A flexible encapsulated MEMS pressure sensor system for biomechanical applications

Abstract

The use of pressure sensors made of conductive polymers is common in biomechanical applications. Unfortunately, hysteresis, nonlinearity, non-repeatability and creep have a signi®cant effect on the pressure readings when such conductive polymers are used. The objective of this paper is to explore the potential of a new¯exible encapsulated micro electromechanical system (MEMS) pressure sensor system as an alternative for human interface pressure measurement. A prototype has been designed, fabricated, and characterized. Testing has shown that the proposed packaging approach shows very little degradation in the performance characteristics of the original MEMS pressure sensor. The much-needed characteristics of repeatability, linearity, low hysteresis, temperature independency are preserved. Thus the¯exible encapsulated MEMS pressure sensor system is very promising and shows superiority over the commercially available conductive polymer ®lm sensors for pressure measurement in biomechanical applications.

Realisation and characterisation of mass-based diamond micro-transducers working in dynamic mode

“…For example silicon has been used for the fabrication of accelerometers [6,7], pressure sensors [8][9][10], resonators [11][12][13], or chemical/bio-chemical sensors [14][15][16]. For emerging MEMS applications such as bio-sensing, diamond appears to be a promising alternative material to silicon.…”

Design of MEMS biomedical pressure sensor for gait analysis

“…It is therefore critical to ensure the availability of an accurate and efficient technique of measuring this type of pressure. Among the key requirements of the pressure sensor specification for the application is its pressure range, output linearity and low hysteresis [5]. It is suggested that for walking analysis, pressure sensor should be able to measure up to 1000kPa, or 10kgcm -2 (about 100Ncm -2 ) [6].…”

“…There are a number of commercially available foot-pressure sensors at current but due to specification limitations, these sensors are not fully fulfilling the requirement of various biomechanical applications. The limitations include the specified pressure span, physical sensor dimensions [7] and hysteresis [5]. These weaknesses may cause erroneous readings or even worse, the malfunctioning of the device as some application may introduce pressure values way too far beyond the specified range.…”

Estimation of Individual Muscular Forces of the Lower Limb during Walking Using a Wearable Sensor System

“…Even though a rigid force transducer usually allows great accuracy of force measurement and multiaxial application, the user's natural motion can be disturbed due to rigidity and weight of the sensor. The foot plantar pressure sensor should be thin and flexible and light-weight, less than 300 g, for natural gait of the user [48,49]. The proposed GRF sensor was made of silicone tubes covered with fabrics to be light and soft.…”