3. The Composition of Autonomous Vehicle
The autonomous system consists of vehicle borne radar, brain processing system, optical rangefinder, type sensor, frequency camera, brain database and so on. It seems that every car manufacturer can say one thing according to his own ideas and can justify it. However, the contents of the above two maps are an important part of the autonomous car so far. If you do not want to know more about it, you only need to understand the two pictures, we can see in the picture above. For environment-aware video cameras, laser rangefinders, and vehicle-mounted radars, it is also possible to see miniature sensors for vehicle GPS navigation functions, as well as a computer database that assists drivers with planning paths. Through this system, we can control the throttle, brake, and steering in the vehicle's motion system, as well as the functions of emergency braking, speed limit recognition, and automatic parking in the vehicle's assisted driving system.
4. Unmanned Vehicle Technical Support
It uses vehicle sensors to sense the surroundings about the road, vehicle locations and the constructions to steer or speed, allowing the vehicle to travel safely and reliably on the road. It is a product of computer science, pattern recognition and intelligent control. Not only a product about computer science, pattern recognition and intelligent control technology highly developed, but also an important symbol to measure the level about national scientific research and industrial. In the field of national defense and national economy has a broad application prospects. Autonomous technology is a combination of sensors, computers, artificial intelligence, communication, navigation and positioning, pattern recognition, machine vision, intelligent control and other cutting-edge disciplines.
4.1. Environmental Awareness Technology
The environment-aware module is equivalent to the eyes and ears of an autonomous vehicle，autonomous vehicles use environmental awareness modules to identify their surrounding environmental information and provide information to support for their behavior decisions. Environmental perception includes two parts of the autonomous vehicle's own position and the surrounding environment.
4.2. Navigation and Positioning Technology
The autonomous vehicle's navigation module is used to determine the geographical location of the vehicle，It is the support about path planning and mission planning, the navigation can be divided into two kinds of autonomous navigation and network navigation.
4.3. Path Planning Technology
The task of path planning is to find a non-trailing path from the initial state, including the position and attitude to the target state, in the context of an obstacle in accordance with a certain evaluation criteria. Path planning techniques can be divided into global path planning and local path planning:
Global path planning is targeted for the surrounding environment is known.
Local path planning is applicable to situations where the environment is unknown.
High precision map is an important auxiliary technology of autonomous vehicle, which enables the vehicle to know the direction and road ahead of the vehicle ahead of time.
4.4. Decision Control Technology
The decision control module is equivalent to the brains of a car, Its main function is based on the information obtained by the perception system to make decision-making judgments, then make decisions about the next step, finally to control the vehicle. Decision-making techniques include fuzzy reasoning, reinforcement learning, neural networks and Bayesian networks. The behavior of the decision control system is divided into reactive, reflective and integrated. Reactive control is a feedback control, its form of realization is:
IF X1 is True and X2 is True……and Xn is True THEN Y Reflective control is a low-level behavior, used to make judgments about emergencies in the course of travel and respond quickly. Integrated control Add a machine learning module to the reaction layer.
5. Conclusion
Autonomous vehicle is also called smart cars, unmanned autopilot, autonomous navigation or wheeled mobile robots, is important applications for outdoor mobile robots in the field of transportation. The Autonomous vehicle system is an integrated system that integrates environmental perception, automatic control, architecture, artificial intelligence, visual computing, planning and decision making. It is a vehicle system that takes full account of traffic lane and coordinated planning. It is also an important part of intelligent transportation system.