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Tubular ultrasonic transducer: MUST with axial excitation versus conventional with radial excitation
19 June 2023
This paper presents comparison between two excitation solutions for tubular ultrasonic transducer. The axial excitation is widespread in conventional ultrasonic transducer. The radial excitation is proposed in order to have an uniform acoustic energy all along the tube. This excitation approach is also proposed to allow the modularity by adding several tubes.
Ultrasonic Piezo Drive UPD for direct drive motorization
19 June 2023
Existing piezo motors such as travelling wave motors present several technical limitations, they are not useable for linear drive, they cannot be easily adapted to specific rotational needs and the development of customised solution is expensive. The proposed Ultrasonic Piezo Drive (UPD) aims at overcoming these limitations. It is a shell-based stator using multilayered piezoceramics in d33 mode. Excited at only 1-10V, it produces an ultrasonic elliptical vibration large enough to direct drive any type of second body by friction. Tangential driving properties of UPD20 are typically in the range of 100-200mm/s max speed and 15-30N max force.
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.
Segmented bimorph mirrors for adaptive optics:segment design and experiment
19 June 2023
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.
Self-tuning semi-active tuned-mass damper for machine tool chatter suppression
19 June 2023
Tuned mass dampers are simple and efficient devices for suppression of machine tool chatter, which is one of the principal effects limiting productivity in many machining processes. However, their effectiveness depends on a proper tuning of the damper dynamics to the dynamics of the machine. This involves the dynamic characterisation of the machining process, in order to identify the critical resonance frequency, and the possibility of matching the resonance frequency of the damper to frequency. The difficulty of meeting these two requirements has been limiting the use of tuned mass dampers in industrial applications.
Servo piezo tool SPT400MML for fast and precise machining of free forms
19 June 2023
Recent requirements for accuracy and resolution demand higher quality in the machining of precision parts in many industries—such as optics, automotive and aerospace—by free form machining. The required operations are possible by using expensive manufacturing equipment in parallel with several processes such as grinding and polishing. By using a new fast tool servo, the so-called servo piezo tool SPT400MML, driven by a piezoelectric actuator for the precision diamond turning of non-symmetrical surfaces, components can be machined with a fast motion control of the tool (diamond or carbide).
