  In this paper, we study wireless networked control systems in which the
sensing devices are powered by energy harvesting. We consider a scenario with
multiple plants, where the sensors communicate their measurements to their
respective controllers over a shared wireless channel. Due to the shared nature
of the medium, sensors transmitting simultaneously can lead to packet
collisions. In order to deal with this, we propose the use of random access
communication policies and, to this end, we translate the control performance
requirements to successful packet reception probabilities. The optimal
scheduling decision is to transmit with a certain probability, which is
adaptive to plant, channel and battery conditions. Moreover, we provide a
stochastic dual method to compute the optimal scheduling solution, which is
decoupled across sensors, with only some of the dual variables needed to be
shared between nodes. Furthermore, we also consider asynchronicity in the
values of the variables across sensor nodes and provide theoretical guarantees
on the stability of the control systems under the proposed random access
mechanism. Finally, we provide extensive numerical results that corroborate our
claims.
