I'm a man in slippers, a long-term car electronics engineer in Shanghai.
Old rules, share a piece of text you like, and avoid becoming an engineer with high knowledge and low culture:
No one follows you. No one needs to follow you either. You have to acknowledge your own worth, you can't stand against yourself by putting yourself in someone else's shoes. In life, the most fearful thing is to take other people's eyes as the only standard of your own life. In the end, I neither lived the way others liked, nor lived the way I wanted.
Only by accepting our true selves, without inferiority or pride, can we have a stronger heart; only by finding our own core values, can we live out our own wonderful life.
Introduction to FlexRay 1
People have long been accustomed to the fact that only electronic functions can meet the requirements of automobile fuel consumption, comfort and safety. For example, the electronic access system can automatically detect the electronic key, and the driver can conveniently unlock and start the car without using the key manually. In addition, the cruise control system can maintain a constant driving speed of at least 30 km/h, making long-distance travel more comfortable.
Other hidden features, such as electronic damping control, can also be cited. This function reduces body roll and ensures good contact between the tires and the road, ensuring optimum body vibration characteristics regardless of road and vehicle conditions.
Today, it is widely accepted that electronic features can improve driving safety. The main reason is that active safety systems such as ABS (Anti-lock Braking System) and ESP (Electronic Stability Program) have made a significant contribution to reducing accidents. To make driving safer, the automotive industry is paying particular attention to developing advanced and innovative active safety features and driver assistance functions.
For example, in the future, there will be an electronic assistant that can automatically adjust the speed of the vehicle according to the traffic flow, and another electronic assistant that can continuously monitor adjacent lanes within a range of 50 meters. If a car is detected in the adjacent lane, it will send an alert when the driver is overtaking or changing lanes. There are also electronic assistants that can help with parking safely.
In these systems, the application program is not only in one ECU, but multiple ECUs are required to work together with the help of a communication system. The control system is no longer a single ECU, but a distributed system that is gradually becoming the backbone of new safety systems and driver assistance systems.
It is not enough to simply incorporate communication systems, one also needs to ensure a strictly time-based chain of causality. The focus is on how to provide deterministic communication that is not affected by the bus load and ensure equidistant signal transmission, that is, a time-triggered real-time communication system.
Vehicle electrification has not shied away from an area where traditional mechanical and hydraulic systems dominate. In order to realize driver assistance functions with greater advantages, electronic interfaces to the chassis system, mainly the braking system and the steering system, are required.
Such electronic interfaces include electrohydraulic braking systems and electromechanical braking systems (EMB). The brake calipers of the electrohydraulic brake system are still hydraulically driven; while in the electromechanical brake system, the braking force of the brake calipers on the wheels is generated by an electric motor. The electromechanical braking system is controlled by an electronic control unit which takes input signals (force feedback) from an electronic brake pedal with a pedal feel simulator. Relevant control and sensor signals are transmitted via communication lines.
The brake-by-wire system can not only brake each wheel individually, thereby significantly improving braking stability, but also can modify the software to adjust the pedal characteristics and braking effect according to the driver's needs. An additional advantage is that the electronics are easier to diagnose, thereby increasing operational safety. The brake-by-wire system allows the brakes to become part of the vehicle dynamic control system, which can enhance the active safety of the vehicle to a certain extent. It should be pointed out that this kind of system still has certain security risks, as long as a fault or error occurs, it may cause serious consequences. Therefore, the brake-by-wire system must have fault tolerance. Only in this way can the specified basic braking function be guaranteed in the event of an error.
