Different types of automation systems for farm vehicles
are invented and introduced in agricultural fields.Experimental tests
illustrated that in the stationary test, distance measurement
errors were between +-0.31% and +-0.37% in the distance
range of 5.2-6.8 m. In the dynamic test at the four constant
travel speeds, maximum lead error (when the master was
ahead), and maximum lag error (the slave was ahead), were
32 and 23 cm, respectively.As an example of drive
assistance, to allow the operator to focus more on other
systems and processes taking place on and around the
machine, Foster et al. developed an automatic velocity controller for a self-propelled hydrostatic drive-train windrower to improve operator performance, reduce operator
fatigue and increase the productivity of the machine.As implements get wider, this task
becomes more difficult, so different marking systems have
been developed, such as using a disc coulter to mark the
correct driving distance while cultivating and using foam
markers while spraying and crop edge detection.In terms of the involvement
of a human operator in maneuvering the vehicle, Mizushima et al. classified automated guidance systems into
operator-assistant and autonomous systems.More precisely,
Blackmore et al. categorized automated farm machinery
on three groups; (1) drive assistance (2) automatic steering
and (3) autonomous machines.Various driver assistance
help to reduce the complexity and difficulty of field operations as well as to help improve efficiency.An operator-assistant system uses an auto-track function to guide
the vehicle, following crop rows automatically, and relies
on a human operator to drive the vehicle to make endrow turns [10].A
Proportional-Integral-Differential (PID), closed loop control system, is applied to satisfy the desired conditions.In a research by Zhang
et al. a leading tractor as a master and another unmanned
agricultural machine, which follows the other leading one
as a slave are evaluated.Both vehicles used GPS signals
and inertial sensors to evaluate their positions.Two tractors cooperated in three modes:
standard mode, obstacle avoidance mode and headland
turning mode.In another similar research
Lee et al. evaluated, two self-propelled citrus canopy shake
and catch for citrus harvesting, worked in pair (mater and
slave), one on each side of the row of citrus trees.Two
mentioned vehicles synchronized accurately using laser
scanner.High trackin