scholarly journals Performance Evaluation of Capacitive Based Force Sensor for Electroencephalography Head Caps

Author(s):  
Warsito I.F. ◽  
Hunold A. ◽  
Haueisen J. ◽  
Supriyanto E.

Accurate electrode signal measurement using EEG head caps can only be achieved through sufficient contact or force. A flexible force sensor is required to obtain accurate force measurement underneath EEG head caps. In this study, we evaluate the performance of a capacitive based sensor including its accuracy, repeatability, hysteresis, and stability. The result shows that accuracy error and repeatability error were 3.03±2.8 % and 3.84±2.92 %, respectively. The stability errors were 2.37±0.15 %(10 gram), 2.54±0.00 % (50 gram), 2.37±0.15 % (100 gram), 5.07±1.16 % (150 gram), 7.27±0.39 % (200 gram). The hysteresis error of the sensor was 4.48±0.47 %. Based on the results, the capacitive based force sensor provides sufficiently low errors in accuracy, repeatability, stability, and hysteresis and is thus suitable for measuring adduction force in EEG cap applications

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Yuanyuan Li ◽  
Wenke Lu ◽  
Changchun Zhu ◽  
Qinghong Liu ◽  
Haoxin Zhang ◽  
...  

Pressure sensors are commonly used in industrial production and mechanical system. However, resistance strain, piezoresistive sensor, and ceramic capacitive pressure sensors possess limitations, especially in micro force measurement. A surface acoustic wave (SAW) based micro force sensor is designed in this paper, which is based on the theories of wavelet transform, SAW detection, and pierce oscillator circuits. Using lithium niobate as the basal material, a mathematical model is established to analyze the frequency, and a peripheral circuit is designed to measure the micro force. The SAW based micro force sensor is tested to show the reasonable design of detection circuit and the stability of frequency and amplitude.


2010 ◽  
Vol 36 ◽  
pp. 41-51
Author(s):  
Yusaku Fujii ◽  
Koichi Maru ◽  
Tao Jin ◽  
Takao Yamaguchi

This paper reviewed the present status and the future prospects of a method for precision mass and force measurement based on levitation mass method (LMM). The LMM has been proposed and improved by the author The mass which levitated using a pneumatic linear bearing in LMM is used to producte a inertial force which used as the reference force applied to the objects under test, such as to force sensor calibration, material and structure test. The inertial force is calibrated only from Doppler shift frequency. The stability of laser’s wavelength has improved in the LMM. The futhure work and the method to improve the precision have described.


Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2504
Author(s):  
Francisco Javier García Fierros ◽  
Jesús Jaime Moreno Escobar ◽  
Gabriel Sepúlveda Cervantes ◽  
Oswaldo Morales Matamoros ◽  
Ricardo Tejeida Padilla

Deaths due to heart diseases are a leading cause of death in Mexico. Cardiovascular diseases are considered a public health problem because they produce cardiorespiratory arrests. During an arrest, cardiac and/or respiratory activity stops. A cardiorespiratory arrest is rapidly fatal without a quick and efficient intervention. As a response to this problem, the VirtualCPR system was designed in the present work. VirtualCPR is a mobile virtual reality application to support learning and practicing of basic techniques of cardiopulmonary resuscitation (CPR) for experts or non-experts in CPR. VirtualCPR implements an interactive virtual scenario with the user, which is visible by means of employment of virtual reality lenses. User’s interactions, with our proposal, are by a portable force sensor for integration with training mannequins, whose development is based on an application for the Android platform. Furthermore, this proposal integrates medical knowledge in first aid, related to the basic CPR for adults using only the hands, as well as technological knowledge, related to development of simulations on a mobile virtual reality platform by three main processes: (i) force measurement and conversion, (ii) data transmission and (iii) simulation of a virtual scenario. An experiment by means of a multifactorial analysis of variance was designed considering four factors for a CPR session: (i) previous training in CPR, (ii) frequency of compressions, (iii) presence of auditory suggestions and (iv) presence of color indicator. Our findings point out that the more previous training in CPR a user of the VirtualCPR system has, the greater the percentage of correct compressions obtained from a virtual CPR session. Setting the rate to 100 or 150 compressions per minute, turning on or off the auditory suggestions and turning the color indicator on or off during the session have no significant effect on the results obtained by the user.


Author(s):  
Farhad Aghili

A heavy payload attached to the wrist force/moment (F/M) sensor of a manipulator can cause the conventional impedance controller to fail in establishing the desired impedance due to the noncontact components of the force measurement, i.e., the inertial and gravitational forces of the payload. This paper proposes an impedance control scheme for such a manipulator to accurately shape its force-response without needing any acceleration measurement. Therefore, no wrist accelerometer or a dynamic estimator for compensating the inertial load forces is required. The impedance controller is further developed using an inner/outer loop feedback approach that not only overcomes the robot dynamics uncertainty, but also allows the specification of the target impedance model in a general form, e.g., a nonlinear model. The stability and convergence of the impedance controller are analytically investigated, and the results show that the control input remains bounded provided that the desired inertia is selected to be different from the payload inertia. Experimental results demonstrate that the proposed impedance controller is able to accurately shape the impedance of a manipulator carrying a relatively heavy load according to the desired impedance model.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Kyungrim Kim ◽  
Jinwook Kim ◽  
Xiaoning Jiang ◽  
Taeyang Kim

In force measurement applications, a piezoelectric force sensor is one of the most popular sensors due to its advantages of low cost, linear response, and high sensitivity. Piezoelectric sensors effectively convert dynamic forces to electrical signals by the direct piezoelectric effect, but their use has been limited in measuring static forces due to the easily neutralized surface charge. To overcome this shortcoming, several static (either pure static or quasistatic) force sensing techniques using piezoelectric materials have been developed utilizing several unique parameters rather than just the surface charge produced by an applied force. The parameters for static force measurement include the resonance frequency, electrical impedance, decay time constant, and capacitance. In this review, we discuss the detailed mechanism of these piezoelectric-type, static force sensing methods that use more than the direct piezoelectric effect. We also highlight the challenges and potentials of each method for static force sensing applications.


2015 ◽  
Vol 780 ◽  
pp. 1-5
Author(s):  
Khairunizam Wan ◽  
H.E. Nabilah ◽  
Nor Farahiya ◽  
M. Hazwan Ali ◽  
Rashidah Suhaimi ◽  
...  

Modernization of human technologies overtime results the need of more freedom technology likes the use of natural interaction to replace a current trend interface devices such as joysticks, mice, keyboards and other related output devices. Dataglove is one of the interface devices that could serve a natural interaction between user and computers. In this paper, a dataglove called GloveMAP is introduced which has the capability of measuring fingertip force. The flexible force sensors are attached to the fingers location of the glove. Several object grasping experiments are conducted and the grasping force signals are measured. A Gaussian filter is introduced to smoothen the acquired force signals.


Author(s):  
E R Komi ◽  
J R Roberts ◽  
S J Rothberg

Three types of thin, flexible force sensor were studied under a variety of loading conditions to determine their suitability for measuring grip force. Static accuracy, hysteresis, repeatability, and drift errors were established, the effects of shear force and surface curvature were considered, and dynamic accuracy and drift were measured. Novel tests were developed to consider dynamic accuracy and sensitivity to shear loadings. Additionally, three sensors were evaluated in a real-life gripping scenario, measuring grip force during a golf shot. Comments are made on sensor performance, ease of use, and durability.


2018 ◽  
Vol 121 ◽  
pp. 34-40 ◽  
Author(s):  
Golam Mustafa ◽  
Cho-Ying Chuang ◽  
William A. Roy ◽  
Mohamed M. Farhath ◽  
Nilisha Pokhrel ◽  
...  

2020 ◽  
Vol 238 ◽  
pp. 12009
Author(s):  
Walter S. J. Ferreira ◽  
Paulo S. S. dos Santos ◽  
Paulo Caldas ◽  
Pedro A. S. Jorge ◽  
João M. S. Sakamoto

In this work, a long-period fiber grating (LPG) based sensor was evaluated as a sensing device for micro-force measurement, in the order of micro Newtons. It was used an LPG fabricated by arc-inducted technique in a SMF-28 standard optical fiber. The optical fiber was fixed between two clamps with a separation of 150 mm with the middle of the LPG located at the center. Characterizations were performed in terms of temperature, curvature and strain. The grating was then used as a micro-force sensor by means of both curvature and strain, induced by a hung mass in a stretched fiber. Furthermore, the evaluation of a precurvature LPG was performed to assess if an increase of sensitivity is achieved. Micro-force sensitivity achieved with the stretched LPG was 1.41 nm/mN and it was demonstrated that its sensitivity can be enhanced to 5.14 nm/mN with a pre-curvature of 2.2 m–1 applied to the LPG, achieving a spectral resolution of at least 15.6 μN.


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