When cars enter thousands of households, safety is becoming more and more important. The safety of the occupants is closely related to the advanced electronic systems of the vehicles used. The airbag ABS (Anti-lock Break system) system is a conventional safety protection system that everyone is familiar with. The vehicle stability system is a more advanced vehicle safety protection system. According to the German investigation, the installation of a vehicle stability system can reduce vehicle accidents by 50%. Many people may only know nouns but don't understand their meaning. And because of the different car systems, the nouns are also different.
This article refers to the address: http://
In fact, the core of the vehicle stability system is to add an inertial sensor, and measure the angular velocity and acceleration or inclination of the vehicle's rotation through the inertial sensor. Then, a control command is issued to a certain wheel through the ECU to ensure normal safe driving.
Vehicle stability systems have many different names, and their essence is similar. There are mainly different terms:
ESP: Electronic Stability Program.
ESC: Electronic Stability Control electronic stability program control system.
VDC: Vehicle Dynamic Control vehicle dynamic control.
VSC: Vehicle Stability Control body stability control system.
RSC: Roll Stability Control
DSC: Dynamic Stability Control.
Based on the ABS brake anti-lock braking system, ESP collects information such as the steering angle and lateral acceleration of the steering wheel through peripheral sensors. These information are processed by the microprocessor, and then the hydraulic regulator sends a brake command to the wheel brakes. Achieve correction for skidding. Especially when turning, that is, when the lateral force acts, the ESP stabilizes the vehicle and keeps driving safely. ABS and TCS only work in the longitudinal direction. ESP not only uses all the components of ABS and TCS, but also includes a yaw rate sensor and a direction sensor integrated with a lateral acceleration sensor.
ESC is functionally equivalent to ABS (Antilock Brake System), EBD (Electronic Brake Force Distribution), TCS (Traction Control System), AYC (Active Deflection Control) and other functions, it can automatically correct oversteer Insufficient steering, and by keeping the driver's direction of travel and the actual direction of the car, keep the car on the correct route. When a deviation is detected, the ESC brakes each wheel independently while reducing engine torque to help the driver maintain control of the car. The ESC is actually a brake system that can brake four wheels separately or simultaneously, which is not possible with a driver who is more technically advanced.
VDC is based on ABS and TCS. It increases the angular velocity sensor for lateral swing when the car is turning. The ECU controls the driving force and braking force of the inside and outside, front and rear wheels to ensure the horizontal dynamic stability of the car. The successful development of the VDC enables the driver to provide active and effective driving safety guarantees under all working conditions. The system mainly uses wheel speed sensor, steering wheel angle sensor, yaw rate sensor, lateral acceleration sensor and wheel displacement sensor.
The VSC will detect the driving state of the vehicle at any time. When the vehicle is in a critical state of turning during the turning process, the system will automatically reduce the power output of the engine, and the front and outer wheels will brake to generate an outward force to pull the vehicle back to normal. The driving state; if the vehicle is about to understeer, it also reduces the engine power output, and applies braking to the rear wheel according to the degree of understeer, so that the vehicle returns to the normal driving path.
The RSC anti-rolling stability control system uses a slewing sensor. When the driver makes a sharp turn or a quick turn, the following operations are completed in an instant: the system records the speed at which the vehicle's tilt angle changes; according to this speed, the final angle of the tilt is calculated to determine the risk of tumbling. Degree; if there is a danger of rolling, the brake system is activated to stabilize the vehicle; thus, the driver is given time to cope with and deal with the danger.
The DSC is a further extension of the accelerated anti-skid control or tracking control system to ensure that the car still has the best tracking performance when cornering to ensure the stability of the car. The system is still good for turning the car. Tracking, equipped with more advanced detection and control equipment, if it can detect the wheel speed, as well as detecting the rotation of the steering wheel, the speed of the car, and the lateral acceleration of the car, according to the information detected above To determine whether the wheel is slipping during the turning process. If there is a danger of slipping or slipping, the computer will immediately command the brake hydraulic control system to properly brake the slipping wheel, or to reduce it. The fuel injection amount and the delayed ignition method reduce the output of the engine power, which can prevent the tire from slipping under various driving conditions, so that the vehicle can obtain good tracking in the process of starting acceleration, re-acceleration, turning and the like. Sex.
As can be seen from the above, in addition to the existing rotational speed sensor and steering wheel angle sensor, these systems require a sensor that can measure the rotation of the vehicle body to measure the angular velocity or angular velocity of the revolution, and some additional measurements of the lateral and longitudinal lines of the vehicle. Acceleration. This leads to the problem of inertial sensors.
The development of MEMS technology (Micro-Electro-Mechanical Processing System), especially its high cost performance, brings possibilities and implementation to vehicle stability systems. Xi'an Zhongxing Measurement & Control Co., Ltd. has developed two gyro and stabilizers for vehicle stability control according to the requirements of domestic and foreign manufacturers, using advanced MEMS technology to meet the needs of different customers. The CS-ARAS contains an angular rate gyro and a linear acceleration that simultaneously measures the body's angular rate of rotation and lateral or longitudinal linear acceleration (according to the mounting direction). The CS-A2LAS stabilizer contains an angular rate sensor and a two-axis accelerometer that simultaneously measures lateral or longitudinal acceleration and angular velocity of the body's rotation. It has three national patents and exports to Finland, Italy and Israel.
The CS-ARAS series of vehicle inertial sensors are independently developed by Xi'an Zhongxing Measurement & Control Co., Ltd. for measuring angular velocity and acceleration. The CS-ARAS series of vehicle gyroscopes are one of the low-precision gyroscopes and accelerometers. It is mainly used for high reliability automotive electronics, and can also be used for antenna stabilization, camera, robot and other systems.
The angular rate gyroscope of the CS-ARAS series of automotive sensors operates according to the principle of the resonator gyro. Two polysilicon-sensitive structures, each containing a frame of high-frequency vibration, which is electrostatically driven to resonate to form the necessary velocity components. The two outer ends of the frame form a capacitively sensitive structure that senses the Coriolis motion generated at an angular rate and produces an electrical signal that is delivered to the amplification stage and the demodulation stage such that the output is proportional to the angular rate. electric signal.
The accelerometer for the CS-ARAS series of automotive sensors is a surface MEMS polysilicon structure built on top of a silicon wafer. The polysilicon reed suspends the structure on the surface of the wafer and provides a resistance to the acceleration sensing force. The deflection of the polysilicon structure proportional to the acceleration is measured by a differential capacitor mechanism comprising two separate fixed plates and a central plate connected to the moving mass to produce a voltage output signal.
Main technical conditions
powered by
Input voltage 15±0.25 VDC
Input current ≤30mA
Gyro performance
Measuring range ±100°/s; ±75°/s
Offset (at 25 ° C) 2.5 ± 0.1V
Output voltage (at 25 ° C) 0.5 ~ 4.5V
Nonlinearity 0.5%FS
Resolution ≤0.1°/s
Start time ≤ 35ms
Bandwidth ≥40Hz
Noise ≤10mV
Accelerometer performance
Measuring range ±1.8g
Offset (at 25 ° C) 2.5 ± 0.1V
Scale factor 1000±120 mV/g
Nonlinearity 0.5% FS
Resolution 1mg
Start time ≤35ms
Bandwidth ≥ 40Hz
Noise ≤ 5mV
working environment
Operating temperature -45 ° C - +85 ° C
Storage temperature -55 ° C - +100 ° C
Impact 2000g
B
Weight 150g Size See Dimensional Drawing Dimensions and Product Drawing
The CS-A2LAS stabilizer was developed by Xi'an Zhongxing Measurement & Control Co., Ltd. It is used in the automatic vehicle stability system and is also a good sensor for many commercial applications of multi-axis automatic mode.
Technical indicators:
Output form: analog output;
Supply voltage: 5 ± 0.05V;
Temperature range: -40 ° C ~ 85 ° C;
Startup time: <35ms;
Impact: 1000g;
The main indicators of angular rate sensor:
Range: ±75 °/S
Scale factor: 25 ± 2.5 (mV ∕ ° / S);
Bandwidth: >20Hz;
Zero offset: 2.5±0.1V;
Nonlinearity: ≤0.5%FS
Temperature change of zero bias: ±4°/S;
Acceleration sensitivity: 0.2 ° / S / g;
Main indicators of acceleration sensor:
Range: 1.5g;
Scale factor: 265 mV∕g;
Bandwidth: >20Hz;
Zero offset: 2.5±0.1V;
Nonlinearity: ≤0.2%FS
Dimensions:
CS-ARAS and CS-A2LAS consider the electromagnetic interference of vehicles and have designed anti-electromagnetic interference. At the same time, according to different system requirements to meet the individual needs of customers. In addition to the analog signal output, the Can bus output has also been developed recently, and the appearance can also be made according to customer requirements.
The CS-ARAS car gyro has similar functions to similar products of foreign companies. It has been used in a small number of heavy trucks in Europe and has been applied in a special vehicle in China and has been well evaluated.
The CS-A2LAS stabilizer meets the requirements of ESP or ESC and is being tested in several universities and research institutes in China. It is believed that it can meet the requirements.
Different system names are proposed and named and used by different car manufacturers or automotive electronics manufacturers. Functionally speaking, ESP, ESC, VSC and DSC are almost the same. Bosch and Mercedes-Benz of Germany adopt ESP system; Continental, TRW and Delphi adopt ESC system; Toyota of Japan adopts VSC system, among which Guangzhou Toyota 09 Camry G series is; DSC system is adopted by German BMW brand, and Volvo adopts It is called the DSTC system. These systems can be used with a CS-A2LAS stabilizer or two CS-ARAS car gyros from Xi'an Zhongxing Measurement & Control Co., Ltd.
The VDC system was adopted by Nissan, Japan, and Bosch in the early days called the system VDC; Volvo, such as the XCPO off-road vehicle and the JAGVAR brand, adopted the RSC system. This is suitable for high adhesion coefficient pavements and is mainly used for preventing rollover. Both the VDC and RSC systems can use the CS-ARAS gyro from Xi'an Zhongxing Measurement and Control Co., Ltd.
Die-Casting Products,Led Die Casting,Pressure Die Casting,Aluminum Die Casting Led
Yangzhou Huadong Can Illuminations Mould Manufactory Co., Ltd. , http://www.light-reflectors.com