How do AI's perception, decision-making, and control modules work together in autonomous driving technology?

Hey, autonomous driving is a fascinating topic. You can imagine a self-driving car as a 'robot driver.' Just like human drivers, it needs to 'see and hear everything around it,' then 'think' about how to drive, and finally 'operate' the vehicle.

These three processes correspond to the AI's three major modules: Perception, Decision-Making, and Control. They form a tightly coordinated team.

1. Perception - The Car's 'Eyes' and 'Ears'

Imagine when you're driving: your eyes are watching the road, other cars, pedestrians, and traffic lights, while your ears are listening to the surrounding sounds. The perception module in autonomous driving does precisely this job, but with even more advanced senses.

• What are its 'eyes'?

  • Camera: Just like our eyes, it can identify colors, shapes, and understand traffic signs, lane lines, and traffic lights.
  • LiDAR (Light Detection and Ranging): Similar to a bat's echolocation, it emits countless laser beams. By receiving the reflected signals, it can precisely map out a 3D environment. It accurately knows how far away an object is and what it looks like, even in the dark.
  • Millimeter-wave Radar: Its key feature is its ability to 'see through' rain, snow, and fog, and it's particularly sensitive to object speed. It excels at determining the distance and speed of vehicles in front and behind, acting as your 'safe distance' assistant.

• What does it 'see'? The perception module integrates the information collected from these 'senses' to build a real-time dynamic map in its 'mind.' It labels everything around it: 'This is a car, moving east at 50 km/h,' 'That's a pedestrian, likely to cross the road,' 'There's a traffic light 200 meters ahead, currently green.'

In short, the perception module is responsible for answering the question: 'What is around me?'

2. Decision-Making - The Car's 'Brain'

Once your eyes relay road information to your brain, you have to 'think' about what to do next. For example, 'The light ahead is red, I should brake,' or 'The car next to me is signaling, it looks like it wants to merge, I should yield.' The car's 'brain'—the decision-making module—performs this thinking process.

This 'thinking' also occurs at several levels:

• Global Route Planning: This is the easiest to understand, just like when you enter a destination into your phone's navigation, it plans a complete route from A to B. This is the most macroscopic decision.
• Behavioral Decision: This is the 'on-the-spot reaction' based on current road conditions. For instance, if navigation tells you to go straight, but you find a broken-down car ahead, you have to decide whether to 'change lanes and go around' or 'stop and wait.' This decision must adhere to traffic laws and also predict the intentions of other vehicles and pedestrians, making it the most 'intelligent' part of the entire system.
• Motion Planning: Once you've decided to 'change lanes and go around,' how exactly should you move? Should you sharply turn the steering wheel or gently cut across? Motion planning is responsible for calculating a specific driving trajectory (a curve precise to the centimeter) that is both safe, smooth, and comfortable, telling the car where it should be at each point in time over the next few seconds.

In summary, the decision-making module is responsible for answering the question: 'How should I proceed next?'

3. Control - The Car's 'Hands' and 'Feet'

Once the brain has decided what to do, it relies on the hands and feet to execute. The control module is the 'hands and feet' of autonomous driving.

• What does it do? It receives instructions from the decision-making module (that precise driving trajectory) and translates them into specific vehicle operation commands, such as:

  • 'Turn the steering wheel 5.8 degrees to the left.'
  • 'Increase throttle opening to 20%.'
  • 'Apply 0.3g deceleration with the braking system.'

• How does it ensure proper execution? This is a very precise 'execution and feedback' process. After the control module issues a command, it checks through the vehicle's sensors (e.g., wheel speed sensors): 'Did the car really do what I told it to? Is there any deviation?' If there's a deviation (e.g., due to a slippery road, wheel rotation doesn't match actual speed), it immediately makes fine adjustments to ensure the vehicle consistently follows the planned trajectory with precision.

Therefore, the control module is responsible for answering the question: 'How to precisely execute commands?'

Summary: How Do They Work Together?

These three modules act like an assembly line, specifically a high-speed, cyclical one:

Perception (seeing the road) → Decision-Making (thinking) → Control (operating) → Perception (seeing new road conditions) → Decision-Making (thinking again) → Control (operating again)...

This cycle occurs dozens or even hundreds of times per second.

For example:

1. The perception module detects that the vehicle ahead suddenly brakes hard.
2. This information is immediately transmitted to the decision-making module, which determines there's a 'collision risk' and instantly makes a 'hard braking' behavioral decision, simultaneously planning the fastest braking trajectory.
3. The control module receives the command and immediately sends a maximum braking force command to the braking system.
4. While braking, the perception module continues to monitor the distance to the vehicle ahead, feeding new data back to the decision-making module. The decision-making module then assesses whether to slightly adjust braking force or prepare for a lane change to avoid danger.

In this way, these three modules, through millisecond-level rapid iteration and communication, enable autonomous vehicles to drive smoothly and safely, just like an experienced human driver.