Abstract
Probabilistic cellular automata are extended stochastic systems, widely used for modelling phenomena in many disciplines.The possibility of controlling their behaviour is, therefore, an important topic. We shall present here an approach to theproblem of controlling such systems by acting only on the boundary of a target region. In particular, we are interested inoptimal control, which is rather demanding in computational terms, so we present also a less demanding suboptimalmethod. Finally, we present an example of optimal control with avoidance.