Magnetic actuators & motors
Magnetic Actuators use magnetic effects to generate forces which impact on the motion of a part in the actuator.
The first large family of magnetic actuators is based on the magnetic forces acting at distance, the Laplace-Lorentz forces and the reluctance forces. Linear types offer strokes in the range of 1 to 20mm, and are complementary to piezo actuators. They can be sorted in 3 categories:
- Moving coil actuator : Placed in static magnetic field, a mobile coil driven by a current is submitted to the Laplace-Lorentz force. This force is proportional to the applied current. Thus these actuators are controllable. Since first applications were loud-speakers, they are also called voice-coils. CEDRAT TECHNOLOGIES has developed high performance Voice Coils (also called Moving Coils) and LAT Limited Angle Torque actuators for various automotive, industrial or space applications.
- Moving magnet actuator : Placed between two magnet poles, a mobile permanent magnet can be switched from one pole to the other using coils. Such moving magnet actuators are bi-stable. They present high forces but are not so controllable. Miniature devices have been developed by CEDRAT TECHNOLOGIES for locking and haptic applications.
- Moving iron actuator : A soft magnetic part placed into a coil system naturally moves in a way that minimises the system magnetic energy. In standard electro-magnets, this reluctance force is larger than the Laplace force but it is only attractive and not controllable. The new MICA™ Moving Iron Controllable magnetic Actuator developed by CEDRAT TECHNOLOGIES thanks to Oseo is an innovative biased (polarised) electromagnetic actuator in which the force can be reversed all along the stroke. It is used for vibrations generation or for active damping in embedded applications. It offers larger strokes than piezo actuators. It offers higher forces and much less heating than any Moving coil actuator.
The second family of magnetic actuators is based on magnetically-controlled active materials. Two types are used by CEDRAT TECHNOLOGIES for innovative devices :
- Magnetostrictive actuator : These actuators use the magnetostrictive effect, which consists in the deformation of a magnetostrictive material when subjected to a magnetic effect. For example magnetostrictive deformation of Terfenol-D achieves 1600ppm, making this active material an interesting competitor of piezoelectric PZT ceramics for high power transducers or low voltage actuators.
- Magneto Rheological Fluid Actuator : A Magneto Rheological Fluid (MRF) can solidify when subjected to a magnetic field. This effect can be used to design various MRF-based actuators : valves, brakes, clutches, semi-active dampers, smart hydrostatic / hydrodynamic bearings…
The third broad family of magnetic actuators is the electric motors also called electric rotating machines. CEDRAT TECHNOLOGIES computes all sizes as services but develops only small electric motors, such as Brushless DC motors (BLDC) and stepper motors.
These technologies are presented in the examples hereafter. You can also download our Piezo and magnetic products catalogue. Furthermore, publications are available on magnetic actuators.
Electromagnetic Actuators
CEDRAT TECHNOLOGIES develops customised ElectroMagnetic Actuators, which are dedicated to customer’s specific applications when off the shelves standard products are not suitable. They cover a wide spectrum of applications and markets such as industry, automotive (for example, e-Lift 3 project with PSA), air & space, medtec, etc.
Applications
Valve actuation, locking and unlocking Pin-puller, contactor…
STATUS
Product
MICA500L
MICA™ actuator fullfills requirements in which compact, highly dynamic, precise, reliable and robust actuators are needed. This technology has been designed to fill the gap between the well known voice coil and the solenoid technologies.
Applications
Valve control, pump and compressor actuation, test benches, vibration generation, active control of vibrations, fast gripper, fast positioning…
STATUS
Product
Compressor MICA™ 300W
This MICA-type linear actuator has been developed to deliver 300W of power with high efficiency (~80%) and virtually infinite lifetime. It was used in a feasibility project for continuous hydrogen liquefaction for long-duration space missions.
Applications
Applications requiring mechanical power, such as compressors
STATUS
Prototype
Compressor MICA™ 100W
This MICA-type linear actuator has been optimized to deliver 100W of power with high efficiency (~80%) and virtually infinite life. It has been developed for a cold generation application for optical space instruments.
Applications
Applications requiring mechanical power, such as compressors, coolers, etc.
STATUS
Prototype
Switching power amplifier for magnetic actuator CSA96-ES
The Compact Switching Amplifier CSA96 is a compact size and large output power amplifier box for driving linear magnetic actuators like Moving Iron Controllable Actuator (MICA™). This CSA96 box is supplied by an External DC power supply up to 96 VDC.
Applications
Current amplifier for magnetic actuators
STATUS
Obsolete
Battery-based power supplies for embedded actuators, sensors & mechatronic systems
Power supplies for piezo or magnetic actuators, sensors & mechatronic systems based on 3.7V (typical) lithium polymer cells voltage.
Applications
Embedded piezo & magnetic actuators, motors, sensors, mechanisms, valves
STATUS
Proof of concept
Voice-Coil 15N
This Vocie Coil Actuator is based on the Lorentz-Laplace force. This actuator has has a 15N nominal force and about 30mm stroke.
Applications
High linearity actuators, Aerospace…
STATUS
Prototype
Voice-Coil 60N
The Moving Coil Actuator is based on the Lorentz-Laplace force, which is strictly proportional to the applied current. This is the most usual linear magnetic controllable actuator. Several CEDRAT TECHNOLOGIES voice coils have been developed for space application (ex MTG, IASI).
Applications
High linearity actuators, Aerospace…
STATUS
Prototype
BRUCE - Electromagnetic Actuated Pin Puller
Upon request of CNES, the French National Space Agency, CEDRAT TECHNOLOGIES has designed a resettable electromagnetic actuated pin puller, called BRUCE (Broche Rétractable Utilisant une Commande Electromagnétique)
Applications
Space, electomagnetic, pin puller, HDRM…
STATUS
Prototype
Bi-stable Linear Moving Magnet: BLMM
The Moving Magnet Actuator is based on a permanent magnet moving between two opposite electromagnets. It is a bistable magnetic actuator with high force at rest. CEDRAT TECHNOLOGIES’s BLMM are miniature linear actuators.
Applications
Locking mechanisms, Vibrations generators, Micro-valves…
STATUS
Product
Constant effort voice coil rotary motor
This rotary actuator provides constant torque along a 10° angular stroke for precision control. It combines two voice coils assembled around an axis to balance inertia.
Applications
High resolution rotating motion, Micro nano Positioning, Pointing, Acquisition
STATUS
Prototype
Limited Angle Torque Actuators: LAT
The Limited Angle Torque (LAT) actuator offer a rotating motion over an angle of +/- 15°. Thanks to its principle and an elastic guiding, it offers a smooth, high resolution rotative motion and precise pointing assemblies for air & space & optic applications.
Applications
High resolution rotating motion, Micro nano Positioning, Pointing, Scanning
STATUS
Prototype
Extra-wide-travel rotary motor
This rotary actuator provides constant torque over a wide angular range (±90°) for precision control on a test bench. This is a Voice-Coil type actuator.
Applications
High-precision rotary motion over a wide angular range
STATUS
Prototype
Brushless DC Motors Upgrade
CEDRAT TECHNOLOGIES upgrades Commercially Of The Shelves (COTS) BLDC Brushless DC motors for improving torque & speed and for reducing electric power, by means of FLUX FEM re-design, parts changes and tests on benches for micro rotating motors.
Applications
BLDC Micro Motors for demanding applications : air & space, UAVs
STATUS
Prototype
Extra Flat MICA™
This MICA proof mass actuator has been developed to generate a force of 600N peak over ±3mm and to integrate easily into narrow systems perpendicular to the actuating axis.
Applications
Thin, compact linear actuator, proof mass
STATUS
Prototype, feasability
Extra Flat MICA™ XY Stage
This stage has been developed for 2-axis positioning over several millimeters around an optical device such as a lens or mirror. It uses an assembly of extra-flat MICAs generating linear forces with respect to current to facilitate servoing. Compact parallel actuation ensures high dynamics and homogeneity of axis commands.
Applications
2-axis positioning with high dynamics and long stroke
STATUS
Prototype
Moving iron electromagnet 80N
Specific moving iron actuators are necessary for controllable dynamic operations. This special design illustrates a moving iron actuator equiped with flexure bearings for long life time purposes. Elsewhere, this actuator works by pairs, in a push-pull mode in order to provide high force level at resonance frequency. The customisation includes an embedded drive electronic, one displacement sensor and a closed-loop control.
Applications
High efficiency, long life time, long stroke actuator for alternate motion.
STATUS
Prototype
Single Phase Stepper Mini-Motor: SPSM-1
A single phase rotating stepper micro motor featuring axial tunable air gap and flat permanent magnet has been developed in FP6 M2EMS EC project, in collaboration with CEA and ETA. This stepping motor is compatible with Si technologies.
Applications
Micro-Motors, Micro-technologies…
STATUS
Proof of concept
Magnetostrictive Actuators
CEDRAT TECHNOLOGIES’ Magnetostrictive actuators are solid state magnetic actuators based on Terfenol-D Giant Magnetostrictive Materials. They can be designed to produce high forces (>20kN) & large strokes (>200µm) at low voltage (<12V) in static or dynamic.
Applications
High Force Generator, Low Voltage actuators, Sound transducers (sonar) …
STATUS
Prototype
