Design, Modeling and Performance Optimization of a Novel Rotary Piezoelectric Motor

This work has demonstrated a proof of concept for a torsional inchworm type motor. The prototype motor has shown that piezoelectric stack actuators can be used for rotary inchworm motor. The discrete linear motion of piezoelectric stacks can be converted into rotary stepping motion. The stacks with its high force and displacement output are suitable actuators for use in piezoelectric motor. The designed motor is capable of delivering high torque and speed. Critical issues involving the design and operation of piezoelectric motors were studied. The tolerance between the contact shoes and the rotor has proved to be very critical to the performance of the motor. Based on the prototype motor, a waveform optimization scheme was proposed and implemented to improve the performance of the motor. The motor was successfully modeled in MATLAB. The model closely represents the behavior of the prototype motor. Using the motor model, the input waveforms were successfully optimized to improve the performance of the motor in term of speed, torque, power and precision. These optimized waveforms drastically improve the speed of the motor at different frequencies and loading conditions experimentally. The optimized waveforms also increase the level of precision of the motor. The use of the optimized waveform is a break-away from the traditional use of sinusoidal and square waves as the driving signals. This waveform optimization scheme can be applied to any inchworm motors to improve their performance. The prototype motor in this dissertation as a proof of concept was designed to be robust and large. Future motor can be designed much smaller and more efficient with lessons learned from the prototype motor

The Roles of Piezoelectric Ultrasonic Motors in Industry 4.0 Era: Opportunities & Challenges

Piezoelectric Ultrasonic motors (USM) are based on the principle of converse piezoelectric effect i.e., vibrations occur when an electrical field is applied to piezoelectric materials. USMs have been studied several decades for their advantages over traditional electromagnetic motors. Despite having many advantages, they have several challenges too. Recently many researchers have started focusing on Industry 4.0 or Fourth Industrial revolution phase of the industry which mostly emphasis on digitization & interconnection of the entities throughout the life cycle of the product in an industrial network to get the best possible output. Industry 4.0 utilizes various advanced tools for carrying out the nexus between the entities & bringing up them on digital platform. The studies of the role of USMs in Industry 4.0 scenario has never been done till now & this article fills that gap by analyzing the piezoelectric ultrasonic motors in depth & breadth in the background of Industry 4.0. This article delivers the novel working principle, illustrates examples for effective utilization of USMs, so that it can buttress the growth of Industry 4.0 Era & on the other hand it also analyses the key Industry 4.0 enabling technologies to improve the performance of the USMs

Research on a symmetric non-resonant piezoelectric linear motor

Nowadays, piezoelectric linear actuators draw wide attention of researchers around world as its advantages of simple structure, high precision and rapid response. To improve the performance of the non-resonant piezoelectric motor, a symmetric piezoelectric linear motor driven by double-foot is studied in the paper. The vibration model of the stator is established based on the structure and the working mechanism of motor. Then guide mechanism and preload device is designed and a prototype is fabricated to verify the feasibility of structure. The performances of motor under different driving signal are tested in experiment. By applying three-phase square-triangular waves signal and four-phase sine waves signal of peak to peak value 100 V with 50 V offset and frequency of 100 Hz, the speed of prototype reaches 733 μm/s and 667 μm/s and the maximum thrust is 8.34 N and 6.31 N respectively

Wireless Tagging and Actuation with Shaped Magnetoelastic Transducers.

The promise and the challenges of patterned, micro-scale magnetoelastic transducers and their integration with silicon is the focus of this thesis. As demonstrations, wireless magnetoelastic chip-scale resonant rotary motors and miniaturized magnetoelastic tags are investigated. The motors consist of a magnetoelastically-actuated stator, a silicon rotor, a “hub” structure, and DC and AC coils. Two generations are described. The first-generation motor uses a stator with a bilayer of silicon (ø8 mm x 65 µm thick) and magnetoelastic foil (Metglas™ 2826MB bulk foil, ø8 mm x 25 µm thick). The motor provides bi-directional rotation capability, and typical resonant frequencies of the clockwise and counterclockwise modes are 6.1 kHz and 7.9 kHz, respectively. The counterclockwise mode provides a rotation rate of ≈100 rpm, start torque of 30 nN∙m, a step size of 74 milli-degree and a capability for driving a 100 mg payload while a 8 Oe DC and a 6 Oe-amplitude AC magnetic field are applied. The second-generation of motors includes bilayer standing wave and traveling wave designs (ø5 mm stators) with integrated capacitive sensors for real-time position measurement and speed estimation. Clockwise and counterclockwise mode shapes with resonant frequencies of 12 kHz and 22.4 kHz, respectively, are measured for the standing wave motor. Two mode shapes (with π/2 spatial phase difference) at resonant frequencies of 30.2 kHz and 31.7 kHz are measured for the traveling wave motor. The wireless actuation capability and the hybrid integration of the bulk magnetoelastic material with silicon show promise for use in many microsystems. A lithographically patterned, frame-suspended hexagonal magnetoelastic tag design (ø1.3 mm x 27 µm thick) is also investigated. These tags provide ≈75x signal amplitude improvement compared to a non-suspended disc tag, while occupying ≈100x smaller area than typical commercial ribbon tags. Signal strength can also be boosted by taking advantage of tag signal superposition. Linear signal superposition of the response has been experimentally measured for clustered sets of frame-suspended tags that include as many as 500 units. Miniaturized tags with sufficient signal strength may enable new applications, such as distributing the tags into a network of cracks and subsequently mapping the distribution.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/108961/1/juntang_1.pd

NEAR WALL SHEAR STRESS MODIFICATION USING AN ACTIVE PIEZOELECTRIC NANOWIRE SURFACE

An experimental study was conducted to explore the possible application of dynamically actuated nanowires to effectively disturb the wall layer in fully developed, turbulent channel flow. Actuated nanowires have the potential to be used for the mixing and filtering of chemicals, enhancing convective heat transfer and reducing drag. The first experimental evidence is presented suggesting it is possible to manipulate and subsequently control turbulent flow structures with active nanowires. An array of rigid, ultra-long (40 μm) TiO2 nanowires was fabricated and installed in the bounding wall of turbulent channel flow then oscillated using an attached piezoelectric actuator. Flow velocity and variance measurements were taken using a single sensor hot-wire with results indicating the nanowire array significantly influenced the flow by increasing the turbulent kinetic energy through the entire wall layer