ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: NanoactuatorsOutlineReference listTo probe further (survival pointers of web references etc)Major applicationsNanowiresPrinciple of operationExperimental setupResultsLimitationsDielectric-Capacitor Nano-motorSome math…ObservationsNano size linear motorNano linear motor applicationsNano motor : top viewNano motor operationNano/micro tweezerTweezer operationMajor specificationsSlide 21Future scopeECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Assignment#01: Literature Survey on Sensors and Actuators Topic: Nanoactuators3/10/2006Prepared by: Shayok MukhopadhyayDept. of Electrical and Computer Engineering Utah State UniversityE:[email protected] ; T: (435)754-5758W: http://www.csois.usu.edu01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-2Outline –Reference list–To probe further–Major applications–Nanowires–Operation of nanowires–Experimental setup, results & limitations–Dielectric capacitor nanomotor–Nano linear,rotary motors and their operation–Nano/micro tweezer–Major specifications–Limitations–Future scope01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-3Reference list•Silicon Nanowire-Based Nanoactuator, Maggie Chau, Ongi Englander and Liwei Lin, Berkeley Sensor and Actuator Center, Department of Mechanical Engineering, University of California at Berkeley•Nanoactuators Based on Electrostatic Forces on Dielectrics, NASA Tech Briefs, NPO-30747, NASA’s Jet Propulsion Laboratory, Pasadena, California 91109-8099•http://www.aleph.se/Trans/Tech/Nanotech/01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-4To probe further (survival pointers of web references etc) •http://www.aleph.se/Trans/Tech/Nanotech/•http://physicsworld.com/cws/article/news/17938•http://medgadget.com/archives/2006/10/nanoactuator_a.html01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-5Major applications •Thermally actuated nanoscale optical switches.•Dielectric-Capacitor Nano-motor•Nano-tweezers01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-6Nanowires•These are chromium coated silicon nanowires.•They demonstrate bimetal thermal effect in nanowires.Maggie Chau, Ongi Englander and Liwei Lin01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-7Principle of operation•The coefficient of thermal expansion (CTE) for the metals chromium and silicon are 6x10-6/˚K and 2.66x10-6/˚K respectively.•The chromium layer expands 2.3 times more than the silicon layer when heated, hence causing the actuation.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-8Experimental setup•The micro heater showed in the figure is U-shaped, 50μm thick, 2μm wide and 150μm long.•The silicon nanowires are grown on this micro heater.•The wires are typically 10μm long 30-80nm in diameter.•When power is supplied by the microheater, the resistive joule heating raises the temperature of the heater.•The heat is transferred by conduction to the nanowires.•The temperature rise in the nanowires cause them to deflect.•Since the wores are too small hence the experiment has to be viewed through a scanning electron microscope (SEM).01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-9•Nonlinearity appears because: with rise in temperature heat loss increases and temperature rise in wires decreases.•The CTE of the metals are also nonlinear with increase in temperature.•Obstruction from other wires.Results•The input voltage to the heater is 3.32V•The maximum deflection is 1.52μm for a power input of 31.4mW•The deflection is linear upto 15mW of input power.•After this point, nonlinearity sets in and the deflection is only about 0.15μm for another 15mW increase in power as compared to the initial deflection of 1.37μm for 15mW or power.Maggie Chau, Ongi Englander and Liwei Lin01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-10Limitations•The tip deflection if directly read from the SEM image, then the viewing angle must be accounted for. Otherwise there may be an error in the actual deflection and the measured value.•If nanowires are grown without any direction of motion, then the wires will deflect randomly in any direction depending on the initial conditions.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-11Dielectric-Capacitor Nano-motor•Shown above is a circuit with a capacitor, a is the length of the plate, x is the distance to which the dielectric is inserted, d is the distance between the plates, ε1 & ε2 are the dielectric constants of the dielectric material and air respectively.NASA Tech Briefs NPO-3074701/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-12Some math…Energy stored in the capacitorRelation between charge Q and capacitance C,F is the force and x is the displacement,Q = CV, V is the voltageThe force thus depends on the ratio of a and d. If both decrease at the same rate then the force obtained will be the same.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-13Observations•As the ‘a’ and ‘d’ reduce at the same rate, as seen from the previous slide, the force remains unchanged.•But the mass reduces at the third power of the size. Hence the force obtained becomes significant at the nanoscale.•If a=d=1μm then acceleration obtained is 450m/s2 which is really high acceleration.•If a=d=1nm then the acceleration is 450km/s2, hence this force can definitely be used to build a nano size linear motor.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-14Nano size linear motorNASA Tech Briefs NPO-3074701/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-15Nano linear motor applications•By alternating the voltage on the two capacitors shown in the previous figure, reciprocating motion can be obtained.•This reciprocating motion can be used to construct a nano scale piston.•It may also be used for making a nano/micro reciprocating pump.01/14/19ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuatorsSlide-16Nano motor : top viewNASA Tech Briefs NPO-3074701/14/19ECE5320 Mechatronics. Assignment#1 Survey on
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