Many applications require long-term position stability, which relates to the notion of absolute precision over time. Until now, the long-term stability of strain gages (SG) for position measurement was questionable. Using its extensive know-how of strain gages integration and new instrumentation equipment, Cedrat Technologies has managed to demonstrate nanometric position stability of a closed-loop piezo-mechanism with integrated strain gages sensors. This technology opens a wide range of new possibilities for industrial, aeronautical, and space applications.
While Cedrat Technologies has been active in space for more than 20 years with piezoelectric mechanisms, we have also been increasingly involved over the last few years in the development of magnetic actuators for space projects. In this paper, a focus is made on the case of magnetic actuators that are developed in the frame of the Meteosat Third Generation (MTG) project. The first one is the Scan Assembly (SCA) actuated by Rotating Voice Coil Motors (RVCM) for the East/West (E/W) axes and the North/South (N/S) axes developed in collaboration with Sener and the second one is the Voice Coil Motor (VCM) developed in collaboration with CSEM for the Corner Cube Mechanism (CCM)
This paper discusses a concept of light weight segmented bimorph mirror for adaptive optics. The segment consists of a monocrystal Silicon substrate actuated by an array of in-plane piezoceramic (PZT) actuators with honeycomb electrodes. The paper focuses on technological aspects of the segment design which are critical for space applications and describes a single segment demonstrator. The morphing capability of the segment is evaluated experimentally. The paper also discusses the local deformations (dimples) associated with the shape of the electrodes acting on the PZT array.
Two typical characteristics of direct piezoelectric actuators are displacements of ten micrometers and high stiffnesses. recently, multilayers actuators have been improved, and they now display strains of approximately 1200ppm at low excitation levels (less than two hundred volts). Thus, they are well suited to perform precise positioning of optical devices. But for industrial needs, this performances is still insufficient for positioning devices with larger displacements (in the range of several hundred micrometers).
PICARD is a French space scientific mission. Its objectives are the study of the origin of the solar variability and the study of the relations between the Sun and the Earth's climate. The Satellite wassuccessfully launched, on June 15, 2010 on a DNEPR launcher from Dombarovskiy Cosmodrome, nearYasny (Russia). The payload consists in two absoluteradiometers measuring the total solar irradiance and animaging telescope to determine the solar diameter andasphericity.
Stepping Piezoelectric Actuators (SPA) are new long-stroke linear piezoelectric motors for micro/nano positioning applications benefiting of the advantages and the heritage of the APA. SPA are formed of only 4 parts: the well-established Amplified Piezoelectric Actuators (APA), a front mass, a clamp and a rod.
Abstract: Stepping Piezoelectric Actuators (SPA) are new small long-stroke linear piezoelectric motors for micro/nano positioning applications benefiting of the advantages and the heritage of the APA. SPA is formed of only 4 parts: the well-established Amplified Piezoelectric Actuators (APA), a front mass, a clamp and a rod. SPA operates by accumulation of small steps, using inertial mode, impact forces and stick-slip effects, allowing performing long strokes (> 10mm). Main advantages induced by the choice of the APA above a usual inertial drive mechanism (IDM) are high reliability, low peak current (<0.1A), relatively high speed (> 20mm/s), useful forces (from 1N for XS to 30N for SM type) and nano positioning mode.