Automotive Test Dummy Test Method for Experiments: There are many evaluation indicators of automobile collision testing, including the acceleration impact values of each organ in the fake human body, the power and torque sizes of the extruded deformation displacement. In addition, it is necessary to comprehensively assess the body acceleration sensor signal, the body deformation amount, the collision, the door opening state, and the amount of fuel leakage. Among them, a large part (especially in dummy, sensor signal data) is a collection process that needs to pass the electric measurement data acquisition system, and finally feeds back the test results to the test personnel to calculate the fake human harmony value and other evaluation indicators. In some cases, the number of electric measurements is more than 150, which involves the type of acceleration, force and torque, displacement, current, and switching amount. It can be seen that the data acquisition system is a very important measurement in a car crash test. The link.
First, the characteristics of automobile collision test data acquisition system
Collision test data is one of the most important basis for evaluating passive safety performance of vehicles, analog letter from the sensor inside the body and dummy The data acquisition analysis system is converted into a digital signal, eventually proceeds through hardware circuit and software program to obtain various collision curves, indicators, show the results in quantization, and easier to implement and more detailed vehicles passive safety. Evaluate. At present, more data acquisition systems using more Data acquisition systems in the automotive collision test mainly include the Minidau, Japan DTS of the Japanese DTS series of KT, US DTS, Na33, and the NA33 of German Messring. These products can realize the basic functions of data acquisition in the car collision. They use each characteristic: MINIDAU's acquisition control software adopts ISO / DTR13499 standard, and uses MS-Access to establish and maintain sensor database, high automation. However, it is a bit more complicated; the DIS3000 is characterized by simple practical, easy to operate; TDAS is compact, flexible installation, high interface visualization, support ISO / DTR13499 data format standard; NA33 is more flexible, can be integrated with traction system Control usage, sampling frequency and recording time have higher indicators.
1. Structural impact performance requirements
in the automotive collision test
In the automotive collision test, the vehicle needs to reach a certain speed, which is usually implemented by the motor traction system. During the traction acceleration, the vehicle must accelerate dozens of meters to 100 meters, so the data acquisition and analysis system currently applied to the automotive collision test is mainly in-vehicle, real-time completion of the data collection task. In addition, data acquisition instruments must have high impact resistance, usually requiring an impact of 1000 intensity of 980 m / s2 (10 ms) in three directions. This is also an important feature of the automotive collision test collector distinguishes between ordinary collectors. In addition, the data collection instrument should be integrated.The internal battery and the memory can be guaranteed for at least 30 minutes, and the sampling frequency should not be less than 10 kHz.
2. Electrical performance
The AD converter resolution is not less than 16bit, and signals from strain and dielectric sensors, semiconductor sensors, and voltage measters can be acquired. Each channel has its own analog-to-digital converter to ensure that all channels simultaneously sampled, no delay. The input of the numerometer simulation channel currently used for collision test is mainly measured by the voltage signal, and the amount of charge cannot be measured. It is possible to perform Shunt shunt check and automatic zeroing, support DALLAS sensor ID identification. The low-pass filtering is based on the ISO standard and the SAE standard CFC1000. In addition, the digital switch is input to at least 12 channels, each channel is isolated from each other.
3. Recording mode
No matter what data acquisition system, first set the sampling frequency, recording time. The current record storage technology has greatly developed, and the sampling frequency is usually 10 kHz or 20kHz, the corresponding recording time can reach 100 seconds or 50 seconds, and the test requirements can be fully met.
4. Trigger mode
For conventional electric measurement data acquisition systems, there is no problem with the acquisition task. However, for automotive collision tests, it is not possible to acquire data smoothly. Any subtle mistake may result in failure of data collection. Regardless of China or abroad, there have been a failure of collecting, the most common reason is that the number mining system is not properly triggered and the battery is low.
Whether there is a correct trigger signal generation, it is related to the success or failure of data acquisition. Since the collision test is not reproducible and cost is high, it is required to maximize the one-time success rate. To this end, the products of each company provide multiple insurance triggers, that is, the digital quantity trigger caused by the strip switch, also uses some typical simulation (acceleration of the B-column and the head of the dummy) to generate triggers. . Depending on the triggering method in the test, it can be divided into single-communication mode and dual trigger mode. Single trigger mode is also called transient trigger mode, that is, when a collision is generated, a trigger signal is generated, and data is started. At this time, the generation of triggered can be generated by the collision squeezed strip switches, or because a certain channel analog amount exceeds the set threshold and is automatically generated by software. The former can get an accurate collision zero, and the latter can only roughly estimate when it is zero. Double trigger mode is also called record mode, to use two trigger signals: The first trigger signal starts a record, and the second trigger signal is used to indicate the collision zero. The current digital recording time can be more than 50 seconds, while the time used by the vehicle from starting to the collision wall will generally not exceed 30 seconds, so we can start recording data for a few seconds in front of the departure. This way, even if there is no trigger signal production behind it.Birth, it can also ensure that collision data is recorded. In the world's collision test agencies, some single-trigger modes are used, and there is also a double trigger mode. Two compared that the double trigger mode is more insurance than the single trigger mode, that is, it can guarantee at least one trigger generation, so there is a problem before the trigger signal is generated; The trigger mode cannot know if the trigger signal is generated in advance, and can only observe the indicator light of the data acquisition device after the collision is over. Double trigger mode has long recorded time, the amount of data is large but more comprehensive, including the data of the acceleration phase is also recorded, which can be used to check whether the acceleration phase is smooth.
5 Channel Range Set (Amplitude Level CAC)
The channel range CAC value actually selects the range, which is equal to the upper limit of the measurement range, and it should not be too small, and it should be considered And select according to experience. The collision speed is different, the form is different, the position is different, the corresponding acceleration range is also very large, may reach 5-10 times, so the channel range Cac is not constant. Too small CAC values will cut some peaks of test data, resulting in data loss, too large CAC values will reduce resolution. Taking a frontal collision test as an example, its Hybrid-III false human internal sensor can be selected according to the recommendation value of EuronCap (Table 1). Most of the body sensors are accelerometers, the accelerometer CAC value at the B-column can take 100-200 g, and the accelerometer CAC value of the front portion of the front of the A-column should be 500-1000G, and other parts are taken in Table 2. The positive and negative number of the channel signal should be determined according to the actual installation direction of the inner sensor and the vehicle sensor. It should be pointed out that the positive and negative direction of the signal affects the fake human injury value, and should be tried to meet the specifications. According to the provisions of SAEJ 211, the X, Y, Z positive direction of the coordinate system is the front, right and bottom right of the vehicle, respectively. Therefore, in the frontal collision test, the normal head X direction acceleration measurement is negative, the Z direction is positive; the chest displacement and the thigh power are negative.
6. Channel Digital Filtering Frequency Level (CFC Value)
The CFC value indicates the digital filter frequency level of the channel. Preferably, it is preferred to be greater than the CFC 1000 or the unfiltered data, and the corresponding digital filtering is required in accordance with the requirements when calculating the damage indicator.
7. Sensor connector and grounding
Acceleration sensors are generally used in voltage resistance (eg, Endevco, Meas), and there is also a strainable (such as Kyowa). If a piezoelectric is used, the charge / voltage converter is also required to match the numerometer. The acceleration sensor is susceptible to damage in a collision test, which is determined by the strong impact characteristics of the trial and the mounting position.
During the collision test, the numerous instrument, sensors, and cables will be huge.If it is improperly handled, it will cause interference signals, and the weight will cause damage to the connector and signal loss. Therefore, the plug must be secure and is convenient to use. A 7-core LEMO self-locking connector is usually used. Some vendors use other forms of plugs (such as 8-core Lemi connector and Tajimi connector), resulting in unrequited communication and brought trouble. The dummy, numerometer and battery should be grounded. The pin definition of the Lemo plug is preferably unified, and is grounded along with the numertric shell.
8. Battery maintenance
For the need for the car, the data acquisition instrument comes with a lithium battery, and some have an additional set of spare batteries. In order to extend the life of the battery, it is best to make a complete discharge every month, and do not take more than three months. The battery can be fully charged and discharged in the self-contained software.
Second, the development trend of data collection technology
With the rapid development of electronic technology, automotive collision test data collection technology also shows fast, convenient, small, flexible, intelligent development trends, greatly improved The efficiency of the data acquisition process.
1. Interface Technology of Number and Computer:
Most of the 10 megabytes BNC Ethernet interfaces or RS232 serial interfaces are used. With the rapid development of computer and communication technology, many laptops have not supported 10 megabytes of Ethernet interfaces and not providing RS232 serial interfaces. Therefore, new interface communication methods, such as wireless network interfaces, USB interfaces have been applied. Especially for the head type HeadForm and leg-type LegForm that experiences free flight in the test, wireless communication technology is more advantageous.
2. Advanced Sensor Information (ATI):
The sensor information is combined with the sensor. The latest version of the Dallas ID chip provides 4-16KB memory space to store sensor information, including the calibration information of the sensor and the relevant parameter settings. Therefore, it is not only the sensor ID information, and the other information about the sensor can be read directly from the test preparation database, transmitted to the sensor chip through the data collector, and this process is mutual. This makes the sensor and dummy have good portability during use, i.e., the same sensor can be very convenient to share use in different laboratory, and there is no need for more parameter settings.
3. Better support ISO13499 Data Exchange Format:
This will make the data better versatility, which is easy to communicate with each other.
4. Multi-language environment support:
, especially the support of Chinese language environment.
5. Number-Dummy Integration Integration (in-Dummy Technology):
Dummy's sensor accounts for a lot of channels in collision test, and the harness of the fake people alsoInvisible increases the weight of the dummy and the level of trouble.The latest in-Dummy technology is installed in the dummy in the dummy, so that the dummy can be produced by multiple data acquisition devices equipped by the dummy.These data acquisition devices are connected via HUB and uniformly communicate with computer via digital interface.For example, DTS and FTSS have developed the IDUMMY system, KT and DENTON working with NXT system, M Bus technology products developed by German Messring.Number-Dummy Technology (in-Dummy Technology) has become increasingly mature through these years, more mature, foreign countries have used, such as the French PSA Group, in China in the market development phase.In terms of long-term, this technology will be widely used.
More related knowledge Learn: http://www.manikin.cn/newslist/list-109-2.html
You can also send a message to us by this email firstname.lastname@example.org, we will reply tu you within 24 hours.Now tell us your need,there will be more favorable prices!