Hi Xin,
In the action server callback implementation, the Preempt logic is outside the while loop and is never reached when the goal is being cancelled. When the goal is running by the server and we send a cancelGoal request from action client to action server, due to incorrect implementation of action server callback the goal keeps running and tries to send the feedback even if the actionclient is deleted and hence the issue.
The goal will be active until we make the status of goal as preempted or aborted in the action server. In this case, this is being done outside of while loop, which makes it infinite loop. So, to avoid this error please follow one of the below solutions.
Solution 1: Move the Preempt logic into while condition as below.
while(as.isActive())
{
...
...
//----------------------- Preempt -----------------
if(as.isPreemptRequested() || !ros::ok())
{
ROS_WARN("%s: Preempted", action_name.c_str());
as.setPreempted();
success = false;
}
else
{
success = true;
ROS_INFO("\nType: %i [0 - Basic mode 1 - Pinch mode 2 - Wide mode 3 - Scissor mode] \nWidth: %i \nSpeed: %i of 255\nForce: %i of 255", goal->type, weite, gswk, kraft);
}
oldStatus++;
r.sleep();
}
The same is recommended by ROS Community : Link.
Solution 2: Change the while condition as below:
while(as.isActive() && !as.isPreemptRequested() && ros::ok())
{
....
}
Thanks,
Karthik Reddy
