Agriculture Reference
In-Depth Information
Cover
Cushioning material
Actuator plate
Mounting screw
Load line
Elastic spacer
[Operating load measuring method]
Load
Base plate
Tape switch
FIGURE 2.19
Laser scanner, a tape sensor, and a proximity sensor attached to the robot tractor.
system, three types of obstacle detection sensors have been implemented in the robot
tractor. Figure 2.19 shows a 2-D laser scanner attached at the front of the robot trac-
tor. The laser scanner is a noncontact measurement system (NCMS), which can scan
its surrounding in 2-D measurements, the object's distance, and the object's angle
with respect to the direction of transmission, which is counterclockwise. The laser
scanner's scanning angle and distance range were set to 180° and 8 m, respectively,
with an angle resolution of 1° and response time of 13 ms. Moreover, the robot trac-
tor implements both a tape sensor and a proximity sensor for detecting an obsta-
cle. A tape sensor is activated by pushing a 10 N force to a bumper of the robot.
Because the proximity sensor can sense displacement of the bumper, the robot can
stop immediately when it hits an obstacle. However, even though the laser scanner
has a high accuracy, it is expensive and therefore not economically viable for users.
Bosch Cooperation has been developing the obstacle detection sensor unit com-
posed of various sensors used in automobiles. According to an investigation of an
unmanned ground vehicle used in real-world situations such as an unmanned trans-
port vehicle in a factory, the obstacle detection sensor's specification is made. The
sensor covers all directions surrounding the robot vehicle by integrating a radar,
vision, and ultrasonic sensors, as shown in Figure 2.20. The sensor unit has a func-
tion of making a decision whether it is safe to continue or there is a danger of col-
lision based on multiple sensor inputs. However, the level of safety that needs to be
achieved before a robot can be released on the market is not just a technological
question but also a question requiring community consensus. If the robot must take
full responsibility in the unlikely event of an accident, it will lead to an enormous
