FOLLOW LINE - Ackermann Car Model Drifts

Academy: Vision in Robotics
1

Hi everyone,

I’m trying to implement line following with an Ackermann car model (using version 4.8.3).

Even when commanding a constant low linear velocity and zero angular velocity, the car drifts significantly from a straight path. This makes tuning a PD controller very difficult.

A simpler car model in the same simulator doesn’t have this drifting issue.

Is this drift a potential simulator bug for the Ackermann model, or expected behavior I need to compensate for? Any advice on handling this?

Thanks,
Diego González Oviaño

code
code1600×900 106 KB

2

Hi @d.gonzalezo.2019 ,

uhm… quite bizarre. Although your code commands V=5 and W=0 the robot may not advance exactly in straight line, that is natural up to some level. Could you please record a video of it? Just to see the size of the deviations on your settings.

The Ackermann car is more unstable than the holonomic car, such instability may lead to have some bias in its movement. But with a fast closed-loop control your solution may overcome it and let the car follow the red line.