There are a number of different types of sensors which can be used as essential components in numerous designs for machine olfaction systems. Electronic Nose (or eNose) sensors fall into five categories, conductivity sensors, piezoelectric sensors, Metal Oxide Field Effect Transistors (MOSFETs), optical sensors, and these employing spectrometry-based sensing methods.
Conductivity sensors could be made up of metal oxide and polymer elements, both of which exhibit a modification of resistance when exposed to Volatile Organic Compounds (VOCs). In this report only Metal Oxide Semi-conductor (MOS), Load Sensor and Quartz Crystal Microbalance (QCM) is going to be examined, as they are well researched, documented and established as essential element for various types of machine olfaction devices. The application, where proposed device will be trained onto analyse, will greatly influence deciding on a sensor.
A torque sensor, torque transducer or torque meter is actually a device for measuring and recording the torque over a rotating system, including an engine, crankshaft, gearbox, transmission, rotor, a bicycle crank or cap torque tester. Static torque is fairly easy to measure. Dynamic torque, on the contrary, is not easy to measure, as it generally requires transfer of some effect (electric, hydraulic or magnetic) from the shaft being measured to a static system.
One way to accomplish this would be to condition the shaft or perhaps a member attached to the shaft with several permanent magnetic domains. The magnetic characteristics of these domains will be different in accordance with the applied torque, and thus may be measured using non-contact sensors. Such magnetoelastic torque sensors are typically utilized for in-vehicle applications on racecars, automobiles, aircraft, and hovercraft.
Commonly, torque sensors or torque transducers use strain gauges applied to a rotating shaft or axle. With this particular method, a way to power the strain gauge bridge is essential, in addition to a means to have the signal from the rotating shaft. This can be accomplished using slip rings, wireless telemetry, or rotary transformers. Newer varieties of torque transducers add conditioning electronics and an A/D converter to the rotating shaft. Stator electronics then read the digital signals and convert those signals to Micro Load Cell, such as /-10VDC.
A more recent development is using SAW devices connected to the shaft and remotely interrogated. The stress on these tiny devices since the shaft flexes may be read remotely and output without the need for attached electronics on the shaft. The probable first use in volume are usually in the automotive field as, of May 2009, Schott announced it possesses a SAW sensor package viable for in vehicle uses.
An additional way to measure torque is through twist angle measurement or phase shift measurement, whereby the angle of twist as a result of applied torque is measured by utilizing two angular position sensors and measuring the phase angle between the two. This method is used inside the Allison T56 turboprop engine.
Finally, (as described inside the abstract for people Patent 5257535), when the mechanical system involves a right angle gearbox, then the axial reaction force felt by the inputting shaft/pinion could be related to the torque experienced by the output shaft(s). The axial input stress must first be calibrated from the output torque. The input stress can be easily measured via strain gauge measurement of the input pinion bearing housing. The output torque is readily measured using a static torque meter.
The torque sensor can function such as a mechanical fuse and is an important component to have accurate measurements. However, improper setting up the torque sensor can harm the device permanently, costing money and time. Hence, cdtgnt torque sensor must be properly installed to make certain better performance and longevity.
The performance and longevity from the torque sensor as well as its reading accuracy is going to be affected by the style of the Force Sensor. The shaft becomes unstable at the critical speed of the driveline and results in torsional vibration, which can harm the torque sensor. It is required to direct the strain for an exact point for accurate torque measurement. This point is typically the weakest point of the sensor structure. Hence, the torque sensor is purposely made to be among the weaker aspects of the driveline.