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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - Design and Fabrication of a Piezoelectric Micromachined Ultrasonic Transducer Array Based on Ceramic PZT
摘要： This paper presents a piezoelectric micromachined ultrasonic transducer (pMUT) array fabricated using high-piezoelectric-coefficient ceramic PZT wafers. A new process for polishing ceramic PZT layers down to 5 μm has been developed and applied for manufacturing high-sensitivity pMUTs. A 2 MHz working pMUT array (8×8 elements) based on ceramic PZT has been designed, modeled, fabricated and characterized.
关键词： pMUT,piezoelectric transducers,ultrasonic,micromachined transducers,ceramic PZT
更新于2025-09-19 17:15:36
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Fast Attitude Maneuver of a Flexible Spacecraft with Passive Vibration Control Using Shunted Piezoelectric Transducers
摘要： This paper is concerned with designing a bang-bang control input to perform a quick rotational maneuver of a rigid spacecraft hub connected with flexible appendages. The control design is based on only the rigid body mode making it very simple to design and at the same time achieve the quickest maneuver possible. The induced vibrations are suppressed using piezoelectric transducers bonded to the appendages and connected to an electric circuit with the objective of converting the vibrational energy to electrical energy and then dissipating it using passive electric elements, such as a resistance and an inductor. The proposed control design method is applied to a spacecraft containing a rigid hub and flexible appendages. The attitude control torque is produced using either the reaction wheels contained inside the rigid hub or jet thrusters mounted outside it. The control design process starts with deriving the nonlinear partial differential equations of motion for the spacecraft using Hamilton’s principle which accounts for the electromechanical coupling and the presence of resistive or resistive-inductive circuits. To simplify the analysis, the nonlinear ordinary differential equations of motion are then obtained using the assumed mode method. The effectiveness of the control design method is numerically tested on a spacecraft that is required to perform a quick attitude maneuver and, simultaneously, suppress the induced vibrations. The simulations show a quick and accurate maneuver has been achieved combined with very low levels of vibrations resulting from the reduced coupling between flexible and rigid motions as well as the damping added as a result of the passive shunt circuit. Furthermore, the resistance-inductance shunt circuit is shown to be more effective in damping the vibrations than the resistance shunt circuit.
关键词： vibration control,piezoelectric transducers,attitude maneuver,bang-bang control,flexible spacecraft,shunt circuits
更新于2025-09-19 17:15:36
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[ASME ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems - San Antonio, Texas, USA (Monday 10 September 2018)] Volume 2: Mechanics and Behavior of Active Materials; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting; Emerging Technologies - Parametric Testing of Surrogate Knee Replacement Bearings With Embedded Piezoelectric Transducers
摘要： In the United States, Total Knee Replacement (TKR) is a surgery many people go through, but frequently, patients find that they are unhappy post-surgery due to misalignment and loosening of the knee. An estimated 20% of knee replacement recipients report discomfort or undesired functionality within their first few years after surgery. Surgical techniques currently rely heavily on experience and tactile feedback to correctly align the knee replacement. If surgical teams were to have access to data regarding compartmental forces within the knee over the life of the implant, then a more precise balancing procedure could be implemented. As it stands, the only way to obtain this in vivo data is for patients to undergo post-operative procedures; unfortunately, patients have no incentive to undergo this process. This study tests the capabilities of knee bearings embedded with piezoelectric transducers to estimate the magnitude and location of loading given certain inputs. The prototype is fabricated from ultra high molecular weight (UHMW) polyethylene using Computer Numerical Control (CNC) machining. For this study, to simulate loads under both normal and irregular knee positions, a custom fixture is designed and fabricated for use in a uniaxial load frame. The problem at hand necessitates a more realistic knee testing environment that can simulate the loading types of both balanced and imbalanced knees. Thus, the fixture permits various degrees of internal and external rotation. Additionally, through use of an X-Y translational table, the setup allows for in-plane translation between the condyles of the femoral component and the bearing prototype. This study compares values of force location from the piezoelectric sensors to measurements from pressure sensitive film. The piezoelectric knee bearing is tested to lay the groundwork for in vivo testing. Future work expanding upon this research would include designing and optimizing an in vivo knee bearing replacement to facilitate force location and magnitude data collection in a system free from external power sources by utilizing the energy harvesting capabilities of piezoelectrics.
关键词： Total Knee Replacement,UHMW polyethylene,CNC machining,pressure sensitive film,piezoelectric transducers,internal-external rotation
更新于2025-09-10 09:29:36
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[IEEE 2018 10th International Conference on Modelling, Identification and Control (ICMIC) - Guiyang, China (2018.7.2-2018.7.4)] 2018 10th International Conference on Modelling, Identification and Control (ICMIC) - Parameter Estimation of Piezoelectric Transducers Circuit Model Using GA-PSO Algorithm
摘要： The parameters estimation problem for the equivalent admittance circuit model of piezoelectric transducers with high non-linearity near the resonance frequency is studied. A novel Genetic-Particle Swarm Optimization (GA-PSO) algorithm with cascade structure is proposed. The variance of fitness value of population as a criterion is given to evaluate the population convergence, and the population convergence is used as an adaptive switching strategy of Particle Swarm Optimization(PSO) to Genetic Algorithm(GA). The proposed GA-PSO method can also be used for estimating parameters of others. Simulation results are provided to demonstrate the feasibility. Comparison of the proposed GA-PSO method with the existing method is given, which shows that the GA-PSO algorithm is more efficient.
关键词： circuit model,Parameter estimation,GA-PSO,population convergence,piezoelectric transducers
更新于2025-09-10 09:29:36