Characterization of improved tactile sensors using piezoelectric resonator

Safety of human-robot physical interaction is enabled not only by suitable robot control strategies but also by suitable sensing technologies. For example, if distributed tactile sensors were available on the robot, they could be used not only to detect unintentional collisions, but also as human-machine interface by enabling a new mode of social interaction with the machine. Starting from their previous works, the authors developed a conformable distributed tactile sensor that can be easily conformed to the different parts of the robot body. Its ability to estimate contact force components and to provide a tactile map with an accurate spatial resolution enables the robot to handle both unintentional collisions in safe human-robot collaboration tasks and intentional touches where the sensor is used as human-machine interface. In this paper, the authors present the characterization of the proposed tactile sensor and they show how it can be also exploited to recognize haptic tactile gestures, by tailoring recognition algorithms, well known in the image processing field, to the case of tactile images. In particular, a set of haptic gestures has been defined to test three recognition algorithms on a group of 20 users. The paper demonstrates how the same sensor originally designed to manage unintentional collisions can be successfully used also as human-machine interface.

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Characterization of a nonlinear MEMS-based piezoelectric resonator for wideband micro power generation

Applied Mathematical Modelling ◽

10.1016/j.apm.2016.08.019 ◽

2017 ◽

Vol 41 ◽

pp. 121-142 ◽

Cited By ~ 17

Author(s):

Abdolreza Pasharavesh ◽

M.T. Ahmadian

Keyword(s):

Power Generation ◽

Piezoelectric Resonator ◽

Micro Power

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A Frequency Reference for Carrier Synthesis in Wireless Standard 802.11g

The Scientific Bulletin of Electrical Engineering Faculty ◽

10.2478/sbeef-2020-0112 ◽

2020 ◽

Vol 20 (1) ◽

pp. 56-61

Author(s):

Iulian Ursac ◽

Florin Constantinescu ◽

Mihai Marin

Keyword(s):

Frequency Synthesizer ◽

Fixed Ratio ◽

Frequency Divider ◽

Piezoelectric Resonator ◽

New Approach ◽

Frequency Reference ◽

Reference Oscillator ◽

Wireless Transceiver ◽

Low Phase Noise

AbstractA new approach to a frequency synthesizer is proposed: instead of a fixed frequency reference oscillator and a variable ratio frequency divider we use a variable frequency reference oscillator and a fixed ratio frequency divider. The implementation and characterization of a low phase-noise compensated oscillator used as frequency reference for a wireless transceiver is described. This circuit employs a high Q piezoelectric resonator together with a CMOS cross coupled pair amplifier. A calibration circuit for compensation of frequency errors with respect to process variation is proposed.

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Experimental Assessment of the Interface Electronic System for PVDF-Based Piezoelectric Tactile Sensors

Sensors ◽

10.3390/s19204437 ◽

2019 ◽

Vol 19 (20) ◽

pp. 4437 ◽

Cited By ~ 3

Author(s):

Moustafa Saleh ◽

Yahya Abbass ◽

Ali Ibrahim ◽

Maurizio Valle

Keyword(s):

Low Power ◽

Electronic System ◽

Tactile Sensing ◽

Tactile Sensors ◽

Prosthetic Device ◽

Experimental Assessment ◽

Sensing System ◽

Sensing Material ◽

Sense Of Touch

Tactile sensors are widely employed to enable the sense of touch for applications such as robotics and prosthetics. In addition to the selection of an appropriate sensing material, the performance of the tactile sensing system is conditioned by its interface electronic system. On the other hand, due to the need to embed the tactile sensing system into a prosthetic device, strict requirements such as small size and low power consumption are imposed on the system design. This paper presents the experimental assessment and characterization of an interface electronic system for piezoelectric tactile sensors for prosthetic applications. The interface electronic is proposed as part of a wearable system intended to be integrated into an upper limb prosthetic device. The system is based on a low power arm-microcontroller and a DDC232 device. Electrical and electromechanical setups have been implemented to assess the response of the interface electronic with PVDF-based piezoelectric sensors. The results of electrical and electromechanical tests validate the correct functionality of the proposed system.

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Design and Characterization of a Planar Motor Drive Platform Based on Piezoelectric Hemispherical Shell Resonators

Actuators ◽

10.3390/act10080187 ◽

2021 ◽

Vol 10 (8) ◽

pp. 187

Author(s):

Frank Schiele ◽

Bernd Gundelsweiler

Keyword(s):

Open Loop ◽

Excitation Voltage ◽

Piezoelectric Resonator ◽

Measured Velocity ◽

Driving Mode ◽

Hemispherical Shell ◽

Propulsion Force ◽

Working Principle ◽

Oscillating Mode

In this study, a planar ultrasonic motor platform is presented that uses three half-side excited piezoelectric hemispherical shell resonators. To understand the working principle and the harmonic vibration behavior of the piezoelectric resonator, the trajectory of the friction contact was measured in free-oscillating mode at varying excitation frequencies and voltages. The driving performance of the platform was characterized with transport loads up to 5 kg that also serve as an influencing downforce for the friction motor. The working range for various transport loads and electrical voltages up to 30 V is presented. Undesirable noise and parasitic oscillations occur above the detected excitation voltage ranges, depending on the downforce. Therefore, minimum and maximum values of the excitation voltage are reported, in which the propulsion force and the speed of the planar motor can be adjusted, and noiseless motion applies. The multidimensional driving capacity of the platform is demonstrated in two orthogonal axes and one rotary axis in open-loop driving mode, by measuring forces and velocities to confirm its suitability as a planar motor concept. The maximum measured propulsion force of the motor was 7 N with a transport load of 5 kg, and its maximum measured velocity was 77 mm/s with a transport load of 3 kg.

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Fabrication and Characterization of Normal and Shear Stresses Sensitive Tactile Sensors by Using Inclined Micro-cantilevers Covered with Elastomer

MRS Proceedings ◽

10.1557/proc-1052-dd04-07 ◽

2007 ◽

Vol 1052 ◽

Cited By ~ 9

Author(s):

Masayuki Sohgawa ◽

Yu-Ming Huang ◽

Minoru Noda ◽

Takeshi Kanashima ◽

Kaoru Yamashita ◽

...

Keyword(s):

Shear Stress ◽

Normal Stress ◽

Tactile Sensor ◽

Shear Stresses ◽

Tactile Sensors ◽

Orthogonal Direction ◽

Pdms Elastomer ◽

Control Layer ◽

Human Support

AbstractThe tactile sensors for human support robots which can detect both normal stress and shear stress and have human-friendly surface have been proposed. Micro-cantilevers adequately inclined by Cr deflection control layer were fabricated by the surface micromachining on SOI wafer. The cantilevers were covered with the PDMS elastomer for human-friendly surface. When the stress is added to the surface of elastomer, the deformation of cantilevers along with elastomer is detected as piezoresistive layer in the cantilevers. The piezoresistive response of the cantilever is analyzed by FEM calculation. The response of the fabricated tactile sensor to normal stress and shear stress was measured by output from this resistance. The tactile sensor with PDMS elastomer can detect both normal stress and shear stress. On the other hand, it hardly has sensitivity to shear stress of orthogonal direction to the cantilever. It means that the tactile sensor can distinguish the direction of shear stress. The sensitivity of tactile sensor vary widely with cantilever pattern and relation between direction of cantilever and crystallite orientation of Si. It is suggested that the sensitivity of tactile sensor can be improved by using FEM estimation and selective ion implantation.

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