Change sensor data generation to "on demand"
At the moment, the sensor data is generated and set at every simulation step, although they are used by the simulated programs only infrequently. Hence, this could be improved to "on-demand" sensor data generation. That means that only if, say, the ultrasonic sensor is sampled, the actual distance to the next wall is computed.
However, this might break possible reality adaptions on sensors, such as delayed sensing.