1. Automated Guided Vehicles: Hardware
By: Adam Aquino
November 7, 2014

2. Review
An automated guided vehicle or automatic guided vehicle (AGV) is a mobile robot that follows markers or wires in the floor, or uses vision, magnets, or lasers for navigation. They are most often used in industrial applications to move materials around a manufacturing facility or warehouse. (Wikipedia)
Used in every industry (large factories and storage)
Paper, metals, newspaper, general manufacturing etc.

3. Questions to Consider
Why would certain types of AGVs be preferable over others?
What scenarios are the most appropriate for certain types of AGVs?

4. Overview: History and Current State
First AGV invented by Barrett Electronics in The term was not introduced until the 1980’s, but was previously known as driverless vehicles.
The first model was a modified towing tractor that followed an imbedded wire in the floor. Sensors on the bottom of the tow truck sensed and responded to a magnetic field from the wires.

5. Overview: History and Current State
Today, the most advanced AGVs are laser navigated (LGV), which are sophisticated and capable of communicated with other robots. Many are navigated using machine vision as well.

6. Ways to Guide AGVs Between Stations
Embedded wire in floor
Good for applications where paths are not going to change
Magnetic Tape on floor
Requires sensors to detect tape path
Less expensive and can be modified
Laser Target navigation
Requires reflective tape on walls and a laser transmitter on a rotating turret on the AGV.
Good for applications where AGV needs to adjust path by triangulating position.
Inertial navigation
Requires transponders embedded in the floor
Extremely accurate (+/- 1 inch)
Operates in tight aisles or extreme temperatures.
Vision Guidance
Requires cameras (records route and “replays” route)
Good for applications where you cannot modify the environment or infrastructure.

7. Types and Uses of AGV’s Towing Vehicles AGVS Unit Load Vehicles
AGVS Pallet Trucks
AGVS Fork Truck
AGVS Hybrid Vehicles
Light Load AGVS
AGVS Assembly Line Vehicles

8. Types and Uses: Towing Vehicles
The oldest type of AGV
Pulls a trailer
Good for heavy loads
Range from 8,000 to 60,000 pounds
Can link multiple trailers
Increased Safety

9. Types and Uses: AGVS Unit Load Vehicles
Load rests over the majority of the vehicle
Interfaces with stands and conveyors
May be loaded by cranes, forklift trucks, other AGV’s etc.
May communicate between loading/unloading machine and AGV (handshake sensor)
More complex steering than towing AGVs and more expensive

10. Unit Load Principle Principle AGV Application
Stored or moved as a single entity at one time, regardless of the number of individual items that make up the load.
Less effort and work are required to collect and move many individual items as a single load than to move many items one at a time
AGV just needs a single flat platform to transport a unit load, and unit loads can be stacked on the platform.
Does not need a basket (side barriers)

11. Types and USES: AGVS Pallet Trucks
Transport palletized loads to and from floor level
2 general types
Automatically reverse into pallets
Operators manually board vehicles and back them into pallets
Automatically reversing a guided pallet truck adds considerable expense.
Manually loading pallet trucks are more common.

12. Types and USES: AGVS Fork Trucks
“Used when the system requires automatic pickup and drop off loads from floor or stand level and where the heights of load transfer vary at stop locations.”
Conveyers or load stands of different heights can all be serviced
Most expensive of AGVS types
Harder to move large loads
Requires more precise movement.

13. Types and Uses: AGVS Hybrid Vehicles
“Adapted from a standard CAT-style man-aboard truck so that they can run fully automated or be driven by a fork truck driver. These can be used for trailer loading as well as moving materials around warehouses.” (Wikipedia)
Customizable for most load types.
25 – 30% cheaper than standard AGV’s
High Flexibility

14. Types and USES: Light-load AGVS
500 pounds or less
Transport small parts to individual work locations
Trays/baskets
Good for small and tight areas
Applications include electronic fabrication, small assembly manufacturing and parts kitting applications

15. Types and Uses: AGVS Assembly Line Vehicles
Similar to light load AGVS
Good for applications involving serial assembly processes
Cary subassemblies such as motors or transmissions
Allow for parallel operations
Allow for individual tracking and measured work rates
Require extensive planning

16. COSTS
Level 1: Simple Manual Vehicle Dispatch, Load/Unload, No Central Controller, No Host Interface.
Level 2: Medium  Automatic Vehicle Dispatch, Load/Unload, Central Controller, Product Tracking, Multiple Path Options.
Level 3: More  Automatic Vehicle Dispatch, Load/Unload, automatic coupling/uncoupling (applies to tuggers only), Central Controller, Complex Host Interface, Ethernet Link, Product Tracking, Multiple Path Options Multiple Transfer Heights, etc.

17. Primary Vendors Savant Automation, Inc. America in Motion
Ward Systems, Inc.
Egemin
JBT Corporation
TecnoFerrari/Prella Technologies

18. Supporting Technologies

19. Technical Paper: Modelling battery constraints in discrete event automated guided vehicle simulations
Author: R. McHANEY
Purpose:
AGV battery usage is frequently omitted in simulation because battery constraints are mistakingly believed to have minimal impact on throughout and the number of vehicles required to operate a system, many simulation analysts do not have a full understanding of how batteries are used to power AGVs, and battery analysis requires additional input information and varies from vendor to vendor.
Main Takeaway
Do not ignore battery considerations. They are important.

20. Video

21. Standards
ANSI/ITSDF B Safety standard for Driverless, Automatic Guided Industrial Vehicles and Automated Functions of Manned Industrial Vehicles - Applies to system suppliers, manufacturers, purchasers and users for the design, construction, application, operation and maintenance of UGVs

22. Example
The AGV’s in the figure include load station 1 where raw parts enter the system for delivery to any of three production stations 2,3, and 4. Unload station 5 receives finished parts from the production stations. Load and unload times at stations 1 and 5 are each 0.5 min. Production rates for each workstation are indicated by the delivery requirements in Table A complicating factor is that some parts must be transshipped between stations 3 and 4. Vehicles move in the direction indicated by the arrow in the figure. Determine the average delivery distance, L₂.

23. Example Ld= 9 50 +5 120 +6 205 +9 80 +2 85 +3 170 +8(85) 9+5+6+9+2+3+8
= 4,360 42
Ld= m

24. Summary: Main Takeaways
The type of AGV you use is highly dependent on the layout of the workspace
AGVs are highly dependent on specific types of sensors, which depend on the application and type of navigation that the AGV uses.

25. Sources http://www.agvsystems.com/faqs/ http://www.agvsystems.com/
agv.com/en/Solutions/Products/Unit-Load- Automatic-Guided-Vehicles-AGVs
basics/basics-agvs/#fork