Move_base_fault_tolerant navigation stack

This navigation stack is an extension of the popular move_base package. This extension provides a fault detection and recovery architecture to handle unexpected collisions during motion execution improving the default stack with fault tolerant skills. The current solution contemplates the collision detection through sensor fusion algorithms by the merge of different sensing sources.

Move_base_fault_tolerant provides two additional plugin types: FaultDetector and FaultRecovery. Meaning that the diversity of possible detected faults and their recovery is not limited by the approaches given in the current repository. It is important to mention that a FaultRecovery plugin is attached to one particular fault type, in other words, in difference to the classical recovery_behaviors, the execution of the fault_recovery_behaviors is not sequential then a particular recovery method will be executed without any need of executed other ones once a fault is detected.

This stack consists of:

1. fault_core: custom interfaces for faults.
2. fusion_msgs: custom messages for sensor_fusion approach.
3. navigation_manager: consists in a modified version of the move_base(most of them come from adding setters and getter function to private attributes). In addition the move_base_fault_tolerant packages inherits the modified version which enhancing the navigation to hold collisions detection and recovery.
4. collision_detection_nav: provides FaultDetection plugins packages.
5. collision_diagnosis_nav: provides default packages using for diagnosing, each package provides a service which can be tested anytime.
6. collision_recovery_nav: provides FaultRecovery plugin packages.
7. collision_filters: it might be possible to filter false detected for some of the collision detectors.
8. collisions_launch: contains launch files to run the move_base_fault_recovery stack.
9. default_costmap_layers and default_recovery_behaviors: provide templates for MoveBase Layers and Recovery Behaviors.