Controlling the motor

The PMD301 is a 1-axis controller/driver for use with Piezo LEGS motors from PiezoMotor. The two motor connectors provide identical output signals. Several units may be chained together to form multiaxis systems for use in various OEM applications. For linear motors it provides resolution down to subnanometer range.

PMD301 is the ideal choice for system designs where one or several Piezo LEGS motors are used. The unit controls the Piezo LEGS motor by feeding waveform signals to each of the piezoelectric actuator legs. The waveforms are designed specifically to make the drive legs perform a precise walking motion. The motion of the drive legs is transferred via friction contact to a linear rod or a rotary disc.

Communication with the unit is via USB or via 2-wire RS485. Multi-axis chain is possible using the RS485 interface. The PMD301can operate in closed loop using quadrature or serial encoders, or act as a Piezo LEGS amplifier for use with standard motion controllers (Servo Mode via analog or SPI interface).

Running 8192 microsteps produces 1 full waveform cycle (wfm-step), which gives around 5 μm movement with a Piezo LEGS linear motor. Microstep resolution is better than 1 nanometer. The waveform update rate is 65 kHz and maximum cycle frequency (wfm-step rate) is 2500 Hz. Maximum cycle frequency will be set lower for motors with capacitance >1.2 µF.

The motor can be parked (powered down) to minimize position disruption at power off. Still, the position may change somewhat during the parking procedure.The Piezo LEGS motors are capacitive and do not consume any power standing still, so there is normally no reason to park while holding a position. Do however park when connecting and disconnecting motors.

PMD301 is not intended for critical applications such as life support. The user is responsible to prevent any unacceptable damage that may be caused by system malfunction.

PMD301 has been tested to comply with EN and FCC standards for radio emission.