Study of a new type linear ultrasonic motor with double-driving feet

Modeling and analysis of stick-slip motion in a linear piezoelectric ultrasonic motor considering ultrasonic oscillation effect

This study presents a total sliding-mode-based genetic algorithm control (TSGAC) system for a linear piezoelectric ceramic motor (LPCM) driven by a newly designed hybrid resonant inverter. First, the motor configuration and driving circuit of an LPCM are introduced, and its hypothetical dynamic model is represented by a nonlinear function with unknown system parameters. In the hybrid resonant drive system, it has the merits of the high voltage gain from a parallel-resonant current source, and the invariant output characteristic from a two-inductance two-capacitance resonant driving circuit. Since the dynamic characteristics and motor parameters of the LPCM are highly nonlinear and time varying, a TSGAC system is therefore investigated based on direction-based genetic algorithm with the spirit of total sliding-mode control (TSC) and fuzzy-based evolutionary procedure to achieve high-precision position control under a wide operation range. In this control scheme, a GAC system is utilized to be the major controller, and the stability can be indirectly ensured by the concept of TSC without strict constraints and detailed system knowledge. In addition, the effectiveness of the proposed drive and control system is verified by numerical simulations and experimental results in the presence of uncertainties

Design of Total Sliding-Mode-Based Genetic Algorithm Control for Hybrid Resonant-Driven Linear Piezoelectric Ceramic Motor

Exploiting new suitable actuators is key in developing cardiac compression assist devices. In this paper, a self-moving linear ultrasonic motor with large displacement within a limited housing space is proposed and investigated as a primary attempt to develop a new actuator suitable for a cardiac compression assist device. In the motor, the rectangular piezoelectric ceramic plates are directly used as the vibrators of a self-moving element with just one input power. The housing is used directly as a guide. Reversible motion direction is achieved through applying power to different electrodes. The motion principle is analysed on the basis of harmonic response calculation results. Using a data acquisition board with LabVIEW software, a control circuit, a laser displacement sensor, a force sensor, and a spring, an experimental rig is set up. Measured resonant frequencies and frequency properties agree with the calculated results and their analysis. Also under force control of the linear ultrasonic motor, 1 Hz pulse of desired force is realised with thrust force changing from 0 to 68% of the desired force in about 100 ms after 8 mm of displacement.

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Design and evaluation of linear ultrasonic motors for a cardiac compression assist device

We propose a model of a traveling wave ultrasonic motor that includes the elliptical motion amplitudes of the stator and verify this model experimentally using a high-speed camera with a high-power lens (i.e., a high-speed microscope). This approach makes it easy to estimate the motor characteristics, such as the rotational speed and torque. In this paper, we build a mechanical model of the stator and rotor that incorporates the elliptical motion amplitudes. The elliptical motion of a few microns at ultrasonic frequencies is captured and measured by the high-speed microscope. When modeling parameters are determined from the observed vibration amplitudes, the model can predict the motor characteristics. We study how the observed elliptical motion is related to the motor output by varying the frequency of applied voltages, and verify the proposed model by comparison with the experimental results.

Experimental Verification of Elliptical Motion Model in Traveling Wave Ultrasonic Motors

A dynamic model that includes four subsystems is developed to analyze the fundamental characteristics of a bimodal ultrasonic motor. The first subsystem is the driving circuit designed for the motor to achieve bidirectional motion. The stator is modeled as a Timoshenko beam, and the assumed mode energy method is used to obtain the dynamic equations. The normal interface force is represented by an elastic spring existing in between the tip of the stator and the moving platform. The interface forces are coupled into the dynamic formulations of the stator and the moving platform. The behavior of the force transmission between the stator and the moving platform are analyzed using the developed model. Transient and steady-state responses of the system are obtained by numerical simulation, and the results are validated by experiments. Furthermore, the existing of a nonlinear deadzone is predicted analytically, and the causes of this nonlinearity are clarified.

Cheng-Hsueh Lee

Papers

Dynamic modeling and analysis of a bimodal ultrasonic motor