Guidance Control

AGV is operated with onboard batteries and moves in fixed path. One of the significant elements in the AGV is the guidance control. The principle of wire guidance is given in Figure 15. The control wire is embedded in the factory floor together which the AGV is to traverse. For this purpose, a rectangular slot is cut into the concrete floor and the wire is placed in position with the rest of the slot being filled with epoxy as shown in Figure 15. The wire is actually in segments depending upon the actual path to be taken as shown in Figure 16. The transfer of AGV from one loop to the another is completed with the help of the circular transfer elements present in the path.

Figure 15: The Principle of Wire Guidance used in AGV

Each of the travel is identified by a particular frequency, and the wire that forms the part will be energised to that frequency. The AGV's onboard controller will be adjusted for this frequency. The sensor coils that is present in the AGV sense the existence of the magnetic field and accordingly steer the AGV along the path. The two coils placed at equi-distance on either side of the coil help in maintaining the movement of the vehicle along the wire. If the AGV has to follow a different path then its frequency needs to be adjusted for that requirement.

Figure 16: Typical Path of a Wire Guided AGV

As shown in Figure 13, there can be more than one AGV servicing the facilities. Accordingly, the traffic control system will have to take care of all the AGV movements. Since the vehicle is run by batteries, there will be a battery charging station provided which is used for recharging the AGV batteries when the AGV is idle.

The AGV traffic control system has to take care of

• Selection of AGV and administration of idle vehicles,
• Control of the despatching sequence,
• Tracking the AGVs, and
• Controlling the actual traffic.