Control algorithm series pure tracking control

Pure tracking algorithm is a traditional and classic vehicle lateral motion control algorithm. Its basic idea is to guide the current steering wheel through a point on the front target trajectory in each control cycle, so that the vehicle can move to the target point.

The important parameter of pure tracking algorithm lies in the forward-looking distance coefficient. Generally speaking, the forward-looking distance is positively correlated with the speed.

Take the following figure as an example. The tracking target is a blue track, and the initial position of the vehicle is a green point. The constant tracking speed is 2m/s.

As can be seen from the above example, the pure tracking algorithm is greatly influenced by the look-ahead distance.

In practical application, besides tracking data to adjust preview coefficient, it is also closely related to trajectory type.

Summarize some characteristics of pure tracking:

(1) requires the trajectory to have good multi-frame continuity, and cannot respond to the changing trajectory (especially within the preview distance) due to the characteristics of preview;

(2) The ballistic performance is required to be stable, because the calibration coefficient is calibrated according to the ballistic performance. If the trajectory performance changes, it may lead to the phenomenon of vehicle inversion.