Cedrat Technologies, innovation in mechatronics

Modular Stepping Piezo Actuators (MSPA) use the stick-slip principle to combine high resolution positioning (<μm) with long stroke (>cm). These motors provide unlimited motion in both rotation and translation. Fine mode allows precise positioning (<10nm). Since it is a module, it easily fits any existing devices requiring up to 25N of driving force with a speed up to 50mm/s. This motor module benefits the use of space qualified Amplified Piezo Actuators (APA®). It is then deemed a good candidate for severe environments such as vacuum, cryo, vibrations, nonmagnetic etc… This paper presents three technical challenges encountered for the development of MSPA product. The first one is the issue of noise resulting from stick-slip actuation below ultrasonic frequencies. The second is the miniaturization at low voltage: One is macro size (sugar cube) working at 45V is characterized, the other is micro size (grain of rice) powered at low voltage below 60V. The third challenge is the successful and reliable integration of the module within new customer applications and new Cedrat Technologies’ products.

Stepping Piezoelectric Actuators (SPA’s) – based on the Piezoelectric Friction-Inertial Actuation (PFIA) principle – are made from Cedrat Technologies Amplified Piezoelectric Actuators (APA). They use the stickslip principle to couple high resolution positioning (<µm), long stroke (>cm) and low volume (<15cm3). These motors are used in optronic, medical and military applications. However, current rubbing contact between the shaft and clamp limits the potential evolution of SPA’s. In this paper, a new concept: called Module SPA (MSPA) – offering long stroke capabilities (>10cm), allowing easier multi-DoF mechanism developments and miniaturization possibilities – is presented. Results obtained on three innovative engineering models – linear long stroke, rotary and three-DoF actuators – are presented, giving the reader actual benefits of this concept and allow addressing new applications such as consumer goods and medical devices.

Piezomotors are well known in various applications where high precision actuation is required like AFM or handling equipment for semiconductor production. Their specific low speed in direct drive and high torque characteristics combined with high holding torque in off power conditions make them very attractive for any positioning application and especially space mechanisms where low electrical consumption is always sought. A new concept of rotating stepping piezomotor has been developed in the frame of the LISA space project where the mechanism of the telescope orientation was addressed.

Piezo-electric motors have been successfully developed for various applications like autofocus drives in camera lenses and handling equipment for semiconductor production. Their high speed and accurate positioning capability, combined with a favourable holding torque in unpowered condition, make piezomotors also very attractive for actuation purposes in spacecraft mechanisms. The paper introduces a new concept of a versatile ultrasonic piezomotor. The testing campaign carried out on the designed rotating piezomotor has validated the vacuum compatibility and the lifetime of the motor in air.

Piezo-electric motors have been successfully developed for various applications like autofocus drives in camera lenses and handling equipment for semiconductor production. Their high speed and accurate positioning capability, combined with a favourable holding torque in unpowered condition, make piezo motors also very attractive for actuation purposes in spacecraft mechanisms. However, so far only a few studies have been reported considering their suitability for actual use in space.

The applications of piezoelectric actuators are spreading in various fields such as precise micro-positioning, shape control or vibration generation, control or damping.

Implementation of 3D capabilities on ultrasonic imaging systems tantalizingly proves the high interest for this diagnosing modality. However, to become a clinical tool, 3D ultrasound has to spend further technological efforts in acquisition performance and probe size to deliver on the fly, quality volumetric images as well as current functionalities.