in this study, a novel variable impedance control for a lower-limb rehabilitation robotic system using voltage control strategy is presented. the majority of existing control approaches are based on control torque strategy, which require the knowledge of robot dynamics as well as dynamic of patients. this requires the controller to overcome complex problems such as uncertainties and nonlinearit...

We use AC impedance methods to investigate the effect of mechanical deformation on ion transport in commercial separator membranes and lithium-ion cells as a whole. A Bruggeman type power law relationship is found to provide an accurate correlation between porosity and tortuosity of deformed separators, which allows the impedance of a separator membrane to be predicted as a function of deformat...

Stochastic seismic inversion is a family of inversion algorithms in which the inverse solution was carried out using geostatistical simulation. In this work, a new 3D stochastic seismic inversion was developed in the MATLAB programming software. The proposed inversion algorithm is an iterative procedure that uses the principle of cross-over genetic algorithms as the global optimization techniqu...

This paper presented an improved algorithm using digitally synthesized excitation signal sources for efficient and accurate measurement of the E/M impedance for structural health monitoring with PWAS (piezoelectric wafer active sensor) transducers. Instead of using a sinusoidal excitation to measure the structural E/M impedance at a single frequency at a time, the digitally synthesized signal s...

In this paper we describe a system which we have developed to measure cat ear canal specific acoustic impedance Zsp, magnitude and phase, as a function of frequency, for frequencies between 200 Hz and 33 kHz, and impedance magnitude between 4.0 to 4.0×105 [Rayles] (MKS). The object to be measured is placed at the end of a 3.5 mm diameter sound delivery tube. After a simple calibration procedure...

This paper reports the preliminary results of a newly developed method for measuring dynamic modulus of thermoplastic materials at a given ultrasonic frequency. In the method, a material specimen is squeezed at the tip of the horn of a conventional ultrasonic welding machine. The mechanical impedance of the material specimen under loading is then deduced by processing the input electrical imped...

Optical nanoantennas have been studied as a means to manipulate nanoscale fields, local field enhancements, radiative rates, and emissive directional control. However, a fundamental function of antennas, the transfer of power between a coupled load and far-field radiation, has seen limited development in optical antennas owing largely to the inherent challenges of extracting impedance parameter...

This paper studies the feedback structure associated with piezoelectric shunt damping systems and introduces a new impedance structure for multi-mode piezoelectric shunt damping. The impedance is shown to be realizable using passive circuit components and digital implementation of the associated admittance transfer function is discussed. (Some figures in this article are in colour only in the e...