Abstract: A control system for a robotic device maneuverable in at least a liquid medium, the system having at least one visual sensor retrieving an image of the device's environment, an image analyzing module receiving the image, determining a presence of an object of a given type therein and analyzing at least one property of the object, a motion calculator determining a desired motion of the device based on the property, and a controller operating a propulsion system of the device to obtain the desired motion. Also, a legged robotic device having a control system including at least one sensor providing data about an environment of the device, the control system using sensor data to determine a desired motion of the device, determining a corresponding required leg motion of each of the legs to produce the desired motion and actuating the legs in accordance with the corresponding required leg motion.