two independent External Input Control pins (pin 1 and pin 2) located on the driver PCB. Input to these pins controls the direction of movement of the motor. A third pin (pin 3) is Ground. Motion is stopped by applying a logical TTL “1”.

The electronic driver PCB enables precision motion control of the piezo motor via a microcontroller based 12 V DC digital system, which also allows for user-generated inputs for motion control.

The driver assembly (Main PCB) is comprised of five main sections as shown in the block diagram. The Power Supply (PS), accepts a 12 V DC input through a DC power jack with a 2.0 mm center positive pin. The 12 V is filtered then regulated to 5 V DC and filtered again to provide the board operational voltage.

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Continuous motor operation 

The Direction Control Unit (DCU), includes manual (push button) directional control signal inputs to the microcontroller (MC) for continuous piezo motor operation. This is implemented through active TTL low inputs to the microcontroller. An external control input (3 Pin connector) signal interface is included to facilitate user-generated signal or pulse train controls for stepping mode operation (i.e. Pulse Width Modulation, “PWM”).  The Current Sense Unit (CSU) monitors current during motor operation.

The Microcontroller (MC), provides software-based control of motor motion in response to directional control inputs. When directional control signals are received, the microcontroller generates enable control output signals proportional to the control signals, and current feedback (via CSU) to the Driver (DR). In PWM mode of operation, the pulse width of the driver enable signal determines the amplitude of motion. A current negative feedback input is used by software to determine the optimal excitation frequency of the piezo motor to maintain the required current.


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Driver voltage

The Driver element (DR) is comprised of two gate driver ICs with FETs (to provide drive current) and step up voltage transformers. The Driver section uses the supply 12 V DC. The enabled gate driver amplifies the 5V TTL phase signals to a 12 V gate drive signal that switches on the FETs. When the FETs are active, the transformer steps up the ultrasonic signal voltage to the level required for excitation of the piezo motor (which can be between 30 V to 120 V depending on the Piezo Motion motor model). Channel drive current is also detected within the Driver element, where it is amplified then integrated to provide an analog signal proportional to the channel drive current. This current sense feedback is used to optimize motor control and performance. Activation of motor motion in a specific direction is performed by command from the microcontroller.

In closed-loop control (feedback control) mode, an additional daughter PCB is mounted on driver PCB (see Motion Control Closed-Loop). Feedback from an external optical encoder, mounted on the piezo motor, is fed to the daughter board and used to close the loop. The position and speed of the motor can then be controlled through an elaborate set of commands via either a USB port (through Piezo Motion’s GUI) or serial (RS 232) port commands.

Motion control


Each motor requires a driver board detailed with three different control options: manual control, PWM, or closed-loop.

Piezo Motion Motion Control Software is designed for optimized motion control via micro USB. Motion Control is also available via Python® using Piezo Motion’s Motor API and via Serial Port with Controller/PC and Driver PCB for structured data commands.


Motion Control Open-Loop


When an external control signal (logical TTL “0”) is applied continuously to the external input control of the driver board, the piezo motor will move in continuous mode at its maximum specified speed. Alternatively, control of speed of motion using PWM is implemented by varying the pulse duration and repetition rate (frequency) of the input signal. The size of each step is determined by the pulse duration, and the speed of travel is determined by the pulse repetition rate. The minimum pulse duration is approximately 30 µs (microseconds). The maximum repetition rate (F), measured in Hertz, for a selected pulse duration (T), measured in seconds, is determined by the formula F = 1/T. The range of speed variation in PWM mode can be up to 6 orders of magnitude.

Similar to DC motors, control of the piezo motor speed in continuous mode can be accomplished by adjusting the power supply voltage of the driver PCB within the range 5V DC to 12V DC (note: this requires custom programming of the driver PCB). This control can enable decreases in the maximum specified speed of the piezo motor at 5 V down to 1/5th of the speed at 12 V. In this mode, PWM can also be used in parallel to vary speed within a higher dynamic range.

Motion control of the piezo motor in this mode can be accomplished using virtually any standard commercially available DC driver/software (e.g. Arduino). However, when implementing this mode of control, it is necessary to consider the following points:

  • A supply voltage, with positive polarity, in the range of 5 V DC to 12 V DC must be applied to the 12 V DC input connector of the driver PCB. Providing the driver PCB has been custom programmed, then the speed of the motor will be proportional to the input voltage. If the driver PCB was not custom programmed and the input voltage is decreased from 12 V DC to 9 V DC, the motor will continue to hold a constant speed (due to an internal algorithm for speed stabilization). However, if the input voltage drops below 9 V DC, then the speed stabilization algorithm will not be able to hold the motor at constant speed and the motor will either slow down or stop.
    Note: In contrast to DC motors, negative input voltages to the driver PCB should NOT be used to change direction of motion as this may lead to failure and damage of the driver PCB. Change of the direction of movement is implemented through activation of the corresponding pins of the External Input Control pins (pin 1 and pin 2).
  • Due to the very high dynamic characteristics of the piezo motor, the minimum response time to a DC driver input will be substantially lower (e.g. 10 to 100 µsec) compared to a comparable DC motor.

Motion Control Closed-Loop



In closed loop mode, an additional daughter PCB is mounted on driver PCB (see figure). Feedback from an external optical encoder mounted on piezo motor is transmitted to the daughter board and used to close the loop. The position and speed of the motor can be controlled through an elaborate set of commands via either a USB port (through Piezo Motion’s GUI) or serial (RS 232) port commands.

The daughter board performs two key functions. Firstly, it enables the communication between the optical encoder installed on piezo motor and the driver PCB microprocessor, which provides for precision linear or rotational closed loop control. Secondly, the daughter board’s communications unit allows piezo motor motion control via external devices using either USB or Serial Port (RS 232) interface.

During installation of the daughter Board, the microcontroller is factory-programmed with proprietary encoder motion control algorithms. Once the daughter board is installed the driver PCB will no longer work as a standalone driver. However, manual control of motor movement can still be achieved by pushing the Manual Control Buttons of the driver PCB (Note: speed of motion will be lower than observed when pressing these buttons in open-loop mode).

Piezo Motion currently uses two types of encoders depending on whether the motor is a rotary or linear model:

  • The linear encoder has a resolution of 2.6 µm after interpolation and quadrature detection.
  • The rotary encoder has a resolution of 196 µrad (32,000 PPR) after interpolation and quadrature detection.

Two output signals from the encoder (channel A and channel B, with phase difference of 90°) can be monitored on the pins of the Encoder Output connector.

Control Types

Manual control

Uses pushbuttons on Driver Printed Circuit Board​.


Via electrical input to control pins on Driver PCB for control of speed and step size​.


Via (optional) encoder and Driver PCB.

Your questions are important to us.

Have a question? Contact Piezo Motion by phone or email and a member of our team will reach back out to you.