  This paper contributes a preliminary report on the advantages and
disadvantages of incorporating simultaneous human control and feedback signals
in the training of a reinforcement learning robotic agent. While robotic
human-machine interfaces have become increasingly complex in both form and
function, control remains challenging for users. This has resulted in an
increasing gap between user control approaches and the number of robotic motors
which can be controlled. One way to address this gap is to shift some autonomy
to the robot. Semi-autonomous actions of the robotic agent can then be shaped
by human feedback, simplifying user control. Most prior work on agent shaping
by humans has incorporated training with feedback, or has included indirect
control signals. By contrast, in this paper we explore how a human can provide
concurrent feedback signals and real-time myoelectric control signals to train
a robot's actor-critic reinforcement learning control system. Using both a
physical and a simulated robotic system, we compare training performance on a
simple movement task when reward is derived from the environment, when reward
is provided by the human, and combinations of these two approaches. Our results
indicate that some benefit can be gained with the inclusion of human generated
feedback.
