Model-Based Action Exploration for Learning Dynamic Motion Skills
  Deep reinforcement learning has achieved great strides in solving challenging
motion control tasks. Recently, there has been significant work on methods for
exploiting the data gathered during training, but there has been less work on
how to best generate the data to learn from. For continuous action domains, the
most common method for generating exploratory actions involves sampling from a
Gaussian distribution centred around the mean action output by a policy.
Although these methods can be quite capable, they do not scale well with the
dimensionality of the action space, and can be dangerous to apply on hardware.
We consider learning a forward dynamics model to predict the result,
($x_{t+1}$), of taking a particular action, ($u$), given a specific observation
of the state, ($x_{t}$). With this model we perform internal look-ahead
predictions of outcomes and seek actions we believe have a reasonable chance of
success. This method alters the exploratory action space, thereby increasing
learning speed and enables higher quality solutions to difficult problems, such
as robotic locomotion and juggling.
