Rotating machines
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Rotating piezoelectric motors for high precision positioning & space applications
19 June 2023
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.
Rotating step by step piezomotor for nanopositioning and space applications
19 June 2023
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.
Limited Angle Torque for fine angular positioning
19 June 2023
A Limited Angle Torque (LAT) actuator has been designed by Cedrat upon request of the European Space Agency (ESA) for fine pointing applications based on gimbals assembly. The required angular stroke for this application is 13°. Other required features are controllability, high resolution, no micro vibration. Therefore the selected concept is a coil-redounded electromagnetic actuator using Lorentz force. The functional test shows that the generated torque is linear until 200mN.m, but torques up to 300mN.m are achievable.
M2EMS Miniature magnetic rotating motor
19 June 2023
Thanks to the help of intensive modelling, the two first prototypes realised in the framework of the M2 EMS project are functional. It consists of prototypes of single-phase stepper motor whose structure has been transformed from the Lavet motor so as to take into account collective production of the magnet film layers, which are developed in the M2 EMS project.
Improvement of MSPA module of stepping piezo actuator
7 June 2018
Modular Stepping Piezo Actuators (MSPA) use the stick-slip principle to combine high resolution positioning (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.
Upgrade of miniature outrunner brushless DC motors
19 June 2023
Miniature Brushless DC motors (less than 5gr) offer some challenges both in the design and the manufacturing. They are used in several mass volume applications, such as hard disk drive, gyroscopes, and more recently in some unnamed aircraft vehicles (UAVs), where Cedrat is involved. For this last application, the efficiency is of upmost importance. Cedrat has used its Flux software solution to optimize the Brushless motor design: Some materials and dimensions have been changed in the motor to improve its efficiency.
