# Count number of collisions while navigating to goal

I have the navigation stack working in ROS Kinetic on my computer. In Stage ROS simulations, I can specify the goal and the robot navigates to it. I need to count the number of collisions (if any) that occurred as it traverses to the goal. How can I go about achieving this ?

Collisions with? If you have an occupancy map, then you can check with that and the robot's base_link. If the objects are static then just having their positions will be enough to check the collisions. It completely depends on the robot and the application.