Autonomous Driving and ADAS

All functions of ADAS (Advanced Driver Assistance System:
Technology supporting advanced driving support system)

Technologies that support the function of ADAS include in-vehicle ECUs that grasp the situation from information acquired by sensors and control the cars, in-vehicle networks that enable on-board ECUs to cooperate fast and accurately, There is an in-vehicle locator that accurately specifies the position. Along with the widespread use of ADA functions, not only expensive options for luxury cars but also adoption in general cars are progressing. ADAS technology also features many elements in common with Autonomous Driving (AD) technology.
This page explains the outline of the technology supporting ADAS.

1. Sensing technology

In order to realize various ADAS functions such as ACC and FCW, we must recognize various elements such as moving objects, structures, road shapes and pedestrians around the vehicle. A sensor for recognizing the external environment is called an "external sensor". For example, an algorithm for processing data recognized by an external sensor into information necessary for realizing the ADAS function, such as retrieving pedestrian information from an image taken with a camera, is also an important sensing technology.

Furthermore, in order to accurately recognize the environment around the vehicle, it is sometimes impossible to grasp the outside world with one sensor at this stage. Therefore, we are also developing sensor fusion technology combining various external sensors.

1-1. Radar

In ADAS, radar generally refers to millimeter wave radar and is mainly used to measure relative distance to surrounding objects. Sensors using millimeter waves have a longer detection distance compared with sensors using lasers, are all weather-resistant, and are characterized by superior motion prediction performance of preceding vehicles. Moreover, the antenna diameter is small with respect to the required angular resolution (antenna beam width), and it is excellent in mountability to vehicles. Millimeter wave radar is mainly developed as a long range radar (detection performance of 150 m or more) by each company as a sensor to realize functions such as ACC.

1-2 LiDAR

Laser radar is a remote sensing technology that uses light to measure the scattered light with respect to laser irradiation that emits pulsed light, and analyzes the distance to objects at long distances and the nature of the object. In Japanese it is called "(LIDAR)". In the LiDAR, the pulsed laser beam changes its direction with an internal rotating mirror and scans the peripheral area in a fan shape. The emitted laser light is reflected when it strikes the object, and the reflected light is recognized by the light receiving part of the scanner. Major uses are the measurement of the distance to the obstacle ahead, the recognition of the shape of the road by the curb and the white line recognition using the reflectance.

1-3. Camera

In-vehicle cameras used in ADAS have the following uses.
· Function as surrounding visibility assistance system: Around view · monitor, the driver can confirm the blind spot of the vehicle with images, back side obstacle alarm at lane change etc.
· Parking assistance with back view monitor
· Detect lane markers on road with monocular camera
· Stereo camera detects forward obstacles and predecessors
· Recognition of road signs such as speed indication
· Pedestrian detection
· Driver like drive recorder · Automobile monitoring
· Driver monitoring technology

Cameras include monocular cameras (mono cameras) and stereo cameras, each of which is explained below.

1-3-1. Monocular Camera (Mono Camera)

A monocular camera is the one that literally functions with one camera lens.
Distance measurement is calculated from the pixel position in the vertical direction of the recognized image coordinates, but the error tends to become large. The main advantage is that it can be installed at low cost and the degree of freedom of the installation place is high. It also makes calibration easy. The downside is that the objects to be recognized are limited. For concrete purposes, it is used for warning function, crosswalk recognition, etc. for drivers by recognizing traffic signs such as white line recognition and limit speed for lane keeping purpose.

1-3-2. Stereo camera

A stereo camera is an object that measures objects with two cameras like a human eye, and its parallax makes it possible to measure distances with high institution. Three-dimensional objects can be detected, so you can measure distance and lateral position to various objects such as pedestrians, bicycles, vehicles with high accuracy. Although the information detected in this way can be used variously, it is a disadvantage that calibration is difficult and the amount of calculation increases. It is used as a specific application when recognizing vehicles and pedestrians.

2. About locators

Although the accuracy of the position of the vehicle used for conventional navigation is about 10 m, as automation of vehicle travel progresses, more accurately grasp the position of the currently running lane, the distance to the intersection and the curve, etc. It will be necessary.

Especially in high-rise building streets in urban areas, the receiving environment of the satellite signal got worse and it was difficult to utilize it for ADAS.

In order to solve this problem, an ADAS locator dedicated to the driving support preventive safety system has been developed. This is improving the satellite positioning rate including urban areas by utilizing other GPS satellites in the United States and other satellite systems such as GLONASS in Russia. Even in Japan, preparations for the operation of the quasi-zenith satellite system "MICHIBIKI" are in progress and are expected to be utilized for GPS.

In addition, technology development that combines information from gyro sensor and vehicle speed measurement and can estimate the current position with high accuracy is under way.

2-1. Position measuring sensor

As a sensor that can be used for position measurement during driving, we are selling position measurement sensors compatible with GPS and RTK, stereo cameras that can utilize point group information and 3D-LiDAR, and as a sensor to estimate our position Products are available.
Compact GPS antenna unit that can acquire GPS information by CAN communication
RTK Position-Z
Position measurement with centi order by position measurement using base station and mobile station possible
RoboVision 2s
Stereo camera unit that can output parallax, distance measurement image, point group information
RoboSense LiDAR-16 / 32B
Acquire point cloud information up to 200 m ahead of RoboSense's 3D rider

3. About in-vehicle ECU

Most of today's cars are controlled by computers. From automatic control of drive system such as adjustment of fuel injection of engine, selection of gear according to vehicle speed, functions such as confirmation of air conditioner and mirror remote controller, and comfort related functions, almost all automobile moving devices are ECU (Electronic Control Unit) is controlled by a computer. It is said that the number of ECUs installed in vehicles is about 50 in general cars and more than 200 in luxury cars.
The ECU used for ADAS is responsible for obtaining information from various sensors via in-vehicle communication functions such as CAN and requesting other ECUs to control brakes, engines, steering, etc. according to driving conditions. Because these information are based on huge amount of computation by public algorithm, very high performance ECU is required. In addition, the adoption of FPGA with high degree of design freedom is expanding for semiconductors that make up the ECU of ADAS.

4. About in-vehicle network

As mentioned above, many ECUs are installed in modern automobiles. Each ECU is connected by multiple in-vehicle LANs with different communication protocols depending on the application and characteristics. These ECUs cooperatively control to create the ADAS function with higher added value. Here, we will introduce the protocols of a representative in-vehicle network.

· CAN (Controller Area Network)
CAN is a protocol that is de facto standard among automotive LANs widely used in backbone networks, powertrain systems, chassis systems, and body systems.

· Ethernet
Ethernet is attracting attention as a protocol for failure diagnosis of connected electronic control unit such as engine, chassis, body etc connected to the network.

· FlexRay
FlexRay is a high-speed communication protocol with high flexibility and high reliability, which has attracted attention as various applications such as next-generation X-by-Wire system, backbone.

LIN (Local Interconnect Network)
LIN is a single master in-vehicle LAN protocol that is excellent in cost performance and is used for various body control applications such as switch input, sensor input, and actuator control.

4-1. Logger system compatible with in-vehicle network

A logger system of the blue PiraT series manufactured by Telemotive of Germany is adopted mainly as a European car maker as a logger system corresponding to the in-vehicle network. ZMP deals with the logger series called blue PiraT 2 and blue PiraT mini.
High-end model latest model Automotive logger manufactured by Telemotive company blue PiraT 2
bluePiraT mini
Entry model latest model Automotive logger manufactured by Telemotive company blue PiraT Mini

5. About HMI

Human Machine Interface (HMI) is a collective term for devices and software for people and machines to exchange information. For automobiles, steering, accelerator, brake, various instruments indicating the state of the car, etc. that the driver operates are applicable.

Originally automobile instruments such as speedometer, tachometer, direction indicator, various warning lights, etc. were mostly simple mechanical type. However, as automobile electronics have advanced, it became necessary to tell drivers more information such as surrounding circumstances.

In ADAS in particular, the driver must correctly understand the information transmitted from the system of the car so that it does not adversely affect the driving operation. It is important to pay attention to the characteristics of the information and to assign visual and auditory senses suitable for it.

The contents transmitted from the ADAS system include the following three levels.
These correspond to the urgency of the situation (margin time to collision) and the severity of the result (presence or absence of conflict).

For example, when designing a collision avoidance function, the driver must correctly understand the degree of urgency to collision and the meaning of information based on the distance to the preceding vehicle and the speed of the vehicle. Based on the information provided, we must decide the visual and auditory indication method according to the urgency and importance of the information so that the driver can operate the appropriate brake pedal and steering.

Also, it is reported that the age of the driver and proficiency with respect to the ADAS system influence the effect of driving support, and consideration of age is also necessary for HMI design.
In particular, in the case of elderly people, because there is a limit to the amount of information that can be processed at one time, studies on display methods according to urgency and seriousness are being taken into consideration of the amount of information to be transmitted.

6. About testing ADAS

In development of ADAS technology, there are various requirements such as front-line sensing technology and vehicle control. Due to the development of sensor fusion technology, testing requirements are getting complicated. HILS (Hardware In the Loop Simulator) based on model-based development is the mainstream in recent automotive function tests. In testing ADAS technology, a model that can reproduce complicated external environments with high precision is required. Finally, it is important to verify by public road test. ZMP has a lot of experience on ADAS, public road test of Autonomous Driving . From model base to public road tests.Please consult us about the test related to ADAS technology by all means.

Travel data measurement service

ADAS, a service called RoboTest (Robotest) is available as a service that can be used for evaluation of products during Autonomous Driving development and evaluation during actual driving. In this service, we will respond consistently from planning data measurement to examination of measurement requirements, selection and setup of measurement system, driver arrangement and travel management, and post-processing work after data measurement.

For details on RoboTest please refer to the below link.

Supports system construction & measurement of running data

7. Inquiries, document request

For inquiries on products and information request, please contact us below.