-on the front to prevent it from sliding on the floor. The main wheels can be
-controlled over two independent motors, each one allowing to turn the connected
-wheel with a minimum of 10~mm/s and a maximum of 500~mm/s in each direction. One
-of the main wheel motors consumes about 300~mA in their slowest rotation speed,
-and about 1000~mA when driving with normal speed. Each wheel is also equipped
-with a drop sensor that tells if the respective wheel has dropped into a hole or
-similar, and does not reach the ground anymore. These sensors are realized with
-a spring pushing the wheel towards the ground, with the spring force adjusted to
-the Roomba's weight, and a micro switch which triggers if the wheel drops below
-a specified level. Furthermore, both wheels feature rotating, toothed discs,
-which in conjunction with an LED and a photo-electric resistor act as an optical
-interrupter. This system can be used to measure the wheel's current speed by
-counting the optical interruptions the wheel causes while moving.
+on the front to prevent it from sliding on the floor. The space between the
+cmainenter of the main wheels (the \definition{wheel base}) is 230~mm. The main
+wheels can be controlled over two independent motors, each one allowing to turn
+the connected wheel with a minimum of 10~mm/s and a maximum of 500~mm/s in each
+direction. One of the main wheel motors consumes about 300~mA in their slowest
+rotation speed, and about 1000~mA when driving with normal speed. Each wheel is
+also equipped with a drop sensor that tells if the respective wheel has dropped
+into a hole or similar, and does not reach the ground anymore. These sensors are
+realized with a spring pushing the wheel towards the ground, with the spring
+force adjusted to the Roomba's weight, and a micro switch which triggers if the
+wheel drops below a specified level. Furthermore, both wheels feature rotating,
+toothed discs, which in conjunction with an LED and a photo-electric resistor
+act as an optical interrupter. This system can be used to measure the wheel's
+current speed by counting the optical interruptions the wheel causes while
+moving.