How Do Anti-Lock Braking Systems Work?
Every moving vehicle needs to be able to brake safely and efficiently. However, when you are on slippery surfaces like water or ice, your brakes can lock up, making them less effective at stopping. This can cause the vehicle to skid, and such instances can potentially lead to a fatal accident. Therefore, the Anti-Lock System (ABS) was introduced to avoid such situations and promote safety during ground operations.
We all know that aircraft land with great speeds, and during conditions like heavy rainfall, it can become hazardous for pilots to apply breaks due to the potential risk of skidding. This led to the introduction of ABS to the aviation industry as a result of incredible speeds and dangerous weather conditions affecting landings.
ABS are critical pieces of equipment in large commercial and military aircraft. There are two functions that ABS perform, one of which is to maintain traction when the landing surface is hard. The second function is to make sure the plane does not nose dive when landing. Meaning, it prevents landing with locked wheels that could lead to dangerous incidents if not applied.
The touchdown phase of landing needs to be choreographed and practiced many times before being attempted in an aircraft. For example, many pilots try to land the plane while engaging the brakes to decrease their braking distance. However, engaging your brakes too early can lead to immediate wheel locking. This can ultimately damage your brakes and may potentially burts tires upon touchdown, making it difficult for pilots to control the vehicle.
The early uses of aviation ABS were connected with mechanical systems, but became increasingly popular as computer and electronic technologies developed. The working principle used for anti-lock braking systems is based on wheel rotation control, alongside the release and then reapplication of the brakes during emergency braking conditions.
There are four major components of an anti-lock braking system:
1. Speed sensors are provided to monitor how fast the wheels rotate.
2. Valves are located in the brake line, which controls the block and release of the pressure on the brakes.
3. Hydraulic pumps are used to apply pressure on the brake drums as required.
4. The ECU or the control system is the brain of the ABS, which decides when to pump the brakes using data from the sensors.
The rotating wheels generate a magnetic field around the speed sensors. The increasing and decreasing speed fluctuates the voltages, and these fluctuations are transmitted to the ECU. Then the controller amplifies and filters the received signals to calculate the acceleration and deceleration values.
In case of an emergency braking situation where unfavorable weather conditions are present, the wheels have the potential to decelerate faster and lock. The ECU will notice this sudden speed decrease and notify the HCU (hydraulic control unit) via signals. In addition, the HCU will close a valve to reduce pressure on brake pads in an emergency. This action will stop wheels from skidding or locking.
Anti-lock braking systems are tested on a routine basis to ensure their functionality under various operating conditions. Whether the runway is slippery, wet, or dry, new linings on your brakes can make all the difference in how well they work. Studies show that plastic deformation of brake lining surface layers and other faults can convert 95% of friction energy into thermal energy. This leads to a significant increase in temperature growth due to braking temperatures, which influences tribological characteristics like durability and reliability for braking systems fabricated using these materials.
In Conclusion
When the aviation industry needed a material that could withstand intense heat and pressure during landings, ABS successfully fulfilled these requirements, making it an essential part of airplanes today. The ABS on an aircraft is responsible for preventing dangerous situations while landing in slippery areas, and it prevents landing with engaged brakes. This critical safety feature used in military and commercial aviation will help keep everyone on board safe from accidents.
NSN Axis is a leading aviation and NSN parts marketplace. We are owned and operated by ASAP Semiconductor and are committed to providing our clients with innovative purchasing options. We have developed our streamlined procurement platform to simplify the purchasing process so you can find the aviation parts you need fast. As we are available and ready to help customers 24/7x365, we are perfect for all your AOG situation and time-sensitive needs.
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