Trajectory planning method and system

A trajectory planning system, comprising:

• a self-propelled device, moving on a path to construct a moving trajectory, wherein the self-propelled device is provided with a sensing module, and the sensing module senses a topographical feature on the path of the self-propelled device so as to generate a sensing data file;
• and
• a calculating device, obtaining the sensing data file and executing the following steps:
• importing the sensing data file into a simultaneous localization and mapping algorithm to construct a map corresponding to the path;
• importing the sensing data file into a loop closure algorithm, obtaining a pose at each unit time, and constructing an optimized trajectory on the map;
• importing the sensing data file into a cartographer localization algorithm, obtaining a pose at each unit time, and constructing a reference trajectory on the map, wherein the reference trajectory is corresponding to the moving trajectory of the self-propelled device on the path;
• comparing the reference trajectory with the optimized trajectory to determine whether the reference trajectory approaches the optimized trajectory;
• if the reference trajectory does not approach the optimized trajectory, adjusting parameters in the cartographer localization algorithm;
• and
• if the reference trajectory approaches the optimized trajectory, importing the parameters in the cartographer localization algorithm into the self-propelled device,
• wherein the reference trajectory and the optimized trajectory are compared by using a difference distribution method,
• wherein a pose error value of the reference trajectory relative to the optimized trajectory at each unit time is calculated by using the difference distribution method, so as to obtain a distribution ratio of a plurality of error ranges of the pose error value.