Robot Explanation Generation Using Behavior Trees (BTs)

This reposotory contains code and the behavior trees in XML for the following paper accepted to ACM Transactions on Human-Robot Interaction (THRI).

• Zhao Han, Daniel Giger, Jordan Allspaw, Michael S. Lee, Henny Admoni, and Holly A. Yanco. Building The Foundation of Robot Explanation Generation Using Behavior Trees.

Everything other than the code is available at https://inside.mines.edu/~zhaohan/#re-bt.

Code

ExplainableBT.h contains all the proposed algorithms, implemented in C++ using the BehaviorTree.CPP library. Please read the header comment for its usage.

• It also depends on BehaviorTracker.h, which tracks the node currently ticking in order to generate explanations related to it.

The main_service folder contains a ROS service package to answer the 5 questions mentioned in the paper as well as dynamic behavior insertion as subgoal.

rosservice call /explain "what: 'What are you doing?'"
rosservice call /explain "what: 'Why are you doing this?'"
rosservice call /explain "what: 'What is your goal?'"
rosservice call /explain "what: 'How do you achieve your goal?'"
rosservice call /explain "what: 'What is your subgoal?'"
rosservice call /explain "what: 'How do you achieve your subgoal?'"

rosservice call /explain "what: 'Can you place screw into caddy?'"
rosservice call /explain "what: 'Can you pick screw?'"

Behavior Trees in XML

kitting-tree.xml contains the tree of the meta kitting task, including the 3 tasks mentioned in the paper:

1. go pick screw
2. go place screw
3. go insert large gear

taxi-domain-tree.xml contains the tree for the optimal policy of the Taxi domain.