Traffic Control

Types of collision situations: #

  • Head-on: This Head-on of collision occurs when the front ends of two vehicles collide with each other while traveling in opposite directions.

  • Stay-on: When a vehicle approaches the vehicle in front at a speed greater than that of the leading vehicle, it is referred to as a stay-on collision.

  • Cross: When a vehicle approaches another vehicle at an angle, it is referred to as a cross collision.

  • Stationary: When a robot faces a potential collision with a stationary robot (which has not been assigned any missions), this situation is referred to as a stationary collision.

How meili system find intersections? #

The intersection of two vehicles is determined based on their paths, missions, dimensions, locations, and safety distances.

First, each vehicle’s location is identified, and a safety box is built around it according to its dimensions. An additional safety distance is added to create a buffer zone around this box. These enhanced dimensions are applied to the entire path the vehicle will follow. Traffic control algorithms then use this information to detect and manage intersections, ensuring they account for both the vehicle’s size and the added safety distance. This approach maintains safe and efficient navigation.

An example of how meili system finds intersection is shown below:

Traffic control parameters #

  • Safety distance threshold(m) : Determines the safety distance between obstacles and vehicles.

  • Collision detection parameters :

    These Parameters determine the distance between the vehicle and the intersection point.

    • Stationary collision detection threshold (m) : It is the distance from the front of the vehicle to the center of the other vehicle.

    • Stay On Collision Safety Distance (m) : It is the distance from the front of the robot to the center of the other vehicle.

    • Cross Conflict Collision Safety Distance (m) : It is the distance from the front of the robot to the point of intersection.

    • Head On Collision Safety Distance (m) : It is the distance from the front of the robot to the point of intersection.

    • AGV Collision Safety Distance (m) : It is the distance from the front of the robot (AMR) to the center of the other vehicle (AGV).

  • Delay Parameters:

    These vehicle-based parameters assist traffic control prediction algorithms in managing any latencies related to the vehicles.

    • Message frequency : This is the rate at which the messages are transmitted from vehicle to meili
    • Traffic control delay : This parameter compensates for additional latencies encountered during collision detection for each vehicle.

Note: How to change the Safety distance threshold and collision detection parameters is explained at Site settings parameters/Traffic control

Note: How to change the Delay parameters is explained at Manage Organisation/Vehicles/Step3

Priorities of Robots for Different Collision Types and Their Actions #

Cross, Head-on #

  • Priority: The priority of the robot is determined by the priority of its mission.
    • If a mission priority is specified during the creation of the mission, the robot’s priority is set accordingly; otherwise, priority is given to the first assigned task.
  • Action: The robot with the least priority will be stopped.

Stay-on #

  • Priority: The robot in front will be given priority (the priority of the robot based on task is ignored).
  • Action: The robot behind will be stopped, allowing the front vehicle to pass.

Stationary #

  • Priority: The stationary robot (robot without any mission) will be given priority.
  • Action: The robot with a mission will be stopped.

AGV #

  • Priority: AGV will be given priority.
  • Action: The AMR with a mission will be stopped.