The problem and possible causes of the robot's instantaneous return to the origin of the world coordinate during rviz simulation

1. Problem

During the simulation , Originally, the robot was normally controlled to move , But suddenly the robot instantly returned to the origin of the world coordinates , Break through all restrictions .
At this time, some variables in the algorithm should be calculated nan, Then the equation for calculating the velocity uses this band nan The numerical , And get nan Value , adopt /cmd_vel This topic Send it to the robot , Cause the robot to return to the origin in an instant

2. Solution

At this time, you can only reverse check in the code , from cmd_vel Step by step, check the data of , Set a judgment nan The sentence of , Slowly check which variable is wrong , as follows ：

if(isnan(inter_the[2]))
cout <<"nan appear!"<<endl;

Cause these variables to become nan There are so many reasons , Many are basic computational logic problems , It's easy to do as long as you locate it , Sometimes, for example, give a function input The variable of has a 0, And this 0 Used as denominator , That's the problem .

This is just right Rviz A possible analysis of an abnormal phenomenon during simulation , I have encountered this problem several times , It's all because of nan As a result of speed , So just find out nan Where you can quickly fix This bug.