Abstract
Since the 1960s, there has been the use of force sensing devices for direct machine interactions of humans through electronic systems. Low force sensors have been extensively used in various industrial applications. Force sensing technology has been developing to a level of sophistication in the last four decades. In future, force sensing might be useful mainly in fields such as medical procedures, surgery in particular; food processing and agriculture; and service robotics and rehabilitation.
Since the 1960s, there has been the use of force sensing devices for direct machine interactions of humans through electronic systems. Historically, E. A. Johnson is known as the first inventor of such a device in the world. From 1965 to 1967, he invented a capacitive non-transparent touch screen for air traffic systems of control. In 1971, Dr. Sam Hurst developed a touch sensor referred to as the Elographics. He then founded a company called Elographics (1974), where he first commercialized a resistive transparent touch screen. In the same decade, Interlink Electronics, for the first time, developed a force sensing resistor (FSR) and its products entered the market in 1985 (Interlink Electronics 2). In 1967, Art R. Zias and John Egan made a patent application for the edge-constrained silicon diaphragm. In 1969, Hans W. Keller made a patent application for the batch-fabricated silicon sensor. The technology takes advantage of the huge IC-technology advancements. From the 2000s, the piezo-resistive has been the most universal technology. It is suitable for pressure ranging between 100 bars-1500 bars. The spread of the technology has been slow since companies have failed to develop decent housing.
Current Applications of Low Force Sensors in the Industry
Low force sensors have been extensively used in various industrial applications. In process monitoring and control, the sensors are used to estimate the forces in the operation and ensure that they are within such limit as to ensure high-quality products. In medical science, force sensors are used to estimate the strength of arms or legs in order to determine if a patient is fully healed through a procedure called dynamometry. Other applications include robotics and material testing.
Theory behind Sensor
Low force sensors have thin piezoelectric crystals that produce analogue voltage signals when dynamic forces are applied. IC chip amplifiers that are build-in, convert the crystal-generated high impedance signals to low impedance voltages appropriate for appropriate coupling to instruments that are readout. Upon stress by external compressive forces, crystals generate an analogous voltage of positive polarity (Faasler 4). An electrode collects the voltage and connects it to a metal oxide silicon field effect transistor (MOSFET) unity input, gaining the source follower amplifier present within the housing of the amplifier. The amplifier lowers the signal output impedance by ten magnitude orders to allow for its display on readout instruments like oscilloscopes, recorders and meters (Dytran Instruments Inc. 3). When tensile loads are put on the sensor (pulled), it causes the release of some of the preload, resulting into crystals generating a negative-going output signal. The internal preload screw strength, which is usually a way below the compression range, determines the maximum tensile loading.
Conclusion of Sensor Project
Force sensing technology has been developing to a level of sophistication in the last four decades. The long-standing and widely held expectation of tactile sensors having a large impact on industrial automation and robotics has always existed. But this is yet to be realized, and very few tactile sensors are in use in factories. Force sensing might be useful mainly in fields such as medical procedures, surgery in particular; food processing and agriculture; and service robotics and rehabilitation. In any case, there is a rapid, continuous creation of new configurations and designs of sensors. However, majority of the possible kinds of physical transduction techniques have been developed, and there’s a seemingly little scope for fresh fundamental transducers. Nicholls and Russell describe the basic transduction techniques, which already existed in 1990. The present offerings of research mainly involve novel packaging, improved engineering, better designs and more comprehensive analysis.
Works Cited
Dytran Instruments Inc. Introduction to Piezoelectric Force Sensors. Chatsworth, CA: Dytran
Instruments Inc., 2013. Print.
Faasler, Mathias. Force Sensing Technologies, Spring Term 2010. Zurich: Swiss Federal
Interlink Electronics. Applications of Force Sensing Technology in Consumer Electronics
Devices and Systems. Camarillo, CA: Interlink Electronics, December 2013. Print.
