CS 326 A: Coordination of Multiple Robots

1 / 7

# CS 326 A: Coordination of Multiple Robots - PowerPoint PPT Presentation

CS 326 A: Coordination of Multiple Robots Two main approaches: Decoupled Planning: Plan for each robot independently of the others and coordinate them later Centralized Planning: Plan the motion of the robots in their “composite” configuration space Planning with Moving Obstacles

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## CS 326 A: Coordination of Multiple Robots

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
CS 326 A: Coordination of Multiple Robots

Two main approaches:

• Decoupled Planning:Plan for each robot independently of the others and coordinate them later
• Centralized Planning:Plan the motion of the robots in their “composite” configuration space
Planning with Moving Obstacles
• Moving obstacles require planning a trajectory t : [t1,t2]  Fi.e., a path indexed by time
• A trajectory is best represented configuration x time space CT. In this space a trajectory is a continuous curve whose tangent always projects positively onto the time axis
• Obstacles map as forbidden regions into CT. Constraints on velocity constrain tangents to t. Constraints on acceleration constrain curvature of t

(See class #9 on Kinodynamic Planning + Programming project)

Coordination of Multiple Robots
• Does not require explicit introduction of time (except if there are moving obstacles)
• Only requires using the same parameter to index the paths of the coordinated robots
• Using the same indexing parameter corresponds to fixing the relative velocities of the robots
Decoupled Planning
• Pure velocity tuning:(1) Separately plan the path of each robot to avoid collision with (static) obstacles(2) Compute the relative velocities of the robots to avoid inter-robot collision (e.g., coordination diagram)
• Robot prioritization:- Plan path of a first robot in its configuration space- Iterate:Plan trajectory of ith robot in its configuration x time space assuming that robots 1,…,i-1 are obstacles moving at some velocities
Centralized Planning
• Plan a collision-free path in the composite configuration C1x C2 x…x Cpspace of the robots
• Forbidden regions in the composite configuration space are all configurations where either a robot collide with an obstacle or two robots collide with one another
• The projection of this path into Ci is the path of the ith robot
Pros and Cons
• Assume p robots with n degrees of freedom each.
• Worst-case complexity of centralized planning ison the order of enp
• Worst-case complexity of decoupled planning ison the order of pen << enp
• But decoupled planning is incomplete