One of the biggest headaches with building a robot with a large number of sensors is integrating all of the sensors despite the various voltages everything runs at. The motors generally run at battery voltage while the sensors end up usually being both 3.3V and 5V.
Sparkfun has a tutorial about interfacing sensors.
Unfortunately, the press release for the dish cleaning robot has not yet been translated. Fortunately however, the pictures are pretty clear showing the development of 3-axis MEMS touch sensors which allow the robot to not only determine how much force is being applied to the dish, but also to be able to determine the frictional shear forces on the dish so as to determine if the dish is slipping. There are also some photos showing examples of the computer vision system used for dish identification.