Fig 1.
Trajectory tracking control system structure.
Fig 2.
Hardware structure of the trajectory following the system.
Fig 3.
Three DOF model of a tractor.
Fig 4.
Steering system model diagram.
Fig 5.
Block diagram of the control circuit.
Fig 6.
Schematic of the torque detection circuit.
Fig 7.
Schematic of the relay control circuit.
Fig 8.
Schematic of current control.
Fig 9.
Schematic of current sensing.
Fig 10.
Overall structure of the control system.
Fig 11.
Structure diagram of the steering angle tracking control strategy.
(a) Block diagram of steering system control, (b) System structure of steering control.
Table 1.
The parameters of the tractor.
Fig 12.
Membership function of fuzzy system.
(a) Membership function of fuzzy input, (b) Membership function of fuzzy output.
Fig 13.
Lateral displacement, heading angle, steering angle.
Fig 14.
Lateral error, heading error.
Fig 15.
Sliding mode surfaces.
Fig 16.
Lateral displacement, heading angle, steering angle with disturbance.
Table 2.
Performance measures for the three methods.
Fig 17.
Lateral error, heading error with continuous channel change.
Fig 18.
Lateral displacement, heading angle, steering angle with continuous channel change.