CEDRAT TECHNOLOGIES PIEZO PRODUCTS & APPLICATIONS 1
CEDRAT Group 2 companies in Electrical Engineering Total Turnover of 4MEuro & 70 people R&D & Products in Electrical Engineering : Electric & Magnetic Devices Active Material Applications CAD Software for Electrical Engineering : FLUX for Electric & Magnetic Devices ATILA for Active Material Applications... 2
Organisation of CEDRAT TECHNOLOGIES DIRECTION Management of Projects Commercial Team Electrical Engineering Mechanical Engineering Electronic Engineering Assembly & test Laboratories REQUIREMENTS DESIGN PROTOTYPING From Technical Specifications... to definition to customised or standard products. 3
Piezoelectric Multi-Layer Actuators (MLA) History of piezo ceramics 1880 : Quartz (P.Curie) 1922 : Langevin Transducers 1960 : PZT ceramics L/L = 0,3mm/m @ V= 2000V 1990 : MLA components L/L = 1,2mm/m @ V=200V Structure of a MLA Piezo layers (PbZrTi) Internal Electrodes (Pt or AgPd) External Electrodes Insulation (Coating or ceramic) The naked MLA ceramic bar is fragile to tensile force... 4
Direct Piezoelectric Actuators (DPA) Two different pre-stress mechanisms Serial Parallel Conventional DPA with serial pre-stress that is why we pre-stress it to increase its life time 5
Parallel Pre-stressed Actuator (PPA) A new DPA concept : the PPA The MLA ceramic is pre-stressed through an external frame. Stress analysis of the pre-stress frame of the PPA (I-DEAS computation of half the frame) The design of the parallel spring is dependent on the applied pre-stress. 6
Conventional piezoelectric amplifier Use of flexural hinges, lever arms & pivots 7
Amplified Piezoelectric Actuators (APA) Objectives in the design of APAs: Magnification of the small MLA displacements using an mechanical amplifier : an elastic shell Robustness due to the pre-stressing shell Optimisation of the overall Mechanical Efficiency : M.E. = (Factuator x Uactuator) / (Fpzt x Upzt) 8
Amplified Piezoelectric Actuators (APA) Design of an APA MLA piezoelectric stack : - Extensional displacement Metallic shell : - Pre-stress of the MLA stack - Protection of the MLA stack - Displacement Amplification - Contraction displacement FEM Modeling of the APA200M (ATILA result) Structure at rest (Dashed lines) & Deformed structure (full lines) 9
Amplified Piezoelectric Actuators (APA) Design of an APA FEM Modeling of the APA200M (ATILA result) : Animation accounting for electric excitation, piezo & structure effects 10
Amplified Piezoelectric Actuators (APA) Range of APAs Deformation : 0.5 to 10% Stroke up to 1000 µm Blocked force up to 2 kn Bandwidth from 0.5 up to 20 khz Fast response time < 1 ms High resolution = few nanometers Non magnetic, UHV and cryogenic options 11
Actuator names Piezoelectric Actuators Comparison Best actuator according to US specialists before Cedrat product launching Some CEDRAT products : Standard & customised P844.60 PPA90L APA120ML APA230L APA500L APA500L- SV APA750XL- SV Actuator Actuator Mass gr 204 147 155 275 200 170 600 Actuator Height cm 13.7 10.7 4.5 8.5 5.5 4.9 7.0 Actuator Volume cm3 43 43 36 74 48 41 91 No-load free displacement µm 90 90 120 236 500 560 1150 Stiffness N/µm 33 39 11.7 5.7 1.14 1.39 0.8 Blocked force N 2 970 3 510 1 400 1 345 570 778 920 Stored elastic energy J 0.134 0.158 0.084 0.159 0.143 0.218 0.529 Output elastic energy mj 33 39 21 40 36 54 132 Performances ratio Free deformation along active axe % 0.07 0.08 0.27 0.28 0.91 1.14 1.64 Output Energy / actuator volume J/dm3 0.78 0.91 0.59 0.54 0.74 1.31 1.45 Output Energy / actuator mass J/kg 0.16 0.27 0.14 0.14 0.18 0.32 0.22 12
Arrangement of piezo-actuators Parallel arrangement adds force Serial arrangement adds displacement 13
Piezo Actuators : Fine Position Control by Closed Loop Electronics Removal of the Hysteresis & Drift Effects Use of strain gages or a capacitive sensor associated with PID controller Displacement (µm) 140 120 100 Actuator's displacement (µm) in Open Loop - Record of the Creep effect using a capacitive displacement sensor 80 60 40 20 displacement measurement (Volts) 9 8 7 6 5 4 3 2 1 0 closed loop off closed loop on 0 5 10 0 0 600 1200 Time (s) 1800 Order (Volts) 14
Piezo Actuators : Centering by Push - Pull Mechanics & Electronics To get a centred stroke Cedrat Actuators can be used in Push-pull configuration Cedrat Electronics are compatible with push - pull operations 15
Piezo Actuators : Summary of Cedrat Technologies offer Use of Pre-stressed Ceramic Multi-layer Actuators Optimization of the efficiency using FEM Use of an elastic amplifier with amplification ratio in the range 2-20 (in case of APAs) Development of specific driving electronics for fast and precise positioning. 16
Piezo Actuators : Advantages & drawbacks Large deformation Fast response Unlimited positioning resolution High precision in closed loop Large force Non-magnetic operation & no magnetic field generated Low Power Consumption Long lifetime Limited displacements (<1mm) Drift & hysteresis in open loop (corrected in closed loop) Sensitive to humidity Temperature dependant (Curie temperature) 17
Cedrat Technologies Piezoelectric motors overview To overpass the stroke limitation of piezo actuators, Cedrat Technologies patented a concept of long linear and rotating actuation based on an Ultrasonic Piezo Drive (UPD) This kind of motor is called piezomotor or ultrasonic motor (usm) 18
Ultrasonic piezo motors (USM) : General concept Working principle : use of a preload use of elliptic vibrations use of frictional forces CEDRAT TECHNOLOGIES motors are based on a piezo stator called UPD : Ultrasonic Piezo Drive. It can drive either a rotor or a plate 19
The Ultrasonic piezo Motors (USM) : General concept Two successive energy transfers Electrical energy Electromechanical conversion Mechanical vibrations Contact mechanics Kinetic energy Voltage Current Dynamic force Vibration speed Torque Revolution speed Losses dielectric mechanical frictional Power limits electrical field stresses slip 20
CEDRAT TECHNOLOGIES solution : the Ultrasonic Piezo Drive UPD Design of UPD: combination of 2 vibration modes flexural mode translation mode Modes combination with 90 phase shift Modelling of half the UPD piezo stator using ATILA 21
CEDRAT TECHNOLOGIES Linear Piezo Motion LPM 20-3 LPS 100 22
CEDRAT TECHNOLOGIES Rotation Piezo Motors RPM 20 RPM 60 23
Piezoelectric Motors : Advantages & Drawbacks Unlimited stroke Unlimited positioning resolution High precision in closed loop Fast response Large holding force at rest Large dynamic force Non-magnetic operation & no magnetic field generated Limited life time (wear of the friction layer) Position sensor needed Temperature dependant (Curie temperature) 24
Piezoelectric Actuators Operating Area 25
Driving Electronics for Piezo Actuators, Motors & Transducers L A 7 5 LA75A : Linear Amplifier for driving Actuators with low noise for precise & quasi-static motion LA75B & LA75C: Linear Amplifier for driving Actuators in power demanding dynamic motion SP75 : Switching Power for driving Actuators in fast on-off motion U S 1 0 0 US100 : Ultrasonic Inverter for driving Transducers & Motors at Resonance Options available: PID and Micro Controller for feedback and monitoring through a PC 26
APPLICATIONS 27
Active Control of Position : Space XYZ stage for ROSETTA/MIDAS EQM model including locking actuators CAD view of XYZ stage displacement = [100*100*8] µm resolution = 4 nm Flying model on board ROSETTA satellite, launching with Ariane V Jan. 2003 Dust analysis of the Wirtanen comet, heart of MIDAS instrument (Courtesy of ESA, European Space Agency) 28
Active Control of Position : Symmetric XY stage XY200M This stage, [+/-100µm]x[+/-100µm], is mechanically & electrically centred and thermally compensated Space qualified model Closed loop options: Strain Gages or Capacitive Sensors ( Courtesy of CNES, French Space Agency ) 29
Piezo Mechanisms with several dof Hexapode HEX100M Tx = Ty = 65 µm; Tz = 57 µm Rx=Ry= 2.7 ; Rz= 1.1 mrad (+/-) XYZ200M-SG Tx=Ty= +/- 100 µm ; Tz = 200 µm courtesy U Mt Pellier (Spectro IR) 30
Active Control of Position : Application in Bio Medical fields Non magnetic Mechanism in a Magnetic Resonance Imaging (MRI) application (Courtesy of INSERM French Medical Research Institute) 31
The tip-tilt mechanisms are the most simple structures that can perform one or two rotations, plus a vertical (z) actuation : one rotation: +/- 0.5 Active Control of Optics : Tilt Mechanisms two rotations: +/- 2mrad TT50S Space qualified DTT35XS Courtesy of CNES Pharao project 32
Active Control of Optics : Applications in telecom & cameras Active Fibber Bragg Gratings for DWDM Tunable Laser Optical switch Fibber alignment APA50S + fibre XY25XS micro-stage Improvement of CCD/CMOS resolution Refocussing 33
Optical filter & External Laser Cavity Hollow PPA ESA/ Lisa Pathfinder/Galileo PPA10M for ELC (WALES / ESA, JPL, Pharao / Sodern / CNES) 34
Fast Piezo Shutter FPS200M - Aperture = 400 µm ; tr = 1 ms Courtesy of EMBL / ESRF 35
Active Control of Shape : Active flaps in helicopters Objective : Reduction of noise during the descendant phase Qualification: Wind tunnel & centrifugal tests (2500g) successfully passed (Courtesy of ONERA, French Institute for Aeronautics) 36
Active Control of Vibration : Damping of a truss by active tendons Truss vibration level after a shock excitation, without control (red curve) & with control (blue curve) Space Truss of ULB using an active tendon concept based on APA100Ms for active damping (Courtesy of Micromega Dynamics & ULB & ESA) 37
Active Control of Vibration : 6 dof Stewart Isolation platform Hexapod based on 6 APA50S Courtesy of ULB & Micromega Dynamics 38
Active Control of Vibration : 6 dof Stewart Isolation platform Experimental results Courtesy of ULB & Micromega Dynamics 39
Active Control of Vibration : One axis flexure beam Control OFF Control ON 40
Active Tool Control: Oval Piston Machining Courtesy of Entech (SP) 41
Active Control of Fluids : Piezo Injectors for Automotive short time response compact structure potential for low cost small piezo ceramic amount few simple parts Car Injectors based on an APA, according to C.R.Fiat 42
Active Control of Fluids : Proportional Pneumatic Valves Pneumatic Valve Prototype (designed by Cedrat Technologies ) based on the APA100S (Courtesy of ENS) 43
Electrical Power Generator References Unit GPA60SM preliminary Notes data input mechanical energy mj 2 Displacement µm pk-pk 11 Output electrical energy mj 0.1 Load impedance kohm 1.5 Min. Voltage V 1.8 Time to maintain the voltage ms 45 Wireless switch based on APA60SM Courtesy of LEGRAND 44
Synthesis : CEDRAT Piezo Actuators Advantages against competitors Best Displacement x Force / Volume Best Displacement x Force / Mass Best Displacement x Force / Price Space Qualifications Aircraft Qualifications Industrial Qualifications 45
Synthesis : typology of applications of CEDRAT Piezo products Position control Optical control Shape control Driving control Vibration control Fluid control 46
Conclusion & Prospects Wide range of Piezo Actuators Best Performance Ratio of the market Best Price Ratio of the market Various Industrial Fields of Applications Space, Aircraft, Defence Instrumentation, Optics, Semi-Conductors, Telecom Machine Tools, Production Bio-Medical equipment, Fluid Industries Electric distribution Automotive 47