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A simple platform is proposed for the accurate characterization of Quartz Tuning Fork (QTF) based sensors. The system is based on a Personal Computer (PC) and takes advantage of the fact that the resonance frequency of standard wristwatch QTFs falls well within the acquisition bandwidth of modern soundcards. The choices in the design of the extremely simple measurement hardware result in the ability...
When performing voltage noise measurements on a biased device, the DC component due to the bias must be rejected in order to avoid saturation of the high gain low noise input stage of the voltage amplifier employed to raise the level of the signal prior to sampling for spectral analysis. This is normally done by interposing an RC high pass filter between the device and the DC coupled amplifier input...
We report on experiments performed in order to verify the ability of low frequency noise measurements to serve as a sensitive tool for the characterization of the degradation of electron devices on flexible substrates as a consequence of mechanical stress. We designed and build a dedicated stress chamber for performing stress (repeated bending) in controlled environmental conditions. Test devices...
We propose a simple topology for the realization of ultra low noise differential-input, differential-output preamplifiers. The input devices can be either low noise JFET pairs (for high impedance sources) or low noise BJT pairs (for minimum low frequency voltage noise). Besides the input devices, the circuit requires only two matched low noise BJT transistor pairs (either PNP or NPN, depending on...
We propose an elaboration and visualization approach for spectral measurement that allows to monitor the progress of the estimation process in real time while maintaining a quaqi-constant resolution bandwidth over frequency ratio in a wide frequency range. The approach we propose is particularly useful in the estimation of low frequency noise, where the flicker component is dominant, since it allows...
We propose a simple but effective approach for the estimation of power spectra at very low frequencies (down to the tens of mHz range) by exploiting the characteristics of the sound system (sound card) and the computational power of modern personal computers. A simple mixer board has been designed that allows to transfer the low frequency region of the spectrum at a higher frequency in the passband...
This paper proposes an architecture for tactile-based fabric learning and classification. The architecture is based on a number of SVM-based learning units, which we call fabric classification cores, specifically trained to discriminate between two fabrics. Each core is based on a specific subset of the fully available set of features, on the basis of their discriminative value, determined using the...
A test and measurement system for the characterization of standard 32 kHz tuning fork crystal based sensors is proposed. A very simple circuit configuration provides for a white noise voltage test signal to be applied to the tuning fork device and to a variable capacitor that, in combination with a differential transimpedance amplifier, allows to detect and amplify the current through the device subtracting...
A possible alternative to traditional, time crunching, endurance tests in accomplishing the reliability assessment of power devices are reliability models. Two possible approaches are compared in this paper to estimate the level of reliability of power MOSFETs working in avalanche mode. Although both the considered approaches exploit mathematical models carried out from the Coffin-Manson law, they...
The noise performances of monolithic operational amplifiers are generally insufficient for the realization of low noise amplifiers for applications in the field of low frequency voltage noise measurements. In order to obtain very low levels of equivalent input voltage and current noise, discrete JFETs input stages can be used, with the disadvantage of introducing a large input capacitance that can...
Small sized solar cells in compact SOIC packages are investigated as candidates for the design of floating low noise voltage reference to be used in low noise applications. The noise introduced by the solar cell as a function of the incident light is investigated and a simplified model is extracted that can be used, together with a proper filtering stage and a closed loop control system, for the implementation...
We present a novel and flexible system to be employed for tactile transduction in the realization of artificial "robot skin". The mechanical deformation detection, which functionally reproduces the sense of touch, is based on Organic Thin Film Transistors (OTFTs) assembled on a flexible plastic foil, where each device acts as a strain sensor. OTFT-based mechanical sensors were fabricated...
A new design of an offset correction system that employs a time varying resistance as a probe for detecting the sign and magnitude of the equivalent input offset of an operational amplifier in a series-shunt feedback configuration is proposed. The time varying sense resistor is implemented by a MOS for which the problem of charge injection is considerably reduced by resorting to a proper discrete...
Johnson noise thermometry is a well established technique that allows the determination of the temperature starting from the measurement of the thermal noise produced by a known resistance at thermal equilibrium. Notwithstanding that, under proper conditions, the Johnson noise thermometer is a primary thermometer, the very long measurement time that is required to reach accuracies in the order of...
In this paper a framework for representing tactile information in robots is discussed. Control models exploiting tactile sensing are fundamental in social Human-Robot interaction tasks. Difficulties arising in rendering the sense of touch in robots are at different levels: both representation and computational issues must be considered. A layered system is proposed, which is inspired from tactile...
In this paper a new method for accurate frequency estimation of a single sinusoid is described. The main feature of the proposed method, mainly based on a simple digital non-linear filter, is its intrinsic low complexity development and use. The method, in fact, needs about 2Ns arithmetic operations, where Ns is the number of samples, and has very small memory requirements even when high accuracy...
This paper presents a novel approach for multi-robot coordination based both on coordinated navigation and task allocation method. The proposed approach exploits RFID technology for implementing a context aware information system which is the base of the coordination strategies; it has extremely low requirements in terms of computational power and does not require direct robot-robot communication...
A novel artificial skin for covering the whole body of a humanoid robot is presented. It provides pressure measurements and shape information about the contact surfaces between the robot and the environment. The system is based on a mesh of sensors interconnected in order to form a networked structure. Each sensor has 12 capacitive taxels, has a triangular shape and is supported by a flexible substrate...
Eye motion strategies in animals and humans have the goal of optimizing visual perception, therefore, the study of eye motions plays an important role in the design of humanoid robot eye systems. Saccades and smooth pursuit in humans and primates are a significant class of ocular motions, which obey the so called Listing's Law, stating that admissible eye's orientations have always zero torsion during...
A fully embedded tactile/force sensor system to be installed on the phalanges of a robot hand is presented in this paper. The sensor consists of a distributed array of analog tactile elements and an integrated three-component force transducer with embedded analog and digital electronics. The tactile sensor is a matrix of electrodes etched on a flexible printed circuit board covered by pressure conductive...
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