Is time stamping necessary in path planning?

I know that time stamping serves a purpose in path planning, I assume that it aids in the repeatability of executing any given path. But hypothetically, couldn’t you generate a path using just encoder ticks as your point of reference? While the execution of a path like this wouldn’t be as consistent as full blown Pathfinder, I imagine it would work just fine for most purposes as long as you still take advantage of velocity and acceleration control, along with generating smooth paths. Just to be clear, what I’m proposing is a path generated by Pathfinder, without the time stamp.

What I have in mind is I want to generate paths for our robot to follow using Pathfinder, but I’d like to write a custom execution system to follow said paths, and I don’t want to make it unnecessarily complicated.

“Why not just use the full functionality of Pathfinder?”

I want to have more control over how our robot follows any given path, and I’d like to be able to customize said process to implement additional features when necessary.

If I’m way off base here, let me know. But I think that although this method of path planning wouldn’t be the most accurate, it would be a lot better than our team has done in the past.

TL;DR: No but you will need a way generate velocity and steering commands.

What you are describing here is a path vs. a trajectory.

A path describes a way to get from point a to point b. It doesn’t have a notion of time or velocity with it. A trajectory on the other hand combines a path with time constraints/velocity constraints. (i.e. at some time t be at this position at this speed). You are correct when you say that a trajectory (timestamped path) is more accurate (and by accurate I don’t only mean arriving at the end point but also knowing where the robot will be from start to finish).

If you just want to generate a path and follow that, you will need to write a path follower that generates velocities and steering commands to follow that path. Pure pursuit alongside with motion profiling is a well researched and robust option, and it is not too difficult to implement.

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