Ultrasonic motor

• 1. It has been known for more than 30 years. The first ultrasonic motor was introduce by v.vlavrinko in 1965. An Ultrasonic motor is a type of electric motorformed from the ultrasonic vibration of acomponent, the stator being placed againstanother, the rotor depending on the scheme ofoperation. Conversion of electric energy into motion byinverse piezoelectric effect.

2. To obtain the levels of torque speedcharacteristics of USM using conventional motorswe require to add a gear system to reduce thespeed. These characteristics of USM makes themattractive for robotic applications where smallmotions are required. This motor achieves high speed and driveforces, while still permitting the moving part tobe positioned with high accuracy. 3. The piezoelectric effect is understood as the linearelectromechanical interaction between the mechanical and theelectrical state in crystalline materials with no inversionsymmetry. Piezoelectricity generation of voltage in response ofmechanical stress. The word is derived from the Greek piezein, which means tosqueeze or press. This effect is also reversible. Deformation is only 0.1 % of the original dimension. Piezoelectric material- quartz(SiO2), barium titanate (BaTiO3)lead zirconate titanate and occasionally lithium niobate . 4. Electromagnetic motors are notorious for consuming high amount of power and creating high ambient motor temperatures respect to USMThe electromagnetic motors produce strong magnetic fields which cause interference. Ultrasonic motors use piezoelectric effect and hence no magnetic interference.Electromagnetic motor has high input to output energy loss ratiosUSM High positional accuracy respect to Electromagnetic Motor. 5. Generation of gross mechanical motion through theamplification and repetition of micro-deformations ofactive material. The active material induces an orbital motion of thestator at the rotor contact points . Frictional interface between the rotor and statorrectifies the micro-motion to produce macro-motion ofthe ROTOR. Working frequency-20 KHz to 10 MHz Amplitude of the actuator motion 20 to 200nm 6. USM 7. Ultrasonic motorStandingTravelingwavewavebidirectional unidirectional 8. This type of motors use three groups ofcrystals: two of which are Locking andone Motive. First, one group of locking crystals isactivated this gives one locked sideand one unlocked side of the sandwich. Next, the motive crystal group istriggered and held the expansion ofthis group moves the unlocked lockinggroup along the motor path. This is theonly stage where motor movement takesplace. 9. This type of motor commonly known under the namesof Inchworm, Piezo LEGS or PiezoWalk motors 10. Superposition of multiple standing wave createa traveling wave. Representation of travelling wave U(x ,p)= A cos(k x) cos(wt) + A cos(k x - 90)cos (wt-90). Phase difference is 90 degree 11. The active material excites a traveling flexural wave within thestator that leads to elliptical motion of the surface particles.Teeth are used to enhance the speed that is associated with thepropelling effect of these particles.The rectification of the micro-motion an interface is provided bypressing the rotor on top of the stator and the frictional force betweenthe two causes the rotor to spin. 12. Camera auto focus lenses Driving fluid Watch motors and compactpaper handling. Optoelectronics area In micro surgery and sensorscanning. 13. Hence the ultrasonic motors, which is a new stepin the miniaturized electrical technology has gotmany applications in small appliances because ofits high torque at low density.