Physik Instrumente – accelerating linear motion technology in ever-tinier steps

Piezo linear motors in particular are enabling engineers to design systems that take the possibilities of what can be achieved at the micron level and below to the very limit, with significant benefits: • Very compact and self-locking – the tip of the motor actuator is clamped to the friction bar - so is free of positional jitter when stationary. With closed-loop electromagnetic and stepper/DC drives the actuator may experience positional jitter caused by the control loop itself. • Low power consumption - and none at all when powered off at the target position, unlike electromagnetic linear motors, which require power to hold position. As well as making electromagnetic motors less efficient this can also result in possibly unwanted heating effects. • High-speed operation, so ideally suited to fast scanning applications. • Very little noise generation; perfect for laboratory environments. Stepper or DC motor-driven linear actuators, on the other hand, incorporate a thread and sometimes a gearbox, which can make them noisier and more prone to mechanical failure. The latest Piezo motor drives are almost free of mechanical parts and are therefore less prone to wear and tear. The state of the art in this area is exemplified by PI's new M-272 and U-264 linear actuators, which utilise Piezo linear motors. The M-272 has a travel range of 50mm, with velocity up to 150mm/s and incorporates a linear encoder for positional feedback and an integrated linear guiding system. The low-profile U-264 RodDrive is a reduced-cost, open-loop actuator without guiding system, but features an extended travel range of up to 150mm, with velocity up to 250mm/s.