ABS is the car's anti-lock brake system. It is an active safety device for cars. With the development of automotive electronics technology, the application of integrated circuits and computer technology, ABS control technology is becoming more and more mature. ABS is already the standard configuration on automobiles abroad. In recent years, ABS has also been popularized on domestic cars. Let's talk about the control method and control principle of ABS, I hope to help you.
ABS control method
1. Double parameter control
ABS (Structure of Anti-lock Braking System) controlled by two parameters is composed of vehicle speed sensor (speed measurement radar), wheel speed sensor, control device (computer) and actuator.
Its working principle is the vehicle speed sensor and the wheel speed sensor. The vehicle speed and wheel speed signals are input to the computer, and the actual slip rate is calculated by the computer, and compared with the ideal slip rate of 15% -20%, and then increased or decreased through the solenoid valve. The braking force of the brake.
This drag sensor is commonly used in Doppler speed radar. When the car is driving, the Doppler radar antenna continuously emits electromagnetic waves to the ground at a certain frequency, and at the same time receives the reflected electromagnetic waves, and measures the difference between the transmission and reception of the car radar, which can accurately calculate the car speed. The wheel speed sensor is installed in the transmission casing and driven by the transmission output shaft. It is a pulse motor and the frequency generated is proportional to the wheel speed.
The actuator is composed of solenoid valve and relay. The solenoid valve adjusts the braking force in order to maintain the ideal slip rate.
This ABS can ensure ideal control of the slip rate, and the anti-lock braking performance is good, but due to the addition of a speed measuring radar, the structure is more complex and the cost is higher.
2. Single parameter control
It takes the control of the angular deceleration of the wheel as the object, controls the braking force of the wheel, and realizes anti-lock braking. Its structure is mainly composed of a wheel speed sensor, a controller (computer) and a solenoid valve. In order to accurately measure the wheel speed, a gap of 1mm should be left between the sensor head and the wheel ring gear. In order to avoid the influence of water, mud and dust on the sensor, the sensor should be filled with butter before installation.
The solenoid valve is used to adjust the pressure of the wheel brake. For the four-channel brake system, one rim has a solenoid valve; for the three-channel brake system, each front wheel has one, and the two rear wheels share one. The solenoid valve has three hydraulic holes, which are respectively connected to the master brake cylinder and the wheel brake sub-cylinder, and can realize the pressure adjustment function of pressure increase, pressure maintenance, and pressure decrease. The working principle is as follows.
1) When the solenoid valve is not working for boosting, the interface between the master brake cylinder and each brake cylinder is connected directly. Due to the strength of the main spring, the inlet valve opens and the brake pressure increases.
2) Pressure maintenance When the pressure in the brake cylinder of the wheel increases to a certain value, the oil inlet valve is shut off. The bracket is kept in the middle state, and the three holes are sealed with each other to maintain the braking pressure.
3) When the solenoid valve works, the bracket overcomes the elastic force of the two springs and opens the unloading meat to reduce the brake cylinder pressure. Once the pressure decreases, the solenoid valve switches to the pressure holding state, or the ready state for boosting.
The main task of the control device ECU is to calculate, analyze, amplify and discriminate the signals returned by the sensors of each wheel, and then output the command signal to the solenoid valve by the output stage to perform the brake pressure adjustment task. The electronic control device is composed of four parts: input stage A, controller B, output stage C, voltage stabilizing and protection device D.
The electronic controller drives the solenoid valve at a frequency of 4 to 101tz, which the driver cannot do. ABS with this single parameter control method is widely used because of its simple structure and low cost.
Most American Chrysler-type high-end cars are equipped with this single-parameter control ABS. It is equipped with wheel speed sensors on the four wheels of the car.
A 45-tooth or 100-tooth ring gear is installed on the wheel shaft, and the sensor head of the wheel speed sensor is mounted on top of the ring gear. When the wheel rotates, the sensor continuously generates a voltage signal and inputs it to the computer. Compared with the ideal speed in RoM, it calculates the speed increase or deceleration of the wheel, and sends a boost or unload command to the solenoid valve to control the brake cylinder system. power.
Conclusion
With the rapid development of the automobile industry, the driving safety of automobiles has been paid more and more attention. The advent of ABS has greatly improved the performance of automobile braking systems. ABS has gradually become the standard configuration of automobiles. Understanding the control method of ABS is very helpful for people to drive safely.
Welding cable is a type of electrical cable that is specifically designed for use in welding applications. It is made up of fine copper strands that are coated with a durable, heat-resistant insulation material. The insulation material is resistant to cuts, tears, abrasions, and other types of damage that can be caused by welding sparks and other hazards.
Welding cable is available in various sizes, ranging from 6 AWG to 4/0 AWG, and is typically sold in lengths of 25 feet or more. The cable is rated for high amperage and voltage, making it suitable for use in welding machines and other heavy-duty electrical equipment.
One of the key benefits of welding cable is its flexibility. The fine copper strands that make up the cable are highly flexible, which makes it easy to maneuver and position in tight spaces. This flexibility also helps to reduce the risk of fatigue and breakage, which can occur with less flexible cables.
Overall, welding cable is an essential component of any welding setup. It provides a reliable and durable electrical connection between the welding machine and the workpiece, helping to ensure safe and efficient welding operations.
Soft Copper Conductor Flexible Core Welding Cable,DC Welding Cable,Flexible Core Conductor Electrical Power Cable,Single Core Copper Welding Wire,Rubber Insulation Electric Welding Cable
Ruitian Cable CO.,LTD. , https://www.rtlinecable.com