Jan 4, PDF | Antilock Breaking System (ABS) is used in advanced automobiles to prevent slip and locking of wheel after brakes applied. 10/ QUICK TIPS: Anti-Lock Braking Systems (ABS). How Does ABS Work? If either of a motorcycle's tires loses traction and skids along the road surface. An anti-lock braking system (ABS) is a safety anti-skid braking system used on aircraft and on Program Task 4: A Test Track Study of Light Vehicle ABS Performance Over a Broad Range of Surfaces and Maneuvers, Jan " (PDF).
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towards the car that turned in front of you. Had your car been equipped with an anti-lock braking system. (ABS), your wheels would not have locked up, and. This is achieved by the use of ABS. (Anti-Lock Braking System), which prevent the road wheels locking up wheels locking up p. g p. (by sensing a locked wheel, . Oct 4, Antilock Breaking System (ABS) is used in advanced automobiles to prevent slip and locking of wheel after brakes applied. It is automobile.
The sensor used for the ABS application converts the velocity of the rotating wheel into a voltage. This application can be modeled as a tachometer. Equation 7 is the transfer function of a tachometer.
The new control loop obtained from the transfer functions above is shown in figure below. In the analysis the gain of the sensor Ktach is assumed to be This assumption is based on the fact that the voltage produced by the sensor is small.
The controller will require a higher voltage signal in order to receive the information from the sensor. Therefore the voltage from the sensor must be amplified and thus the gain is high.
The gain of the actuator Kact is assumed to be 0. This is due to the high pressures of the hydraulic system. The valve and pumping system will not have to do much work in order to achieve the desired pressures at the braking system.
Anti-lock braking system
The results of the P control analysis are shown in figures below. The ECU constantly monitors the rotational speed of each wheel; if it detects a wheel rotating significantly slower than the others, a condition indicative of impending wheel lock, it actuates the valves to reduce hydraulic pressure to the brake at the affected wheel, thus reducing the braking force on that wheel.
The wheel then turns faster. Conversely, if the ECU detects a wheel turning significantly faster than the others, brake hydraulic pressure to the wheel is increased so the braking force is reapplied, slowing down the wheel. This process is repeated continuously and can be detected by the driver via brake pedal pulsation.
Some anti-lock system can apply or release braking pressure 16 times per second. The ECU is programmed to disregard differences in wheel rotative speed below a critical threshold, because when the car is turning, the two wheels towards the centre of the curve turn slower than the outer two.
For this same reason, a differential is used in virtually all roadgoing vehicles. If a fault develops in any part of the ABS, a warning light will usually be illuminated on the vehicle instrument panel, and the ABS will be disabled until the fault is rectified. The modern ABS applies individual brake pressure to all four wheels through a control system of hub-mounted sensors and a dedicated micro-controller.
ABS is offered or comes standard on most road vehicles produced today and is the foundation for ESC systems, which are rapidly increasing in popularity due to the vast reduction in price of vehicle electronics over the years. Here, a minimum of two additional sensors are added to help the system work: these are a steering wheel angle sensor, and a gyroscopic sensor.
The theory of operation is simple: when the gyroscopic sensor detects that the direction taken by the car does not coincide with what the steering wheel sensor reports, the ESC software will brake the necessary individual wheel s up to three with the most sophisticated systems , so that the vehicle goes the way the driver intends. The steering wheel sensor also helps in the operation of Cornering Brake Control CBC , since this will tell the ABS that wheels on the inside of the curve should brake more than wheels on the outside, and by how much.
If, when accelerating, the tire loses traction, the ABS controller can detect the situation and take suitable action so that traction is regained.
Speed Sensor : These sensors use a magnet and a coil of wire to generate a signal. The rotation of the wheel or differential induces a magnetic field around the sensor. The fluctuations of this magnetic field generate a voltage into the sensor.
A schematic of this system is shown in figure below. The ABS controller interprets this signal. Since the voltage inducted on the sensor is a result of the rotating wheel, this sensor can become inaccurate at slow speeds.
The slower rotation of the wheel can cause inaccurate fluctuations in the magnetic field and thus cause inaccurate readings to the controller. Next More Seminar Topics: Are you interested in this topic.A simplified system should reduce the complexity, cost, as well as increase the easy of serviceability. Only a few vehicles are equipped with ABS in Iran and even in other countries [ 2 , 4 ].
Because the latter is unknown, it is extremely difficult to define a controller that guaranties an optimal braking performance for all types of runway conditions. Some vehicle manufacturers provide an "off-road" button to turn ABS function off. Types of ABS 5.
In , American Lincoln firm took the marketplace by making ABS a standard feature for all four wheels .