  In this paper, we propose a novel control architecture, inspired from
neuroscience, for adaptive control of continuous-time systems. The proposed
architecture, in the setting of standard Neural Network (NN) based adaptive
control, augments an external working memory to the NN. The controller, through
a write operation, writes the hidden layer feature vector of the NN to the
external working memory and can also update this information with the observed
error in the output. Through a read operation, the controller retrieves
information from the working memory to modify the final control signal. First,
we consider a simpler estimation problem to theoretically study the effect of
an external memory and prove that the estimation accuracy can be improved by
incorporating memory. We then consider a model reference NN adaptive controller
for linear systems with matched uncertainty to implement and illustrate our
ideas. We prove that the resulting controller leads to a Uniformly Bounded (UB)
stable closed loop system. Through extensive simulations and specific metrics,
such as peak deviation and settling time, we show that memory augmentation
improves learning significantly. Importantly, we also provide evidence for and
insights on the mechanism by which this specific memory augmentation improves
learning.
