Agriculture Reference
In-Depth Information
Missions of robot
Autonomous operation
Following predetermined path
Control of hitch, power
take-off, engine speed, etc.
Mission plan
GIS base
Tillage, planting
Play-back of manual drive
Chemical application, harvesting, cultivation,
transfer between shed and field
FIGURE 2.3
Functioning of a robot tractor.
predetermined path and controlling a hitch function, a power take-off, an engine
speed set, etc., based on the posture information from the RTK-GPS and the IMU in
reference with a navigation map.
A navigation map can be made by both a GIS and actually recording travel paths
with human driving—the developed navigation system can completely duplicate the
same operations and travels that a human had previously performed. Because the
RTK-GPS can gather the position data at the update rate of 10 Hz, the spatial resolu-
tion of the navigation map is limited by the GPS update rate and the travel speed.
Functions for identification of bias of a gyroscope and position correction by roll/
pitch inclinations are also plugged into the mission planner to improve positioning
accuracy. Figure 2.4 shows the construction of a navigation map (Kise et al., 2001).
The navigation map consists of points that have three factors: latitude, longitude,
and code. Contents of code at each nearest point control the work of the tractor and
its implements. Autonomous operation functions provide guidance signals in terms
of an offset and a heading error and determination of a desired steering angle. These
functions include correcting a position by vehicle roll/pitch inclinations, identifica-
tion of bias of a gyroscope, and calculating a steering angle for the robot vehicle.
Autonomous operation functions also dynamically plan the turning path trajectories
Navigation point
ω
i
= (
(lati,
i
,
loni,
i
,
code
i
)
Contents of code
Longitude
Operating condition
(Operating turning)
he path number
Max or manual
1 to 8
On or off
Rising or downing
Working flag
Path ID
Engine speed
Transmission
Power-take-off
Hitch function
Ω = ω
i
|
ω
i
ε
E
3
,0 <
i
<
N
Navigation map
FIGURE 2.4
Construction of navigation map.
