Active control of vibration
Categories
Cardiolock: an Active Cardiac Stabilizer
19 June 2023
Off-pump Coronary Artery Bypass Grafting (CABG) is still today a technically difficult procedure. In fact, the mechanical stabilizers used to locally suppress the heart excursion have been demonstrated to exhibit significant residual motion. We therefore propose a novel active stabilizer which is able to compensate for this residual motion. The interaction between the heart and a mechanical stabilizer is first assessed in vivo on an animal model. Then, the principle of active stabilization, based on the high speed vision-based control of a compliant mechanism, is presented. In vivo experimental results are given using a prototype which structure is compatible with a minimally invasive approach.
ACTUATOR2008 Moving Iron Controllable Actuators
6 January 2008
To meet the demand of controllable millimeter-stroke actuators, there are two possible starting points. One is to consider improvement of moving coil actuators, the other is to consider improvement of moving iron actuators. Following this approach and using its experience on the different types of magnetic actuators, Cedrat Technologies has developed new specific Moving Iron Controllable Actuators, called MICA. This actuator circumvents previous controllability limitations of standard Moving Iron actuators while keeping their high forces capabilities. Compared with moving coils of the same force, the MICA are twice less in mass while requiring 3 times less electric power. Another significant advantage of the MICA is a much better heat dissipation and reliability as the MICA coil is fixed into the iron stator.
ACTUATOR2008 MRF actuators Abstract
19 June 2023
Short Abstract
The MRF actuators are new electromechanical components using Magneto Rheological Fluids (MRF). When submitted to a high enough magnetic field, MRFs switch from a liquid to an almost solid body. The purpose of the new developed MRF actuators is to reach three aims: to offer a blocking force at rest, which can be strongly reduced by applying a current, to provide an electrically- controllable resistive force over a stroke of 30 mm, to perform the control of the force in a very short time, typically in a few milliseconds.
ACTUATORS BASED ON GIANT MAGNETOSTRICTIVE MATERIALS
6 January 2002
Magnetic field induced strain materials are classically represented by Giant Magnetostrictive Materials (GMM) such as Tb-Dy-Fe alloys offering magnetostrain of 0.1-0.2%. This family of smart materials has been extended for some years by cryogenic magnetostrictive materials such as Td-Dy and (Tb1-xDyx)Zn offering magnetostrain of 0.2- 1%. Even more recently, it has been completed by new Magnetic Shape Memory Materials (MSM) such as Ni-MnGa offering magnetostrain of 2-6%. These materials have lead to quite various large stroke and large force actuators. Some of these actuators meet the requirements of applications in different fields such as space or machine tools. The object of this paper is to review the present situation and recent progresses in the field of magnetic field induced strain materials, actuators, modelling and applications, including commercial aspects.
LDIA2007 Moving coil or moving iron controllable actuators
19 June 2023
There is a strong demand of controllable actuators for both traditional and new applications. A controllable actuator should be able to accelerate, break, inverse the motion of the load, all along the stroke. It means the force produced by the actuator should be proportional (at least roughly) to the applied electric excitation, and in particular, the sign of the actuation force could be changed all along the stroke.
Actuators in adaptronics: piezoelectric actuators
19 June 2023
Piezoelectric actuators have increased their number of application in adaptronics over the past decade [1]. They can be used with several drive and control strategies and they are more adapted to mechatronics applications requiring bandwidth, accuracy and/or lightweightness. The purpose of this paper is to recall the different existing piezo actuators, the different drive and control techniques and finally review several applications in machine tools, optics.
