Designing Advanced Driver Assistance Systems
Shawn Wasserman posted on March 10, 2014 |

Texas Instruments has sponsored the following story


Advanced Driver Assistance Systems (ADAS) are a collection of technologies that aid in the safe operation of cars by alerting drivers to hazards and bad habits. They can also make driving easier and somewhat autonomous with features like park assist, drowsiness sensing, and lane drift warnings. These features are becoming so popular that they are starting to appear in lower end cars.

The end game promise is autonomous cars that promise future drivers will use their commute times for work as you would on a train.

The safety and convenience promised by vehicle automation depends on high processing control and data management. This is a challenge that Texas Instruments (TI) has taken on to improve ADAS for automotive control.

TI's portfolio can control various sensors, communicate between sub-systems and provide safe and fast decision-making.

 


Representation of the ADAS systems.

Sensors
The sensor systems that ADAS relies on for inputs include radar, LIDAR (LIght Detection and Ranging); ultrasound, and cameras. Systems can also include radio and satellite communications for vehicle-to-infrastructure or vehicle-to-vehicle monitoring. The input from these sensors allows the systems to determine the vehicle's positioning and road environments.

Low-level processing of the data essentially provides video of the road without filters or conditioning.  Mid-level processing, by comparison, finds objects of concern. Finally, high-level processing determines the speed of objects and what they are: people, animals, vehicles, signs, or traffic lights.

In case of poor visibility (such as fog), data from more than one sensors, like radar or LIDAR, can be used to supplement the compromised systems.

 


Block diagram of an ADAS design. For complete part list click here.

Power Supply
According to the block diagram, a 12 V or 24 V power supply can be connected to the board. This voltage can then be stepped up or down depending on the needs of the uC, DSP, memory, mechanics, interfaces, and ICs.

This could make the design of the power supply tricky to optimize based on need, efficiency, size, and price tag.

Below are a series of suggested choices from TI:

  TPS65023-Q1   Power Management Multi-Channel IC (PMIC)
TLV70018-Q1 Single Channel LDO
TPS54240-Q1 Step-Down Regulator
TPS43335-Q1 Step-Up Controller
LP2951-50-Q1 Standard Voltage Regulator

 

Interface
The interface has to ensure communication between modules, sub modules, external devices, drive, and car. TI offers a few options based on the need of the design engineer.

The High Speed CAN (SN65HVDA1040A-Q1) can handle speeds up to 1 Mbps and is ISO 119898 certified. It consists of a fault tolerant differential two wire bus. This part can actually act as the main bus for the car.

The LIN, on the other hand, is primarily used for low speed connections between sub functions. It can only handle speeds up to 20 kbps and it consists of a single wire bus.

Finally, LVDS interfaces (DS90UR905Q-Q1) are used to quickly transfer large data sets. They are often connected to externals such as touch screens (ADS7843-Q1) and video sources.

 

Control
The chosen controllers should be based on the operations of the design, from simple screen operations to the TDA2x Soc's complex pattern recognition.

For AC, and ADAS, the TDA2x is the chip you will likely need to go with. Using the Vision AccerationPac, the TDA2x can compute 8 times faster and at the same power demand. The accerationPac also allows for a 32-bit programmable RISC core.

Here is a list of TI's suggested controllers:

  TMS320C6747   C674x Low Power DSP
TMS320DM640 TMS320DM64x DSP
OMAP-L138 OMAP-L1x
TMS320DM648 DaVinci DM64x DSP
TDA2x SoC ADAS Applications Processor

 

Safety
SafeTI design packages will assist engineers to meet safety standards in their designs. TI technologies for ADAS are packaged with OEM certified product documentation.

Thanks to TI we are one step closer to a true autopilot systems previously only imagined in popular science fiction. For a more detailed look on how to design your ADAS or AC design I suggest you look into TI's guide.

 

Texas Instruments has sponsored promotion of their industrial communications solutions on ENGINEERING.com. They have no editorial input to this post - all opinions are mine, Shawn Wasserman.

     

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