What is ADAS, the Basis of a Fully Autonomous Driving System?

Global Autonomous Driving Market:

The global autonomous driving market is developing rapidly, with an expected CAGR of 18.3% from 2020 to 2024. By 2024, shipments of L1-L5 autonomous vehicles are expected to reach about 54.25 million units. Market shares for L1 and L2 autonomous driving are expected to be 64.4% and 34.0%, respectively in 2024.

The self-driving car industry is mainly composed of traditional OEMs, component suppliers, technology companies, chip manufacturers, and transportation network companies (TNCs) to form an industrial chain.

Fundamentals of Self-Driving Systems:

To achieve automatic driving, it is necessary to first establish sound ADAS technology. Various micro-electromechanical systems need to work in cooperation to achieve self-driving. Tire pressure detection, pedestrian recognition, electronic braking, and even power distribution systems such as hill-climbing control make up for the driver's lack of driving skills. These technologies will eventually extend to performing actions such as lane-keeping, and Adaptive Cruise Control (ACC). The Internet of Vehicles is being developed to provide other forms of intelligent transportation.

What is An Advanced Driver Assistance System (ADAS)?

The system that assists the driver with in-car driving control is called ADAS. The main function is not to control the car, but to provide the driver with information such as the working conditions of the vehicle and changes in the driving environment outside the car. In some cases, it can assist in controlling the car, but the driver is still the protagonist in controlling the car. The auxiliary system only provides warnings and prompts, as an aid to assist the driver, allowing the driver to take early measures to avoid traffic accidents. This is equivalent to Society of Automotive Engineers (SAE) Level 2.

The key to enabling Advanced Driver Assistance System (ADAS) functionality is the collaboration of cameras, radar, lidar, and multiple ultrasonic sensor systems to identify objects, pedestrians, and potential hazards to the driver. In some cases, these technologies can work independently to ensure the safety of drivers, passengers, and pedestrians.

What Does an Advanced Driver Assistance System (ADAS) Include?

• Sensors: Detects various external signals. The sensors that may be used include Radar, Lidar, ToF (3D time of flight), Infrared, Ultrasonic, etc., to detect distances and other conditions.
• Processor: The Electronic Control Unit (ECU) in the car is responsible for processing incoming signals. It can collect and analyze the signals sent by all the sensors in the car, make appropriate classification and processing, and then output control signals to the actuators. Processors that can be used include Microprocessor and Memory Protection Unit (MPU), Digital Signal Processor (DSP), and Graphics Processing Unit (GPU).
•  Actuator: Controls various actuated devices according to the signal sent by the processor, letting the related devices complete the controlled operation.

What are the Types of Advanced Driver Assistance Systems (ADAS)?

With the advancement of technology and the mass production of sensors, various Advanced Driver Assistance Systems (ADAS) are being more widely used in vehicles.

• Parking Aid System (PAS):
  To assist the driver in parking, the active parking assist system can automatically control the steering wheel to assist the driver in completing the parking action. A passive parking assist system uses reverse imaging and ultrasound sensors to send images and sounds to the driver to assist the driver as he performs the parking action.
• Night Vision System (NVS):
  At night or on rainy days with poor visibility, traffic accidents are likely to occur. High-sensitivity image sensors can be used, coupled with infrared image sensors to provide auxiliary images of pedestrians, animals, vehicles, and the environment in front of the vehicle for the driver.
• Lane Departure Warning System (LDWS):
  Drivers are often distracted by dozing off, talking on the phone, etc., causing the vehicle to deviate from the lane. An image sensor in the rearview mirror or on the side of the car body, or a rear image sensor, monitors the lane lines and judges whether the wheel is pressed against the lane line. If the wheel is pressed against the lane line, but the turn signal is not activated, the system will generate a warning sound to remind the driver.
• Collision avoidance system:
  Also known as Pre-crash system, Forward collision warning system, or Collision mitigating system. A radar sensor installed in front of the vehicle can continuously scan the road conditions ahead, and then judge the possibility of collision according to the driving conditions of the vehicle.
  When the distance to the vehicle in front becomes too short, the first phase of the warning system will activate a sound warning and display a message on a screen to remind the driver to pay attention to the distance between the vehicles. If the driver does not respond, the second-stage automatic light brake is activated, and the seat belt is gently pulled to warn the driver. If the driver does not respond, the system activates automatic emergency braking, and activates the retractable seat belt function to secure the driver and reduce accidental injuries.
• Blind Spot Detection System (BSD):
   Car driving has so-called blind spots in the field of vision which can lead to danger due to failure of the driver to pay attention or respond in time. Blind spots are areas in the field of view where the driver cannot see directly or with the rear-view mirrors. They especially refer to the two sides of the vehicle body from the middle of the vehicle body to the rear. Infrared or radar sensors can be used to detect blind spots around the vehicle. When a pedestrian or vehicle is approaching, a warning sound is generated to remind the driver.
• Adaptive Cruise Control System (ACC):
  A radar sensor installed in front of the vehicle continuously scans the road ahead, and the system is usually combined with a speed control device. The driver sets a speed and when the distance to the car in front becomes too short, the system will automatically slow the car down to maintain a safe distance from the car in front. It will automatically accelerate when the distance from the vehicle in front becomes larger, but will not exceed the speed set by the driver.
• Adaptive Front Lighting System:
  The lights can be adjusted according to different vehicle speeds, roads, environments, and climate conditions to achieve the best lighting angle and range.
• Tire Pressure Monitoring System (TPMS):
  A very small pressure sensor made of a micro-electromechanical system (MEMS) is installed on the tire inflation tube to monitor the tire pressure and temperature and communicate this information to the vehicle via wireless transmission. When the tire pressure is too high or too low, the system will display a warning message on the screen to remind the driver.
• Breaking Electrical Assist System:
  The brake is one of the most important electronic components of the car, and electronic brake assist systems were some of the first driver assistance systems to be installed on cars.

1. Anti-lock Brake System (ABS): Generally, the wheels will have a tendency to lock when the vehicle brakes are applied strongly in an emergency, causing the driver to lose control of the forward direction of the vehicle. With an ABS, when the driver depresses the brake pedal, the ABS will release the brakes 6 to 12 times per second. This will reduce the speed of the vehicle, but at the same time allow the driver to maintain control of the vehicle during deceleration.
2. Brake Assist System (BAS): Often a driver may not be able to apply enough force to the brakes in an emergency. With a BAS, if the system detects the driver suddenly depressing the brake pedal with extreme speed and force, the system will determine that emergency braking is required, and pressurize the braking system to generate increased braking force.
3. Traction Control System (TCS): A vehicle is prone to slippage when driving on rainy days, or through snow and mud. With a TCS, if one of the driving wheels is slipping, the system will reduce the power of the slipping wheel, or even lock the slipping wheel with the brake, so that more power is transmitted to the non-slipping wheel. This will ensure maximum forward power by balancing the driving force on both wheels.
4. Electronic Brake-force Distribution (EBD): The traditional braking system distributes the braking force to the front and rear wheels of the car according to a fixed ratio. EBD can independently distribute the braking force of the four wheels according to different driving conditions to achieve the best deceleration effect and avoid wheel slip and unnecessary ABS action.
5. Electronic Stability Control (ESC): This system automatically detects wheel speed, steering wheel rotation angle, body yaw amplitude, lateral acceleration, and other values to determine whether the vehicle is out of control. The system can provide a single-wheel brake to restore the stability of the vehicle.
6. Brake Override System (BOS): The Electronic Control Unit (ECU) collects and analyzes the signals from all the sensors in the car. If there are any conflicting signals from the sensors, the system will give priority to braking to ensure the vehicle slows down while braking.
7. Electric Parking Brake (EPB): With an EPB, a simple push of a button replaces the pulling of the parking brake handle. The electronic control unit (ECU) can automatically activate and cancel the parking brake when the car is started and accelerated. It can also be used to avoid the problem of vehicles reversing when starting uphill, thus increasing safety.