Most people probably won’t ever think about position sensors – they just aren’t a flashy component likely to grab headlines any time soon. Despite that, position sensors are used in a huge number of areas that people encounter every day.
From construction to almost all transportation methods, incredibly specialised medical tools and almost every combustion engine, position sensors are absolutely core to everyday operation.
Position Sensors Keep Buildings Standing
Anyone who owns a property knows that the ground shifts, potentially leading to subsidence and eventually collapse. For buildings near coastlines or riverbanks, erosion leads to similar concerns. To keep tabs on these, and more, position sensors are used.
In areas where ground movement or erosion are concerns, position sensors are used to monitor the shift, allowing corrective action to be taken before damage is done. The sensors, such as LVDTs, are anchored to a fixed point on known solid ground or to the building on the land as well as to a series of points in the ground, allowing the movement of the ground to be monitored remotely for even the smallest shift.
Position sensors are used to great effect when stabilising structures against the sea floor, as movement is nearly constant. For this there are specialised submersible displacement sensors which remain accurate when entirely flooded with water.
Position Sensors Keep Vehicles Safe
Whenever you drive a car or travel by boat or by plane, you rely on a multitude of position sensors, many of which are detailed on http://www.positek.com/position-sensor-technology-comparison. These sensors keep control elements moving and measured, make sure the brakes are working properly and even keep the engines running.
To start with, many modern vehicles use fly-by-wire systems, where the controls are not directly connected with the control surfaces. Instead, the input of the pilot is converted to an electric impulse, which is then translated to mechanical force on the control surface, such as a ship’s rudder or the flaps on an aircraft.
These systems use position sensors at each end – one set of sensors on the pilot’s controls translating their movements into impulses to control the craft, and another set on the control surfaces sending information back to the pilot in the form of dashboard information.
While few cars use fly-by-wire systems, most hydraulic systems and braking systems include LVDTs. In the hydraulic systems such as brake lines and steering, the LVDT communicates with the car’s computer system to ensure the correct amount of pressure is being applied. In braking systems, the brake calipers are monitored by LVDTs to ensure the correct amount of braking pressure is applied, especially in cases where the brakes are not directly activated by the driver, such as anti-lock braking systems and the separate brakes on a trailer.
On high-performance vehicles, LVDTs will also measure the position of the throttle valve, communicating with the onboard computer to provide telemetry data, allowing for smooth start-up and an extremely responsive throttle.
LVDTs in Medicine
While most applications covered so far have been fairly heavy-duty industrial applications, position sensors also have a place in extremely delicate surgical instruments.
Special-purpose contactless LVDTs crafted on a nearly microscopic scale have an important role in brain surgery, where the difference between success and catastrophic failure is a tiny fraction of a centimetre.
LVDTs play an important part in all small-scale surgical procedures due to their incredible precision and capacity for miniaturisation.
The reason why position sensors are used in so many different ways where mechanical or higher-tech solutions may well be viable is due to their flexibility, as demonstrated by their being used in industrial applications, such as the hydraulics systems on construction equipment as well as extremely precise medical implementations.
Position sensors can be produced to withstand being submerged indefinitely, even in liquids other than water. Purpose-built position sensors can operate either flooded with the liquid or when liquid tight, as well as being produced from a multitude of materials if corrosion is a concern.
Depending on their construction, position sensors can also be produced to withstand extreme temperatures, with even the medically applied sensors being capable of operation between -25 C and 65 C – far outside the range where anyone would hope to perform surgery.
Position sensors are not glamorous, and they aren’t what you think of when you consider the systems they are involved in. They do, however, enable those systems to operate properly. Without them, we wouldn’t be able to accurately measure ground slippage or erosion, our hydraulic systems would be imprecise and the brakes on our cars would be erratic. They may not be glamorous, but they are important and they are everywhere.