Intelligence is an important direction for the development of the automobile industry. Currently, L2 assisted driving is rapidly penetrating, and L2+ high-end autonomous driving is accelerating.
The realization of autonomous driving is inseparable from algorithms, and the realization of algorithms relies on data.
Various sensors, such as cameras, lidar, millimeter-wave radar, ultrasonic radar, inertial navigation, etc., generate a large amount of data at all times during the movement of the car, providing support for the implementation of autonomous driving algorithms.
Data is crucial to the realization of autonomous driving. In view of this, some OEMs have established their own data centers and carry out a series of work such as algorithm development, algorithm training and testing based on the data center.
The establishment and use of the data center are inseparable from three types of test systems, namely the smart driving data collection system, the smart driving data recirculation system and the smart driving HIL closed-loop simulation system.
Figure 1: Schematic diagram of ADAS/AD development and testing based on data center
As a world-renowned testing tool manufacturer, NI has a complete tool chain for smart driving data testing scenarios, and has launched solutions for smart driving data acquisition, recharge, and HIL closed-loop simulation. NI's data refeeding system has occupied the majority of the market share in the Chinese market.
As an important partner of NI in the field of intelligent driving testing, YiXing has carried out multiple intelligent driving-related projects based on NI's software and hardware platforms.
This article introduces the intelligent driving data acquisition system, intelligent driving data refeeding system and intelligent driving HIL closed-loop simulation system respectively.
Intelligent driving data collection system
The data acquisition system is generally placed on the vehicle and is used to collect actual vehicle road environment data.
The main body of NI's data acquisition equipment is a board chassis, which integrates the CPU mainboard and related boards. The system diagram is shown in Figure 2 below.
Figure 2: Schematic diagram of data acquisition system architecture
In the data mining system, the mainboard CPU runs the Windows system and data mining related host computer software, and can be connected to an external monitor for related operations and monitoring. Various types of boards, such as video boards, Ethernet boards, CAN/LIN boards, and serial port boards, can be inserted into the system as needed to meet different data collection needs.
NI's data acquisition system has the following features, which can solve scalability, synchronization and other related needs:
● The PXI chassis provides 18 card slots, and 10+ communication boards can be plugged in as needed to meet the collection needs of sensor data and bus data of high-end intelligent driving vehicles.
● Hardware clock synchronization is implemented between boards, ensuring 1us level synchronization accuracy.
● The system implements PTP clock synchronization, can obtain GPS time and provide timing to each board, and stamp precise timestamps on various types of data.
● Multiple SSD solid state drives can be connected through the disk array card, which can meet the needs of real-time data collection of compressed data and uncompressed data.
● Both the video board and Ethernet board have TAP function, which can realize data collection without affecting the normal communication of the vehicle and ensure the normal driving of the vehicle.
Intelligent driving data feedback system
The intelligent driving data re-injection system injects the collected real vehicle road environment data back to the intelligent driving domain controller to meet the needs of restoring the real vehicle road environment in a laboratory environment and then developing and training intelligent driving algorithms.
The main body of the data recirculation system consists of a server computer and a board chassis. The system diagram is shown in Figure 3 below.
Figure 3: Schematic diagram of data recirculation system architecture
In the recirculation system, the server computer is a high-performance server purchased from the market. This server is the main equipment for data processing and requires multiple high-performance graphics cards. After the server computer obtains the data to be played back, it performs a series of processes such as decompression and video encoding format conversion, and then transmits it to the board chassis through Ethernet. Each board card in the chassis further processes the data and injects the data into the system under test. ECU.
The board chassis of the recirculation system and the board chassis of the data acquisition system have common hardware.
NI's data recirculation system has the following features, which can solve synchronization, reliability and other related needs:
● The PXI chassis provides 18 card slots, and 10+ communication boards can be plugged in as needed to meet the feedback needs of sensor data and bus data of high-end intelligent driving vehicles.
● Hardware clock synchronization is implemented between boards, ensuring 1us level synchronization accuracy.
● The system realizes PTP clock synchronization and can realize the following timing functions:
(1) Obtain the system time of the ECU under test and change the timestamp of the data to be reinjected based on this time;
(2) Obtain the timestamp of the data to be injected back and provide timing to the ECU under test based on this time
● Use RDMA technology to transmit video data to ensure transmission bandwidth and reliability, and the bandwidth can be expanded by increasing the number of RDMA network cards
● Able to dynamically inject multiple types of video-related faults for fault simulation
● Cluster testing can be realized, that is, multiple recirculation devices run in parallel and collaboratively to conduct training and testing related to intelligent driving algorithms, etc.
Intelligent driving HIL closed-loop simulation system
The intelligent driving HIL simulation system is highly similar to the data recirculation system, but there are two obvious differences:
(1) The data source of the recharge system is the collected real vehicle road environment data, while the data source of the HIL simulation system is the data generated through the scene simulation software;
(2) The recirculation system is an open-loop test system and is only responsible for injecting data back to the ECU under test, while the HIL simulation system is a closed-loop test system that can monitor the response of the ECU under test and control the operation of the dynamics simulation model accordingly. Implement closed-loop simulation.
The schematic diagram of the HIL closed-loop simulation system is shown in Figure 4.
Figure 4: Schematic diagram of HIL simulation system architecture
In the HIL closed-loop simulation system, the server computer is a high-performance server purchased on the market. It runs scenario simulation software to generate various sensor data and bus data. These data are transmitted to the board chassis through Ethernet, and each board in the chassis After further processing the data, the data is injected into the ECU under test. In the board chassis, the CPU motherboard runs dynamics simulation software, which receives messages sent by the ECU under test and controls the operation of the dynamics model based on the message information to achieve closed-loop simulation.
The board chassis of the HIL closed-loop simulation system has hardware commonality with the board chassis of the data acquisition system and the recirculation system.
NI's HIL closed-loop simulation system has the following features, which can solve synchronization, scalability and other related needs:
● The PXI chassis provides 18 card slots, and 10+ communication boards can be plugged in as needed to meet the channel requirements for sensor data and bus data of high-end intelligent driving vehicles.
● Hardware clock synchronization and PTP clock synchronization are implemented between boards to ensure the synchronization performance of the system.
● An open platform that can integrate mainstream simulation software in the industry, such as VTD, Prescan, etc.
● The scene simulation software and the dynamics simulation software run separately. The former runs on the graphics station, and the latter runs on the Linux RTOS of the chassis's motherboard CPU. They do not interfere with each other, ensuring the real-time performance of the dynamics model.
● Can realize cluster testing, that is, multiple HIL closed-loop simulation devices run in parallel and collaboratively to conduct training and testing related to intelligent driving algorithms, etc.
Conclusion
With the development of L2+ high-level autonomous driving, data acquisition systems, recirculation systems and HIL closed-loop simulation systems are playing an increasingly important role in the development of intelligent driving.
The data acquisition system, data recirculation system and HIL closed-loop simulation system provided by NI are all based on the PXI platform, achieving a high degree of hardware reuse and achieving standardization of software and hardware products.
Based on NI's software and hardware products, YiXing can quickly integrate and develop smart driving testing systems that meet customer needs, helping customers carry out smart driving algorithm development, testing and training and other related businesses.
The above is all I want to share with you today. You are welcome to further exchanges.