5. Design and function
68
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544305
Power is supplied by two rechargeable 12 V batteries with a rating of 4 Ah. Both of
the rechargeable batteries are mounted to the chassis. Robotino
®
is supplied with 2
additional batteries and a battery charger. Two batteries can thus be recharged,
while the other two are in use.
Sensors for measuring the distance to objects and detecting motor speed have been
integrated into Robotino
®
. An anti-collision sensor mounted around the
circumference of the chassis signals contact with objects.
Robotino
®
is equipped with 9 infrared distance measuring sensors which are
mounted in the chassis at an angle of 40° to one another. Robotino
®
can scrutinise
all surrounding areas for objects with these sensors. Each of the sensors can be
queried individually via the I/O circuit board. Obstacles can thus be avoided,
clearances can be maintained and bearings can be taken on a selected target.
The sensors are capable of accurate or relative distance measurements to objects at
distances of 4 to 30 cm. Sensor connection is especially simple including just one
analogue output signal and supply power. The sensors’ evaluation electronics
determine distance and read it out as an analogue signal.
The actual speed of each individual motor is measured in RPM by the incremental
encoder. If actual motor speed deviates from the setpoint, it can be adjusted to
match the target value by means of a PID controller whose parameters are
configured with the help of Robotino
®
View software.
The anti-collision sensor is comprised of a switching strip which is secured around
the entire circumference of the chassis. A switching chamber is located inside a
plastic profile. 2 conductive surfaces are situated inside the chamber, between
which a given clearance is maintained. These surfaces are short circuited when even
minimal pressure is applied to the strip.
A reliably recognisable signal is thus transmitted to the controller unit. Collisions
with objects at any point on the housing are detected and, for example, Robotino
®
is
brought to a standstill.
5.7
Power supply / battery
charger
5.8
Sensors
Infrared distance measuring
sensors
Incremental encoder
The anti-collision sensor
