Question

Discuss the following types of AGVs and their applications: 2.1 towing machines 2.2 unit load transporters 2.3 pallet trucks 2.4 fork lift trucks 2.5 assembly line vehicles

Answer 1

Ans: .Towing machines:

AGVS towing applications were the earliest and are still the most numerous AGV type. Towing applications can involve the bulk movement of product into and out of warehouse areas or direct service to a manufacturing/assembly operation. Usually side path spurs are placed in receiving or shipping areas so that trains can be loaded or unloaded off the main line and thereby not hinder the movement of other trains on the main path.

Chain movement of product with AGVS trains is also popular. In this case, the AGVS trains are loaded with product destined for specific destinations along the guide path route. The train will make several stops in order for the product to be unloaded at the correct locations.

Unit load transporters :

AGVS unit load applications – usually involve specific mission assignments for individual load movement. Unit load carriers are quite popular in applications integrating conveyors with manufacturing/assembly operations or storage retrieval systems. Here they are a very efficient means for horizontal transportation between hardware intensive material handling subsystems. The unit load carrier, over moderate distances, can move high volumes of material linking other automated subsystems in a totally integrated facility. Usually the unit load systems involve an automatic pickup and delivery of product with remote management of the vehicles in the system.

Unit load carriers are normally used in warehousing and distribution systems where the guide path lengths are relatively short, but the volumes are high. Here the unit load carriers have the ability to maneuver in tight areas where AGVS trains would be too awkward to use.

Pallet trucks :

AGVS pallet trucks are used generally in distribution functions. Vehicles can be loaded in two ways, either they are capable of automatically reversing into pallets on the floor or operators will manually board the vehicles and back them into pallets.

For the product delivery the vehicles normally proceed down the path to specific destinations in storage areas, pull off onto a spur, lower their pallet forks to the floor and pull out from under the pallets, then automatically return empty to the loading areas. Many applications have been done whereby the vehicles are manually boarded in the loading areas and driven off the path to load staging areas where they are manually loaded. The vehicles are backed up under the loads, driven back to the path, given a destination by an operator and automatically proceed to the drop off spurs in the warehouse areas. Automatically reversing a guided pallet truck adds considerable expense to the system and the necessity for accurate positioning loads on the floor for pickup. They can only be justified in limited applications at this time. Manually loading the vehicle gives operators flexibility to position loads anywhere off the path and still be able to retrieve them with the vehicles which then automatically proceed without operators into the warehouse drop locations.

Fork lift trucks :

AGVS fork truck applications are relatively new. Guided fork trucks are used when the system requires automatic pickup and drop off of loads from floor or stand level and where the heights of load transfer vary at stop locations. The guided fork truck has the ability to automatically pickup a load or discharge the load without any human interface.

The vehicle can position its forks to any height so that conveyors or load stands of varying height in a given system can all be serviced.

Since these vehicles are some of the most expensive AGVS types, they can only be justified where total automation is required. AGVS for trucks require more intricate path layout and a method of accurately positioning loads on the floor or on stands for vehicles to service. This normally requires greater system discipline than with other systems, but the benefits include greater flexibility in integrating other subsystems together through the AGVS system.

Assembly line vehicles :

Assembly line AGVS applications are only now being introduced in the U.S. This is an adaptation of the small light load AGVS for an assembly line process. Here the guided vehicles carry major subassemblies such as motors or transmissions to which parts are added in a serial assembly process. Prior to each assembly area is a parts staging area where small parts are placed in a tray onboard the vehicle beneath the major subassembly. The vehicle the proceeds into an assembly area where it stops at assembly work station. The assembler takes the parts from the tray onboard the vehicle and then assembles them onto the major subassembly. When that process is completed, he then releases the vehicle, which proceeds to the next parts assembly area the process repeats several more times. When the assembly process is complete, the finished assembly such as an engine block or chassis is unloaded from the vehicle, which is then sent to the start area for the assembly process. There it is again loaded with a raw subassembly.

AGVS assembly systems give good flexibility to a manufacturing process by allowing parallel operations. They also allow for individual tracking of items and measured work rates. Normally these systems are integrated into an overall production system, which requires computer control and extensive planning.